Engine Operating Temps. Questions and Trouble

[jan9898]

New built and modified engine from a local shop, engine seemed to run great but tempature alarm came on a few times. I noticed the tempature gauge would go almost all the way down then back up and sometimes to high setting off the temp. alarm. The up and down cycle of the temp. gauge seemed very wrong to me so I took it back to the shop.

A new thermostat was modified by the shop by drilling holes in it because

After the thermostat was modified the engine has never reached a decent operating tempature and I actually thought I noticed a decrease in performance when getting up on plane in comparison to the way it was prior to hole drilling.

Can a raw water cooled 454 carb. engine never reaching operating tempature cause short & long term issues/defects/problems?

If yes what are those issues?

Thanks

Is it possible that a noticed a decrease in power from the engine not getting up to proper tempature?

 

[JaseBosto]

Re: Engine Operating Temps. Questions and Trouble

I really don't know why your drilling holes in your t-stat to begin with...just install it as is. If your engine is overheating try a new t-stat. Still overheats then there is another problem.
Hook up a mechanical guage when running to verify the engine temp for sure.

What is the deal with drilling holes?!? That is never an acceptable option in my eyes. It's designed the way it is for a reason.

 

[jerryjerry05]

Re: Engine Operating Temps. Questions and Trouble

Fill out the profile.What motor/drive?How old?
What repairs other than the rebuild.
Sounds like there is a cooling problem.How old is the impeller/pump?How old are the manifolds/risers?Circ pump new?
Drilling a thermostat? Not the way to go.Some rebuilders are great at what they do(rebuild) but shouldn't be working on boats.J

 

[Aloysius]

Re: Engine Operating Temps. Questions and Trouble

It's common, and necessary, for thermostats on many marine applications to have a 1/8th" hole in the flange to allow water to circulate when closed. Reason...some applications don't allow ANY circulation close to the thermostat. This means the t'stat pellet is only reacting to the cool water it's in and doesn't open, as the hot water in the block isn't flowing around the t'stat.

What you DON'T do is drill a bunch of holes..just one!

 

[jan9898]

Re: Engine Operating Temps. Questions and Trouble

The engine is new with 50 hours 450 hp 454, new impeller new everything. Bravo 1 drive.

Thanks for all the responses but the real question that i need anwsered is-------Can running new engines for 50 hours way below the proper operating tempature cause serious damage???

This includes 20 hours of break in time before the throttle ever hit WOT.

Thanks in advance

 

[ChrisCraftJohnny]

Re: Engine Operating Temps. Questions and Trouble

What temp is it running at now? Approx?

I would say you are fine. Colder temp will not cause engine damage. Only lower the overall performance/output of the engine.

I would say you want to run that big block in the 160-180 Deg. range.

Rule of thumb: 200 = too hot - 150 = too cold

Place the correct stat in there and you sould be fine.

Johnny

 

[Aloysius]

Re: Engine Operating Temps. Questions and Trouble

older marine engines (flat head) ran pretty cold. I agree with Chriscraft 100%.

 

[Brentathon]

Re: Engine Operating Temps. Questions and Trouble

I wouldn't think it would cause "serious damage", but I do recall from the old college course I took on internal combustion engines......that very cool operating temps could cause premature flame front extinguishing, and thus, incomplete combustion of the charge.......and possibly extra cabon build-up? And I recall similar issues could happen if operating an engine for very extended periods at low (i.e. idle) rpm's......I think...:redface:

 

[bruceb58]

Re: Engine Operating Temps. Questions and Trouble

older marine engines (flat head) ran pretty cold. I agree with Chriscraft 100%.

What marine engines were flat heads? You must be talking about REALLY OLD engines.

 

[Aloysius]

Re: Engine Operating Temps. Questions and Trouble

Easy there big boy..not THAT long ago..nuther remark like that, I'll hit you with my cane..if I can remember where it is.......