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Triumph TR6 - new bolts for rod & main bearings?

Oh how I wish I would have thought to look for a forum like this earlier in my restoration project. In a nutshell, I'm mid way (250 plus hours of my time and too many of my dollars) through an off the frame restoration. My '69 chassis and suspension has been completely renewed and in about two weeks, the body should be ready to rejoin it. Since the engine runs fine, I opted to only to a replace leaking oil seal and do a clean and paint. A mechanic friend suggested that it would never be easier than now to do a lower end overhaul. That's where I am right now. I have new bearings, oil pump, seals and gaskets. The Bentley Publishers TR6 Manual says to install new bolts for the bearing caps. My mechanic friend says that should not be necessary. While part of me says to go ahead and replace them just in case-the other part says thats another 50 to 80 dollars spent on an already over budget project. What do you think? Is there any good reason to replace them? Thanks for your input.
PS The torque spec for the bearing bolts is 50 to 65 for the mains; 38 to 46 for the connecting rods. Where should I be? Low end, high end, right in the middle?
John Eldridge

I didn't renew mine when I rebuilt the engine a couple of years ago, but I only use the car on the road, I think if I was doing anything that involves more enthusiastic driving such as track days etc I would renew the big end bolts, don't think it is worth replacing the main bearing bolts at all unless you are building an out and out racing engine.
Torque wrench wise I would head for the middle figure, most DIY [and probably a lot of professional] torque wrenches are not that accurate anyway. The other thing to remember that the original UK PI engines were rated at 150hp and used the same bottom end bolts etc as the USA engine so there was a large reserve of strength there if you are building a US spec engine.
Good luck with your project.
Ron
R. Algie

John
Welcome and glad u found us. This site is, to say the least, full of info from a to Z(ed).
Join the forum and you will have access to the archives. Many many hours of reading.
Now that u are here, u have to post to Bills' big thread and give us some info.(TR6 for old guys only).You will get to know a little about the chaps here.
This is not the only forum out there in WWW land but I feel it is the best.
Below is another site and I link you to one page that talks about the lower end. You have done this but I think he also says do not bother replacing.

http://triumph.hottr6.com/tr6bearings.html

I finished by body off restore in '01.
Funny this topic you mention comes up as I have been thinking of doing the lower end. I fully admit I am not an engine guy like others here so one might say this job is intimidating to me. After reading the above link I am seriously considering. I know it needs to be done and Bill B. has this thing about Thrust Washers (like me with the dash light rheostat:).

Anyway, welcome and good luck. When do you expect she be on the road? I presume you also have stock in Jeff Zorns' little enterprise:)
Rick C
Rick Crawford

I have owned my TR3A from new. It has 158,000 miles on it and when I re-do the bearings, I normally don't change the bolts. I restored "TRusty" in 1990 and used new bolts. Everything is stock with an overdrive and I do high speed touring on the road so it's never over-stressed. Since then I've driven more than 78,000 miles and had the bolts out twice and re-used them.

From the TR guys and gals who race Triumphs, they say that the higher torque number is if the threads are dry and the lower number is if the threads are oiled before you torque the bolts.

Don Elliott, 1958 TR3A
http://www.tr-register.co.uk/images/memberscars/trusty.jpg
Don Elliott

Thanks everyone for your advice and kind words. I now have one less thing to worry about and should be able to get the engine and trans. put back together before the body goes back on. I hope to (my wife says I had better) have the car on the road by May, that might be a little optimistic.

I have become a member and just began to scratch the surface of the archives; I'll dig deeper when I have some more time. I'll post to 'old guys only' thread too. I'm 48; My first Tr6 I bought new In '74, my current one I bought last summer while some of my friends were buying Harleys.

John Eldridge
T Eldridge

This thread was discussed between 22/03/2004 and 23/03/2004

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