[Formulabruce]

Originally Posted by guccieng

210 is not too hot, but you could stand to lower it.

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...

[GOAT8U2]

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.

[Milwxman]

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?

[guccieng]

Originally Posted by Formulabruce

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.


tranny fluid starts to cook at 200...

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.

[chiphead]

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.

[GOAT8U2]

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.

[gtome]

Originally Posted by GOAT8U2

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?

[chiphead]

It's all in the combination and intent. While a full-race 496 might run great with locked timing for being consistant, a street 389 is gonna run like ***** with locked timing due to low RPM overadvance.

What works for me may not work for others. But I've found that running as much base timing as possible without starter kickback and then 36* total works best for my street/strip engines. The ideal is to have peak cylinder pressure at 12-14* ATDC, which is a function of basic physics, not choice. This means picking a base timing that approaches the ideal at idle, then lighting the mixture earlier and earlier as RPM increases. The rate of the optimal advance for any one engine depends on the parts chosen for that one engine and what that engine is asked to do.

Since a street engine is loaded by moving the car between 1000-4000 RPM, that is where we care what the rate and amount of advance is.

[67bonnie455]

I think it is too hot if your gauge is correct.


I am concerned about the pump. When you pulled it, did you note the condition of the seals on the two tubes that go into the cover? If you pull the pump, make sure they are in good shape and in contact with the divider plate. Jim Hand's book has some good info on optimum clearance for the vane and the plate if you want to check it. Get a good pump with the original large cast iron vane. If you pull a couple of inches of water out the ratiator and bring the motor up to 1500, there should be strong streams out of visible cores (with themostat open). Becareful, it may puke hot water on you when you close the throttle to idle.

There is a lot of good advice here for you on timing and such. I agee with all of these:
Go with a 180 or lower themostat (but after 200, yours should be open).
Set timing correctly.
Get a shroud on the fan; it pulls the air throught the radiator.
Make sure the radiator cap is good and break the motor in some more. The motor I just finished run hotter than I liked for a couple of hundred miles.

Last thought; I have gotten so many bad parts lately that I would not be surprised if it was a bad thermostat not opening up completely or a thermostat with too small of a valve opening (wrong application of a one all fits all unit). It is getting hard to get correct application parts as noted.


The 75-79 carbs were lean. Once you get it running cooler, you may like fatting up the power valve for more midrange power. The carb base gasket and intake carb plate are restricted and not allow the secondaries to open up completely. Easy to fix.

Hope this helps.

[GOAT8U2]

Apparently you're not running vacuum advance if you're wondering how to get to 24 degrees at 1200rpm.

I have 33 degrees WOT at 2500rpm, I then added 15 degrees of vacuum advance so while cruising, I'm seeing 48 degrees of advance around 2500rpm. I gun it at 3k just to make sure my springs have completely expanded by then. Great for mileage, cooling and response.

[SRR]

Originally Posted by 67bonnie455

I think it is too hot if your gauge is correct.


I am concerned about the pump. When you pulled it, did you note the condition of the seals on the two tubes that go into the cover? If you pull the pump, make sure they are in good shape and in contact with the divider plate. Jim Hand's book has some good info on optimum clearance for the vane and the plate if you want to check it. Get a good pump with the original large cast iron vane. If you pull a couple of inches of water out the radiator and bring the motor up to 1500, there should be strong streams out of visible cores (with thermostat open). Be careful, it may puke hot water on you when you close the throttle to idle.

There is a lot of good advice here for you on timing and such. I agee with all of these:
Go with a 180 or lower thermostat (but after 200, yours should be open).
Set timing correctly.
Get a shroud on the fan; it pulls the air through the radiator.
Make sure the radiator cap is good and break the motor in some more. The motor I just finished run hotter than I liked for a couple of hundred miles.

Last thought; I have gotten so many bad parts lately that I would not be surprised if it was a bad thermostat not opening up completely or a thermostat with too small of a valve opening (wrong application of a one all fits all unit). It is getting hard to get correct application parts as noted.


The 75-79 carbs were lean. Once you get it running cooler, you may like fatting up the power valve for more midrange power. The carb base gasket and intake carb plate are restricted and not allow the secondaries to open up completely. Easy to fix.

Hope this helps.

I like my cars set up for worst case scenarios. I like 160 degree t-stats. T-stats establish the MINIMUM temp the engine will be at not the maximum. I like to see my engine temps "around" 180 degrees. On a hot day stuck in traffic I don't want to start at 210. I don't see much of a buffer zone there.