Arp rod bolt install-> resize rod big ends?

[milkandoj]

I am freshening up a spare motor doing a stock rebuild. 1g motor with stock rods and pistons.

I mentioned to the guy at the machine shop i wanted to install arp rod bolts, he said i should have him resize the big ends as the rods are machined at the torque of the stock bolts, the arps apply more force than stock bolts so the shape of the big end will change slightly so they should be then machined with the arps installed.

I dont remember seeing people talk of doing this is it common practice and needed?

 

[bryanwheat]

This is common practice and a good idea. You can always measure the inside with a bore gauge to see if they are out of round. Most rods are out of round after many years of running anyways. For the price (usually 10 a rod) it is a good idea.

 

[LandSpeed-DSM]

For piece of mind have them run your rods on the mandrel after they press in the new bolts and then get the appropriate sized bearings from Clevite/ACL

 

[92AWDHX40]

Got mine done just now on my build they turned out great. I have pics some where.

 

[ed1380]

Ostar is running 9's with stock rods and bolts, it's your call.

 

[99gst_racer]

Ostar is running 9's with stock rods and bolts, it's your call.

That car is a freak of nature though. Most people won't be able to make that kind of power on OE rod bolts. They were just never designed to be that strong, even if one in a thousand can get them to actually stay together at 650+ HP.

 

[BogusSVO]

YES get the rods checked/resized as needed.

The hi/low spec is about .0007

The rod bore shape will deform due to the remove and replace of the rod bolts.

 

[milkandoj]

The machine shop wants 140 to resize all 4 rods. Not really worth it on a stock rod.
Where do stock bolts start snapping? I’d be aiming 400whp max with this setup.
Are they like head bolt's where they can’t be re-torqued anyway, so can’t be reused due to being stretched.

The machine shop measured up my ptw clearance when they acid dipped the block, and its 40-50 thou with the stock pistons so looks like it needs a 0.5mm overbore and I need to do forged build.

I may be moving for work in 6 months so the car may be sold, what’s the consequence of the larger ptw clearance and the pistons rocking due to not expanding like a forged piston with the larger ptw clearance.
Is it just wear and scuffing or may they shatter?

 

[bryanwheat]

.004-.005 is pretty big for stock pistons. I would bore it and get some nippon pistons. 140 to re size rods is outrageous. I pay about 50 to do all 4.

 

[evileagleawd]

Def get the rods resized if you going to install arp rod bolts. Is the price of $140 labor include pressing in the wrist pin, installing arp hardware, and resizing the rods? If it includes everything that is not a bad price.

 

[milkandoj]

If i bore it an go larger pistons ill go forged rods and pistons.

What will happen running 40-50 thou ptw clearnce on stock pistons for a bit before selling the car?

I may end up selling the car in 6 months anyway. I spent the last 4 years on the car but it may be time to sell her