exhaust cooling questions

[workaholic]

Hi again gang!

Continuing my 283 to 350 swap I am looking for some more pointers. I changed from having the old log style manifolds to center rise manifolds. Thermostat housing that was on my 283 is now bolted on my 350. My t-stat has the big main hose running to the water pump. then it also has 2 oulets on each side of it (4 outlets). 2 lines ran into the front ends of the log manifolds, but now my center rise manifolds have 1 outlet on the bottom near the middle then also an outlet on the top elbow..

I am also converting to thru hull exhaust. I already have 2 4" outlets with internal flappers to install. So i was going to adapt from whatever size the elbows are to the 4" outlets.

So my question is, does it matter what hose outlets on the t-stat go where on the manifolds and elbows?

 

[Don S]

Re: exhaust cooling questions

So my question is, does it matter what hose outlets on the t-stat go where on the manifolds and elbows?

Sure it matters, do you have pictures of your thermostat housing?

What boat is this in, Merc only used the 283 in 63 and 64.

 

[workaholic]

Re: exhaust cooling questions

I will try and get some pics asap. The 283 was a 1963. The 350 is a 1978.. Its for my 1990 Rinker 18'.

 

[workaholic]

Re: exhaust cooling questions

I found a similar style to mine online. Mine has the same 4 outlets at the same side locations. Mine also has the big main outlet coming out of the bottom piece of the housing (not shown in picture) which runs to the water pump.

Thanks

 

[Don S]

Re: exhaust cooling questions

EDIT: You have an OMC, not a Mercruiser. Moving to proper forum

 

[Don S]

Re: exhaust cooling questions

You REALLY need to upgrade to a newer 350 thermostat housing. Not that antique 60's stuff.

 

[workaholic]

Re: exhaust cooling questions

The reason I posted the thread in the mercruiser section is because I am converting to mercruiser. The manifolds and risers are now going to be mercruiser. My old 283 was using all omc, but not the new 350..

The elbows (risers) i have is the sierra 18-1970-1 . And the manifolds are the 87114 's.

I realize my thermostat is the OLD omc style. Would you (or anyone else) be able to explain to me why my omc thermostat wouldnt work. Also should I remove the hose outlets on the new elbows and just run to bottom lines to the bottom of the manifolds?? Whats the pros and cons to running the elbow lines?

Thanks

 

[Don S]

Re: exhaust cooling questions

I just assumed that since you have an OMC stringer outdrive, and asking questions about an OMC thermostat housing, that your post should be in the OMC forum.
What you need to do is find out how that housing is setup inside. Maybe someone in this forum knows what hoses go to what.

 

[workaholic]

Re: exhaust cooling questions

Should I just remove the hose outlets on the risers (elbows) and block them, change the t-stat housing to a mercruiser and hookup the 2 manifolds? or can i just simply hookup all for lines (2 to manifolds and 2 to elbows) to the existing t-stat, which would be nice...

Thanks

 

[Don S]

Re: exhaust cooling questions

I personally would avoid the Mercruiser housings all together. Get the newer OMC (and now Volvo) style. Not all the check balls and special stuff like Merc likes to use. One like this http://compare.ebay.com/like/230774342860?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

Parts are available, preformed hoses are available if you want. Just easy to deal with.

This shows how it works and the hoses are run.

 

[workaholic]

Re: exhaust cooling questions

OK, after further brainstorming, here's what I came up with and would like to do. But I would like some confirmation that this will work correctly (flow correctly)

I was to re-use my old omc t-stat but re-route the lines where needed seeing as I am going to center rise and not using the old log style.

Here's a few pictures of what im thinking. Will this work?

 

[workaholic]

Re: exhaust cooling questions

Anyone

 

[Kainon]

Re: exhaust cooling questions

There are a couple different ways to use the manifolds you bought. a four hose system would send water to the manifolds and risers/elbows. You have to be careful which gaskets you use between the Manifold and Risers & Elbows as you could block off, restrict or allow to much water to flow which would unbalance the system creating hot spots and potential places for cracks and damage.

You really should have the proper Thermostat housing to match the riser setup you ware going to use and or match
the hose setup to the thermostat.

 

[workaholic]

Re: exhaust cooling questions

I already bought my gaskets. Its the semi blocked gaskets... was planning on blocking the outlets on elbows and just running the 2 line system under the manifolds, would that be ok?