Mercruiser stainless risers ...what to do

[godspede619]

Just bought a 22 eliminator extreme with a 454 that was hydro locked from what looked like a shredded impeller and overheat. Motor is almost of of the shop. Full rebuild. My question is I am going to replace the manifolds because they are original and have rust In The exhaust chamber. The risers are oem mercruiser stainless steel. Looks like they are in perfect shape. Only rust wast tiny on mating surface where water might have got passed the gasket at one time. So should I buy the new manifolds and reuse the stainless steel riser. If I check the gaskets and torque yearly is it safe to use the ss riser? Thank you. Btw this boat is primarily fresh water use. Maybe 4 salt trips a year.

 

[alldodge]

Re: Mercruiser stainless risers ...what to do

Don't see any reason to replace them. Suggest taking them to a machine shop and have the surface trued

 

[godspede619]

Re: Mercruiser stainless risers ...what to do

I thought they look good too. I have just heard mixed stories about these risers. Some say they are a good upgrade and others talk of constant leaks. Ill definitely true up the surface just want to be careful with the new motor.

 

[alldodge]

Re: Mercruiser stainless risers ...what to do

I thought they look good too. I have just heard mixed stories about these risers. Some say they are a good upgrade and others talk of constant leaks. Ill definitely true up the surface just want to be careful with the new motor.

The risers that leak are usually the high rise header type which go on the HP engines. The ones you have, I personally (keep in mind my opinion) have not heard of issues.

 

[achris]

Re: Mercruiser stainless risers ...what to do

I had SS elbows on my previous engine. Sold it to a friend (complete with the elbows ) and it's still going... it's coming up to 20 years old... Still have original shift cable, gimbal bearing, uni joints...

If you're not going to use those elbows, send them my way. I have another friend who could use them (I can't, I have dry-joint manifolds on my new engine)... (And if anybody reports this for soliciting, I'll slap him.... )

Chris.....

 

[alldodge]

Re: Mercruiser stainless risers ...what to do

I had SS elbows on my previous engine. Sold it to a friend (complete with the elbows ) and it's still going... it's coming up to 20 years old... Still have original shift cable, gimbal bearing, uni joints...

If you're not going to use those elbows, send them my way. I have another friend who could use them (I can't, I have dry-joint manifolds on my new engine)... (And if anybody reports this for soliciting, I'll slap him.... )

Chris.....

I reckon you got one heck of a long arm there

 

[AZSenza]

Re: Mercruiser stainless risers ...what to do

I have these stainless risers on my 5.7L Bravo 3 from 1997. I had them off 3 years ago and they looked great. I've had zero problems and may even use them when I change to Aluminum manifolds in the near future.

 

[HT32BSX115]

Re: Mercruiser stainless risers ...what to do

(And if anybody reports this for soliciting, I'll slap him.... )

Chris.....

Hey......... Chris!! STOP THAT!!:laugh:

Just bought a 22 eliminator extreme with a 454 that was hydro locked from what looked like a shredded impeller and overheat.

The engine was probably hydrolocked because the riser gaskets were neglected and they leaked.

Part of the problem with the stainless steel risers, are people think they don't EVER need to inspect the riser gaskets.

If you're spending the money to rebuild the engine (new block?) I would spend a little more money and install FULL closed cooling.

This way there'll be a "block-off" gasket between the manifolds and risers and a NPT connection at the bottom of the risers that connects to the raw water output of the heat exchanger.

This way, you'll reduce the risk of the corrosion at the riser/manifold gasket that is the cause of most riser gasket leaks...

The BEST choice would be "Dry-Joint" manifolds that eliminate the possibility of a leak altogether. Unfortunately, I don't think anyone makes a dry-joint manifold for a 454............


Regards,


Rick

 

[godspede619]

Re: Mercruiser stainless risers ...what to do

No it's not a new block. Didn't cause any severe damage that warranted a replacement. Everything is being milled, balanced and blueprinted. Mechanic almost finished. New pistons cam and everything else minus valves. Closed cooling system not really an option right now. I run 99% in fresh water anyway so should be alright. I follow you when you say that people neglect to inspect and replace the $10 gasket. I wanted to keep the ss so I think that it gonna be the route. Inspect often and use them. I will take the risers down to the motor guy and have him mill the mating surface.

As far as dry joint that would be the best option. Someone told me I could use the 496 manifolds for dry joint application but not sure if this will work or not.

 

[HT32BSX115]

Re: Mercruiser stainless risers ...what to do

Someone told me I could use the 496 manifolds for dry joint application but not sure if this will work or not.

I would like to do the same thing.......but "someone" else told me that 496 manifolds/risers will not fit a 454. (the bolt pattern might be the same but the riser height may be different enough to make everything else NOT fit without more modifications!

Dry joints absolutely fix the riser gasket problem once and for all..............