News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

39 LaSalle fan

Started by Jack Carroll #18687, December 20, 2006, 04:44:54 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Jack Carroll #18687

Can anyone help me? I want to change my 4 blade radiator
fan to a 6 blade one.Can anyone tell me what will fit?
I know this subject has been on the forum before but I
couldnt find it.
Thanks Jack Carroll

Doug Houston

Surely, the fan blade you want can come from a Cadillac 75 from the same year as your car. Ive given this a bit of thought, and realize that the fan is most important at slow speeds, and particularly at idle for long periods. At highway speeds, its actually better if you have no fan at all.

I would gather from what youre asking that the engine is running hotter than it should. The solution to that would be a good clean-out of the block and radiator, or possibly a re-core. Timing is also critical. It should be advanced the maximum for the best performance with the fuel youre using.

One other thing that is frequently overlooked. That is the fact that the rear axle ratio is relatively high; usually higheer than 4:1. In 1941, when the turnpikes opened, axle ratios dropped to let the engine run slower at high speeds. Unfortunately, later axles wont fit earlier cars, so its wise to keep down the highway speeds to around 55 MPH maximum.

So, a 5 blade fan shouldnt show a difference in driving the car.

Bill Ingler CLC# 7799

Living in Phoenix I deal with heat and the flat head engine probably more than most.My 41 60s has the 4 blade standard fan, my 47 convert has a 5 blade from a series 75. Both cars have a 3:36 rear, both have new cores. The 47 engine block & heads were chemically cleaned when the engine was rebuilt. The 41 engine was rebuilt but block and heads were not chemically cleaned. The 41 runs hotter than the 47 both at speeds and in stop and go traffic. I have switched fans on the 41 and found no difference in operating temps from the 4 blade to the 5 blade. As was pointed out by Doug, a good engine clean out and possibly a new radiator core might negate the need for the larger 5 blade fan.

Geoff Newcombe #4719

I agree ---- fix the problem, not the symptom!

Randall A. McGrew CLC # 17693

I can attest to this.  My 47 had the original fan and overheated in the Texas heat.
I had the radiator recored and the engine completely cleaned out.  That was it.
The car never... that is right... never ran hot again.  

Of course, it was timed and advanced properly, had the right pressure rated cap on the radiator, and all that, but it never overheated again, not even at 4000+ ft in 90 degree weather.   Dougs advice is worth its weight in gold.

Jack Carroll #18687

Thanks for all the info.I am in the process of having the
engine rebuilt complete with a block and heads boil-out and an ultrasonic cleaning, Im going to have the radiator cleaned and recored if nessisary, the distributer is being completely
rebuilt and recalabrated,the exshaust pipe has been insulated
ext... Its probabilly over kill especially since Ive only
had a couple of minor overheating occations, but since Im
doing everything else I just wanted a little extra insurance.

THanks again
Jack Carroll

Bryson Talamini 21505

Jack, I endorse everything the other blokes said. In Brisbane we get 95-100 thru summer and my 37 LaSalle runs at 175F. Idle is when you need the fan, definitely insulate the exhaust [it was in the factory] and make sure you have the correct fan pulleys as they changed somewhere [40? 41?] because the grille was lower. On My 37 the leading edge of the fan blade is 1 1/16 from the radiator core. Too big a gap and the fan will bypass the core at idle. I also idle at about 500rpm to get more air flow. hope this helps.
Bryson on Oz