Logo
FULL SITE MENU

327 F's water temp too low

D

dcbullington

Contributing Member
I have a pair of rebuilt 327 F's with new thermostats installed. When I first ran the engines they would run at around 135 deg F (thermostats are 160 deg). After I broke them in, I can't get more than 100 deg or so even at WOT. I re-checked the thermostats and they seem fine. I got a set of 180 deg thermostats but I'm wondering if there is some simple problem I'm overlooking (i.e. bad ground on gauges, etc)?

Dave Bullington
St. Charles, MO
 
If engine has 160 degree T'stats it should run close to 160 degrees, not 135. I'd look for an electrical system problem. You could always buy or borrow an IR temp gauge to see what the temp really is at the t'stat housing.
 
Thanks for the input. I bought an IR tester a few weeks ago but I haven't finished painting the bottom yet so I haven't had the opportunity to test it. If the temp is right I will look into the gauge issue, but since it's happening on both engines, I wasn't sure if the same ground goes to both gages.

Dave bullington
St. Charles. MO
 
Actually... the ground for the gauge's circuit is the engine block. +12 is fed to the gauges and a "sense" lead goes from the gauge to the sensor. The circuit is completed to the block thru the sensor.
 
Are you running Raw Water in Salt Water, or a Closed Cooling system?

If Raw Salt Water, you shouldn't be running more than 130 degrees as higher temperatures will cause trouble with the Salt Water.

Bruce
 
I'd check with the IR meter first. Its unlikely that both sensors died in the same way at the same time. Do these engines have the original Chris manifolds/elbows? The F series engines I've worked on (283FLV and 305FLV) have an unusual cooling system (Thermocon Develvo) and sometimes mechanics "re-engineer" these systems when putting on generic manifolds/elbows and things don't ever run quite right again.
 
sandkicker said:
I'd check with the IR meter first. Its unlikely that both sensors died in the same way at the same time. Do these engines have the original Chris manifolds/elbows? The F series engines I've worked on (283FLV and 305FLV) have an unusual cooling system (Thermocon Develvo) and sometimes mechanics "re-engineer" these systems when putting on generic manifolds/elbows and things don't ever run quite right again.
Click to expand...

To the best of my knowledge I believe the manifolds are CC, not too sure about the elbows. Also, I had to replace the intake manifolds on both engines due to the rusting through problem created by the exhaust passage intended to warm the intake air. I had the replacement manifolds (very hard to find btw) modified to close off that passage. Do you think that could be the culprit? Also, on just the starboard engine, if I run it in very cold weather I get condensation in the block after a few days which turns the oil milky. If I change the oil and run the engine in the summer (65+ deg) I do not get any water build up in that engine. The port engine does not have any issue with this, regardless of the ambient temp.

Dave
 
Condensation is one of the side effects of the oil in the engine (and the whole engine) not getting warm enough. Problem should go away when you get the engine to run at correct temps.

That said... There are supposed to be a pair of pressure relief valves in the water system. They are usually mounted directly to the exhaust elbows with a line fome each to the T'stat housing. If these are missing or failed in the open position, this could cause the engine to not warm up enough.
 
sandkicker said:
Condensation is one of the side effects of the oil in the engine (and the whole engine) not getting warm enough. Problem should go away when you get the engine to run at correct temps.

That said... There are supposed to be a pair of pressure relief valves in the water system. They are usually mounted directly to the exhaust elbows with a line fome each to the T'stat housing. If these are missing or failed in the open position, this could cause the engine to not warm up enough.
Click to expand...

OK, I will check it out as soon as I can, once I get the bottom done and the boat back in the water. This is the first time anything has made sense as to what the *%&$#& may be going on! Thanks very much!

Stay tuned.....
 
Having a boat is never having to ever wonder what to with a spare dollar or a spare minute...

re: t'stat... I seem to remember (it's been awhile since I owned an "F" series) but I believe that there is supposed to be a plastic insert in the housing that seals the gap between the cylinder of the t'stat and the housing. If missing, likely to mess up water flow in some way. If I'm misremembering this, someone please correct me.
 
Friend of mine with a 19 ft Lancer got fed up with the Thermocon Develvo thing and the special CC manifolds. I was able to help him convert the cooling system to run with "standard" parts and still keep the "warm" manifold feature of the T/D system.
 
I have some updated information. I spoke to the shop that re-built the engines and they admitted that the new t-stats they used "might not" have been "exactly" correct. They said they had a lot of trouble finding NOS replacements and used a unit that was "pretty close".

I have a pair of 180 deg NOS t-stats I found online. As soon as I get the boat back in the water, (approx. 2 weeks) I will change out the t-stats and also the pressure relief valves.

Stay tuned....

Dave
 
Update....

Got the boat back in the water. Ran the engines and checked with a digital thermometer. Both are running around 135 (t-stats are 160) at the t-stat housing. I pulled the housing and the seals were missing, allowing water to bypass the t-stats. Got some new seals ordered.

We will see....
 
135* is a very low operating temperature, IMO.

Do not forget that if Raw Water cooled, and IF running in Salt Water, you will have "Salt Crystallization" issues to consider as for engine operating temperature!
Salt crystallizes at/near 145* or so...... so if RWC, and in S/W, the stat selection should be offering engine temperature of around 145*.... and no higher!

If River/Lake....., or equipped with a Closed Cooling system, you will want operating temeratures closer to 160*/170* or so.

Just a heads up on that for you. :)
 
I was having trouble with my Temperature Gauge, and using a Laser Temperature unit, I have found that the Gauge is reading 28 Degrees F higher than what the engine is.

I have now converted to Closed Cooling for the engine, using a 180 F Thermostat, and mounted the H/E in the vertical position, and at the moment, everything seems to be working beautifully. More testing to be done, as I have retained some of the Thermocon Develvo's function, but life wouldn't be good if everything went according to plan.

Bruce.
 
Bruce,

What was involved in converting to closed loop cooling? Is there a kit available or do you have to wing it? What was the approx. cost involved?

Thanks,

Dave
 
I did some research and found that the "normal" operating range for the 327 F with raw water cooling is 130 - 150 deg so I think I am OK on Temp.

As for the milky oil, I pulled the intake manifold and found both fwd water passages leaking into the block. Replaced the gaskets and the problem got worse. I talked to an engine re-builder and he suggestd I have the mating surfaces re-ground by a machine shop. I had that done, re-installed the manifold and to my surprise, there is no water in the oil (so far). I have ran the engine about an hour under no load (the Mississippi is flooded so we can't take her out right now, go figure!).

This has all been good expierence but unfortunatly expierence is what you get when you don't get what you want! :cool:

Dave
 
Back
Top