Exhaust Riser Question

[Tugboatdave]

I had to replace one of my exhaust risers on my 350 Volvo and was wondering if I should use gasket sealer on it, the Osco instructions say to use nothing on it but I just can't see the 4 5/16 bolts providing much clamping force, any suggestions
Thanks
Dave

 

[chiefalen]

Re: Exhaust Riser Question

Those four bolts are enough believe me. I just hoisted my motor out and in with a old fan belt tied around my riser just 4 bolts on it. And another fan belt on the lifting eye on the front.

There should be a gasket though if i remember right.

 

[Tugboatdave]

Re: Exhaust Riser Question

Yes it does have a gasket, I have this thing about putting in gaskets dry but the instructions say to do so, I was thinking about using ultrablue or some such just to make sure it seals...

 

[Tugboatdave]

Re: Exhaust Riser Question

Another question while I'm at it, sorry to be a pain, but I wonder about setting the timing on the engine, the original manual calls for the initial ignition timing to be set at 8 degrees BTDC but this is for gas in '78 and the engine was also rebuilt 4 years ago so there are many variables. I know that with older higher compression cars we would simply advace the timing in increments from 0 deg. untill pinging happened under heavy load then back it off a degree or two but boats are a different animal, can one simply adjust the timing at high cruise or full bore untill it runs rough or pings and then back off?
Dave

 

[JustJason]

Re: Exhaust Riser Question

exhaust riser gaskets go on dry

if you used a sealer.... under normal conditions it would probably be fine.... but the first time you have the mildest of overheats your going to cook the sealer, and it WILL leak. and if it leaks internally and you don't catch it, it will trash your motor.
Your much more likely to survive an overheat if you do not use sealer.

 

[littlebookworm]

Re: Exhaust Riser Question

Timing is still 8 degrees. Octane hasn't changed; timing on auto engines is a little more forgiving than on marine engines because of the RPM range of operation.

 

[Tugboatdave]

Re: Exhaust Riser Question

Thanks for the replies, I found some related threads on the riser gasket question and the consensus seems to be dry installation so that is done. as far as the comparison to cars the RPM range is about the same but the RPM and power are more sustained on boats, I would say it is the same as a car climbing an endless hill, I was wondering if power timing was possible, if anybody has tried it. my engine was rebuilt before my ownership so the compression ratio is an unknown, that said it will be set at the factory specs till I know otherwise.
Thanks
Dave

 

[chiefalen]

Re: Exhaust Riser Question

My 2 cents: Gasket goes on dry.Ok, there are sealers that won't cook.

I did use stuff that was permatex aviation form a gasket. Maybe i spelled it wrong.

Used it maybe 20-25 years ago while in the Air Force. Don't know if they still make it.

Maybe someone else makes something like it.


Good luck!

 

[Tugboatdave]

Re: Exhaust Riser Question

Yep, they still make it, hard to find but its still around, still went dry on the riser gasket we'll see how it holds. Permatex also makes a red hi-heat gasket goo but like they say you have to avoid using too much.

 

[Uraijit]

Re: Exhaust Riser Question

I used the red Permatex on mine. I guess we'll see how it holds...