fan cooling - Page 2

mdross1 · #21 (**permalink**) 07-13-2014, 04:27 AM

The biggest problem with trying to put a mechanical fan shrouded correctly with the engine sitting high compared to the radiator height is fan diameter will not be enough to pull the required air cfm to cool the engine.

Dominik · #22 (**permalink**) 07-13-2014, 08:32 AM

Pulling/pushing, no big difference. Get a decent shroud and drive above 30mph. If is still overheats you have another problem. Fix that, then work on the speed (and airflow) below 30mph - with a decent fan. Also check if your timing at idle and very low engine speed is not too retarded. Glowing headers or boiling brake fluid are a clear sign of that.

Sydney · #23 (**permalink**) 07-13-2014, 11:51 AM

I have a 10 year old Shell Valley with a 351 w. I didn't want the pusher fan setup because I wanted to add the twin fans in the front. Basically I made a new lower radiator support bracket. What I did was to get a big puller fan and mount it on the rear of the radiator and moved and shifted it around until it fit with the fan on. This was a pretty big job, it involved some considerable cutting and shaping of the fiberglass around the radiator. Also fitting around the hood hinges was an issue. After I got it all to fit, I blocked it up and made a new lower bracket to support it. I was able to reuse the upper support by modifying it a bit.

I think the biggest thing is to have a shroud between the top of the radiator and the nose so that all of the air coming in the nose goes through the radiator. I made an aluminum trim piece that bolts to the top radiator support that accomplishes this. It is a pretty rare day that my fan even comes on. I think my fan switch is 207 degrees and my thermostat is a 195 degree unit. My engine runs between 185 and 200 degrees most all of the time.

Dominik is right about the initial timing. On of the things I have to do to pass state emissions testing is to retard the timing 10 degrees. It is amazing how much hotter the engine runs. I have to have all the fans running the full time at the test station just to keep the engine at 215 degrees. I hope that gives you a few ideas.

Mastiff107 · #24 (**permalink**) 07-13-2014, 02:45 PM

This is all you need...

Guido36 · #25 (**permalink**) 07-13-2014, 07:51 PM

Quote:

Originally Posted by Mastiff107

This is all you need...

I have lost three radiators due to flex fans cracking at the hub. I would strongly advise against using flex fans. '$1000' fans are an expensive choice and the last one exited through the hood - luckily nobody was in range at the time!

Mastiff107 · #26 (**permalink**) 07-14-2014, 09:22 AM

In the past 64 years I've never been lucky at anything....until now! 20 years on this bad boy. Gotta go tell someone!

Xack · #27 (**permalink**) 07-14-2014, 06:21 PM

Quote:

Originally Posted by Mastiff107

This is all you need...

The problems I see.
(1) pusher fan
(2) Pusher fan not shrouded.
(3) Flex fan
(4) Flex fan not shrouded.

But, if it works that's great. I have a kit that came with a fan which was a pusher installed as a puller. The blades did not function well at all in reverse. I got a different puller fan and the results were night and day. It lost too much efficiency trying to use the fan backwards.

BevanWright · #28 (**permalink**) 07-15-2014, 02:16 AM

Are you running a 50:50 mix of coolant to water? Decent sized expansion tank? Try running an electric water pump and an oil cooler.

jim adams · #29 (**permalink**) 07-15-2014, 05:01 AM

Keep the electric fan, use a thermostat and see if you can put an OEM type fan and clutch set up on the water pump, as close to radiator as possible, if possible shrouding. The electric fan can assist in traffic, long idle, and when you shut car off. while factory type set up does the main cooling. Try what the others suggested first, it's what you got. Had good luck with "Flow Cooler" water pumps, high pressure cap, "Red Line" water wetter.

Mastiff107 · #30 (**permalink**) 07-15-2014, 11:51 AM

Don't want to beat this to death. The guy has a Shell Valley, I have a Shell Valley; he's got a 302, I got a hi-pro 289; he wanted a quick fix and I got one. No shrouds, moldings, no water wetter, no nothing but a flex fan. Don't have to move nothing around. The guy I bought it from a guy in New Mexico who drove it in parades in the summer with no over-heating. I do have a question on the flex-fan. I've used many, known many who have and researched it on the internet with my limited technical ability with no mention of problems with flex fans. You now have me concerned on account of I'm retired and have nothing else to worry about....up until now. What can go wrong with a flex fan? Is there some inherent problem with them? I'm not trying to be a dick, but I never have the solution to any of life's problems and finally thought I had one.

Xack · #31 (**permalink**) 07-15-2014, 05:35 PM

I apologize for being negative. However, I did say that "if it works, great". If your after a fix that works for you, then more power to you. I'd say that normally, fixes are just that, attempts to cover, mask the real problem. The underlying problem still may exist and get worse without you knowing it. Typically you want to shroud fans for safety, and efficiency. a properly designed and maintained system will keep everything cool in almost any driving condition. I am not judging you or your solution as much as I was just commenting on the photo.

fasterthebetter · #32 (**permalink**) 07-16-2014, 11:31 PM

Thanks Guys alot of helpful info here!

avdcav · #33 (**permalink**) 07-17-2014, 07:51 AM

24 pound radiator cap was a big help for me also " with the bb the standard
18lb just couldn't do it . I also use a 16" puller with complete shroud I can let that car run
Till it runs out of gas. Never goes past 95c water. 105c oil and that's beating on it on the hwy and back roads 4500 rpm plus.

My rad is also tilted and I have the little push bleeder installed in my intake, that little
15$ thing is priceless. Bleeds my motor in seconds.