MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Problem with Alternator mount

I have an ongoing problem with the main mounting bolt for the alterator (ie the lower bolt). I go through bolts at a rate of one every 6 weeks. It seems that it gets sheared half way along the bolt near the engine block mounting bracket. I originally was using grade 5 bolts and most recently went up to grade 8, the higher grade lasts no longer. The bolt looks like it was cut by a bolt cutter.. Unfortunately I lost the large spacer long ago and substitued various lengths of pipe or rod connectors that fits snuggly over the bolt giving the right geometry for the fan belt.

HELP!! Has anyone else ever experienced this problem?
Steven

That is a bizzare thing for a grade 8 bolt!
Sounds like you have some terriffic vibration going
on at that location, check fan blades and belts for balance. Short of that drill the holes two sizes up and use a bolt of the same dia. Grade8 of course.
Christopher
catrace@primus.ca
Christopher Trace

Well I tried going the other route ie instead of higher grade which is more brittle, I went softer so that it would bend rather then shear.

The grade 2 bolt lasted only 50 miles and this time it broke the upper alternator bracket (which was from another car initially)

So I pose my question again and add another one:
anyone else experienced this and how did they solve it. And secondly, the original TR upper Alternator bracket is very thin and tends to break, anyone found an alternative bracket that fits easily?
Steven

The large bushing has a machined collar (for want of a better description) this is about 1/8 inch long and fits into the engine block. Many years ago on a Peugeot we had a similar problem. The torque of the belt going over the pully pulls on the alternator which multiplies the torque and applies it to the bolt/mount.

You did not mention where the bolt was breaking. But you might try getting a bushing made with that collar on it. The collar acts more like a tounge and groove fit and provides substantial strength


Steve
Steve Hanselman

Thanks for the suggestion,

I am missing that large bushing and substituted lengths of pipe and rod connectors cut down to the size (albeit missing that 1/8 collar) The bolt is breaking right at the block mounting where the bushing would be.

Unfortunately the bushing is not available (no listing at TRF, Moss, or Victoria British).

I wonder if drilling out the mount and holes in the alternator to the next size up solve the problem, from 5/16 to 3/8 which is the size of the machined collar work?
steven

Steven,
There are hundreds of TR-6's out there that are being broken for parts. Don't modify your block until you try fixing your problem with the correct parts. There are a couple of cars posted on this page. There is a yard near here that has dozens of cars, including MGs, Morris, Spitfires, TR-4s, TR-3s. If you can't locate the parts locally contact aott@mindspring.com. As some one said, "They ain't cheap, but they have everything you could possibly be looking for".
Joe Justice

Almost anyone with a lathe should be able to make the part. Unfortunately we have not yet got our new(well to us) car so I can't give you the dimensions. get a dial vernier and measure the inside diameter of the hole in the front of the block. Next measure the depth. To make the part shouldn't take more than about 30 min. It is effectively only three moves, 1. drill the hole, 2. cut the shoulder and then 3. cut to length

steve
Stephen Hanselman

This thread was discussed between 29/07/2001 and 23/08/2001

Triumph TR6 index