Overheated this weekend - 0 compression in 5 and 7

[pridekit]

The vitals:
2006 Launch 21V
Indmar Assault 325 - non-Cat (I believe) with half system
1890 hrs
0 Compression is cylinders 5 and 7.
All 8 spark plugs have some sort of dry black "dust" on them. Wipes off pretty easily, but comes back after running for just a couple of minutes.

What happened:
A couple weeks ago I replaced my alternator, I checked the belt to make sure it looked fine, no fraying or anything. Everything checked out and I installed the belt. I couldn't seem to get the belt tight so my friends and I got the bright idea to use a ratchet strap to tension the alternator. This past weekend I took the boat out, we were cruising a long just fine, I brought the boat down to an idle for a few minutes because I wasn't familiar with the water around me. I look down at my temp after I've been idling and I see the needle pegged. I shut the motor down and start checking everything. Eventually I see the alt belt in the back just laying their with teeth missing and split. I had purchased an extra belt, just in case (I had a gut feeling). I put the new belt on at the dock (after getting a tow back to the dock, and letting the motor cool down for a couple hours). I cranked the boat up and everything seemed good.

I took the boat out the next morning and after about an hour I started to notice white smoke coming from the exhaust. Got back to the dock and checked the oil, it looked clean, but had definitely burned some (it was full when I started the weekend, it was at half way on the dipstick). I checked for leaking around the manifolds, nothing there. Coolant levels looked good, temperature looked fine, oil pressure was starting to dip, but I assumed that was because of the decreasing oil level. So I decided it was time for a compression test. I pulled all of the plugs out and they were all black on the end (I'll take a picture in a couple hours). While I had them pulled, I had the motor cranked to make sure it didn't spit out any water or coolant, nothing came out.

I changed the plugs and cranked the motor up and waited for it to warm up. I gave it a little gas once it warmed up (around 2500 rpm for 10 sec), brought it back to idle, then shut it down and looked at the plugs. Black again. Back to the compression test. Port side (2, 4, 6, 8 ) were around 160, with 8 being 155. Starboard side was 1: 180, 3: 120, 5: 0, 7: 0. So, sounds like I've either warped my head or wrecked my gasket on the starboard side. I have a few questions though.

Questions:
1) has anyone replaced the head gasket on one of these Indmar motors? If so, any tips or things I should no before I dive in head first?
2) I don't understand why all 8 of my plugs were black on the end even after replacing them! Any ideas?
3) Should I replace both gaskets while I'm doing this work, or should I leave well enough alone on the port side?
4) Is there anything else that I have missed when checking? Anything I should check when I pull the heads off?

[gogger]

At 1890 hours once I had the heads off I would have the valves done and the machine shop will check to make sure the heads haven't warped. I would get or you can probably down load a manual on the engine. Have you removed heads before? Familiar with internal engine work? Make sure there is no damage to the pistons ect. There will be a sequence for torquing the head bolts. Unless I am missing something generally most spark plugs have some black carbon on them from the ignition process. Don't recall ever seeing a perfectly clean spark plug upon removal.

[pridekit]

I've never done any internal engine work before, but I'm not afraid to get my hands dirty. I was thinking about getting the valves done as well, and definitely going to have someone check the head for warping and cracks. I found an engine manual that seems to show what to do (https://www.bakesonline.com/images/MediaLibrary/Indmar_5.7RepairSpecs.pdf). I do have a friend and his dad that have done this kind of work before (his dad was a mechanic in his younger years).

Will I or should I pull the engine for this kind of work? I'll snag that photo of the plug while I'm at work, I'm used to seeing a golden brown, this was like a pitch black almost powder covering the entire end that was in the cylinder.

[Broke Pilot]

The blCk powder is likely just carbon dust from unburned fuel now that you've lost 2 cylinders.
First off, do or have someone do a leak-down check on all 8. That's gonna t ol you way more than a compression check. You're problems are way beyond a bad head gasket unfortunately. If you can crank and run the engine with no water leaks, the head gasket is fine.
If you got the motor hot enough twice to burn up some of your oil, you likely burned either a couple valves or most likely trashed some piston rings which are now in little tiny pieces down in the oil pan since you said you saw smoke (I'm guessing blue smoke - oil) in the exhaust.
The leak down test will hopefully tell you where the issue is. When you shove the air in the cylinder if you hear it coming of the crank case vent (PCV) your rings are toast. If you hear it coming out the throttlebody/carb, your valves in that cylinder are trashed.
Good luck with it all, but hey, motor work is fun! Put ya some dome top Pistons in if you have to tear it down and get a couple more ponies outta the ol girl. These engines are nothing more than old school Chevy 350's. There's all sorts of parts out ther to help her out!
If you need any help or have questions feel free to pm me.

[pridekit]

I'll look into the leak down procedure. The smoke was definitely white. I've seen the blue smoke from a car before, but this was definitely white.

The attached picture is the plug from number 7. It's the only one that had crud around the electrode, the rest of them had the same black powder though. (the little rust spots were not originally there, those have developed since it has been out of the boat).
16550

Interestingly, the motor does sound alright when it's running. No excessive noises. A bit of RPM shifting around the 3200RPM mark if you leave the throttle alone (shifts up and down about 50RPM as per Perfect Pass). I do notice there was a loss of power at take off, it seems to take forever to get up to speed and plain (or plane, I can't remember the correct grammar right now) off.

[CJD]

You will have to pull the heads to see how bad it is. Common overheat issues include:

Stuck valves, cracked head, melted Pistons, stuck rings, cracked block.

Any or all of these definitely occurred to get zero compression in 2 holes. No matter what, the intake and heads have to come off to see what you are facing. A leak down check will give you an idea where the compression is going...but there is nothing that sends compression to zero that can be fixed with the heads on the motor. You might as well pull them and get a head start.

Also, do not get your hopes up. This is a serious failure that very well could leave the motor an anchor. I have never seen a motor with a serious overheat run right afterward without a full rebuild.

Sorry...

[pridekit]

That's sucks, but I'll figure it out. I'm only able to work on it during the weekend, so progress will be slow, but I'll definitely keep the thread updated. I'm going to perform a leak down test on Sunday and begin disassembly.

I have a slight issue with storing the boat, I am unable to keep it in an enclosed area, it will be sitting in the driveway. My plan is to spray fogging oil on any exposed components and wrap the engine in a plastic sheet. Anyone see a problem with this or have other suggestions?

Also, any idea why the plugs in the "good side" are covered in the black powder?


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[sailnaked6842]

The plugs likely suffered from pre-ignition and oil burning (picture of it here) http://www.motoredbikes.com/showthread.php?42539-Detonation which was likely caused from the overheating. Unfortunately CJD is pretty much spot on and this will most likely a full rebuild since the pistons likely (guaranteed) scored the cylinders, and your valves probably stuck, if not bent. Michigan Motorz has great prices (2,300 last time i looked) on long blocks which can be cheaper than a rebuild

[lively]

you cant do a leak down with blown head gaskets , look there is alot you can do and alot you can spend .. how long was the engine hot ?

if we are talking about 3-5 min then put some gaskets on it and check the valves ,

more than 10 min , put gasket on do a leak down , rebuild and deck heads ARP studs

i blew my head gaskets out once under way , i never stopped it reached 220 degrees , my heads were fine ..

.2cents.

[2500HD]

Before tearing it all down just do a simple test. Put a couple of teaspoons in the cylinder that is at 0 compression then do a compression test. if the compression comes up then it's your rings, piston or block. if it doesn't then your in luck and it is probably your head or gasket. Then just to make sure it is just your heads have them sent off for a test. Hopefully you will get luck like i did and it is just a vortec head. 400.00 from napa and very simple to install. It's just torqueing in the right order. Start in the center and spiral outwards from there.
Best of luck

[Moor]

Before tearing it all down just do a simple test. Put a couple of teaspoons in the cylinder that is at 0 compression then do a compression test. if the compression comes up then it's your rings, piston or block. if it doesn't then your in luck and it is probably your head or gasket. Then just to make sure it is just your heads have them sent off for a test. Hopefully you will get luck like i did and it is just a vortec head. 400.00 from napa and very simple to install. It's just torqueing in the right order. Start in the center and spiral outwards from there.
Best of luck

i think he means a couple teaspoons of oil. It would be difficult to get the teaspoons through the spark plug hole.

[CJD]

A little oil will raise a low compression...but afraid it's asking too much to fix a zero compression

[2500HD]

A little oil will raise a low compression...but afraid it's asking too much to fix a zero compression

it's simply a test to see if it's rings, Old school trick so you don't waste to much time.

[CJD]

That it is, but for for worn rings. If the rings are melted to the pistons, as it would take for a zero compression reading, the oil will just blow right on by. A zero reading is a sign of pretty significant damage.

[pridekit]

So, I got the head pulled off this weekend. It was a lot easier than I was anticipating, short of getting anti-freeze everywhere -_-
I didn't feel or see any scoring in the cylinder walls.

Here are the pictures :)

16610

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[pridekit]

#7
16613

#5
16614

#3
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#1
16615

[pridekit]

#7
16617

#5
16618

#3
16619

#1
16620


I forgot to mention that I dropped the head off at a local machine shop for them to look at and see if it is warped, cracked, etc.

[CJD]

Nothing jumps out at me from the pics...except that you have been getting water in the #5 and 7 holes. If they don't find a crack in the head, then the exhaust valves may be sticking, which would then allow water in from the riser on the intake stroke. It isn't likely a crack would result in 0 compression, but stuck valves could account for it.

The water is indicated by the very clean pistons compared to the normal carbon you would expect, like on the 1 and 3 holes...and also the corrosion on the valve heads. I'm not sure what the goo is on the #7 chamber. Was it hard or soft and gooey?

Hopefully it's just sticking valves, as they are an easy (and relatively inexpensive) fix.

[pridekit]

That stuff was soft. Before the overheat, the plug in #7 would always have gunk on it. I figured it was some build up in the chamber that would eventually burn off. Also, the water theory makes sense as the plug was hard to pull out of #7. It had a slight bit of rust on it, I thought it may have just been from a splash of salt water getting on it a while back (the trans cooler intake hose had a small leak and I had salt water entering the engine area, had to limp home)


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[pridekit]

I'm thinking I may replace or at least clean the lifters while I have it disassembled


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[CJD]

If its soft, I bet it's just a gel from oil and water mixing. Neither of those should be inside the cylinders in significant quantities. The water can come from either the riser, a crack in the head or block, or a blown head gasket. The oil could come from bad rings or a bad head gasket. So, let's hope the common factor is the head gasket.

Is there a reason you think the lifters need cleaning?

[pridekit]

Not particularly, just because I have access to them I figured I would give them a cleaning. I don't plan on pulling the intake off again any time soon, and figured I should take advantage of the easy access


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[pridekit]

According to the machine shop the loss of compression came from the valve seats. They were corroding away and would no longer seal. They suggested that I replace both heads and the exhaust manifolds. I can't quite swing heads and manifolds, and feel that I can still get at least another year out of the manifolds (they are going on 2 years old right now). The suggestion for doing both heads came from the idea that it if it has corroded on one side, it is likely corroding on the other, and I'm inclined to only pull this motor apart once (preferably :p).

What is everyone's thoughts on this?

[CJD]

You mentioned coolant...so I assume you have a fresh water cooling system. If so, I can't believe the heads can't be freshened up for a reasonable cost. Look on the Summit website, as they have really good prices for either the parts (SS valves, guides, and seats), or entire heads. Small block Chevy heads are common and interchangeable.

The risers do see salt water and will eventually corrode from the inside out. I'd still use them until they blow out from rust, though.

[pridekit]

Yes, it's got a fresh water cooling system. He is asking $330 for each head (each one would be rebuilt on new castings, using a mix of whatever he can salvage from my heads and what he has collected over the years).

Did the vehicles and boats use the same heads? I called my family mechanic to see what kind of price he could get.

[pridekit]

Here are some pics from the shop (they are a couple hours away so I'm not able to take my own).

http://images.tapatalk-cdn.com/15/09/22/5047d85c361aecdc279c959df453d4cf.jpg

http://images.tapatalk-cdn.com/15/09/22/883af3e1431fffbec7fd75669bfd3560.jpg

http://images.tapatalk-cdn.com/15/09/22/3fd8415b143bd3987592fd00a7686e51.jpg

http://images.tapatalk-cdn.com/15/09/22/287a1531d73c81e05839fd0746cba0d4.jpg


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[CJD]

Yes...the car and boat heads start the same. For a boat, it is preferable to use bronze valve guides ( you'll note that yours have iron guides) and stainless steel valves (yours did not have stainless). I would avoid aluminum heads, since you are running in salt water.

There are 3 choices in valve sizes you will see. The 1.88" intake valves for low performance motors. The most common heads are set up for 1.94" intakes...which is mild performance, and likely what yours has currently. And finally 2.02" intakes, for best flow and performance.

The 1.88" are junk, as the intake runners are also tiny. The 1.94" can be opened to take the 2.02" valves, but the runners are not quite as good as factory 2.02" heads, which are often referred to as "double hump" (for street heads), or "Bowie" (for Chevy performance heads). Chevy is so popular with racers that there are a dozen aftermarket heads too. I'd avoid these, as they sometimes alter the exhaust ports so they may not fit your risers. But if you check the shape and position of the intake and exhaust ports, there are some that will work.

I have rebuilt heads that looked a whole lot worse than yours. You need guides and valves. If you go with the next size up valves, you could even get by with the original seats. New, hardened seats would be better...but then the price starts to go up, if you replace them all.

$330 a head is not unreasonable. Be sure he is using SS valves...and ask if he plans to use iron or bronze guides, and if the seats are being replaced or not. Insist on the SS valves...the other stuff is preferred, but not necessary if price is a factor to you.

What I find interesting is that the damage I see is not from overheating, but long term corrosion. In your salt environment you should probably start fogging the intake before shutting down the engine anytime it will sit for a week or more. That should prevent this from happening again. Also...are the flapper valves on your exhaust still working? You could be getting more back flow up the risers than you should.

[pridekit]

I was thinking about buying the stainless valves and giving them to him so he has no excuses. I'm kind of entertaining the idea of doing the work myself, I'm a bit nervous though as it seems like a rather important job to do right :p Also, I've never rebuilt a head before, but as I've said before, I'm not afraid to get my hands dirty.


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[CJD]

Head work is very specialized, and not so much a do it yourself item. The seats have to be cut with special grinders (old school), or cutting tools (modern). You can buy the valves...but check the heads first. With a new Guides, you want standard size valve stems. If it is a used head, it is common to ream the old guide oversized, and then use valves with oversized stems. If it already has oversized stems...then you have to replace the valve guides.

The seats are similar....you can cut the old seats for larger valve heads, or use the same valve head size and cut/fit new hardened seats.

Now, once you have the shop do the work on the valve seats and guides, it is an easy job if you want to assemble the heads yourself. In fact, it's so easy that most shops charge the same whether you or they do the final assembly.

[pridekit]

Thanks! I'll get in contact with the shop then. I was doing a quick Google search and noticed that there are some z28 kits that come with new springs and all. Is it worth spending the extra for the springs or just get the stainless valves?


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[pridekit]

As for the flappers and fogging. The flappers are still in tact, but thinking about it now I vaguely remember having a flapper get sucked back into the exhaust a while back. I can't remember now if that was when I pulled it out of the water or on the hose.

I never thought of fogging before this. I always figured it was only need for winterizing up north, but I'm definitely going to start doing it more often now.

The overheating may have just drawn my attention to a problem I was overlooking or could have helped take the metal over the edge. Either way I know the heads need some work so I will get that taken care of and do another compression test to make sure I'm not having another issue.


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[CJD]

I've been sitting here thinking. We now know the source of water was through the bad exhaust valves, but what has me puzzled is where the oil came from. If the valve guides are totally shot, it could be from them, or from a bad head gasket after the overheat.

I'm worried that your rings in 5 and 7 may be as corroded as the valves, and are not sealing. I've been trying to think of a way to check them before you get everything back together. It may be worth the trouble to put a good head back on the engine and compression check those cylinders again to make sure the rings are sealing. I'm probably over thinking this...but I'd hate for you to be surprised later...

[pridekit]

Check my post right above. We posted similar things around the same time :)


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[CJD]

Thanks! I'll get in contact with the shop then. I was doing a quick Google search and noticed that there are some z28 kits that come with new springs and all. Is it worth spending the extra for the springs or just get the stainless valves?


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Springs are easy to check. Ideally, you want to measure the length they will be on the head, by installing the valve and spring retainer without the spring, and measure the installed height of the spring. It will be slightly different for each valve. Then use a scale and compress each valve to that height and measure the force it takes. I found an old bathroom scale I use by placing it on a cheap hydraulic press for checking.

You can then compress the springs the additional amount corresponding to the valve lift for the camshaft you have. This should be listed in the engine manual, or measure a cam lobe lift and multly by 1.7 (the rocker arm ratio).

These 2 numbers...the installed pressure and the open pressure...should be close for all the valves. If they are close, but one or two are a little weak, you can place a shim under those springs to bring them up to spec. Just be sure not to shim so much that the spring binds on itself from being compressed too much.

Now...I know this is long winded...but here is the answer, finally!?! If you measure and get springs that are much weaker than others, then it's time to replace your springs. Boats don't rev nearly as high rpm as a Z28, so those springs are likely much stiffer than you need. Stiffer isn't bad, but it can cause the valve train to wear faster.

[pridekit]

If I go with the 2.02 intake valves, should I go with the 1.5 or 1.6 exhaust valves?

I'm going to give the shop a call tomorrow and discuss the plans. I remember him saying for $330 each, that the castings were new, and he was going to use as many parts as he could from my heads and whatever he has collected over the years. I'm going to insist on the SS valves for sure.


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[lively]

i would shop around for a machine shop , the valve s are cheap , seats are cheap , and guides are cheap .. get a 3 angle cut on the valve / valve seat .. at $330 each is that just labor or new valves and such ?

here in tx they do heads for $220.00 for rebuilds plus parts .. most of the time valves are salvageable but in your case its time for new for sure .. :cool:

[pridekit]

Labor, new head casting, and any valves that can't be reused from my old heads.


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[lively]

have you searched for new valve kits ? i mean if hes gonna do a valve job might as well just put new back in there .. but thats just me being picky i guess ... i just would hate to do all that work and have something else mess up and have to pull it back apart again ya know ?

is that assault a SBC ?

[pridekit]

Yes, I'm trying to decide between 1.5 or 1.6 exhaust valves.


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[CJD]

On a high rpm engine I would definitely recommend the 2.02 intakes and 1.6 exhaust. Remember that most of the time we want these big boats to come cleanly out of the hole, and never get over 5k rpm. So low rpm torque is what we need. The 1.94 intake/1.5 exhaust valves will be fine. They tend to be more durable, as you have more "meat" between the valves in the chamber. The only difference is you will get a bit more top end out of the larger valves, but could lose a bit of grunt on the bottom end. So I guess if it were my decision, I'd go with the size that is the best price...and never look back!

I did think of something else...your heads are large chamber, often referred to as "open chamber". This is a rather low compression head, and I'd recommend going with the same chamber size so you don't have to worry about the gas octane. The marina here in Texas only sells 86 octane...so 8:1 compression is about all I could run without bringing my own gas to the lake. Just something else to look at. Most later heads are large chamber...but some of the early street heads (before 1971) and aftermarket may have the smaller "closed" chambers. Interestingly, although the closed chamber heads are considered the high performance heads, the open chamber heads actually breather better, since the valves are not shrouded by the tight clearances.

[pridekit]

The 2.02 and 1.94 are pretty close in price. I haven't noticed the chamber size when looking at new castings, I'll look for it though. These are the vortec heads by the way.


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[pridekit]

What do you think of these?

http://m.summitracing.com/parts/sum-151124
A review said they had SS valves


Or these

http://m.summitracing.com/parts/nal-12558060

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[CJD]

I wanted to make sure, so spent some time looking up the individual parts they are using. I like the second set...the 12558060's. They have everything you need, including stainless valves, bronze guides, and even the hardened exhaust seats. It is better than what came on the boat to begin with.

The first set seems to be what Indmar used, with the addition of the stainless valves. They would work fine, but don't have the bronze guides or hardened seats, so a bit less durable for your marine application.

Given a choice of a rebuild with a lot of used parts or these, I'd personally choose the new heads. There is no question about what you are getting with them, and summit has a reputation for good quality at a great price.

[lively]

Look at the pricing . I mean new heads make more sense to me . Plus that's free shipping too right ?

[pridekit]

Correct. At that price I'll go with the new ones. I'm going to pick up a pair of the heads and the arp head bolt kit. Now I just need to find a gasket kit (I've seen a ton, just need to decide on one).

CJD, thanks for your help in explaining the heads and the research you've done. It's helped a ton!


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[Broke Pilot]

Glad to see you're going with new heads... I finally got to read the rest of all this, and I was screaming a little internally when they were telling you they'd use anything the could salvage outta the old heads. Never, ever put used parts in a head unless it's a race motor that will get torn down regularly anyway.
Good luck to do with it, you'll enjoy the new heads much more!

[pridekit]

@Broke Pilot: Funny thing is, multiple machine shops in the area wanted to do that.

So I finally ordered all the parts, and I was thinking about my source of water in the heads. I'm wondering if I might have a riser gasket that is leaking. I pulled the manifold and riser off as one whole piece, but now I'm thinking about it and it may be worth it to replace the gaskets in the risers as well (along with all of the rusted bolts :/). I have a half system system, so the coolant/anti-freeze is only running through the block and heads, the manifolds and risers are typical setup with salt water passing through them.

[CJD]

The risers wear from the inside, so there is a chance the baffles are rusted away. Definitely worth looking at while they are off.

[pridekit]

That was my thought as well. I went ahead and bought new riser gaskets and all SS bolts for both sets of manifolds and risers.


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[pridekit]

Well I've got good news and bad news.

The good news:
I got the heads installed this weekend and the compression is even on all my cylinders except one (will get to that). The install wasn't too bad, we took things slow and steady. Here's a couple of quick picks I took.

http://images.tapatalk-cdn.com/15/10/04/5e5272127e9f2588759c16a961abc78b.jpg

http://images.tapatalk-cdn.com/15/10/04/78dabd346784dcbdd8152f84eed9b1e5.jpg

http://images.tapatalk-cdn.com/15/10/04/2b84d745b11b89fac0eed2a1882321d1.jpg

The bad:

First, the #3 cylinder is still a bit low on compression. It's 120 while the others are around 150. I'm going to see if I can do a wet test next weekend to determine if it's the rings or maybe the head didn't get torqued right.

Second, I found 3 bad/collapsed lifters and I suspect there are a couple more (one being used on the #3 cylinder. The bowl where the push rod sits just fell down into the lifter there was no spring what so ever. I bought 3 new ones, but I think I'm just going to be proactive and replace them all.
http://images.tapatalk-cdn.com/15/10/04/898327ddd6d7f966dc18b3e90f9eed45.jpg

Third, things were going great until I broke a bolt off when installing the intake manifold. I misread the torque specs on the gm torque spec sheet indmar sent me and I managed to break a bolt off in the head. A few minutes later it began to rain so I decided to pack it up for the weekend. I'll have to see how far down it snapped off, I'm hoping it's not too bad and at worse I can snag it with an EZ-out (I've unfortunately had to do that before on other things...)


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[pridekit]

One other piece of good news, my buddy was able to clean up my pedal position sensor/throttlemate assembly and it is now working wayyyyy better. It was binding up through its range of motion due to a lot of crud building up around the shaft, plastic bushing, and some other moving parts. Now it's super smooth and snaps right back to 0 if you don't have a cable hooked up to it (before it wouldn't even move with out you forcing it). That saved me $250 :)


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[CJD]

I love new motor parts!

Strange about the #3 compression. If it was good before the head came off, then it seems it would have to be head related...or maybe the bad lifter was affecting it...

I'm especially glad to hear the compression was good on 5 and 7. That means the rings are good. You should see a world of difference next time you take the boat out.

[pridekit]

It was low prior to the whole overheat scenario, I thought it may have just been a bad reading from a cheap compression gauge. I'm not ruling the lifters out though, I'm going to buy a new set and see if it helps. If that does nothing then I'm going to try a wet compression test.

[wotan2525]

Wiped lifters means oil starvation. I'm not optimistic about the long-term for this engine. The good news? You'll be pretty damn good at wrenching on it by the time you're done with this! ;)

[pridekit]

It would mean oil starvation to the valves and rockers, which are now replaced. My understanding is the valves/rockers are the last thing to get oiled in the GM 350, and the lifters are what provide the oil to that (and only that). I'm trying to wrap my head around the way the pistons get oil, it can't come through the valves because that would cause detonation. I'm struggling to find a good diagram of how the 350 provides oil there (everyone seems to talk about the crank and valves, no one mentions the pistons :( )

[wotan2525]

It would mean oil starvation to the valves and rockers, which are now replaced. My understanding is the valves/rockers are the last thing to get oiled in the GM 350, and the lifters are what provide the oil to that (and only that). I'm trying to wrap my head around the way the pistons get oil, it can't come through the valves because that would cause detonation. I'm struggling to find a good diagram of how the 350 provides oil there (everyone seems to talk about the crank and valves, no one mentions the pistons :( )

The pistons are oiled from the crank bearings. Oil from those is flung off and into the bottom of the pistons and on to the piston skirt.

[pridekit]

I wish I could see through the block and watch that process. It doesn't seem like there would be much oil actually getting to the piston.


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[CJD]

It's enough. The SBC was the mainline engine at GM for over 40 years, so it works very well. If you get into heavy super charging, then it becomes necessary to add more oil to the cylinder walls.

If a couple squirts of oil in the plug hole raises the compression, then you know it's a ring problem.

[pridekit]

I took a part the manifold on the bad side. One side of the gasket looked a bit funky. Other than that it just looked orange and a bit bubbly in there.
http://images.tapatalk-cdn.com/15/10/05/fb80f99ec6c6213a288fc5d1f282a29b.jpg

http://images.tapatalk-cdn.com/15/10/05/1bd7aa7f330e992ed9b17f90c6b7f4ec.jpg

http://images.tapatalk-cdn.com/15/10/05/e1a855f58d4d70ba59fd07b5f88f5af7.jpg

http://images.tapatalk-cdn.com/15/10/05/39b07c5fef267b247660915029dac664.jpg


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[pridekit]

http://images.tapatalk-cdn.com/15/10/05/835048c357c9770888e2186b56f3a9fd.jpg


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[CJD]

I'm finally out of my element...not really sure what to check. It appears the slots are where the water from the cooler rises outside of the center exhaust. If so, then that bad area of the gasket would allow the water from the slot to leak into the "dry" exhaust area of the manifold...and therebye into the lowest cylinders. So it seems to me you may have found the route the water took.

Hopefully someone that understands risers will chime in.

[pridekit]

It rained off and on this weekend, but I got the broken bolt pulled out and the intake manifold properly torqued down. I replaced all of the lifters with brand new ones while I was at it.

I pulled the other riser off and the gasket looked fine. I replaced the riser gasket and bolts (found some nice stainless bolts with gasket on mr cool).

Just need to mount the exhaust, put the distributor in, and plug in all of the electrical goodies. I didn't get a chance to perform the wet test, but I want to warm the motor up and perform a dry test first.

http://images.tapatalk-cdn.com/15/10/11/ee7525d5ecd0d21c961934a847f36636.jpg


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[pridekit]

So I got everything put back together a few weeks back, but I've been struggling to get the motor to show any signs of life.

Primed the oil galleys with the priming tool and drill.

I have reset the timing, turned the motor to #1 TDC, lined up the white line on the distributor housing with the indent in the gear. Hooked up the coil and plug wires. I verified in getting spark to all 8 plugs with a plug tester.

The fuel rails have fuel (haven't checked the exact pressure value), the plugs have some gas on them when I pull them out.

I've primed the fuel pump about 4 times, I tried advancing the throttle to 25%.

The only thing I haven't checked is if my plugs themselves are sparking.

What else am I missing?

https://vimeo.com/145787691


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[roosm]

Hi,
Really there are just a few thing that can be wrong when it doesnt start at all. Right?
Fuel, air, spark and compression. If you have all of those at least it should try to fire.

I had an issue a couple of years back. After a lot of testing it turned out to be the high pressure fuel pump.
I am not 100% sure we use the same system, but if we do I have a pretty good understanding of what can be wrong. As I spent not hours but days and weeks figuring this out myself.

My issue was as easy as an corroded wire.

Since you have done some testing I would start with the easiest.

We know you have spark.
Air shouldn't be a problem.
So fuel.

Try pouring an ounce of fuel down the throat of the carburator (or wait, do you have TBI or MPI?, might be totally different if you have MPI? I'll assume you have TBI and otherwise someone else might find this useful in the future).
When I did this it fired right up.

This tells you either of two things are wrong. Your injectors aren't firing or your fuel pressure.
I disconnected one of the injectors and put a small LED there instead. The LED should be flashing as you turn the engine over.
If the LED isn't flashing you have a problem with some part of the electronics. There is a module on the distributor connected to the ECU that controls the injectors. That module could be broken, or bad connection.
Or the distributor isn't sending the correct signal, out of magnetization? Or something?

If it doesn't start when you pour a shot of fuel down the carb I would suspect compression.
If you have good compression, then the spark could be too weak or badly out of sync.
Like you put the distributor in backwards, it goes in one of two ways. 180 degrees. From what I have read.

PM me if you would like a very long trouble shooting guide for MEFI 4. Which is what I have at least, you might have a newer system.

Good luck!

Mike

[docdrs]

make sure you press the neutral safety switch when you advance the throttle

[Moor]

are you sure the distributor is not 180 degrees out? When you set piston #1 to TDC, did you verify it was on TDC on the COMPRESSION stroke, instead of the exhaust stroke? i've done this before, and ended up with the same results you have. its a very easy thing to overlook.

[pridekit]

Both valves are in the up position. There is a mark on the balancer and the housing. I lined those up to ensure TDC. I lined up the indent and white line on the distributor and dropped the distributor in. The rotor is sitting just to the left of the number 8 on the distributor housing (roughly above the hole located there). This lines up to be just before the number 1 on the cap.


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[ssa]

What Moor said. You have to make sure that the intake valve was what closed before #1 came up on tdc and that it wasnt the exhaust closing coming up on tdc. In both cases both valves are closed and the balancer will show tdc.

[pridekit]

I understand now. I'll check that next time I'm near the boat.


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[pridekit]

Now that I think about it, I was basing it on when the valve closest to the stern (front of engine) would go up. With out checking any pictures, Im almost that is the exhaust valve. :)


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[ssa]

Yeah if you look at your picture in post 50 of this thread you can see that the exhaust valve is whats located at what would be the front of the motor. Look and you'll see that ajoining cylinders have mirror image valve layout (exhaust,intake,intake,exhaust,exhaust,intake,inta ke,exhaust). Turn the motor and watch the exhaust open and then close (exhaust stroke) and then the intake open and close (intake stroke) and then bring motor up on TDC on balancer (compresssion stroke).

[pridekit]

So, I finally had a chance to get back and deal with the timing issue. I was definitely 180 out, long story short, I got the motor running today. I didn't run it long, but I did bring it up to 1200 rpm and checked the cam angle with diacom, it was at 640 so I need to adjust the timing a bit.

I found my impeller had lost a few vanes so I disassembled it and my trans cooler to clean out the debris. I've decided to redesign how my hoses are set up back there (I was loosing about 1/3 diameter from a funky turn I made with the impeller to trans cooler hose, swapping to a 90 degree elbow instead).

I heard a ticking noise, but it might be a lifter that isn't pumped up yet or a loose rocker, I'm going to investigate that after I get the timing set right.


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[pridekit]

I got the rockers adjusted today, which seems to have solved the ticking/clicking noise I heard. I also got my raw water pump installed again, to find out that the rear seal is leaking -_-

As for the timing, when trying to adjust the timing at 1200 RPM, the motor started to choke and eventually die at 650 degrees.

When I raise the rpm over 2000, the motor stumbles and dies as well. I'm at a bit of a loss, any suggestions on what I can do to get this timing set right? Am I off by a tooth or two on the distributor?

Here's a little video of it running at idle :)

https://vimeo.com/150497087


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[CJD]

650 degrees??

[pridekit]

Yep, 650 degree cam angle. That's what diacom is reporting.

According to this, I should be at 705.
https://www.bakesonline.com/images/MediaLibrary/IndmarIgnitionTiming.pdf


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[CJD]

My 2005 uses the 10 BTDC at the crank timing spec. Are you sure yours is MEFI 5?

If it is, the 705 cam degrees would be the same as 7.5 degrees BTDC at the crank. Even if you skipped a tooth installing the distributor, it would merely result in an odd distributor angle, but you would still be able to adjust it.

[pridekit]

I'm positive it's mefi 5. Very strange, I wonder why it's so far off.


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[pridekit]

Here's someone from the Malibu forums with a similar issue (skip down to the last couple of posts).

http://www.themalibucrew.com/forums/index.php?/topic/43900-383-hammerhead-rebuild/page-2


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[pridekit]

Well, I figured out what I did wrong :)

Here's where my rotor at 1
http://images.tapatalk-cdn.com/16/01/02/6cabd6899b9a599c0157634fc707e28a.jpg

And here's my crank position
http://images.tapatalk-cdn.com/16/01/02/788ae69fc401e0a912859013ebcf4ecb.jpg


So I'm firing way after TDC. I'm still trying to figure out how it even cranked up and idled.

Resetting the dist. now.


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[pridekit]

I reset to 1 TDC, pulled the distributor out until I cleared the cam gear. I was off a little bit on my alignment so I turned the rotor clock wise a smidge, dropped the distributor in. The point on the rotor was perfectly centered on the 8 stamped in the distributor.

She fired right up, let her warm up, the checked my cam angle, I was at 706, I adjusted around and couldn't hear much of a difference in sound so I decided to settle right on 705. :)

Thanks for the help everyone! I learned a hell of a lot from this adventure!!!

https://vimeo.com/150545371


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[CJD]

It was an interesting project! What tool are you using to read the cam timing?

[pridekit]

Rinda tech's DIACOM.


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[CJD]

Neat software...did you find a reasonable price source for it, or end up paying retail? I'd love to have it, but $500 is a bit steep just to set timing every few years.

[pridekit]

Unfortunately I bit the bullet and bought it direct from Rinda. It's definitely a really cool piece of software, and in someways I hope I don't have to use it very much. But, at least I have it if I need to lol. I was primarily concerned with DTCs when I purchased it, I didn't expect to have to use it to set the timing :P

It also came in handy to troubleshoot an issue with my pedal position sensor (it was getting stuck in spots and I thought it was my throttle position sensor).


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[CJD]

I was afraid of that. Guess I'll wait for a major fix to warrant the investment. Glad you got your boat all set for next season!

[Brian_289]

Bumping this back from the dead. I just bought this boat. Glad I found this post. I got most of this story before I closed the deal. Interesting to read the whole thing through. Looks like I’ll be rebuilding this over the winter. I just rebuilt the 350 in my last boat. Best part is I also had my distributor 180 degrees out and spent two days trying to figure out what I did.


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[Brian_289]

I got it apart:

No compression on 5 and 7 and I found out why. The manifolds and risers were shot by the time I took ownership. It was parked for sale for nearly 2 years. My guess is salt water leaked out of the manifold or riser and puddled up on the back side of the exhaust valves. Being that the engine sits on an angle, cyl 1 was ok, 3 had some pitting and 5 & 7 were toast. I’m taking the heads to the machine shop now for new seats. Thankfully I had a set of these heads sitting here that were cracked, the valves in those were perfect. I can’t even describe what the valves looked like when I pulled them from these heads.. Pictures attached.
https://uploads.tapatalk-cdn.com/20200716/71828c03a6bc4edf48e54638b59e8f31.jpg
https://uploads.tapatalk-cdn.com/20200716/d2243fb0cce54db9ee2d2914ce3537e2.jpg
https://uploads.tapatalk-cdn.com/20200716/5eca0a710e8197dbee51e034fe29ed50.jpg
https://uploads.tapatalk-cdn.com/20200716/d3a6eae020c9c1ba70ea805e3eb8a1ea.jpg


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[Brian_289]

Update, the valve seats were able to be cut and we replaced the valves. New manifolds installed and she’s running again. I broke the perfect pass throttle cable extension, but I’m putting a ball and socket end on the cable direct to the pedal sensor for now. I don’t need the perfect pass this summer or what’s left of the summer I should say. I have a huge project ahead of me this winter with the interior. I’ll start my own thread for that. I figured I would just add on to this one since it’s relevant and the same boat, new owner.


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