Big end bolts

[buzzer]

A question on big end bolts on my special twin cam. I am halfway through my engine rebuild, I'll post some pics in the next day or 2. I am upgrading the std rods to ARP, well hoping to. The little leaflet refers to the requirement to resize the big ends! Hmm is this necessary? Or is it just a precaution? Anyone know?

Dave

[jbcollier]

I assume you are replacing the big end bolts but reusing your old rods.  If so, you need to have the rods checked over by a good machine shop.  They may very well require resizing.  "Resizing" involves machining a wee bit off the cap faces and then machining the big end true and round again.

[buzzer]

Yes that's right. I think I'll ask the guy who did my other engine work. i didn't realise you needed to check the big end bearing dimensions when replacing big end bolts.

Dave

[buzzer]

Update. In talking to the guy who did my engine bits (David knight) resizing is needed when the bolts are pressed into the rods as they can distort them slightly. However as the big end and located with collars the big end bolts are therefore a loose fit (ie don't need pressing in) and there is no need to re size.

Dave

[jbcollier]

Used rods need to be check dimensionally if you are overhauling an engine: small ends wear, big ends can distort, rods can be twisted or bent.  Get 'em checked.

[Bainford]

Yup, I agree. Get them checked. You will be buzzing that little Twin Cam pretty good when it's back together. To reduce the chance of grief and foster piece of mind, make sure the bottem is done right.