Correct riser gasket

[Deepwtr]

I pulled off my risers to inspect all of the internal cooling ports on the risers and manifolds. Everything looks good, which is a good thing. However I was somewhat shocked to see restrictor gaskets there instead of full flow gaskets.

From my research I see there was warm and cold exhaust setups and that basically determined what gasket to use. I believe I have the cold exhaust as I only have one hose running to the bottom of the manifolds on each side.

I have read everything from people using one particular gasket or the other because they have done it that way with no problems to just replace the same thing that was there.

Well, in my humble opinion just because it was there doesn’t mean it was right, or really just because something has worked for someone doesn’t mean it’s right.

So, I guess what I’m asking is, if I have a cold exhaust system as determined by the single hose, is the proper gasket really the full flow one? Would there be a specific reason to use the restrictor gasket on a cold system? I would think it wasn’t designed for that and the full flow is needed to bypass the extra water from the alpha drive.

I have a 97 EFI 5.7L with a serial number 0K034415

 

[wingless]

This parts list shows the lower gasket should have two slots and the gasket above the riser has four slots.

 

[scoflaw]

Mercs thinking was to restrict the flow a bit to keep the manifold/ elbows warmer to reduce condensation

 

[Deepwtr]

Ok, so looking at the parts diagram again, I realized I have screwed up in terminology. I have the manifolds and the exhaust elbows bolt directly on to them. I have incorrectly called the elbows “risers”.

So, basically according to that diagram with the elbows directly bolting to the manifolds I do indeed need the partial restricted gaskets? Part number 863724. The full flow gasket is an optional part used only if you had the actual riser between the manifold and the elbow.

I think I’m getting this now.

 

[wingless]

That all looks correct to me. The model and serial number range looks correct, based on your posted info (very helpful BTW). When you travel, are you required to say: "we're not in Kansas anymore"?

Remember you are responsible for determination of correct parts prior to ordering / installing parts.

Yes, for your engine the four slot gasket is only used when the optional 3" or 6" riser is used.

 

[Deepwtr]

I followed the suggestions of the forum stickies on what to have in your signature. I know, I know, what was I thinking reading those!

I have figured out in life there are people who know a lot more than I do, any anything I can do to make asking for help easier on the folks willing to give help is the right thing to do.

And..... We make it easy by just staying in Kansas so it doesn’t have to come up. We own a boat so we are too poor to travel.