cracked manifold????

[docdrs]

are the cracks on the manifold or the riser? did you have problems with water in the bilge, or was there exhaust/noise coming from the manifold? how did he discover it?

[agetech]

They could have been leaking when the mechanic winterized the engine. Did the he run the engine to fog it? If he did, the leak would have been noticeable.

[Irish_Jack]

I would hedge bets that everything is kosher. GM inboard manifolds will usually crack close to the center exhaust ports.. sometimes all the way down to the manifold bolts. I traveled to one of our other locations this past fall durring winterization to take alook at three indmar GM engines that had hairline cracks--all in the same places. It almost seems like a heat transfer problem(caused by poor water circulation) or impure casting problem... I will talk to one of the other senior techs that is at that location and find out what the solution was. He is the one who did the follow-up. I was sent there because I was the only other senior tech in the district when he was on vaca. Keep in mind indmar's are extremely sensitive to week impellers...

[szarik5]

I had a freeze-up problem on my TS6M pcm cast iron manifold. Water froze inside of it and created a hairline crack along the side of the manifold. If not the rust and visible water dripping it would be difficult to see.

Last thing I would do is try to depend on JB weld to plug it. Do it right! The manifold may be perfectly fixable but take it to a reputible shop too have it cleaned (inside and out) and checked. You want it to be cleaned good so you dont have any oil or anti-freeze soaked into the cast. The cast can act like a sponge and hold chemicals.

Braze it - Take a large propane torch (the kind on a wand -$25 at menards) and get the entire manifold hot. Keep heating it while you are brazing it (about the easiest thing to braze). When done, run it into your house into a pre-heted oven to full heat and reduce the heat by 50F every 10 minutes and leave it in there untill cold.

The heating could warp the manifold a bit and it should be checked and possibly planed flat. Not a bad idea to get it planed anyways to clean the surfaces under the gaskets.

My suggestion is to fix it right or buy new manifolds.

[docdrs]

Do a search on You tube, there are vids on how to do, sounds like they are close to the port exits and tend to agree with Jack and szarik5. Plus a new manifold doesn't look that expensive

[cmtaylor777]

DOCDRS,

Can't really answer the question referring to having water in the bildge. I was also having issues with my front ballast overfilling when I was in motion. Turned out to be the silonoid.

They did do a full winterization and fog the engine. I guess they could have discovered the problem then.

Guess I'm in denial. Just got the boat in december and was looking forward to getting a little use before having to shell out money for repairs.

Thanks to everyone for giving advise. I never post on forums but I have found this to be extremely helpful.

[beast 496]

Wait until spring, If the crack is small and on the outside only it will basically rust shut. Exaust water pressure is only around 3 to 5 lbs in this area. If you do notice some seepage, save yourself some money and use some Marine Tex to seal the crack. No reason to go into extra expense of removing and having the unit welded. Cast Iron is not easy to weld anyway. I have fixed dozens of maniolds and blocks this way, No it is not new but $20 verses $200 it is up to you Al

[cmtaylor777]

Thats what I'm talking about! Is it easy to apply. Forgive me, I haven't ever heard of the stuff.

[beast 496]

Yes, Marine Tex is used in the Marine service industry quiet abit. Basically industrial JB weld. Look at Jamestown distributing for supply. The Black or grey version is the strongest. Easy to apply clean up with acetone. overnight to set up. Al

[cmtaylor777]

Thanks Beast

I will give that a shot.