# Electric cooling fan?



## kjk990 (Sep 1, 2010)

I have a 67 GTO the 15.5" radiator. The engine is a 400 from a 69 firebird (according to engine numbers). The cooling fan is 20" seven blade fan which possibly came off a 70's charger (according to numbers). I have no fan shroud.

I just had the engine rebuilt and during the break in I began to overheat. I shut it down and let it cool off. refilled the radiator and tried again this time the the radiator cap off. when I got to 180 degrees I saw the fluid moving through the radiator. I topped it off but after about 5 minutes at about 2000 RPM I was over 200 degrees. I shut down and called my machine shop. He asked about my fan shroud and suggested I get one.

Long story short I looked on line to buy a fan shroud which cost $60 - $100. But I would also have to buy the correct fan which is $100. Added all up with shipping I am around $200 for a stock system. 

Has anyone tried an electric fan? If so, do you like it? do they work well? I know they are not stock but I am more about drivability.

Thanks 

https://picasaweb.google.com/InesKaney/67Cabra#


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## Eric Animal (Oct 28, 2007)

IMHO...I would use the stock set up, with the shroud. Electric fans are nice if you need one.... It sounds like you might have other issues: like,timing, air in the new system, or improper waterpump plate clearances. None of these are a big deal to correct. You need to diagnose the problem before you can cure it. Eric P.S I checked out your pics, nice work!


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## kjk990 (Sep 1, 2010)

I have heard people say there may be air in the system. Is there a way to remove it? 

I'm thinking about pulling the new water pump and bang on the plate with hammer to bring it closer to the impeller. I checked it when I put it in. On one side it was about 1/16. But the other side is larger, a little less than 1/4. I should have done it when I installed it.

I talked to Vic Hubbard (local performance parts store) they said new engines run hot. One guy said 220-230 degrees would not be abnormal. Another disagreed and said 212 degrees was the magic number.

Thanks, It's coming along. just need to figure out this cooling problem and some paint.


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## Eric Animal (Oct 28, 2007)

Look familiar????:cheers New engines sometimes do run a little hot....to purge air: just keep topping the radiator, run at varied RPMS, and look to see if the upper hose is HIGHER than the rad fill...if so, push it down and squeeze it and see if you can burp any air out. The water pump clearance seems to be a big issue....Keep us posted and Good Luck, Eric P.S. 200* at 2000rpm isn't too bad. Clearance the pump, get a shroud, and drive the car...see what happens Also...is your temp gauge accurate?


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## jray1 (Jan 2, 2008)

I am running a 16" on my 68 400 and it works great . I built a shroud out of a sheet of aluminum and added a fan thermostat although I am changing to an adjustable thermostat shortly as it is getting warmer outside.


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## GTO JUDGE (May 14, 2005)

Drain enough to add a bottle of Water Wetter.
IMO... Electric fans on a stock motor is masking a running hot problem. The additional fans is fighting a hot issue rather than having the engine run at its optimum. I have seen some hideous added on fan set ups. Rather than correct the issue they add additional fans. Personally for a stock motor I'd want to know what is causing this and correct it rather than add additional parts to fight it.


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## geeteeohguy (Feb 2, 2008)

My vote is for a stock clutch-type fan and a fan shroud. I also prefer 160 degree 'stats. Normal operating temps for these engines is 180-230 degrees. If it's running at 215 on a hot summer day all is well. "212" is not the magic number....merely the boiling point of unpressurized water at sea level. There's a reason cooling systems are pressurized...."modern" cars are set to run at 220 degrees most of the time. More efficient. Fan shrouds on these cars are a huge help.....the temp on my '65 went down 15-20 degrees across the board when I put a shroud on it recently.


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## kjk990 (Sep 1, 2010)

Thanks for all the comments. I am going to try adjusting the pump plate and then burping the system first. If there is no change I will try a new fan and shroud. Judge that is a good point about masking a running hot problem. 

I have not done much with the timing because I have been keeping the RPMs up and more focussed on the temp gauge, which I don't know how accurate it is (Eric). Can adjusting the timing lower the temp. 

I have also read that running an engine rich will lower the temp. How do I do that. I have an edelbrock 650 CFM carb which worked fine before I had the engine rebuilt. How do you adjust it rich? 

Thanks again for all the advice.


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## kjk990 (Sep 1, 2010)

I took the pump off and adjusted the plate. I got it as close as possible and reinstalled it. Tried again and the same thing. I turned it off at around 220 degrees and it ran on for a few seconds. 

I'm stumped.

I have ran the engine for a total of about 30 minutes at 2000- 2500 RPM over three days. Do you think the cam is broken in enough that I can let it idle?


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## BearGFR (Aug 25, 2008)

kjk990 said:


> I took the pump off and adjusted the plate. I got it as close as possible and reinstalled it. Tried again and the same thing. I turned it off at around 220 degrees and it ran on for a few seconds.


Running on is a clue that the timing is off a little --- that can also make it run hot.



> I have ran the engine for a total of about 30 minutes at 2000- 2500 RPM over three days. Do you think the cam is broken in enough that I can let it idle?


Do you have a timing tape on your balancer? If so, then use it to set total timing at 34 degrees with the motor at 2700 rpm (or so). That's a much better way of setting tmiing than using the "initial' method anyway. If not, you're probably safe enough at this point to let it idle long enough to set the timing "the normal way" and see what that does to your overheating problem.

With it running on, I'm betting timing is causing both problems. In any event, you really should get a shroud on it. That'll make the fan work MUCH better.

Bear


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## kjk990 (Sep 1, 2010)

I just ordered the fan shroud. Should be here in a couple days. 

Bear, I don't have timing tape. I also don't have a tach for the car so I bought a timing light that has one. It also does timing advance. I don't know how to use it. When I had the RPMs around 2200 I tried it let a 0 and the mark was jumping all around. I tried the same thing with a normal light and the mark is normal. I'm sure I'm doing something wrong. 

when the fan shroud gets here I'm going to install it, adjust the timing and try again.

I'll let you guys know. thanks again


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## BearGFR (Aug 25, 2008)

kjk990 said:


> I just ordered the fan shroud. Should be here in a couple days.
> 
> Bear, I don't have timing tape. I also don't have a tach for the car so I bought a timing light that has one. It also does timing advance. I don't know how to use it. When I had the RPMs around 2200 I tried it let a 0 and the mark was jumping all around. I tried the same thing with a normal light and the mark is normal. I'm sure I'm doing something wrong.
> 
> ...


An advance light like the one you have should work, but sometimes they can pick up "noise" from adjacent plug wires, or if the plug wire itself is a little "weak", the light can get false triggers at rpm that will make the marks dance like that. Try connecting it at a spot where it's isolated from other nearby plug wires, make sure the contacts are clean, etc. The way most of them work that I've seen is you run the engine at a steady rpm, use a control on the light to zero the timing marks, then read the actual advance from a dial or indicator on the timing light. I prefer setting timing on a new motor/new ignition system to the "total" amount I want at an rpm high enough to make sure the centrifugal advance is "all in" as opposed to setting initial timing at idle because that way I'm sure how much total advance I'm getting. Once that's set, then I'll use the light "the normal way" to see how much initial that is so that in the future it's easier to return to the same setting.

Good move, getting a shroud :cheers

Bear


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## kjk990 (Sep 1, 2010)

I got the fan shroud and new fan to fit. I had to use a spacer to get the fan in the correct location inside the shroud. Put everything back together. 

I just have to say fan shrouds are magic. I also adjusted the timing a little better which probably helped. I ran it for 20 minutes in the 2000-3000 RPM range at around 200 degrees. Adjusted the idle and let it run. It idled at a temp of around 185. I had it running for a while as I filled the transmission. 

The guy at the parts store suggested holding a dollar bill in front of the radiator. If it gets sucked to it you have good air flow. I never tried it before the shroud because I hadn't talked to him until after I got it. But now... That bill was stuck to it.

Thanks to everyone for the advice and input.


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## GTO JUDGE (May 14, 2005)

Add a bottle of water wetter.

:cheers


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