Rod Bolts

[Doc Oc]

So my car goes under the knife next month to have the bearings replaced. I'm going with the wpc treated bearings but am undecided on which bolts to use. The shop doing the work suggests the arps, but some very smart people on here have said to stay with stock. Not worried about the stretching process necessary with the stockers, just want the best in terms of longevity. Anyone have any input?

Thanks

[VictorH]

Where are you having it done?

[OM VT3]

Stock

[chris719]

See the main thread. If not stock it seems that Lang Racing has measured no bore distortion with the Carrillo WMC bolts at 50 ft/lbs.

[Atomicteal_M3]

Subscribed

[OM VT3]

Originally Posted by chris719

See the main thread. If not stock it seems that Lang Racing has measured no bore distortion with the Carrillo WMC bolts at 50 ft/lbs.

But they didnt do the bolts up as per carrillo instructions i dont think

[BzsBimmer]

Stock

[pbonsalb]

Originally Posted by leigh

But they didnt do the bolts up as per carrillo instructions i dont think

Lang is smart. They tested to see what worked.

[OM VT3]

Originally Posted by pbonsalb

Lang is smart. They tested to see what worked.

And your dumb.....incorrect clamping force

[BzsBimmer]

Originally Posted by leigh

And your dumb.....incorrect clamping force

Easy there tiger... no need for personal attacks

[Doc Oc]

Originally Posted by chris719

See the main thread. If not stock it seems that Lang Racing has measured no bore distortion with the Carrillo WMC bolts at 50 ft/lbs.

The main thread is what I was thinking of when i made this post. I was set on the arps, but after reading that I started leaning toward the stockers. Then the guy at the shop said he wanted to use arp and I read the bimmerworld right up where they said they were far superior to stock. Is the bore distortion issue proven?

And does anyone know for sure if the bearing kit at bimmerworld are wpc treated? They say treated but not specifically wpc....

[Doc Oc]

Originally Posted by VictorH

Where are you having it done?

A shop in your neck of the woods, european road and race.....I think. Going to talk to a few places in Charlotte before committing but I'm leaning towards them.

[admranger]

Originally Posted by leigh

And your dumb.....incorrect clamping force

Jackass much?

OP -- stock or if you have to have something else have your shop call Lang and discuss their thoughts on rod bolts.

[BMRLVR]

Use the OEM bolts they are the bolts the rods were made to use. If you were doing a full rebuild and could remove and hone the rods you could use the ARP's with no issue, but since you aren't there is only one choice.

[regular guy]

Originally Posted by Doc Oc

The main thread is what I was thinking of when i made this post. I was set on the arps, but after reading that I started leaning toward the stockers. Then the guy at the shop said he wanted to use arp and I read the bimmerworld right up where they said they were far superior to stock. Is the bore distortion issue proven?

And does anyone know for sure if the bearing kit at bimmerworld are wpc treated? They say treated but not specifically wpc....

I can't speak for the bearings at bimmerworld, but I can speak for the bore distortion. I'm the guy who did the bore distortion measurements. You can find the results in one of the malek@mrf threads. Those measurements were arp 2000 bolts. I also measured arp 625 bolts but haven't published the results. There was still bore distortion, but it was maybe half or less than the arp 2000s if I remember correctly.

[OM VT3]

Originally Posted by admranger

Jackass much?

OP -- stock or if you have to have something else have your shop call Lang and discuss their thoughts on rod bolts.

If lang said 5ft/lbs was ok and there was no bore distortion half the people on here would believe it and recommend it to others when they have no idea at all

[pbonsalb]

Originally Posted by BzsBimmer

Easy there tiger... no need for personal attacks

I am not offended. I'll go with Lang Racing over Leigh for a performance motor build.

[OM VT3]

Originally Posted by pbonsalb

I am not offended. I'll go with Lang Racing over Leigh for a performance motor build.

And thats fair enough but in saying that you must also go against carrillo for there own rod bolts that they have worked out what ft/lbs clamps the cap to the rod best for each materials

[pbonsalb]

I am not sure Lang was going against Carillo. If you read Lang's post on the subject, you will see that Lang stayed within Carillo's stretch spec. I have not read Carillo's instructions for bolts for these motors, but I have read ARPs, and ARP prefers the stretch spec to the torque spec. ARP also says that the stock rods should be resized when using ARP bolts. No one doing a bearing swap resizes the rods since they do not remove the rods. Based on all this, I would be most comfortable going with what a racing shop with experience building these motors has found to work based on actually testing of the bolts in rods on the bench using both the stretch and torque spec. If Lang has found 50 lbs gives the least distortion, that is what I would go with. I would not be surprised if Carillo revises its torque spec to Lang's torque spec.

[Doc Oc]

Thanks for all the responses. Good info

[Doc Oc]

So are the Carrillo's a good choice as an alternative to stock? No bore distortion, more clamping force and an easier install?

[BMRLVR]

Originally Posted by Doc Oc

So are the Carrillo's a good choice as an alternative to stock? No bore distortion, more clamping force and an easier install?

The OEM bolts have been tested and proven as strong or better than the aftermarket alternatives while creating higher clamping force. Couple this with the fact that the rods were bored with an OEM bolt in mind and it is a no brainer. The only reason to use the aftermarket bolts in the OEM rods is an easier less time consuming install.

Id stick with the OEM hardware if I were you.