So called normal operating temperature

[Doug R.]

I have a 65' 327/365,I would like to ask the forum what they consider to be hot weather operating temps.,both cruising and city speeds? My car runs around 190* hi-way, and heats up to 220-230*in town. At idle it will kiss the mark for 240*.I just want know if this is par for the course or abnormal. Thanks Doug

[Michael J.]

Re: So called normal operating temperature

Not sure what "normal" is either, but my '64 L76 sticks at 180 highway speeds, and is at maybe 200 in around town stop and go during summer. Mine is standard bore, I have heard some people say they run hotter if bored .030 or more.

[Mike T.]

Re: So called normal operating temperature

Doug - Have you verified these temps with an IR gun or is this strictly from the dash gauges? If what you're seeing is the real deal, unless you are driving around downtown Phoenix with an ambient (but 'dry' ;-) temp of 114, that's really pushing it. At that point, I'd expect you'd notice some coolant overflowing.

[Domenic T.]

Re: So called normal operating temperature

Doug,
If the 240 is real it's to high. I would do what was suggested with the IR gun to start with. Back in 65 we were using 180 thermostats that normally ran at about 190 under normal conditions. In traffic on a hot day they would reach boiling, (not everyone used coolant, it was called antifreeze).
Perfect circle piston rings said that their rings were a exact circle at 180. Temps way over that on a new engine would but the ring end gaps and scrape the cylinders or break the top ring.
That's how they were back then, things have changed with the newer engines.

DOM

[Edward J.]

Re: So called normal operating temperature

I have a 65' 327/365,I would like to ask the forum what they consider to be hot weather operating temps.,both cruising and city speeds? My car runs around 190* hi-way, and heats up to 220-230*in town. At idle it will kiss the mark for 240*.I just want know if this is par for the course or abnormal. Thanks Doug

Doug sounds like your car is running a tad hot, Normal range on my 63 shp is 180 cruising and traffic about 190-195. As others have posted make sure the temp is measured with a infrared gun @ the themostat housing. first and then get back to us.

[Wayne W.]

Re: So called normal operating temperature

If it is heating in town or at idle, but cools down at speed, there is not enough air flow.

Check fan and fan clutch.

[Gary R.]

Re: So called normal operating temperature

I was out this afternoon in my 72 (350) for about 4 hours, it was 90* and humid, the car ran right on 180* no matter what type of driving. c3'S had more cooling issues then c2's but the engine are pretty much the same. I have the carg jetted, timing correct, 50-50 AF mix, the original copper radiator, 180* T stat, correct clutch & fan, and correct seals in place. The temp sender is the original (correct resistance) and installed in the LH head. Years ago with my 67 I had a hot run condition, checked most of the above only to find the previous owner had the sending unit in the intake. Once I moved it to the head it was dead on.

[Doug R.]

Re: So called normal operating temperature

Here's what I have, I installed a new repro. switzer fan clutch,a new Dewitts 316 radiator,rebuilt 326 water pump,fail safe 180* stat,new seal stapled to the shroud,flushed engine block and system and added fresh Go5 @ 50/50.I have taken Duke's advice on timing by rotating the Distributor drive gear 180*,that solved my problem of not having enough advance adjustment because the VAC hit the intake.The supply tank did overflow before I rotated the Distributor gear.The timing now is in spec with initial timing @13* and WOT timing @ 39*.I have adjusted the the Idle vac screws per the shop manual procedure.The IR gun readings @ the seding unit are within 5* so I belive my guage to be correct, also the sending unit is new.It does seem like it is a air flow problem at low speed and idle,when I start rolling at higher speeds the temp. drop to a about 210*. The engine has been bored .060, could these operating Temps. be the nature of my beast? THANKS Doug

[Mike T.]

Re: So called normal operating temperature

Doug - Can you fill us in on the timeline here. Was the engine recently rebuilt and were all these cooling system items replaced because the overheating began right after the rebuild? At face value, I'd say the .060 overbore should have nothing to do with your high temps, unless there was a core shift and you wound up with a thin wall in some of the cylinders. Do you find the temps rising quickly, basically spiking, or is it a slow and steady rise?

[Doug R.]

Re: So called normal operating temperature

Mke, I have had this car since 1990, the engine is a # matching,but it had a lot of wrong parts that I have returned to correct.I had the engine rebuilt in '95 to see what was inside and to freshen -up everything.The engine had already been bored and it didn't need any other machine work.I had the builder put the stock 30/30/cam in and kept all componets as close to OEM as parts were available.I removed the engine in Feb. this year to detail the engine bay and install the correct parts (mostly around the cooling system) that I gathered up over the years trying to return this car to stock.Before I pulled the engine the car had the wrong water pump,fan shroud,radiator,fan clutch, fan(it had a 7 blade),and from what I know now the cam was indexed wrong. The car did get hot @ idle about @220* but never overflowed.The temp now rises slowly @ low speed/ idle but stay constant about 190* @ speed .I have held a peice of paper in front of the radiator while the car is idleing after it is up to temp. and fast idle has dropped to normal and the paper is sucked towards the radiator hard enough to stick if I let go. Doug

[Michael J.]

Re: So called normal operating temperature

All I know is that in my experience, I have never had an engine that was standard bore that ran hot, but all the over bored engines I have had did, even in the exact same make, model, year, and engine types. I know many people who insist on sleeving an engine that is over bored to make sure it does't happen.

[Edward J.]

Re: So called normal operating temperature

All I know is that in my experience, I have never had an engine that was standard bore that ran hot, but all the over bored engines I have had did, even in the exact same make, model, year, and engine types. I know many people who insist on sleeving an engine that is over bored to make sure it does't happen.

Mike ,I don't know if there is enough proof on the over bored engines, My 63 shp and my freinds 63 300hp neither over heat. and run pretty cool. I can say that my 63shp engine has never been above 195, In bumper to bumper traffic. both wire bored one 40 over and the other 30 over.

[Mike T.]

Re: So called normal operating temperature

Doug - When you say the engine got to a hot 220* at idle, has this been the case ever since the rebuild or only since you pulled the engine in February? As to the overbore, I've run 327's that were .030 and .060 and none of them overheated after the overbore/rebuild. Most people don't go to the bother of having their early smallblocks sonic tested for wall thickness and usually don't need to but there is always that chance that there was some core shift and after the overbore one of the walls is a bit on the thin side but it's not that likely. I know you mentioned your timing specs but did you say where you have your vacuum canister connected on the carb? Or does the #2818 Holley only have one vacuum port to use?

[Leif A.]

Re: So called normal operating temperature

Why did you remove the 7-blade fan? Is it the same fan that they used in the '67 A/C cars? If it is, it is a highly efficient fan designed for the extra heat from a A/C loaded engine.

[James W.]

Re: So called normal operating temperature

Hello Doug,

As a comparison, I have a '65 coupe equipped with an L79 and A/C which is almost identical to your L76. I have replaced the radiator with a Dewitt's 316 aluminum radiator, rebuilt the original 326 water pump, installed a new GM replacement Eaton type fan clutch, flushed the block, replaced all hoses & belts and replaced the coolant with the Zerex G05. The distributor timing is set to factory specs and the rest of the ignition components are all original spec parts as is the correct 7-blade fan. My car runs at a steady 180 degrees in town and on the hiway/interstate with or without the A/C on. If it sits in traffic at idle with the air on it may climb to 195 but that is if the air temp is really hot and the car sits at idle for an extended period of time.


Regards,

James West

I have a 65' 327/365,I would like to ask the forum what they consider to be hot weather operating temps.,both cruising and city speeds? My car runs around 190* hi-way, and heats up to 220-230*in town. At idle it will kiss the mark for 240*.I just want know if this is par for the course or abnormal. Thanks Doug