1990 OMC 4.3L exhaust manifold - GLM?

[asdasc]

Hi All,

Apparently, a couple years back I waited too late in the season to winterize the boat and I had a freeze issue. There is a very minor crack just above the middle spark plug on the Port side. It really doesn't 'leak', it is more of a 'weep' as I can see a fine line of rust forming there.

I have run it like this without issue for a couple years, and have been keeping an eye on it. I am thinking that one of these days, I would like to replace it, but of course can't get OEM parts anymore.

What advise can you give about how urgently I should fix this, if ever?
Has anyone had experience with the GLM Manifolds for this year 4.3L OMC?
Any other makers that are more popular?

I am looking for some opinions so that I can make a somewhat intelligent decision.

Thanks,

 

[Lou C]

Re: 1990 OMC 4.3L exhaust manifold - GLM?

If you have the one piece batwings, I think they were in the GLM catalog but never were produced, probably too difficult to cast. I have em on my engine too. There was a conversion using aftermarket 2 piece manifold/riser units made for this engine, do a search on OMC V6 conversion manifolds, not cheap but the best alternative.

 

[asdasc]

Re: 1990 OMC 4.3L exhaust manifold - GLM?

Thanks, Lou.

It looks like there were some issues with these, so I may go with one of the other brands, most like ESCO.

It seems that if I were running the company (GLM), I would run them over a surface mill to true up the mating surface prior to sending them to customers.

It also seems odd that all brands paint the mating surface. It seems that should be kept clear.

Thanks again,

 

[HT32BSX115]

Re: 1990 OMC 4.3L exhaust manifold - GLM?

It also seems odd that all brands paint the mating surface. It seems that should be kept clear.

I think they may do that because they sometimes sit on the shelf for a long time. (rusting)

 

[zbnutcase]

Re: 1990 OMC 4.3L exhaust manifold - GLM?

That small of a crack, you can prob just get away with epoxying it.

 

[asdasc]

Re: 1990 OMC 4.3L exhaust manifold - GLM?

Yeah, you are probably right. By the way, when winterizing this year, I think I know what I may have done. I opened the drain plugs in the manifolds, and nothing came out. This time, i had just run the boat and KNEW there was water in there. I jabbed a small screwdriver up there and niagra falls opened up. In years passed, when I had the boat in rack storage, I wouldn't run in water for weeks prior to winterizing, so I may have assumed that there was no water in there and not poked up there to verify.

I will run it another year and keep an eye on it. I really need to sort out my temp sending unit issue also so that I can keep an eye on the temp. It is not giving any output. Hopefully just a broken or disconnected wire.