TR2/3/3A Connecting Rod Bolts

[RedTR3]

I went over the parts list with the machinist today for my rebuild...He did not list Connecting rod bolts. His comment was that they looked good to re-use for a street engine, that "He's never had one fail" (I don't know if I really believe that). He said if I want, I can certainly order them but not necessary in his mind.

I am thinking that I want to go ahead and spend the $150 for peace of mind since I don't know the full history of the car...What is the experience of you guys?

 

[TR3driver]

My preference tends towards reusing bolts, if they are in good condition. Kinda lost track of how many times I've had a TR engine apart, always reused the bolts (except when Dad's engine blew up and bent the rod into a pretzel), never had a bolt fail.

That said, if I were shooting for significantly more power than stock, I'd probably spring for some ARP bolts. I actually have a set on the shelf, next to the 89mm liners, Larry Young cam, headers, etc.

 

[MDCanaday]

Just go the full monte, buy the carillo's and you will sleep fine(if you dont tell the wife)
They are pricy but stronger and MUCH lighter. 640gr VS 825gr stock.This takes a huge load off
the crank at road speeds,and allows for an increased redline.
MD(mad dog)

 

[DNK]

Don't think the rod bolts would have changed the outcome

 

[Marvin Gruber]

For a std rebuild and casual driving, the original bolts will be fine.

Marv

 

[CJD]

It's all about RPM. If you don't wind it tighter than stock it'll be good. I always trust the original bolts better than aftermarket anyway...with the exception of ARP's.

 

[svtmikey]

Don't skimp......for the little bit of money you save.....buy new ones. Then if your engine "packs it in" you know at least it wasn't the bolts. I personally never have understood why you would mix new parts with old parts on critical items like internal engine components...unless you are on a very tight budget....but then, perhaps British cars may not be the best choice, as they a simply endless money pits anyway.

 

[CJD]

Don't skimp......for the little bit of money you save.....buy new ones. Then if your engine "packs it in" you know at least it wasn't the bolts. I personally never have understood why you would mix new parts with old parts on critical items like internal engine components...unless you are on a very tight budget....but then, perhaps British cars may not be the best choice, as they a simply endless money pits anyway.

You reuse the crank and rods, don't you? When properly installed and not overrevved, the bolts do not see any fatigue loading. The only way they could is if the revs were high enough to pull the mating surfaces of the rod and cap apart, or if the bolt was not torqued enough to allow the same to happen. Unless they are damaged or corroded, they have no limit to their useful life.

Some of the newer engines actually use bolts torqued to stretch them past their elastic limit, so they cannot be reused. These old tractor motors are old school, and the bolts are not "overtorqued".

If you sleep better, they are not expensive, so change them. But I would not change mine and will not loose a minute of sleep...unless I planned to rev a good bit higher than stock...in which case I would not use a stock connecting rod anyway, making the issue moot.

 

[glemon]

I agree with John, and couldn't have said it better myself, everybody is entitled to their own opinion, I have not rebuilt that many engines, but I have driven British cars for over 30 years, many of those years using them as daily drivers, never had a con rod bolt break, never seen any signs of stress on them when taking motors apart. I replace the parts that wear, bearings, pistons, rings and chains, chain tensioners, when rebuilding. The TR motor is probably over-engineered in that area anyway, don't worry, you will break the crank before you break a con rod bolt (if that makes you feel any better) Greg

 

[PatGalvin]

But Greg, he already broke the crank!!!

 

[HarryL]

For what it's worth; when rebuilding my engines I always replace the bottom end with the best stuff.
Most have been racing engines, but recently did a 4A's with Carrillo rods, ARP bolts, lightened and
balanced the flywheel(so when I drop it ,it'll only break one toe) & balanced the crank. Minor stuff to the top end.
The carbs will keep the revs down to a point. Had an old racing engine builder tell me to try to build the engine for
about a 1000 rpm's over redline. It's the missed downshift that'll get you.
Harry