TR4/4A yellow fan

[nbailey]

I am trying to install TRF's yellow TR250 fan on my 67 4A. I was instructed to just turn fan backwards and bolt on. I did not get the bolts fully tightened, before tips of fan were touching the blocks on the steering rack mounts. Has anyone else had this problem? Any suggestions would be greatly appreciated. Thanks

 

[Merlin63Tr4]

Check and see if some prior owner installed a TR3 hub extension on your TR4A. It is around 3/4 inch shorter that the TR4/TR4A one.
If that's the case see if you can install the fan in "normal" attitude to make the problem go away, check radiator clearance!
For your information the crankshaft bolt for the TR4 measures 6 1/4 inch and the TR3 measures 5 1/2 from under the hex head to the tip.
I'm running a TR3 extension on my TR4 with the "yellow" fan in the normal attitude (not backwards) and everything clears (rack mounts, radiator, etc).

M.

 

[nbailey]

Check and see if some prior owner installed a TR3 hub extension on your TR4A. It is around 3/4 inch shorter that the TR4/TR4A one.
If that's the case see if you can install the fan in "normal" attitude to make the problem go away, check radiator clearance!
For your information the crankshaft bolt for the TR4 measures 6 1/4 inch and the TR3 measures 5 1/2 from under the hex head to the tip.
Im running a TR3 extension on my TR4 with the "yellow" fan in the normal attitude (not backwards) and everything clears (rack mounts, radiator, etc).

M.

Thanks for the reply, particularly the measurements. It appears I do have the shorter fan extension. I just set the radiator back in for a dry fit, and looks like I will only have about 1/4 inch clearance. Do you think this is enough considering possible fan flex etc? Thanks again

 

[Merlin63Tr4]

That was the clearance I had on my TR4 using the yellow fan and the original (TR4) hub extension, ran it for years like that, your milage might differ...

The fan itself is rigid and in my experience had very little longitudinal flex, the main worry would be longitudinal engine movement, specially if your engine mounts are suspect.

1/4 inch clearance is going to be a problem come "change the fan belt" time and that is why later (when I located a TR3 extension and crank bolt) I went with the thin belt conversion along with the TR3 hub extension.

My TR4 radiator (original) has two sets of mounting holes on each lower bracket, not sure if the TR4A radiators are the same.
I just measured the fan to rad clearance on my TR4 and it is exactly 1 inch using the rearmost set of lower mounting holes.

M.

 

[nbailey]

That was the clearance I had on my TR4 using the yellow fan and the original (TR4) hub extension, ran it for years like that, your milage might differ...

The fan itself is rigid and in my experience had very little longitudinal flex, the main worry would be longitudinal engine movement, specially if your engine mounts are suspect.

1/4 inch clearance is going to be a problem come "change the fan belt" time and that is why later (when I located a TR3 extension and crank bolt) I went with the thin belt conversion along with the TR3 hub extension.

My TR4 radiator (original) has two sets of mounting holes on each lower bracket, not sure if the TR4A radiators are the same.
I just measured the fan to rad clearance on my TR4 and it is exactly 1 inch using the rearmost set of lower mounting holes.

M.

Followup:
After bushings were compressed, I ended up with about 7/16 clearance. Fan is quieter and really moves air. I was ready to reinstall stock fan, so thanks again for your help.

 

[Merlin63Tr4]

Glad it all worked out!

M.