Overheating C-2

[Merrill Anders 32014]

Hey Guys new radiator,new thermostat,check timing,check mixture and all the other stuff that goes with it,run down the road 180 stop at light get into taffic 10 minutes 210 and climbing Do not really want to install electric fan but I think I am to that point. Have been told puller better than pusher but would like to keep it out front more out of sight if possible.What type do you suggest or is their another way

[Mike M.]

Re: Overheating C-2

install an original ac delco temp sending unit before spending a bunch of bucks on fans which probably not needed . few small block c-2's overheat and with what you've replaced, very unlikely its actually overheating--temp sender the usual culprit in giving falsely elevated temp readings. do you have a theromometer to objectivly measure actual coolant temp? see previous posts on this issue on this forum. good luck, mike

[Patrick H.]

Re: Overheating C-2

Also, is the radiator cap correct and new?

Patrick

[Donald O.]

Re: Overheating C-2

Merril,
You said new radiator, is it brass/copper or a correct aluminum DeWitts>? There is a hud=ge difference in the amount of heat that the correct can reject over the aftermarkets.
Are you sure of the temperature? Have you verified it with a non-contact IR type gun on the thermostat housing?
How good is your fan clutch? A good (but non ncrs correct) unit is available from your FLAPS. Or you might be able to get one from Fred Oliva - he advertises in the Driveline or he can restore your original.
Have you checked your water pump? These too can be rebuilt if original.
Have you checked you thermostat for opening at its specified temperature?
Don

[Duke W.]

Re: Overheating C-2

What does "timing check" mean? The initial timing? That's only one point on the timing map.

You need a fuctioning vacuum advance signaled by full manifold vacuum at idle and the vacuum advance specs must be matched to the idle vacuum characteristics or the engine, which is primarily a function of valve overlap. Higher valve overlap requires a more "aggresive" vacuum can that provides full vacuum advance at 2" or more than typical idle vacuum. That's why most SHP engines have vacuum cans that provide full vacuum advance at only 8" because with a 30-30 cam idle vacuum is only 10".

The combination of initial, full vacuum advance, and maybe a couple of degrees of centrifugal if the curve starts below idle speed should yield about 30 degrees of total idle timing.

If the engine does not have a properly engineered vacuum advance there is a good chance it will run hot or overheat at idle. If the radiator and fan are not right on new OE performance, I can practically guarantee you that the engine will run hot or overheat if it doesn't have a proper ignition map.

At least half of low speed overheating problems can be traced back to a poor ignition advance map.

Duke

[Merrill Anders 32014]

Overheating C-2

that has been checked unit is correct

[Merrill Anders 32014]

Overheating C-2

all have been completed

[Jack W.]

Re: Overheating C-2

Merrill - just one personal experience, when my 65 (with 365 hp L76) came to me, it had a BRAND NEW radiator in it (brass) as well as an elec fan and I thought, hmmmm, maybe a good sign, maybe not. NOT a good sign, for I soon learned that the p.o. had been chasing a chronic overheat problem, one that was (I now know) being caused by two different issues: (1) even though the p.o. thought he had ruled out the rad as an issue by having a brand new one installed, when I swapped in a correct Harrison aluminum rad from Dewitts (and ditched the elec fan) the problem almost cured; and (2) fully cured the problem with a dist overhaul/rebuild with correct for my application advance springs, vac can and timing (set that using a total timing method at 2500 rpm). Oh, and I also learned that my temp gauge itself reads about 10 degrees high (determined with an I.R. temp "gun"). Duke and John H and Tom Dewitt himself were all extremely helpful in my quest to get her running cool.

If I had not taken the advice here and on the other vette forums, I would have ruled out the shiny new brass rad as a cause, and never would have thought that engine timing and various advance issues (when it appeared to be running fine) could have also been contributing to the issue. And I would have assumed my temp gauge was telling the truth, and tried to "cure" the problem beyond the point where I needed to.

I wish you good luck, of course, for I know how disgusting it can get driving around with one eye on the temp gauge, and cursing the appearance of stop and go traffic on a hot day, the death sentence!

[Merrill Anders 32014]

Overheating C-2

To everyone a big THANK YOU not their yet but we will try the distributor vac. route