Exhaust Manifold Temps

[SS MAYFLOAT]

On my Bayliner which is I/O (volvo 280/350 Chevy with Marine Power Exhaust manifolds) I have noticed that the exhaust manifolds seem to me that they run a little bit too warm. Engine water temp runs steady at 160 deg.F.<br /><br />The exhaust manifolds are not discolored or show any signs of being overheated, but is it normal that they run hot enough to burn your hand if you place it on the manifold? On my small 4 cyl chevy, it never seemed to run that hot. This is my first 8 cyl. an I am not sure if I have a problem or not. The T-stat is fine, it maintains engine temp as it is surposed to. I do have good circulation coming from the raw water pump.<br /><br />The heat off of the Exhaust Manifolds is not hot enough to ignite anything or melt wires. Just wondering if this is normal or not. Thanks......

 

[Gene70]

Re: Exhaust Manifold Temps

No, the manifolds should not run this hot.To check, remove the risers and inspect discharge flow. All passages should be wide open on exhaust risers at the rear. Check water outlet openings in manifold and risers. If you still have problems you can call me at 1-800-949-2189

 

[Yepblaze]

Re: Exhaust Manifold Temps

I know that if I'm working on an I/O in the yard on a warm summer day in the sun, I sure don't want to lean over and rest my arms on the black manifolds. They do get hot enough to burn just sitting in the sun. Perhaps it's time to borrow an Infared heat gun or starp a thermometer to one to see what temp it's actually at.

 

[SS MAYFLOAT]

Re: Exhaust Manifold Temps

I'm going down to the dock tonight. I'll take my pyrometer and check the heat from front to rear and see if there is any spots that are inconsistant. I'll post later what I find out. Thanks.

 

[russthemuss]

Re: Exhaust Manifold Temps

Heat guns are the best tool in the world! Youll find that a mere 60 celcius will burn your hands.Sure solves all the guessing and worry.

 

[Boatist]

Re: Exhaust Manifold Temps

I agree with Gene70 should not be that hot. Has sea water running thru them, granted when thermostat opeans has 170 water going to them but that is mixed with sea water. When the manifolds start to go bad (4 to 6 years in saltwater if you flush every time) very normal to get rust and scale that plug up output of manifold or riser and restrict water flow. If it gets bad enough motor will start to run hot wide open then cool as you slow down. Also if manifold rust thru water will run back into exhaust manifold and rust exhaust valve or worse yet fill cyl with water then on compression stroke bend rods and sease up engine until you pull plug with water in it.