Who uses sealant on exhaust stuff?

[Pavetim]

I read different opinions on this. I have the good mercruiser gaskets for my riser and spacer, think they are graphite and stainless. I block sanded everything and they are not totally uniform due to corrosion. Who uses sealant and who doesnt. I am guessing NO sealant with the graphite gaskets?

 

[Scott06]

If the surface is not uniform either take them to a machine shop and have them milled Or replace the manifolds and risers. This isn’t a good place to use sealer because the manifolds and risers are damaged

You can ingest water in the engine and ruin the engine if this seal is compromised

 

[Pavetim]

Here are pics. Manifold looks the worse idk if machining that will help. Riser and spacer looks like machining may help. Hell depending what a shop would charge might be better buying new ones, have to find prices.

 

[Bt Doctur]

They look marginal at best , glue some #120 grit and massage them some more

 

[achris]

The elbow's ok. The riser is ok. The manifold is 'goodnight nurse'....

 

[Bt Doctur]

WHAT, not a "Happyending Nurse"

 

[Pavetim]

Would it be cheaper to keep the manifold and convert to dry joint? Manifold has the plughed holes for it. I should just need the tall riser but not too sure about that one

 

[achris]

'Standard' and dry-joint manifolds are different. To convert to dry joint, you need new manifold, riser and elbow.

Those 'plugged holes' are not for dry joint elbows, they are for tube fittings for closed cooling. Those manifold will not and never will work with dry-joint elbows and risers. It's a complete change of EVERYTHING.

Chris....

 

[Pavetim]

Oh. Well last question, any tips to install the studs? They do not have the allen key end like car ones

 

[AKJohne]

I have had a couple of things beat in to my head about strendrives, corrosion kills outdrives, and water ingress, kills engines. I can honestly say that so far I haven't had to learn the hard way as I heeded the good advice I found on this forum. In any case, I did mine last year

https://forums.iboats.com/forum/engi...use-or-replace

We put 170 hours on last year and so far so good, I will probaly plan to revisit next winter.

if you take them to a machine shop ideally they would set them up on a mill as that will give you the best flattest finish, However its much faster/cheaper to just place them on a big belt sander. result can vary depending on several things. Mine were done on a belt sander and I ended up lapping them by hand on a piece of quartz.... ok if you have time. I dint ask how much to mill, but I will next time, or buy new.

No sealant on the gaskets

 

[fishrdan]

Oh. Well last question, any tips to install the studs? They do not have the allen key end like car ones

Thread 2 nuts onto the end of the stud, tighten them together, then turn in(out) with the locked nuts.

 

[Pavetim]

AkJohne. I read your post how did you keep the miriatic acid in the ports? Did you use it straight? How long do you soak for

 

[AKJohne]

I did not dilute, I set them in a pan upside down, maybe blocked it up so I could get as much in the elbow as possible, I let it sit for awhile, not overnight although I doubt it would hurt it, muratic acid attacks the minerals not the metal. primarily the elbows were clogged as the manifolds are on the closed cooling side.