Mercruiser big block V8 cooling question

[NateZ]

So with the stock raw water cooling system on the big block v8's, the exhaust elbows are cooled by the cool water from the front of the thermostat housing, but the manifolds get water from the already warmed water from the block/thermostat. The manifolds would run hot anyway being closer to the source, wouldn't it seem right to have the manifolds cooled by the cooler water? Is it because the manifolds could get too cool and crack or somthing?

Nate

 

[littlebookworm]

Re: Mercruiser big block V8 cooling question

Basically, yes, probably. Just accept that Mercruiser and Volvo have done a great deal of testing, designing, and retesting of their cooling systems to make them work correctly. Why mess with something that works right the first time. Just go boating and enjoy it. Hy

 

[TilliamWe]

Re: Mercruiser big block V8 cooling question

Well, not to confuse you Nate, but at some point Mercruiser changed the cooling system, to do exactly what you are asking, cool the manifolds all the time with the coolest water, straight from the thermostat housing.
My 1997 5.7LX EFI Gen + with a Bravo outdrive only had one hose (on each side) that went to the exhaust. And that hose went to the bottom of the exhaust manifold. It cooled the manifold and then travelled up to the riser and out the exhaust. No hose to the riser at all.

 

[Hansolo99]

Re: Mercruiser big block V8 cooling question

Well, not to confuse you Nate, but at some point Mercruiser changed the cooling system, to do exactly what you are asking, cool the manifolds all the time with the coolest water, straight from the thermostat housing.
My 1997 5.7LX EFI Gen + with a Bravo outdrive only had one hose (on each side) that went to the exhaust. And that hose went to the bottom of the exhaust manifold. It cooled the manifold and then travelled up to the riser and out the exhaust. No hose to the riser at all.

Yes BIG change-COOLER water! Now go boating......