[ve3wireless]

Awhile back here a reader raised the point that running a car WITHOUT a thermostat was self-defeating, in that the coolant flowed through the system far too quickly for the radiator to do its job properly...

I ran this by a friend who used to run laps on the Mosport Raceway here in Ontario with his 1960(?) Austin-Healey...he agreed 100% with that point, and even went on to show me an actual after-market coolant "restrictor" that the racers would place into the thermostat housing to slow the coolant flow (It looked like a sort of a miniature brass bullhorn.) He went on to say that his coolant temperature was 180F without the thermostat --- once the restrictor was installed in its place, the temperature stayed at an even 160F all day long at the track...

Anyway, I removed the spring and all of the "innards" of an old thermostat that I had here (yet ANOTHER suggestion from a helpful reader!), and installed the remaining brass "receptacle / shell" into the housing, along with a fresh gasket, to act as an ad hoc restrictor in my '78 T/A.

I guess I'll see what develops here in the coming days with the coolant temperature, as warmer weather approaches southern Ontario...

Eddy
Ontario, CANADA

["QUICK-SILVER"]

Stock car racing, a long time ago, we had stainless steel plates that fit the thermostat hole and had different size holes in them. We used a different size hole depending upon air temps and engine temps. Had them in 1/8" increments that ranged from about 5/8" up to 1&1/8th inch.
FWIW

[ve3wireless]

Well, I can see that I have still more work ahead of me here re. the cooling of the '78...

I just returned from a roundtrip visit to the town next to us here---some 15 miles or so, away---and it is HOT outside. I stuck to the secondary highway (maximum speed = 50 mph) & the city streets, and in the stop-and-go stuff the temperature of the coolant wanted to edge just above 220F on my guage.

It crept down just a little below that marker with steady driving at 50 mph.

Next step: flush the system, then dump the Prestone "lemonade" that's in the car now, & replace it with an old-fashioned ethyl-glycol blend designed for older cars like mine...

Eddy
Ontario, CANADA

["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?

[Colin]

Originally Posted by "QUICK-SILVER"

Stock car racing, a long time ago, we had stainless steel plates that fit the thermostat hole and had different size holes in them. We used a different size hole depending upon air temps and engine temps. Had them in 1/8" increments that ranged from about 5/8" up to 1&1/8th inch.
FWIW

Yep, you can still buy those. Im pretty sure Summit or Jegs has them. I know for sure Speedway has them.

[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?

**********************************************

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

[Don 79 TA]

something else to consider is to make sure you are not running the carb lean
timing and total timing also play a crucial part
air flow does too and of course the approriate thermostat
you want a stat to keep a closed system, this way the fluid in the rad has time to cool off
kindda hard to understand, but after learning the lesson with the Jeep, i know it now
hence the reason alot of cars have smaller radiators now (well technology also helps too)

if you don't need an original pump, check out the high flow pumps and balanced sleeved thermostats too