Radiator fan clearance

[Zealous]

Hey All,

I need opinions and checking on my conservatism. I just test fitted a new Aluminium radiator one of the many from ebay, Champion 3 row. I had originally purchased a two row as I was worried about the fan, but they did not have any and sent me a 3 row instead. After test fitting here are the pictures. I think the fan is way too close for my liking if the engine happens to lurch forward but I wanted to hear from you guys. It looks like my cars radiator frame may not perfectly straight along with the radiator mounting flanges. At the top you can see I have around 25mm (1 inch) clearance on the fan blades but at the bottom this decreases to 13mm (1/2 inch).

Is this far enough? I think not but wanted to hear from the guys in the know. This still does not include any rubber isolators which will reduce the gap a little but not much.

Should I try hammering the radiator frame to see if I can improve the bottom clearance? As I bolt in and tightened up the radiator it looks like one of the flanges is bending backwards to match the contour of the support.

Or is it time to return it? Or buy electric fans? Kinda wishing I had just paid the bit extra and got the koyo radiator at this point. This radiator is 3 inches wide and the old one used to be 2.5 inches. The old one didn't have any clearance problems.

Any advice and help as always is greatly appreciated.

[5150 will]

James, I think that is a little too close for comfort. If you have any deflection in that fan, the new radiator is toast IMHO.

[Zealous]

Thanks Will, That is exactly my very big concern.

Anyone had experience with a 3 row and know if it is my car or simply the radiator being too thick?

[clayton 260z]

I had the same dilemma. I removed the clutch fan and went with twin electric fans. For me it was the best thing I could of done.

[manny1973]

On my 72 I had about 2 inch clearance. I also used the Champion 3 row. Don't understand why your's is so close. Collision damage maybe? You should just remove the fan and go to electric fans, then you would be safe.

[esmit208]

Well Zealous

I would probably be ok with the clearance. As the fan speeds up you actually get more distance between the fan and the radiator. If you do not re-install the shroud the fan needs to be pretty close for efficiency. It doesn't look as if your factory shroud will fit unless you make modifications to the radiator which I DON'T SUGGEST. If it will give you piece of mind the switch to electric fans would be the route I would take and plan to take on Project 3/72. There should be no "lurching forward" of the engine unless the motor mounts are basically kitchen sponges.

[ezzzzzzz]

I'd try to determine what the radiator is hanging on that is causing the flange to pull like that. Resolving that should get you additional 1/2" clearance at the bottom. If the engine moves over an inch you've got problems. These heavy plastic fans do not flex that much. In some of my old street cars and 4x4's I've actually installed limit straps to stop rotation (block to frame rail) and forward engine movement (transmission crossmember to block or transmission). The other big issue you're not dealing with is electrolysis. Bolting that aluminum radiator directly to the steel support will make it one big anode. In less time than you can imagine the radiator will be full of pin holes and leaking like a sieve. It has to be fully isolated using rubber/nylon/washers/tubing. Been there, done that, bought the new radiator too.

Edited March 16, 2011 by ezzzzzzz

[twsutt]

Zealous,

I just finished putting a 3-row in my car and I had the same clearance problems...right down to the lower part of the radiator being closer than the top of the radiator. And I have to disagree with esmit208's assertion that the fan gets more distance from the radiator as it speeds up. And my radiator has the bent fins that disagree too...the blades pitch cause the fan to flex toward the radiator slighty.

Solution: Either have your old radiator re-cored or install an electric fan or two. I went with a pair of electric fans. They turn on at 180* and my engine temp doesn't rise above 195* under hard driving or heavy traffic. Hopefully, that won't change much once the mercury climbs into the upper 90's to lower 100's...Houston!

[Zealous]

Thanks for all the support guys and advice. Yeah it is really close for comfort. There is some distorting of the radiator frame from what looks like an old accident but after measuring it is minor and I think I can easily bang some of it out although not at 1130 at night the neighbours might not be happy. I think after measuring I have an extra wide core as it is 3 inches wide and then a bit more for the tabs, not much. I measured a lot and it looks like the radiator itself with the mounting tabs is not exactly straight either. All this stacking up I think is causing the problem but any small gains I make now are negligible when I add in a bit of rubber isolation.

Yeah I don't think the motor will move that much at all, I was more worried about the fan and also trying to slip on and off new fan belts, small movements during heavy cornering, etc.

Thanks ezzzzzz yeah as I mentioned this is without the rubber isolation I plan to do this it is just a test fit before install.

I think I am going to return this one and buy the koyo, I got a good deal from a local shop here and am going to go with that. By the time I buy electric fans, the thermo switch and the radiator I may as well have bought the koyo which is much higher quality and will be one less thing for me to worry about taking it to the track.

[FastWoman]

Zealous, my fan was about that close to my radiator when I upgraded to a 3-core in my '66 Mustang. That motor didn't have a fan clutch, but of course when the 280Z fan clutch locks up, neither does the L28 (effectively). Anyway, long story short, I went for a long victory drive with a car load of friends and started hearing an occasional "ting." I said, "I think I have a problem," and my passengers insisted, "No, there's no problem. Just keep driving." About when I said, "No, I really think...," all hell broke loose. The (metal) fan blade sliced into the new radiator, and steam and coolant flew everywhere. It was a looooooong tow back into town.

Yeah, I'd look for a bit more spacing.

[Zealous]

Hey All,

Thanks for the advice and help, I ended up getting the Koyorad Racing Radiator part number R022352. It is a gorgeous and amazing looking radiator much higher quality than the ebay champion. It fit in nicely but again there was a noticeable twist and far less clearance at the bottom, although less pronounced since this radiator was straight. So I decided enough was enough and went over the car with measurements and the spirit level. I know the car was hit on left side at one point in its life because the lower circle in the radiator support frame is no longer a circle. After an hour or two of hammer and dolly work I go the the support frame more straightened, it is not perfect but no longer bowed, warped or sticking out.

Then I went back and installed the Koyorad which was great and easy to do, I used rubber grommets to isolate the radiator but I think Ill get some rubber stripping just to further isolate it. Here are some pics of the install for others that are interested in this product. Note it takes a non-standard radiator cap that you also need to buy, koyo sells a high pressure cap (I bought a lower pressure one at the local NAPA). Also you need to modify a lower radiator hose for the upper hose as the OEM upper hose will not work or get a long pre-molded 90 degree hose. It is raining for the week here but once I get out driving on the open road again Ill report back on the performance.