elbow gaskets

[biggjimm]

I'm getting ready to swap out the old log style manifolds on my '79 260 with a set of center riser manifolds & elbows that I picked up off of an '02 6.2 B-3 set up.

My cooling system on my 260 requires restricted gaskets which only have a small hole, about an 1/8" diameter, in one of the coolant passage areas. The remaining passages are completely blocked.

The restricted gaskets for the center riser manifolds have the small hole in the front & rear coolant passages but the area on either side is completely open.

Is this because of a difference in the design of the newer style elbows & should I use those gaskets that are actually only half restricted or find or make some that are fully restricted like my original ones?

I understand my original cooling system to be what they call "warm" manifolds & very little water exits the exhaust until the engine warms up & the T-stat opens. The majority of the water recirculates back to the engine. My guess would be to allow the engine to warm up faster??? Or to allow it to warm up at all.
These newer style gaskets look like they will allow too much water to exit the system prior to the engine reaching operating temp.

I just want to make sure it's correct the first time it goes together because it's a real pain to pull the elbows off once everything is back together.

Thanks.
Jim

 

[achris]

The small hole in the old elbow plate was to allow air in the end of the manifold to escape. The water flow into the elbow was through a hose, not the gasket.

Which new gasket you use will be dependent on how you plumb the rest of the system. If you intend on keeping the 'warm' manifold scenario, the you use the restrictor gaskets, and again, the water flow into the elbow is via hosing. If you go to 'cold' manifolds, then full flow would be needed.

Chris.......

 

[biggjimm]

Does it need to be set up with the "warm" manifolds?
If not, it would be much simpler to plumb & less places to worry about a leak or burst hoses or whatever.
I thought the "warm" system was to help the engine get to "operating" temp. If that's not the case, & "cold" manifolds will not hurt anything, then maybe that's the way to go???

 

[achris]

Colds are fine... And yes, they make for easier plumbing. What area are you in? If it's normally a 'cold' place, then 'warm' might be better. I'm in Australia, so colds are perfect.

Chris.......

 

[biggjimm]

I'm in north central Indiana. Typically, it's plenty warm outside when this boat gets wet. However, some nights it might get down to the high 50's or low 60's. At those times it only sees maybe 1000 rpm's as its idle only & we may cruise the lake for 4 or 5 hours at a time.
Maybe I should keep the "warm" set up?

I think it's got a 140° T-stat in it & it never even gets close to running hot, even in the the 95°+ July & August heat.

 

[Lou C]

Didn't they go to the warm manifold style to burn off condensation that forms from cold running in the exhaust and that if not burned off can get sucked back in the exhaust gas passage?
I think Merc was the only one who did this, all the OMCs and Volvos I have ever seen had fully open cooling passages and elbows fed by the water passage, via the manifolds. Is the warm manifold system any more prone to overheats or is that not really a factor?

It sounds like for your use above it might be good to keep the warm system...

 

[Bondo]

I'm getting ready to swap out the old log style manifolds on my '79 260 with a set of center riser manifolds & elbows that I picked up off of an '02 6.2 B-3 set up.

Ayuh,.... Did ya get the T-stat Housin' to go with the newer manifolds,..??

The T-stat Housin' is an important piece of the warm/ cold manifold set-ups,.....

 

[biggjimm]

Bondo, I do not have the t-stat housing from the newer engine.

I figured my original one would be fine if I ran the cooling system like mine was originally. With the warm manifolds.

That was actually one of my next questions, of I changed from the warm set up, would I need the newer style stat housing?

It's looking like I'll probably keep it with the warm manifolds. Unless someone gives me a good reason why I should change it.

 

[achris]

Keep it warm. No more prone to overheating (than cold style) and it does help with getting the engine warm quicker. It also means the manifold aren't stressed as much with a sudden cold water flow.

 

[biggjimm]

OK thanks achris.
One more thing, the hose that takes the coolant from the manifold & returns it to the lower portion of the t-stat housing, should that connect to the port that has the large torx headed plug in it that is just forward of the exhaust elbow?
That is the highest point on the manifold & seems reasonable to me that is where it should be connected???

Thanks again.
Jim

 

[achris]

Yep.