Good Operating temp
 

I have a 1977 Pontiac 400 out of a Firebird. It seems to run hot. The timing has been set and it seems to climb up to about 210 degrees. What temp is too hot for operating?

It has a freshly cleaned radiator, new water pump and 180 degree thermostat.

Thanks in Advance

Thats gettin pretty hot. I dont like to see mine go over 200. Thats gettin pretty hot for a stock low compression engine.
Have you checked your jetting?
Also there is a mod the guys are doing with the new water pumps that are giving good results. Do a search for that, it should help alot.

My 1994 Olds has always run about 210 deg. My '66 Pontiac runs around 210 deg, but then I have a 195 deg thermostat.

I would not be worried about it.
Doug

210 is not too hot, but you could stand to lower it. stock timing settings were designed around emission requirements, not performance or comfort. you can try to add timing and see if that helps. the ported/full manifold vacuum advance still rages on. many things can help you lower your temps. make sure the basics are covered: coolant level, coolant flow, and airflow.

What are the specific timing specs?

Fan?

Fan shroud?

My Timing was set to factory settings. The manifold is from a 1969 (non-EGR). I have a 6 bladed flex fan and no fan shroud.

Enigine has a larger cam in it. I do not know the specifics, but I was told it was it is similar to the 68 HO cam.

Something I noticed was the oil pressure. At start up it is running a strong 60 psi. After the engine heats up the pressure starts to drop a little. At about 2000 RPMs after warm the PSI is only 40. Could the oil be thinning out too much and lower the lube factor and increase the heat?

I had a buddy that had this build on his 77 400 and he had the same issue. Hot Start and high temps. He added a shroud and it did not help his issue.

I appreciate any insight on this, the engine only has about 60 miles on it after being completely remanufactured.

Youve raised my curiosity. What temp would you expect for 11:1 compression? How much higher?

we need to know what 'factory settings' are for your timing.

You may have several issues here:
1 - you really don't have a 1977 engine anymore. With a more aggressive cam, older intake and higher compression you've duplicated the '68 specs. Go with '68 timing or just play with to a more advance state.
2 - no fan shroud IS a problem. The air needs to be directed through the radiator to cool properly. Do you also have the air dam below the radiator area? That deflects air up towards the radiator. Without it you will lose additional air flow.
3 - oil pressure will always be higher when cold. It will drop when the engine warms up. 40 psi at 2,000 rpm? Could be OK ... compare readings as the engine gets more miles.
4 - 60 miles since the rebuild? They are always tight when fresh which makes them run hotter.. Get some miles on it and that will help.
5 - someone else in this post mentioned waterpump divider plate clearance. The massive post regarding "chalk one up for the cat impeller..." is very long, but very informative. If you don't know the tolerance between the divider plates and the impeller I'd pull the pump and double check. Doesn't take much time when compared to overheating your engine.
6 - you have driven it 60 miles, but how much on the highway and at what speeds? Without a fan shroud your air flow below 40mph probably isn't very good.
None of the above will cost much money ... just time. Best to spend the time and research all possibilities before overheating your new engine.
Good luck.

I am going to get a shroud on it and replace the thermostat with a 160 degree high flow. I know that the water pump is not a cast one and there was some clearance between the pump and the plate.

What would be the proper timing for this engine? I can get that reset, and I hope that helps.

I have been running different speeds. The longest trp was to the NPD Octoberfest car show at Silver Springs this weekend. I had the heater on and the temp was about 190 th whole was there. After there it slowly moved up while in traffic and stopped and waiting. On the way home I was in traffic from the start and it got to about 205-210 before I got moving on the roads. It never came back down from there though.

You can try a thermostat, but that probably won't help. The thermostat is only there to get the engine up to operating temp. A 180 degree stat will open around 180 degrees, but the ultimate operating temp is controlled by other factors after that.
The timing should be set at 9 degrees at idle with the distributor vacuum advance disconnected (mechanical advance only). You may go as high as 12 degrees, but 36 degrees maximum advance at about 2,500 rpm.
190 degrees isn't bad, but 180 would be better. 210 is ok for a modern engine with aluminum heads, but not our old cast iron stuff.
The cast iron, curved vane water pumps work better than the stamped steel units. Pontiac never used the stamped steel ... these are rebuild replacements. You may need to go to several parts stores until you find a cast style. The rebuilders just use what they have available and four different boxes may have different styles. I'd try the shroud before doing the water pump. You need that anyway and it may be the total issue.
Air will go the easiest route ... kind of like water or electricity ... path of least resistance. If it is earlier for the airflow to go around the radiator instead of through it then that's what it will do. The shroud (and air dam) forces the air through the radiator. If you have weak air flow then once the engine temps get high it is difficult for the limited air flow to cool down the radiator.
I always go with the easiest, least expensive path when trying different corrective repairs. Try the thermostat if you want, then the timing, then the shroud and then the water pump ... rebuilds are fine and probably about $30.

No clue? And that was a generalization. Im sure it has to do with more than just the compression.
Maybe we could get someone to throw some shaved 400 heads on their stock 455 and see if the temps go up?

milwxman, good to see a local here. I'm west of ocala, I missed the NPD show, but went to the curise the day before. I agree with the shroud, also check the fan clutch operation. I'd say if it's staying under 210 in traffic your not doing too bad, I have trouuble w/ my '68 in stop and go, but at spee it's ok. tells me it's airflow speed it needs through the radiator, but I'm too poor to get a bettter leec fan. as long as it doesn't go over 210..... in my long quest for cooler temps years ago w/ this car, also found water pump spped to be a factor. while "parts swapping" you may have changed the water pump speed. although I don't use it now, when I had my electic water pump drive hooked up (1500 rpm ) the car ran cooler. FYI there's a few pontiac guys who come to a cruise at the dunnellon sonic on rt 41 every thursday at 6pm.

If you have an automatic 210 is TOO HOT
ask any 3rd gen Firebird owner. No offence meant, its just I hate to see trannys cooked.
keep in mind that a Thermostat rating is "static" so it doesnt FLOW full open till 9-10 degrees HOTTER than that rating. I would use a 170, or 160 if in the south.
A 170 flows full at 180@ roughly..
tranny fluid starts to cook at 200...

To expand on gtoformula here is what I have and run 170 all day long.

Manifold Vacuum with Vacuum Advance
9 initial
48 cruise
33 WOT all in at 2500rpm

Electric fans start at 180 and I have a 170 Thermo. I have a feeling your factory timing specs use ported vacuum and very little advance timing making the car run hotter than it should.

Get the shroud and do searches on here about the fan shroud, many aspects to keep an eye on concerning fan and shroud clearances/distances etc.

I want to say that the timing was set at idle to 12 degrees. Do you guys think this is too high and could be causing my extra heat?

most engine temps are taken from the head or intake by the water outlet. this is the hottest coolant temp in the engine. the trans cooler is on the outlet side (or cool side) of the radiator and usually 20 or more degrees cooler. if the engine is reading a max of 210, the tranny shouldn't be over 190, which is ok for an automatic. they came from the factory running this hot. :2cents:

I've read here that stock thermostat in pontiacs was 180-195 depending on year. 210 isn't too hot, but it's on the boderline. 215 makes me real nervous, 220 I'm looking to pull over, at 225-230 you risk detonation/boilover and 230-above is gonna blow a headgasket or crack a head.

I had a P350 that used to run 200-220 all the time. It hit 230 once and blew the headgaskets. I put it back together and it ran, but the rings were hurt and it started to get weak and lose compression.

Tuning is very critical on these engines and it would take paragraphs to explain it all in one post. I'll condense in a nutshell:

12-14* base timing, 36* all in by 2800 RPM
You need a 4-core brass radiator minimum, 2-core aluminum better
Cast-iron impeller waterpump with good divider plate clearance
fan shroud, high-lift flex fan or 7-blade stock fan and HD clutch
160-180 high flow thermostat and good hoses. 16lb radiator cap and puke tank.
25% antifreeze if in warm climate, 40% in colder climates
verify carburetor is not lean anywhere in fuel map.
Verify sparkplug selection and heat range and gap.

Low timing makes the engine run HOTTER, you can prove it with an EGT gauge as timing causes the EGT to go down. And usually your car idles more than cruising so running 8 to 12 degrees at idle is an easy way to heat up the cooling system on a Big Block. Modern era vehicles have this timing due to emissions, not cooling.

IF you have vacuum advance and an adjustable Mechanical Advance Distributor, I don't see the reason in running anything higher than 10 degrees initial/base. The higher initial timing will cause starting issues on higher compression motors and when the engine is hot and possibly heat soaking the starter. Ever since I went to this method of timing I've never had an issue starting after a long drive on my 11.3:1 compression engine.

I have 24 degrees of timing at 1200rpm, this will ensure that the timing is lowering the EGT at idle and reducing the demand of the cooling system. Those who lock out the timing at say 34 degrees will add they notice a HUGE difference in idle temps over their old Ported Vacuum setup.

So you are saying run 10* initial and 24* by 1200 rpm? If so how are you getting the extra 14* in just a few hundred rpm?