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View Full Version : TR4/4A Bad Break - Ouch! TR4 Fan



Geo Hahn
09-16-2008, 05:06 PM
On the way back up the mountain from our weekly LBC coffee clatch I heard a loud BANG. Thought it was probably a rock kicked up but did some quick side-to-side movements to be sure the suspension was still all connected -- that is when I saw something metal bouncing down the road behind me. Pulled over and did a quick check and all seemed attached and okay.

When I got home I was under the bonnet and found what happened.

https://www.cybertrails.com/~ahwahnee/Fan%20Blade%201.JPG


As I recall, that fan is supposed to have 4 blades. Apparently 44 years of metal fatigue finally did its work. Not an unknown TR problem I think.

I assume I can drive it some distance (about 20 miles) if I keep the RPMs reasonable? I have already driven it 15 miles (aggressively) before I was home and found the problem.

Oh yes, the fan blade departed on the upstroke so I got a fine dent in the bonnet where it hit the underneath side.

https://www.cybertrails.com/~ahwahnee/Fan%20Blade%202.JPG


That's the 'OUCH!'.

Tomster
09-16-2008, 05:13 PM
Youch, Have heard of and live in fear of this
Same blade set in mine
seems fine when I have mauled it by hand

TR4nut
09-16-2008, 05:48 PM
Geo-

I have one of those fans, still with 4 blades attached, on a peg in my garage. PM me and you are welcome to it. But I still don't recommend it - I haven't looked back since changing over to the plastic TR6 yellow fan.

As painful as the dent is, at least the fan had the decency to not shred the radiator!

Randy

tdskip
09-16-2008, 05:52 PM
Be glad you were not adjusting the timing when this happened....

Glad you made it home OK.

Bob_Muzio
09-16-2008, 06:11 PM
George, I agree with Randy as it's a perfect time to install the yellow TR6 fan, I believe Moss has the shorter hub available, unless you have access to a TR3 one.
Bob

Lou Metelko
09-16-2008, 07:55 PM
George:

I can relate because the TR2 also has one of those "inside out" dents when the front stud on the water pump departed. When the pulley departed shortly thereafter, it did the number to the four bladed fan. I was really fortunate that the very rare early TR2 radiator was not damaged. Don't even ask about the warranty from the new and improved multi vane pump.

Lou Metelko
Auburn, Indiana

Banjo
09-16-2008, 08:23 PM
My dad got towed home from ther vintage at Watkins when the waterpump let go in his MGB and the fan bored itsself into the brand new radiator. thankfully it did not seperate and go into the bonnett.
I've been debating on weather or not to do the plastic TR6 fan in the TR2. I'm leaning twards doing the conversion, and painting the fan black so it dosen't stand out quite so bad. (the car isen't going to be 100% original anyway. Its a TR4A motor)

Bob_Muzio
09-16-2008, 10:31 PM
Banjo, I'm not sure about the TR2 but on the TR3 I believe that you must move the radiator forward about an inch for clearance.
Bob

KVH
09-17-2008, 01:47 AM
That seems crazy. I can't imagine a fan blade would crack off like that even after 100 years.

Good you weren't messing around under the bonnet.

Geo, I'd be curious who you trust with that bonnet repair. I've seen Dent Busters do great work when no painting is required. I really like that "Hot Rod" place on the Old Casa Grande Highway, too. They'll fix it like it never happened. If the paint on the top side looks good, I'd at least talk to Dent Busters.

Good luck. Sorry to hear that happend. Strange.

vivdownunder
09-17-2008, 08:42 AM
A shame, but history repeating itself after almost 50 years. Disintegrating fans put the three factory entered TR3S cars out of LeMans in 1959, two with blades through the radiator, and I think the third car expired through resultant engine imbalance.

The only early TR2/3 fan like this one I've seen break was examined and found to have been bent and repaired at some stage, thus creating a fault line. I've not heard of the later 3A fans with the radius cornered blades breaking at all. An improvement is a five blade Triumph Sedan fan, which fits straight on, and has smaller, yet more efficient blades, which do not let go. TR250/5/6 Yellow or red plastic fans are too wide to fit on unmodified sidescreen cars.

Viv

2wrench
09-17-2008, 11:46 AM
Geo: Looks like your last pic is some kind of message out of the cosmos
delivering subliminal messages that it is time to repaint your bonnet.

Brosky
09-17-2008, 11:49 AM
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]That seems crazy. I can't imagine a fan blade would crack off like that even after 100 years.[/QUOTE]

I've seen fan blades with 1/4" steel rivets come unglued at 6-7,000 rpms and it isn't pretty. That's one of the reasons that racers and then the manufacturers went to electric cooling fans.