'72 454 running warmer??

[Tom L.]

Hi to all. Over the winter I went through the front end of the car while having the heads off to get the valve guides done. Sooooo much more room with them off. Anyway, since I've done that the engine is running a little warmer than last year under the same conditions. In 90* temps it runs about 190* on the highway and creeps up to about 220* in stop and go traffic. This morning I went for a ride and it's about 80*, ran about 180* at highway speed and crept up to about 210* in stop and go traffic. Not super hot and not losing coolant but it never ran that hot in the past, generally it ran 10-15* cooler than what I'm experiencing now. So here's what I changed.

Swapped my "functional replacemnt" fan for an original "Tipped" fan.

Put in a correct water pump and removed a "FlowKooler" pump

Painted my fairly new aluminum radiator black

Had the heads rebuilt, stock but used Manley Street Flow valves

Everything else is set up the same as last year. I'm not in a panic, I just don't like the higher temps. Any ideas???

Thanks!!!

[Timothy B.]

Re: '72 454 running warmer??

Lynn,

The problem could be the fan, as it may pull less air at low speeds than the previous fan. If the distributor is original and you know the centrifugal specs, increase inital timing so total WOT timing is 40*, hopefully this will help cool the engine.


Your engine probably has a timed (ported) vacuum advance control so you can benefit from a better distributor curve using a manifold vacuum advance source OR a shorter centrifugal curve allowing more inital advance with the ported vacuum control. I am talking 14-18* inital with centrifugal 20-22* all in at 2800-3000rpm.

[Michael W.]

Re: '72 454 running warmer??

Painted my fairly new aluminum radiator black

This decreases the heat rejection capacity of the rad.

[Russ S.]

Re: '72 454 running warmer??

Not only do I have an idea-I have the answer. Global engine warming

[Edward J.]

Re: '72 454 running warmer??

Lynn, you'll get quite a few responses and everyone will have there own opinions. I would start by saying checking the easy things, are the foam seals all in tack around the radiator? a correct pressure radiator cap and releasing at the right pressure, a 50/50 mix of anti freeze, nothing that maybe obstructing the A/C Condensor or radiator(sometimes crude and leaves will slow air flow down in front of the radiator). also as Tim says checking the tune up spec.s and carburator mixture that maybe lean.

Also as you say 220 is not really a overheating condition but a few easy items that may not be correct can help in small increments.

[Dick W.]

Re: '72 454 running warmer??

After fooling with big blocks for.over 40 years I have come to the conclusion if it ain't a pushin' water outta the overflow or not havin' it PV'd fergitaboddait, worrying about the temps ain't worth the effort

[Tom L.]

Re: '72 454 running warmer??

Thanks for the responses.

Tim, I did notice that the "Functinal replacement fan" has slightly more pitch than the Original I put in, it's also evident when runnig. There is much less fan noise. The replacement blade was super loud at highway speeds, made my ears ring after the run to Carlisle a couple of years ago. The distributor is stock and in good working order, I rebuilt it a few years back. Didn't map it though.

Mike, I figured the paint would insulate the radiator to some degree. Didn't think it would make a significant diffrence sinse they're all painted.

Ed, The seals are all in place, except for the radiator support to hood seal (Wasn't there last year either so that hasn't been a change). When I tried to install it whan I did all the others it was too big, made the hood visibly move upward when trying to close the hood, that made me nervous so I removed it. The other items are all OK and there are no restrictions. All these parts were removed and cleaned during the engine bay clean-up this winter. Will check the carb though.

Russ, never considered "Global engine warming". Suppose I'll have to consult Mr. Gore on that

Any thioughts on the water pump?

Thanks again!!

[Timothy B.]

Re: '72 454 running warmer??

Lynn,

My opinion is that the circulator (water pump) is fine, are you confident the coolant level is high enough in the radiator?

If all is in stock configuration and the engine tune is good, I suggest looking at the timing. Does this car have a temperature control switch for the vacuum to the distributor? If so it's using a ported source except high idle temps where the switch will let the distributor see manifold vacuum.

Try setting initial timing with a vacuum gauge to max vacuum at warm curb idle. Just go far enough to get the best vacuum and back off just a touch. After that you need to check the centrifugal advance in the distributor so total WOT timing (initial plus centrifugal) does not exceed 40*, this is important. I bet with the new initial setting the engine temps will cool and the motor runs better. As long as the engine does not have hot start cranking problems with the new initial timing setting it will run better.

I don't think 210-220 in stop and go traffic is a problem but I understand your concern.

[Edward J.]

Re: '72 454 running warmer??

Lynn, I not sure that all rebuilders of water pumps use the old impellers, With kits that some use they will throw the original impellers and use a common stamped steel impeller that may not flow as the originals. If you used one of the NCRS rebuildes they more that likely re-used the factory impeller which to re-used with there bearings will require some machining.

I know that in most cases with other cars theres no problem with the stamped impellers, with C2/C3 corvette they need all the help they can get to keep cool.

[Jim T.]

Re: '72 454 running warmer??

Lynn the first thing that I would check since you mention that temp goes to 220 in stop and go traffic is vacuum going to your vacuum advance. If your vacuum line connected to your vacuum advance comes from a solenoid this is most likely the reason for the temps going up in traffic. Driving the highway the solenoid permits full time vacuum advance, driving in traffic and at idle stopped in traffic the solenoid inhibits full time vacuum to your distributors vacuum advance. Using a full time vacuum source on your carb and a direct line to your distributors vacuum advance should give you better gas mileage in city driving and your 454 should run cooler in traffic. The full time vacuum source from your carb is necessary for full time vacuum at idle to the vacuum advance.