TR2/3/3A Tr3 belt alignment

[sp53]

Hi all over the years my tr3 fan belt has squeaked a little for the first few minutes after a cold start. I am thinking that the generator is not perpendicular to the other pulleys, and felt that if I could pull the back end of the generator out about 1/16, the alignment would perhaps stop the squeak. My friend suggested that I put a washer behind the back end of the mounting bracket to tip the generator in, but I am such a caveman that I thought I could just loosen the back end up and pry it out a fuzz and tighten it up. I guess the right way is to use a dial indicator and check it for run out, but with everything in there I cannot see how to accomplish that. Anyways any ideas about what I am attempting would be much appreciated.

 

[TR4nut]

The only thing I did to confirm alignment was take a straight edge to each pulley and checked that they all lined up on the same plane. At least it helped me shim out the alternator I put on my TR4 and I've had no squeaks or strange wear on the pulleys. If your generator is slanted you'd see it pretty easily I think with that approach.

 

[martx-5]

If it's squeaking right after start-up and then goes away, it's most likely because the belt is too loose. Because starting the engine uses alot of juice from the battery, the generator will work much harder after start-up and if the belt is too loose, it will squeal. Try re-tightening the belt first.

 

[MGTF1250Dave]

Aloha SP53,

I had a similar problem with generator alignment, however my problem was the front mounting arrangement. The problem at first appeared to be front mounting bolt coming loose. Further investigation revealed that the mounting pedestal was damaged and partially stripped resulting in pedestal bore being "ovaled". This moved the bolt and the front of the generator to move toward the engine. When replacing the mounting pedestal and found that the front engine plate had been worn in a half moon indentation where the pedestal mounted. It seems that a loose pedestal had vibrated and worn the engine plate so that even when the pedestal was tightened it was misaligned which may have been the cause of the "ovaling" and stripping pedestal bore. I used a large steel washer to cover the half moon dished in area, ground down the top of the pedestal equal to the thickness of the washer and remounted the generator. It solved my alignment problem.

 

[Geo Hahn]

I, OTOH, like a loose belt -- or at least one that is far from tight. I am more concerned with not overworking the bearings in the water pump and dynamo than with maximum charging. But then I drive it most days and few nights so maintaining the state of charge of the battery is not much work for the dynamo.

So, if tightening doesn't eliminate the squeak maybe loosening will. Oh, and the alignment of my dynamo pulley isn't perfect -- that pulley is slightly out of the plane of the other pulleys.

BTW -- if I understand what is meant in the above post about the pedestal bore being ovalled -- perhaps this is a result of using a standard bolt to mount it rather than a bolt with a long shoulder? Threads inside of a mounting hole can sometimes act like a little file working on the shape of the hole.

 

[TR3driver]

Threads inside of a mounting hole can sometimes act like a little file working on the shape of the hole.

True, but there has to be relative movement for that to happen. The pedestal should be tightened firmly to the front plate, there should be no relative movement there ... until it works loose of course. What Dave describes is fairly common, IMO. Seems that people forget to tighten that lower front bolt, so it allows the generator to wiggle around, which in turn loosens everything up. Even with the right shanked bolt, the generator front plate is frequently worn oval from the constant movement.

But I agree that looseness somewhere is more likely the cause of a squeak than the generator being out of line. A damaged pulley (especially the crank pulley, which is just pressed sheet metal) can do it too. So can a belt that is hard and glazed, so it doesn't grip properly any more.