Marinette Boat Forum

how hot does your exhaust manifolds get on a 440 ?

Hot! I know ur supposed to be able to touch them. My engines have plenty of water flow and I'm sure these old manifolds are in the best shape and water may not be disbursed as evenly as it should be. With that said many people say replace them every ten years. I've run the shit out of these and its nit hurt anything. Hoses don't over heat, mufflers are good. I wouldnt worry about it unless they are smiling the paint off.

Ironically, I was planning on bringing a laser temp gun on the boat this weekend to check a few things. I will report back my findings.

Whether going fast or slow I can always hold my hand on the manifolds for 2 seconds or so. The elbows and hoses are quite noticeably hotter which I may need to look into.

Raw or fresh water cooled? Fresh water are much hotter for sure.

"...Fresh water are much hotter for sure..."

about 20 degrees

On my old boat (RWC 360s) they ran about 140 degrees at idle. The temperature alarms were around 200 ' F and never went off.

Hope that helps.

Jeff

"Temp alarms".... How fancy! Nice add on! You will have guys on here looking for their alarms

They were on my 1974 32' with 318's and my present 1975 37' with 360's came from Marinette with them. I believe
Probably came from Chryler Marine as standard equipment.
bill

Hey, they came with 'em! Temp switches (not sensors to run a gage) are located in the riser and intake manifold of most Ms I've seen (and all Chrysler powered ones). The stock unit's trip point is around 180 ' F. These are $$$ so (being a cheapskate) I use stock GM units that trip at 200 something. I added a third temp switch in the other riser, just to be sure.

Cool Jeffie

Can't tell you about 440's but with old 318's with NEW exhaust manifolds they're running in the mid 130's. That's at 2400-2500 rpm's with no thermostat's, in the next couple weeks I'll install 140's, don't expect that will change much though.