TR6 Big-end / Main Bearing Replacement

Original Query: (from Shane Ingate?)

[Can one replace the bearings on the TR6 with the engine in situ?] I used to do it all the time on my MGB, which was a daily driver and suffered the abuse of about 10-15,000 miles a year for the fifteen years I drove it. This winter I will undertake the same thing with the TR6. From what I have read and from the people I have talked with, it's the same thing on a Triumph.]

Responses:

Date: Tue, 6 Oct 1998 15:31:34 -0500 (CDT)
From: Mike Mason
Subject: Re: TR6: big-end and main bearing replacement

I always used a feeler guage to push the upper half of the bearing out, careful not to scratch anything. Lubricate the upper half of the new one and slide it back in, careful to make certain that the little tab thingie gets into its groove. (You can only take them out and put them in one way, 'cause of that little tab.) I figure it's cheap engine insurance to do it every 20-30,000 miles and it's not that tough. Seal the pan well and nobody will know it's an LBC, 'cause it won't leak enough!

You can Plasti-Guage the crank to make sure that it's not too worn, but if there is still a good surface on the old bearing, you should be fine.

'Course if you follow my advice and the whole thing blows up, I don't know nothin'!! ;-)

If I'm wrong I'm sure someone will let us both know!

Take care and good luck
Michael

Dave Massey writes:

Shane,

Do not replace only the lower shell halves. Once you get to that point it is plenty easy to remove and replace the upper ones, too. I know, I did this last winter. What you need to do is loosen the fan belt (or you wont be able to get #1 out) and remove only one main shell at a time while loosening the two adjacent ones about one turn to allow the crank to drop a little. You should be able to push the old one out with the new one. If you have trouble there are tricks as outlined in Len Renkenberger's 6-Tech book I can relay to you.

You will also probably need a lower gasket kit as the block-to-front cover gasket will likely get damaged when removing the front sealing block. Anyway some of these parts could be handy and some will be necessary. And use standard bearings unless the crank has been turned.

While you are in there you should also look into replacing the thrust washers. I bought a standard set and a set +.005 and wound up using one of each to get the end float down below .005.

This whole operation is more or less painless (if you count lying on your back with oil dripping in your face for several hours painless) and the results are encouraging. And I did it in the cold weather. (And being in San Diego you are saying "what's cold weather?") ;-D

Have fun and good luck.

Dave Massey
St. Louis, MO USA

57 TR3
71 TR6
80 TR8