Recomend a tool for checking roundness of big ends and crank

[BMWChris]

I assume I need a dial gauge for the big ends but i don't know anything about them - do they come in differnt sizes / designs?

Also, how should i use it and is any out of roundness ok?

I need to check that the crank was reground correctly too. What shoud the differnce be between the crank and the new big end shells be?

(I keep running big ends in my Triumph 1500 and am trying to work out why)

Thanks

[Old Merc]

These are specialist engineering tools found in a machine shop and are very expensive.Have you fallen out with the firm that reground the crank?as you need to get the crank and con rods checked by an engine builder.Please dont think I`m rude but if your not sure of the job get it sorted by an expert.As the ends "keep going??" what about the lubrication? has the oil pump or the oil pressure been checked?

[stevieturbo]

BMWChris said:

I assume I need a dial gauge for the big ends but i don't know anything about them - do they come in differnt sizes / designs?

Also, how should i use it and is any out of roundness ok?

I need to check that the crank was reground correctly too. What shoud the differnce be between the crank and the new big end shells be?

(I keep running big ends in my Triumph 1500 and am trying to work out why)

Thanks

there could be a multitude of reasons. But it is highly unlikely the crank has been reground with the journals anything but round.

A more important question would be. After the first failure, detail exactly what steps were taken to repair and ensure it doesnt happen again, and by whom ?

[Pumaracing]

I suggest you read this thread where it's all been covered already.

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[BMWChris]

All the details here:

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Out of interest I've had a "reconditioned" engine supplied with the wrong endcaps in the past (though in this case they were too tight) and a friend had a crank which was wrong. After much confusiuon, the conclusion was that the guy at the machine shop had ground and polished it and left it on the desk and a helpful colleague had come to "finish it off" for him before putting it back on the desk. Consequently it was undersize.

In my case I wanted to check the roundness of the big ends and the size of the crank (see OP).

Having read that the gauges are difficult to use I might be better of taking the head off and extracting the pistons and rods and getting a machine shop to check the roundness.

Edited by BMWChris on Friday 20th August 11:22