Do they ALL overheat?
#21
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if your radiator is indeed original you are on borrowed time. if its a copper/brass replacement it is not as efficient as a stacked plate aluminium
#22
Team Owner
Neither my C1 or C2 small blocks have ever even seen 200*, 190* is a rare occurrence and this is in traffic in Orlando during the summer...
Has the engine been bored out ??
Has the engine been bored out ??
#23
....and since I'm on this subject, I really don't know how to see IF the fan clutch is working correctly. I have heard that blowing air on it from my air compressor against its rotation when the engine is up to temp will stop it from turning if it isn't working correctly. Has anyone tried this?
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silverado69vette (02-11-2019)
#24
Team Owner
Nonsense - here is what the top rebuilder of our fan clutches says:
http://www.kirkconnellcorvettes.com/q---a.html
http://www.kirkconnellcorvettes.com/q---a.html
#25
That's good stuff, Frankie. I just read it. I didn't know the difference between big block and small block fan clutches. Hmm, I wonder if moving the fan 1/4" farther into the shroud by using the big block fan clutch would help lower engine temps. ....just a thought. I wonder if anyone has done this.
Thanks,
Bob
Thanks,
Bob
#26
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That's good stuff, Frankie. I just read it. I didn't know the difference between big block and small block fan clutches. Hmm, I wonder if moving the fan 1/4" farther into the shroud by using the big block fan clutch would help lower engine temps. ....just a thought. I wonder if anyone has done this.
Thanks,
Bob
Thanks,
Bob
#27
Team Owner
I run a 7-blade BB fan and a Hayden 2747 "truck" fan clutch on my '63 along with the '67 A/C car rubber upper seal (it'll fit any midyear with some trimming). All this ONLY because I added aftermarket A/C - I prob didn't need to do it...
Dr Rebuild sells the correctly molded flap and the clips to mount it.
HOWEVER - you shouldn't have to resort to this - you have something else going on..
Dr Rebuild sells the correctly molded flap and the clips to mount it.
HOWEVER - you shouldn't have to resort to this - you have something else going on..
Last edited by Frankie the Fink; 02-10-2019 at 04:54 PM.
#28
Race Director
A temp of 180 going down the road indicates your radiator and basic cooling system is fine. A 230 temp at idle means you are not pulling enough air through the radiator core to get rid of the engine heat. Simple as that. You need to pull more air through the radiator core to solve your problem.
However, if for some reason the water pump doesn't pump much if any water at idle, it will also over heat.
Its kind of messy, but disconnecting the upper hose from the rad while the car is warm (not hot) and starting it up at only idle speed will verify good water flow or not.
Doug
#30
Lot's of really good stuff stuff ...and advice here. I really appreciate all of it.
Yes, I did pressure test the system. All seems good.
Thanks Frankie for the BB fan and 'truck' fan clutch ....AND AC car seal info and photos. That could be very useful info. I didn't know about the AC car 'seal'.
The weather here is still cool so I think that I won't pursue fixing this problem that might not even exist until the advent summerlike temps.
I will live with what my owner's manual says and not attempt to fix something that might not be broken. ....at least until it is.
Thanks to all,
Bob
Yes, I did pressure test the system. All seems good.
Thanks Frankie for the BB fan and 'truck' fan clutch ....AND AC car seal info and photos. That could be very useful info. I didn't know about the AC car 'seal'.
The weather here is still cool so I think that I won't pursue fixing this problem that might not even exist until the advent summerlike temps.
I will live with what my owner's manual says and not attempt to fix something that might not be broken. ....at least until it is.
Thanks to all,
Bob
#31
Drifting
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I never hear much mention of adding an electric pusher fan to a c2, but it would seem like an easy thing to do that would add a level of reassurance that you can always flip a switch and cool the motor when needed? I know the purists dont go for things like this, but i wouldnt mind it myself.
#33
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[QUOTE=Rob_64-365;1598854590]I never hear much mention of adding an electric pusher fan to a c2, but it would seem like an easy thing to do that would add a level of reassurance that you can always flip a switch and cool the motor when needed? I know the purists dont go for things like this, but i wouldnt mind it myself.[/QUOT
You want a sucker fan not a pusher. A pusher fan is just more blockage of the radiator.
You want a sucker fan not a pusher. A pusher fan is just more blockage of the radiator.
Last edited by 68hemi; 02-10-2019 at 06:21 PM.
#34
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You can test air flow with whatever fans you can gather or I even used electric leaf blowers. If you can get the temp down with "artificial" wind then it's a inability to reject the heat back into the environment.
Water can either move too slow or too fast, (flamesuit on) I prefer a 192* TS.
Or heat rejection from the radiator.
Water can either move too slow or too fast, (flamesuit on) I prefer a 192* TS.
Or heat rejection from the radiator.
#37
Former Vendor
Trust me when I say I have solved this HUNDREDS of times because that's what I did for the last twenty years. The forum will throw dozens of ideas and suggestion on how to solve this issue, the problem is where do you start? Well, the natural reaction to slow speed and idling problems is to suspect air flow. Air flow is vital to a cooling system but the symptoms of idle overheating are almost always a timing issue, and by timing I mean the distributor map and advance function. Of course you want to make sure your engine driven clutch is working and going the right way and all the obvious stuff but don't let that get you off track and onto special mods and stuff. I just posted this comment on a C3 thread, so I'll cut and paste it.
This problem is real easy to check....
A: Get set up with a timing light and check the timing as specified in the manual. Before disconnecting everything, plug the vacuum hose back onto the distributor and the timing will jump an additional 15-18 degrees over the static timing. If it doesn't, you have a problem.
B: This overheating problem is real easy to prove...
If the timing does not increase 15-18 degrees, then simulate the advance function by turning the distributor. Add the 15-18 degrees manually but do not drive the car. Let it idle and see what happens then. You should be able to idle for 45-50 minutes with no issues. Again, do not drive the car like this. Change the timing back to the static setting before driving and get a new vacuum can and/or fix the problem.
You might have a good vacuum can, it might just be the wrong one. The difference between these timing issues and all other cooling problems is that this one MAKES heat. Well, it actually transfers it from going out the exhaust and into the coolant. All the others just limit the cooling function whereas you run 10-20 degrees hotter, not 30-40.
I am still not sure you have a good radiator in there. It should be some form of aluminum, either the correct 3155316 or a good replacement aluminum. See DeWitts 1249063M as an option. I like this one because it is equal in performance, Black color, and only cost $825. Not show correct but a real good performance radiator.
This problem is real easy to check....
A: Get set up with a timing light and check the timing as specified in the manual. Before disconnecting everything, plug the vacuum hose back onto the distributor and the timing will jump an additional 15-18 degrees over the static timing. If it doesn't, you have a problem.
B: This overheating problem is real easy to prove...
If the timing does not increase 15-18 degrees, then simulate the advance function by turning the distributor. Add the 15-18 degrees manually but do not drive the car. Let it idle and see what happens then. You should be able to idle for 45-50 minutes with no issues. Again, do not drive the car like this. Change the timing back to the static setting before driving and get a new vacuum can and/or fix the problem.
You might have a good vacuum can, it might just be the wrong one. The difference between these timing issues and all other cooling problems is that this one MAKES heat. Well, it actually transfers it from going out the exhaust and into the coolant. All the others just limit the cooling function whereas you run 10-20 degrees hotter, not 30-40.
I am still not sure you have a good radiator in there. It should be some form of aluminum, either the correct 3155316 or a good replacement aluminum. See DeWitts 1249063M as an option. I like this one because it is equal in performance, Black color, and only cost $825. Not show correct but a real good performance radiator.
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#38
Team Owner
Makes me wonder how my dual point 61 distributor without vacuum advance kept the engine cool back in the day..
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GTOguy (02-11-2019)
#40
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