Ok here's the problem, I have a 67, 427 with about 500 miles on a complete rebuild. The radiator received a new core at the same time and I'm running a 160 thermostat. The car runs about 180 degrees while moving but, as soon as you stop in traffic the temp will run right up to 220 or more if you don't get the car shut off or moving very quick. I tried to take the cheap way out and bought an off brand electric fan off e-bay. What a JOKE!!! When the fan gets hot it spins so slow that it's worthless. My question is what type of fans are you guys using to keep these things cooled down. Where is a good place to order one? I would like to take the fan off the engine. Is anyone having any luck doing this? The radiator core measures aprox 22" X 16".

 

doug dewitt suggests the use of Spal fans with his radiators...perhaps look at his website and or contact him for his suggestion for your application

 

'Doug' DeWitt ?????
Bill

 

1. Where did the new core come from? Does it have the same heat rejection capability as the original? Tom DeWitt has complete original radiators, original cores, and direct-fit aluminum replacements.

2. Do you have the original shroud, fan, and clutch, or are you depending only on an electric fan for traffic cooling? The original shroud, fan and clutch will work just fine; the only electric fan setup that will come even close to moving enough air to cool it in traffic compared to the stock arrangement is the Spal dual-fan setup DeWitt's has.

3. The 160* thermostat isn't doing anything differently than the correct 180* would - it's wide open all the time anyway. Thermostats only control the MINIMUM coolant temperature - operating temperature is a function of the radiator's heat rejection capability and the amount of airflow through it.

 

Dewitts sell the complete Dual Spal setup with controller and shroud and it works great even with air conditioning. I have 572 ci motor and it keeps it at 180 in stop or go traffic or air. I also am using the DeWitt big block aluminum radiator.

 

POUNDING NAILS IN MY WRISTS NOW....TOM...TOM DEWITT...SORRY

 

I am using a Derale Tornado and a Derale control that has a probe to put in the rad fins.

If you want to use a mechanical fan, IMO the stainless flex fans outperform the GM clutch driven fans.

Here's the current status of my cooling system: http://forums.corvetteforum.com/show....php?t=1752309

 

Do you know if your sender and gauge work correctly ? Is the car actually running that hot ? You might want to try an IR gun to get an accurate engine temp. to make sure you're not chasing your tail.

 

"My question is what type of fans are you guys using to keep these things cooled down. Where is a good place to order one? "


A stock fan/clutch should keep your engine cool. You can get a replacement that will fulfill your needs at your Chevy dealer. If you have to go to the extreme of an electric fan, you're treating a symptom, not the problem.

If it doesn't stay cool with a new GM clutch fan, you have other problems. Re-read a couple of the posts above for corrective action.

 

In addition to the excellent advice above, I would try to ensure you have your timing map sorted out.

First take a look at your vacuum advance can. If you can test it with a vacuum pump. It should start advancing around 4" and achieve full advance at a pretty low vacuum (8" or so). It should also hold the vacuum. If yours fails these tests, I think you will probably want an Eichlin (sp?) VC1810. You can get this at any parts store and I believe Napa uses the same part number.

If your vac can checks out, make sure the car's mechanical advance (with the vacuum advance disconnected and plugged) is in the 34 - 36* range once it all comes in. "All in" will depend on your springs and weights. Once you have this dialed in, take a look at your initial timing reading and write it down for future reference and then reconnect the vacuum lines and drive the car. If you continue to have issues, the next step (from a timing perspective anyway) would be to switch from ported to manifold vacuum. To do this, take the vac advance line off the carb and use a tee connector to splice into the manifold fitting on the rear of the manifold just forward of the distributor. If your car has a plug in this location you should be able to buy a vacuum fitting.

 

I think joel67 has you on the right track, after fighting 2 1967 big blocks that ran fine while moving, but overheating while sitting in traffic, having the correct distributor setup is the key. Find someone with a distributor spinning machine that can set your distributor up correctly (correct vacuum, weights, advance, etc).

 

Aftermarket copper/brass radiator short on capacity and/or not enough rows of tubes on the new core in addition to the above suggestions.

Copper/brass rad was only OEM on AC cars all rest were alum.

 

Not being argumentative here but what do we do about all the mid-years out there running around that don't even use a vacuum advance and they don't overheat. SB and BB. Are they broke?

Everybody now knows the extra advance gives cooler exhaust temps but that's only a symptom, not the root cause of the problem.

 

not sure I am with you on that statement; but I do agree that, whatever your C2, the best cooling is provided by an aluminum rad - the GM 3007436 rad, which was used in in the L78 (65 396) and the L88 (67-69) is likely the highest cooling capacity alumn rad that will work well with our C2 applications. Tom D sells it as his p/n 955.

The easiest thing to do would be to drop in one of Tom Dewitt's "direct fit" aluminum rads into your 67 BB (which came with a copper unit originally unless it was an L88) - his p/n A66M will easily outperform the rad that came with the car, even when it was brand new.

 

All BB midyears, with or without A/C, used the same 22.5" core copper/brass radiator (except the '65 396 and the L-88 - they used a 2"-wider version of the stacked-plate aluminum SB radiator).

 

Not saying this is the problem or solution but it is one more place to look, and factory specs can be a little on the low side for initial. My '62 with mechanical advance only gets hot if the initial is less than 10* and total advance of 36*. I believe the factory spec is 8* so if I ran that I'd be sweating it at every stop light

 

This is as important as anything else.

 

The Cooling problem has been solved . To cover all the concerns with the timing I did go over the distributor one more time just to be sure. Everything there was right so I moved on to the airflow concern. I tried to install a SPAL dual 11 inch fan but ran into clearance issues. What I ended up with was a Flex-a-Lite single 16 inch with a full shroud part number 180. This fan fits like it was made for the car and moves 3300 CFM of air. My temp now will not go over 200 even sitting in traffic. If anyone else is thinking about going to an electric fan and would like pictures of the install let me know and I'll try to post some. Thanks to everyone who posted trying to help me out. See you all in CARLISLE .

 

I'd like to see pics of your install. My 69's copper rad with shroud cooled fine while cruising with the mild 509 that was there except it ran hotter than I'd like at idle and stop n go traffic. I had it checked out and it is fine. I'm going to a much bigger than stock hipo 555 in my 69 but like the stock look so I'm thinking of adding an electric pusher or puller fan to keep it cool. Which side of the rad did you mount it to? If you don't want to post em here, send me an email at mshellberg@yahoo.com

Thanks

 

And to add to John's excellent advice, don't forget all of the seals between both radiator and rad support and radiator and shroud. You want the fan sucking air through the radiator, not from your hot engine compartment. I've found Doc Rebuild to have the best ones.