Overheated this weekend - 0 compression in 5 and 7

[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.







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.


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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