["QUICK-SILVER"]

Ignition timing will make these cars run hotter than normal, 220°F-230°F range: Base timing too low, sticky or froze up centrifical advance or bad vacuum advance and temps will climb no matter what you do to the cooling system.

[2manyT/A'S]

Originally Posted by "QUICK-SILVER"

Ignition timing will make these cars run hotter than normal, 220°F-230°F range: Base timing too low, sticky or froze up centrifical advance or bad vacuum advance and temps will climb no matter what you do to the cooling system.

I'd be checking out the timing,etc. BEFORE tossing 2 year old coolant.
You can get away with ALOT more intial timing on a smog (low compression) Pontiac V8
Just keep advancing it in 2 degree increments until it starts to detonate underload going up a hill. Then back it off 2 degrees & you should be in the "sweet spot"

As quicksilver says,retarded timig will make them run hot.
How old is your timing chain?

[ve3wireless]

Originally Posted by 2manyT/A'S

I'd be checking out the timing,etc. BEFORE tossing 2 year old coolant.
You can get away with ALOT more intial timing on a smog (low compression) Pontiac V8
Just keep advancing it in 2 degree increments until it starts to detonate underload going up a hill. Then back it off 2 degrees & you should be in the "sweet spot"

As quicksilver says,retarded timig will make them run hot.
How old is your timing chain?

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A VERY good point, guys --- and checking the timing on the car, admittedly, has NOT been done...at least not for the past 4 years, when I had a minor re-build done on the engine. which INCLUDED the installation of a new timing chain (the old one had gotten "sloppy" after 26 years).

I shall put the touch on a buddy of mine & borrow his light before the end of the week.

Thanks for the tip --- stay tuned...

Eddy
Ontario, CANADA

["QUICK-SILVER"]

Depending upon which 400 you have, 18° or 20° initial timing is factory. 20° is bottom of the tab on 220 hp engine, setting initial 1/4" below the plate is not unusual.

40° plus (initial+centrifical) is not unheard of for these engines, that does not include vacuum advance.

From TDC to 20° is right at 1.25". If centrifical is working right, (watching with timing light), you should gain about that distance when you rev the engine a little, timing mark on balancer should end up 1.25" to 1.5" below the plate.
Vacuum advance hooked up and working, should add close to that distance again.

Just something to go by if you don't have a dial back timing light.

[ve3wireless]

Well, a buddy of mine here kindly loaned me his new Sun timing light this morning, & I went under the hood to check it out...

The factory specifies a timing advance of 18-degrees for my car --- the actual timing was just under 12-degrees.

I re-set it to 18, and left it there. As I advanced the timing, even the idle RPM went up a tad which was OK, because it was lower than the specified 750 RPM on the tune-up label, at 12-degrees.

I should have removed the distributor cap to take a look at the condition & movement of the weights & springs, but I didn't...perhaps another time.

Now I'll be watching the temperature guage to see if the advance has done any good in helping the car run cooler.

Many thanks to all for the very fine suggestions received to date --- much appreciated by your truly!

Eddy
Ontario, CANADA