TRactor Motor Rear Seal

[martx-5]

I'm getting ready to tackle the engine on the TR3, and have read alot about a modern rear seal conversion. What's involved, and what are the pros and cons of doing this modification?

 

[Guest]

You gotta machine the block. Good conversion.


Bill

 

[Tinkerman]

Beg to differ with you Bill, it's the crankshaft that needs the machine work. You have to grind off the scroll work at the rear of the crank. See Roger Williams book " How To Restore Triumph TR2,TR3 & 3A", page 92. Gives a good description with pictures.
Regards, Tinkerman

 

[Guest]

[ QUOTE ]
You gotta machine the block. Good conversion.


Bill

[/ QUOTE ]

Whoops, did I say block? Crank.


Bill

 

[trfourtune]

i've heard that some of these don't work very well. does anyone know which ones are good or bad? is it purely a machining problem? is the recommended diameter to machine to correct in the instructions?
rob

 

[Guest]

When I was in the process of tearing down my "free" TR3 engine, the one thing that I noticed was the rear seal on the engine was one of the few things that held up well. Because of this, I had no intention of installing the upgraded seal. Of course, I abandoned the whole project so for me the point was moot.

Bill

 

[Banjo]

The original holds up well because it never really touched the crank. It's a tight clearance, but not an actual "seal" It only really work while the engine is running and the scroll in the crank slings the oil back into the sump. when the engine stops, the oil drips out a little.
the key to using an original setup is to have the centering tool to line up the two halves of the "seal" correctly. otherwise it'll leak a lot more than it should, and may wear agenst the crank.
I think the key to a good "retrofit" is in the machining. as long as that's done properly the new seal should work beautifully.
Can't give you a first hand comparison of offered kits. And mine will be getting the original type "seal" as I don't mind the drip so much.. I think it's part of the charecter of the car. (not a necessary one, but still part of it)

 

[Bruno_69z28]

Art,

I did the rear seal conversion about six months ago. I used the Moss Motors conversion and had the crank ground to 63.5 mm (as per instructions). I installed the seal exactly as written in the instructions. The seal leaked as soon as I started the motor. Well at this point I couldn’t go back to the old style seal. I spent over $700 to have the crank reground, hardened and balanced.
I called British Frame and Engine and was told they use the Racetoration seal conversion kit. The Racetoration kit uses the same lip seal as the Moss kit. The aluminum seal holder is a little different than the Moss one. I was also told to shorten the lip seal spring to 8 in. They are usually about 8.25 to 8.5 in. long from the factory. This puts more tension on the seal. Also, Racetoration now says to grind the crank to 64 mm, this will also put more tension on the seal.

Well I put it all together again (FOR THE SECOND TIME!!) and it doesn’t leak a drop. I don’t know if I would do the lip seal conversion again. You can have your original seal blue printed for tighter clearances. The reason these motors leak oil out the real seal is to much blow-by. Good breathers or a PCV system should keep the crankcase pressure to a minimum thus stopping the oil from being forced out the seals.

Bill