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Re: Exhaust Riser gasket change
1 Attachment(s)
For sale: Slightly used, gently worn 21 year old log style manifolds and risers. They do not leak (in). Still have more than 50% flow capacity on the water side and nearly 90% (accounting for rust) on the exhaust side.
Fits SBC to Cobra. Very common perf boat combo. Extra weight from rust makes ride much better. Don't pass up these rare, original OMC parts. (The pic only shows one, but trust me... they are all as nice as that one.) |
Re: Exhaust Riser gasket change
Hard to tell from the pic... but one each of the long water slots is completely filled in with some kind of a rust/steel organic alloy.
Like growing metal in a petri dish. :D I should weigh them and compare to the new ones. |
Re: Exhaust Riser gasket change
I see rust on the manifold side.
Scary. Wonder how much water was flirting with my combustion chambers and when? I haven't done a compression check... but engine ran, idled and had good oil pressure. Maybe I caught them just in time? |
Re: Exhaust Riser gasket change
Fund Razor,
Only do a compression check if you are ready for the results. Mine were both running too, started, idled, good oil pressure, etc. I blew a water drain plug on my port engine. Decided to pull them both last winter. Turns out the block was rusted beyond repair along with the manifolds. So far I needed 1 new engine. Then I figured I would go thru the GOOD one. The compression was all over the place. Blown head gasket on 1 side and water from the manifold in 1 cylinder on the other side. I'm sure alot of the rust was from the salt water, but I have never seen a worse engine torn down that actually ran pretty good. There wasn't much water moving thru the heads. Most of the water jackets were plugged. Probably could have salvaged the 1 block and built 2 new ones myself but would have lost whats left of the summer. Ended up with 2 long blocks. I powder coated all the tin with a triple coat epoxy, used stainless bolts and added freshwater cooling for the engines and manifolds. I would be interested if you pick up any top end with your new manifolds if you don't change anything else. |
Re: Exhaust Riser gasket change
Originally Posted by Island Time
Fund Razor,
Only do a compression check if you are ready for the results. Mine were both running too, started, idled, good oil pressure, etc. I blew a water drain plug on my port engine. Decided to pull them both last winter. Turns out the block was rusted beyond repair along with the manifolds. So far I needed 1 new engine. Then I figured I would go thru the GOOD one. The compression was all over the place. Blown head gasket on 1 side and water from the manifold in 1 cylinder on the other side. I'm sure alot of the rust was from the salt water, but I have never seen a worse engine torn down that actually ran pretty good. There wasn't much water moving thru the heads. Most of the water jackets were plugged. Probably could have salvaged the 1 block and built 2 new ones myself but would have lost whats left of the summer. Ended up with 2 long blocks. I powder coated all the tin with a triple coat epoxy, used stainless bolts and added freshwater cooling for the engines and manifolds. I would be interested if you pick up any top end with your new manifolds if you don't change anything else. I do like small block work.... so maybe if I keep this boat I will re-block it next winter. I can afford new power much more than new boat. :) And I would swap them myself in the garage over the winter. Anyway... I am curious about top end, too. My top speed with a clean bottom and half a tank is about 52 gps so far. All stock. Thru hub exhaust. It's a heavy boat... as you know. If the manifolds get here Friday I will do them over the weekend. |
Re: Exhaust Riser gasket change
I won't be able to tell a difference in planing time, I don't think.
My boat planes quickly. Freaks people out. Don't even have to do a hole shot. Rpms are not that high to get on plane. Bet yours planes quickly too. |
Re: Exhaust Riser gasket change
Ya, Mine got on plane pretty quick too but lost some top end last year. I should have known something was up but kept putting off dealing w / it. The engine w / the blown head gasket started knocking at high speed so I just backed off figuring it was timing.
You should be OK if you have no rusted plugs and no H2O in the exhaust side of the manifold. Mine had rust droplets all the way to and including the valve. When you replace the manifolds make sure the exhaust valves (If not Stainless valves) and ports do not have rust on them. Good Luck! |
Re: Exhaust Riser gasket change
Originally Posted by Island Time
Ya, Mine got on plane pretty quick too but lost some top end last year. I should have known something was up but kept putting off dealing w / it. The engine w / the blown head gasket started knocking at high speed so I just backed off figuring it was timing.
You should be OK if you have no rusted plugs and no H2O in the exhaust side of the manifold. Mine had rust droplets all the way to and including the valve. When you replace the manifolds make sure the exhaust valves (If not Stainless valves) and ports do not have rust on them. Good Luck! No actual water in the exhaust side. Just corrosion. doesn't continue into the block though. Hoping to get the new manifolds tomorrow. Would like to rebuild them over the weekend. Gonna do new hoses too. |
Re: Exhaust Riser gasket change
New manifold came. (1)
is the cast surface of the new manifold ok for assembly or do I need to work the surface or remove the paint? Not exactly a machined mating surface like you get with machined steel. It's like what you would expect from a casting. Flat but not knife edge. |
Re: Exhaust Riser gasket change
Originally Posted by fund razor
New manifold came. (1)
is the cast surface of the new manifold ok for assembly or do I need to work the surface or remove the paint? Not exactly a machined mating surface like you get with machined steel. It's like what you would expect from a casting. Flat but not knife edge. |
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