440 Running cool

[mopar367]

I finally got my truck on the road with the 446/ 727 I rebuilt. So far all is well. Has ridiculous amount of power hehe . Just wondering the temp gauge reads like 150 after like 30-40 mins of running. That's without a fan shroud. Should I change thermostat to get it to run hotter? or is it fine running cool like that? Performance wise.

 

[Budnicks]

That is a little cool, is the water temp. gauge an accurate one ??, what temp. sending unit are you using ??, where is the temp. sending unit installed ??, also don't wrap the sending unit in Teflon tape it will give it a false reading, in layman's terms, they work as a ground for the gauge, that varies the resistance basically... what temp. thermostat does it have ??, the oil temp is really more important at low temp.s, than water temp. is, try a 180* thermostat or 190* maybe, in the winter if your driving the truck still, your heater & defroster won't be very efficient with 150* water temp.s... What carburetor is on it ??, what jetting does it have ??, what ignition timing ??, does it have a performance camshaft ??, what kind of fuel ??... Sometimes that low of engine water temp., it will make the engine run a little on the "fat" {rich fuel} side also... I'd say drive it some, let it break in, change the oil, to your regular oil, if it's still too cool, then go to a higher temp. thermostat &/or thinner viscosity oil... It's allot better to have it run cool, than too hot...

 

[mopar367]

That is true rather cool than too hot. It is an accurate gauge, and my oil psi is pretty high too like 80 when cruising. So i think its a bit thick because its cool. It is a 446 906 heads, 8.6 compression with flat top pistons. .455/.455 cam and torker on top with a 600 holley. Its not running rich either plugs are light tan colour. Guess Ill let It break in more and play with the thermostat, I think it has a 165 on it now. Would you agree that 180 is optimal operating temp?

 

[RustyRatRod]

Proper operating temp is around 200*. It should have a 195* thermostat.

 

[67 B-body]

I like 180* myself.....
Funny,,,,,, this argument/discussion is usually had when people are having issues keeping there rides cool enough, not too cool!!!! Lol!!!!

 

[mopar367]

Ya I know it is funny it is the other way around. It was running real hot when I first ran it. But now its super cool. I can believe it. Guess ill put the 195 Thermostat back in.

 

[FatJack]

If it is running 150 or so be sure you use a light weight oil. 0 W30 or 10W40

 

[bigmanjbmopar]

I run a 180° stat and it gets to 195°-210° then opens and stays at 180° running 10W-40 brad penn oil. compression ratio is 9.6:1

 

[mopar367]

YA that is a good idea on the thin oil. My pressure is pretty high.

 

[Cranky]

Modern oils are designed to run at around 180 minimum and will still do well with temps in the 210+ range. Newer cars came with a 195 stat and I believe the new cars are even a bit higher. If you do short trips, your oil will build up more acids because it won't be getting hot enough to boil off the normal moisture and combustion blow by that occurs during the warm up process of the engine. Running 210 is actually better than running 150-160 but I'm usually happier with 185-190.

 

[tpodwdog]

Rat....we DOOOOOOOO think exactly alike ! 195-210 is perfect!

 

[mopar367]

I put the 195 stat in, gonna test drive see how it is. I was worried about my distributor/oilpump drive shaft. I heard the hex end can shear off with extreme oil pressure. I was around 80 while driving

 

[RustyRatRod]

You shouldn't have any trouble with the oil pump drive shaft unless you have a non HP shaft on a high volume pump. That's a pretty big no no. Cheap as they are, it's good insurance to replace with every rebuild.

 

[mopar367]

Ya it isn't a high volume pump . I think it is a melling stock replacement, So I put the 195 stat in now it runs at 175 according to the gauge. But the header is close to the starter and doesn't start good when hot.

 

[Budnicks]

If it isn't one problem, it's another, freaken cause & effect...LOL...

 

[mopar367]

I think my timing might be too far advanced causing it to run really cool, and hard to crank when hot like that.

 

[coloradodave]

What is your initial timing? Total timing? Are you using a vacuum advance? Is it connected to full manifold vacuum? Answers will help diagnose the problem.

 

[Cranky]

Did you modify the head gasket water passage ways any? Head gaskets have a slit to control the flow from the block into the heads and if you modify them too much, you can create a too cool running engine but I would think there is another problem like your gauge reading isn't on the money. What type of gauge is it and how did you verify it to be accurate? And timing that's off in either direction can make it run hotter if it's off enough but I've never really had heating problems from having a lot of advance when there wasn't a heating problem to start with....if that makes sense.

 

[mopar367]

Well my initial Timing was at like 16, I adjusted it down to 13. It seems better. My vacuum advance is hooked up to carb port vacuum. And distributor has stock advance springs. I read somewhere that when you are running your timing too far advanced that It can be hard to start when hot. Thats why I figured that was my problem.
Cranky I know what you mean about the head gasket slits. But I didn't modify them when I installed them. The gauge Is just a 3 pod mechanical gauge set. I got it from local parts store. I had it on my smallblocks for a few years and It appeared to be accurate. Read about 190 on them. Maybe because the coolant sensor is mounted on the waterpump? Instead of the intake like a smallblock. Could be causing it to read lower.?

I really appreciate the responses, seems like the more I play with it the better it runs. And your suggestions always help.

 

[coloradodave]

By 'carb port vacuum' do you mean 'ported' vacuum, where there is no vacuum at idle? Have you ever checked what your total timing is with the vacuum advance can disconnected? Short of checking the above, the best way to 'wing it' is to advance the timing a little at a time until either it 'labors' to turn over or it 'pings' on acceleration. When you get to that point, retard it a little at a time until the problem goes away. BTW, if it pings (detonates), get off the throttle right away. Unless the motor is emissions controlled, it will run better, cooler and get better mileage hooked up to full manifold vacuum (vacuum at idle).