SR3 Exhaust Manifolds cracked! Is repair possible?

[Sportouring]

Hi all,

I know it's going to make me look an absolute numpty, but I was too busy to winterise my 4.3L V6 Mercruiser at the end of last year and I simply put the boat in to storage! What could possibly go wrong? That winterising scam is a total waste of money! Right?

Well know I now know the answer to that one and it appears that I may have been just a tiny bit wrong!

Does anyone have any experience of repairing a pair of cracked exaust manifolds? ops:

When you've finished laughing, the manifolds have split as a result of frost damage. Water has frozen in the exhaust manifold resulting in a cresent shaped split on the outside surface of each manifold. There is no leak in to the exhaust, it just pours water in the the bilge. It's quite a feature really!

I'm going to try to effect a replair using Belzona metal repair solution. Does anyone have any experience in this area?

New manifolds (dry joint type) are not available in the UK for another month. There is currently no after market part available.

Be gentle with me folks, I would appreciate your views on this.

Thanks,
Mike.

[seapuppy]

well..about the only thing we use out here in the colonies is "JB Weld"...it's a 2 part epoxy that might hold once the surfaces are cleaned of any oils/paint.....the other thing to check is if the engine is raw water cooled..check the block too....that can crack unless you have a full up fwc system......

but about the best solution is to replace the man's with new ones....now..if you have a 4 cylinder engine....I've seen some stainless steel man's that replace the old iron ones...might be a bit more pricy but way cooler!!... :P

there...that didn't hurt much...

SP :mrgreen:

[SilveradoSS]

I had to replace mine last year because the previous owner did not winterize properly. The JB weld probably will not work.

They were not hard to replace. Except on the wallet.

[Gazjen]

Difficult to weld as they are cast Iron its quite a complex process to do properly and rarely takes, Can you be sure there is no water leaking back in to the bores of the engine? as that damage will cost a lot more than a pair of manifolds

I may be able to get a pair of stainless manifolds made for your engine if your interested, they are expensive, but they won't need replacing again

There is a picture of mine on here somewhere

[SilveradoSS]

You also will need to be sure they are not cracked on the inside as well as out. Water in the exhaust port is bad. I pulled all of my plugs out and spun the engine with them out to be sure there was no water in the engine.

[hybris1]

Belzona makes some good stuff. Success will be in the preparation. You may have to grind some metal out to get enough surface area to bond.

[yorkcoparamedic]

What everyone else said! Make sure that you have the engine scoped by a mechanic. If you cracked the manifolds I would expect that there might be other damage. Don't learn the hard way twice. The difference might be a total engine change, instead of just the manifolds. Take the extra time, and spend the extra money to check for damage before you repair or just replace the manifolds and then run it.

I replaced my manifolds, risers, spacers, and boots with products from OSCO. http://www.oscomotors.com/

[TonyA]

Hi there
at a pinch you could try using stainless steel arc welding rods , I have used them on cast ion before and seam to bond well this was on a cast ion press handle , so I don’t know how good it will work on your manifolds due to the temperature shift in them .
But to go through all that work taking them off, cleaning them, grinding a V in the crack, welding with on guarantee it will work and then replacing them
Really you should bite the bullet and buy new ones I shore you can fine some on the
E/net and pay a little more for over night freight

[Stressleave]

Try using a bronze rod and braze the crack if not to big. I have done this on exhaust manifolds on car engines and seem to hold. I have also done this on cast iron radiators. Bronze is soft and handles the heat and cool process well.
Paul

[shrew]

(As posted earlier) You will have no way of guaranteeing there aren't cracks on the inside. Water leaking outside the manifold is bad, but water leaking into the exhaust portion of the manifold will wreak havoc and damage the engine. you'd have to inspect and weld the jackets on the inside as well. I would think this would be darn near impossible.

Factor in how much it will cost to repair vs. how much to replace. Then ask yourself how much a new engine is. Now ask yourself how much you REALLY want to pay.

Replace the manifolds and enjoy your summer.

[TonyA]

Hi Shrew

I am with you ditch them and fit new one on; you will never forgive yourself if anything goes bad out there. Play around with the old one later, and if successful hang on to them for back ups
I had a Suzuki 4x4 ally blocks repaired with a crack in the water jacket perfect job on the out side but there was a hair line crack internally between the oil gallery and the inside of the block and nothing could be done so it was money and time down the drain, best of luck if you go for the repair way