View Full Version : TR4/4A Upgrading the TR4 stock fan

06-07-2009, 11:35 PM
Go with a TR6 8 blade fan or jump to electric fan and dump the engine powered all together?

06-08-2009, 10:37 AM

I've been running the TR6 blade with no problems. An electric fan would be nice if you get stuck in traffic though. (does that ever happen in So. Cal.?) Might be nice for peace of mind.

06-08-2009, 10:49 AM
I have both. The electric one was added when the stock engine fan was in place and worked well. After I added the multi bladed yellow plastic fan (you'll need a TR3 hub (1 inch shorter), although I believe Moss has a kit available) I found I rarely needed the electric one but it's nice to have for peace of mind. I do know fellows who have gone electric and disposed of the engine mounted fan entirely.

06-08-2009, 11:04 AM
consider one of these

Geo Hahn
06-08-2009, 11:13 AM
...I added the multi bladed yellow plastic fan (you'll need a TR3 hub (1 inch shorter...

Is that absolutely the case? I have seen a TR4 with the stock extension and the yellow fan -- perhaps he mounted it backwards to get it on there?

Next time I see it (maybe tomorrow) I will take a photo.

06-08-2009, 11:22 AM
consider one of these

...if you can find one...

06-09-2009, 11:48 AM
Hi guys - so do we have consensus that you need a TR3 hub?

Larry - did you bolt yours right up to the existing hub?

Andrew Mace
06-09-2009, 12:05 PM
Hi guys - so do we have consensus that you need a TR3 hub?For that matter, do we have consensus that you <span style="font-style: italic">need</span> anything beyond stock? :devilgrin:

06-09-2009, 12:10 PM

I definitely needed a TR3 hub to fit the plastic fan on my later framed TR4.


In my opinion, in Texas I'd say yes you do need something better than the stock fan!


Showoff! :laugh: Nice acquisition!

p.s. Here is a snapshot I took a couple of years back, it shows how the fan dimensions are pretty evenly matched between old and new when using the TR3 hub. I believe there is an 0.75" difference if memory serves me correctly


06-09-2009, 12:27 PM
The Moss Motors short hub kit is for TR2-3B, which have the short hub, and need one shorter still in order to mount the fan right way forward.

A stock TR2-3 hub will work in a TR4 with the fan facing the right way. Or, one can mount the fan facing backwards in any TR with no modifications to the hub. The blades are shaped and are probably more efficient when facing the right way around, but it still moves a lot more air than the stock fan, even when mounted backwards.

Andy --
10,000 posts and products available to tame TR overheating can't all be a hoax... All I've done to my TR3 is put in the yellow plastic fan -- backwards. On hot days, I watch the temp gauge creep up in slow traffic. Haven't boiled it yet, but it goes higher than I really want to see it. Fortunately, as soon as I get moving more than 20 MPH, it recovers. Also, fortunately, heavy traffic is fairly scarce and short duration around here. If I lived in LA or Houston, I think I'd have to take stronger measures.

Andrew Mace
06-09-2009, 01:29 PM
Andy --
10,000 posts and products available to tame TR overheating can't all be a hoax...I know, I know....

I mean no disrespect to anyone, and hopefully I'm "preaching to the choir" as it were, but I've seen far too many clogged radiators and equally clogged engine block cooling passages over the years. I've also seen my share of thermostats that simply were too "hot" for conditions, factory air ducting and shrouding gone AWOL, etc., etc.

And yes, I've endured a few 90 degree plus (outside air temp.), stop-and-go freeway traffic jams in my Herald with a completely stock fan and radiator and 40-year-old pressure cap...without incident.

Geo Hahn
06-09-2009, 01:34 PM
...For that matter, do we have consensus that you <span style="font-style: italic">need</span> anything beyond stock?

This place is known for opinions &amp; facts, but seldom consensus.

I alternate between Tucson &amp; a 9000' mountain -- often 100+ degrees when I start up 'The Hill'. I have stock fans on both TRs, but I do like to keep moving.

06-09-2009, 01:40 PM
I blew two head gaskets, and was in a few parades that caused some pretty hot tempertures. I switched to an electric fan and see the engine stay much cooler. I think that yellow plastic one works well also. I have the metal 6 bladed fan on another car and it moves a lot of air but is a little noisy.


06-09-2009, 02:07 PM
Thanks guys

06-09-2009, 03:58 PM
factory air ducting and shrouding gone AWOL,Then of course there were the early TR3As that were not fitted with the cardboard air duct by the factory. It was a later addition after they discovered the problem with the new apron shape.

Complicating the picture I feel, is that drivers today have higher expectations than drivers 40 years ago did. Everyone seems to get all excited if their temp reaches 200F, while actual boiling under some circumstances was not only common but accepted as normal back in the 60s &amp; 70s. You could walk around any rest area on the Interstate during warm weather, and a majority of the cars would have boiled enough to puke a little on the pavement. We even passed one of the old "Radiator water ahead" signs in New Mexico last month.

There are also many other ways for neglected/deferred maintenance to cause overheating. I fought a problem for years that turned out to be worn carburetor jets. Since my buddies MGA suffered the exact same problem, I have to think it's fairly common.

06-09-2009, 05:39 PM

I used a Tr3 hub.

06-09-2009, 08:32 PM
Thanks - I was emailing with Mark Canaday today (who is super helpful BTW) and he suggested I work over the spare TR7 13 blade fan I have to make that fit instead.

Anyone have a write up on that by chance?

06-09-2009, 08:39 PM
The TR4s cool pretty well if everything is in fine fettle, the TR4s came with a number of different fans, I think a simple upgrade to the later aluminum (5 blade? maybe 7 blade can't remember for sure) usually good, I drove my 4A in 100 plus temps with such a fan, got hot, but not as hot as similiar period MGs and AHs I have had.

Have fun.


Geo Hahn
06-09-2009, 09:27 PM
Just to further muddy the waters -- I recall there was a Volvo fan that bolted up to the TR and provided superior cooling (per Bob Schaller). I'm thinking it was the type that flexed so it moved a lot of air at low speed but streamlined itself at high RPMs.

06-10-2009, 10:28 AM
There is an advantage to the electric fan that has not been stated yet, which is:
when the fan is not running (cooler weather, cruising) your engine is not loosing any hp driving the fan, so you might pick up a couple of hp, and is much better in stop-N-go traffic.

09-02-2009, 02:39 PM
The later plastic fan WILL fit with the stock TR4/TR4A extension...at least on a TR4A. I've got about 1/2" clearance between the fan and stock radiator. The fan is not backwards.