another exhaust log to center riser question

[achris]

Re: another exhaust log to center riser question

ok.. I've done the first drawing.. The easy one... Make note of the plate between the elbow and the manifold, it's vented, MOST important... Not full-flow or complete block-off, but a small hole for air bleed.

(Also note the similarly awesome Paint skills )

228 with standard manifolds.

Edit: Now the 228 with 'Cold' dry-joint manifolds.
Note that you need full-flow elbow gaskets with this option...

Edit: Now the 228 with 'Warm' dry-joint manifolds.
Note that you need block-off elbow gaskets with small (1/8") holes drilled for this option...You will also need to fit a straight pipe fittings to the top of the manifold, just in front of and below the elbow. This should be your preferred option as the dry-joint manifold set-up on all engines with them as standard fitment is warm.

Hope this helps you,

Chris.........

 

[steves86ta]

Re: another exhaust log to center riser question

Chris,

Thank you very much for the help. This helps tremendously. Im sorry it took me until today to get back to you i was on the lake for mothers day .. I will for sure update the post as i begin my project.

One question though, would there be any perceived problems with running the middle option? the 228 with "cold" dry joint manifolds?

I think this would be cleaner...

Thank you again!
Steve

 

[achris]

Re: another exhaust log to center riser question

I like the idea of warm manifolds because you can develop gasket issues with the heating and cooling to the extreme that cold manifolds do. (See it a lot in outboard exhaust systems.) There is also the remotest possibility of cracking, again because of heating and cooling extremes...

If you do go cold manifolds, use the full-flow gaskets....

Chris........

 

[steves86ta]

Re: another exhaust log to center riser question

Hi Chris,
The manifolds already have the full flow gaskets. I mainly take the boat out to the local lakes here in SoCal or Lake havasu/the river. It doesnt go out in the winter and the water is not extrremely cool here. But ill probably still go the "warm" route.

Thanks again!
Steve

 

[achris]

Re: another exhaust log to center riser question

If you go the warm manifold route, you'll need to change the gaskets to block-off, with a small (1/8") hole drilled in each end...

BTW, any lakes or ocean water is cold, with respect to the block temperature.

Chris........

 

[Amaier41]

Re: another exhaust log to center riser question

Steve,
Did you put the restrictive plates in ? Between riser and exhaust manifold...
My set up is stock with the logs like yours was..I purchased a Barr center rise conversion kit and they claim I can use full flow gaskets and the stock thermostat housing...
There's a lot of controversy about having to change out and updating thermostat housing...and the restrictive plates
My engine is a 1980 mercruiser 260 5.7

Thanks,
Anthony

 

[85 Ambassador]

Re: another exhaust log to center riser question

....but I managed to reuse the existing hoses (or at least replaced them with some NOS ones that came with the boat), but found that the engine would not come up to temperature. I later discovered that the place that supplied my the manifolds and elbows etc neglected to supply me the stainless steel block off plate that goes between manifold and riser. Put this in and she's all hunky-dory.

Hi Cresco,
Reviving an old thread. When you mentioned using NOS hoses, did you mean they were originally meant for the log manifolds or the center-riser conversion manifolds? I have a similar setup (with center-risers) and I like how your hoses fit.