BottleRocket

damn, and you think building a bottom end is expensive now...?

CHRISPY

Personally I think you should do:

1) ARP main studs
2) ARP Rod bolts
3) Good set of rods (Lunati, Eagle, Oliver etc)

I would do the pistons (forged) at the same time, balance everything and make sure your machine/bearing clearances are PERFECT. It may take a bit of time setting everything up but once you do it should spin to 7500rpm plus without issues.

(This is of course that the cam/lifter/spring/oiling is all taken care of)

If you dont do the above (esp rods) you are going to wipe your motor and probably take out everything. (crank, rods, block, pistons, cam and heads) could all be destroyed

Hardtop

iTrader: (3)

I swapped rod bolts to ARP's. Rev limiter is set to 6900. Have hit it a few times. Shift beween 66-6800 rpm. Through the lights around 6700~. No problems so far. Knock on wood. Cannibal posted some good info. I believe you are rolling the dice spinning a stock bottom end this high even with rod bolts. Certainly you are reucing the life span of the motor if nothing else. My car isn't a daily driver, but if it was my only vehicle, I probably would spin it that high.

Bruce

Dragaholic

iTrader: (180)

Well lots of people spin their motors to 7000+ rpms with a completely stock bottom end and I was planning on replacing the rod bolts since thats what makes a motor goes. Its the first thing to give before the entire bottom end goes or at least thats what everyone here says. I am no expert on this, but I figured if there are lots of people spinning their completely stock bottom end to 7000+ rpms and getting away with it, I would have a better chance than them because I'll be replacing the rod bolts which is the weakest link in the bottom end.

dug

iTrader: (10)

Its kinda funny if you think about it. It would probably be safer to spray a 50hp dry shot and shift at 6500 than to try to get the extra 20-30hp by revin a big cam past 7k.

V8er

iTrader: (2)

I think that is REALLY confusing the issue. I want to rev mine to about 7000rpm to give a wide powerband and make good power but I have zero interest in N2O!

I plan to use ARP rod bolts with an otherwise stock bottom-end on an H/C LDS1I haven't seen any proof that this combo won't last.

dug

iTrader: (10)

Yeah, I know. My point is that tensile stress from high rpms is what kills the rods. They can handle a lot more compressive stresses like from nitrous or boost.

Whatever you guys do good luck. And let us know how everything works out.

Scalpel

iTrader: (4)

This is where you're incorrect and why you need to read factual data that has been posted.

Based on the data that Jason 99 T/A and a few others have posted there have been deformation of the rod bearing bores when the ARP rod bolt installation procedure is performed. This means that the bores are NOT concentric and are more likely to fail. They know this because they actually MEASURED the bores of the rod bore AFTER installing the ARP rod bolts. This isn't hypothetical data.

You'd be BETTER off by keeping the stock rod bolts in b/c at least you'd know your bores were concentric and not deformed.

Scalpel

iTrader: (4)

One person did measure their rod end bore AFTER installing the ARP bolts and the bores were not deformed according to his measurement.

The bottom line is that unless you actually measure it, AKA do it the right way, you'll have no way of knowing if you are indeed more safe than spinning the stock rod bolts to "x" RPM.

Scalpel

iTrader: (4)

Quoting Jason99T/A:

Jarrod, I have checked the housing bore on the rods before and after the rod bolt install (ARP Pro-series bolts). There is some definite deformation after the new bolts are installed. Every motor we build with stock rods has the housing bore re-sized .002" larger than stock to accept a new, oversized bearing from Clevite for this very reason.

You motor is not going to instantly blow up if you don't re-size the rods. Heck, the motor I built that was in my car with the TReX cam/stock heads had the ARP bolts installed without any re-sizing. It is still running just fine after 10k HARD miles and probably over 100 dyno runs and quite a few track passes turning 7200+ rpms. However, it is very important to have to have a housing bore than is within spec, not out-of-round, and free of taper. This is very important for long bearing life.

Another thing to point out is measuring the housing bore with the rods bolts streched to the required amount, not just torqued to spec. Having the ARP pro-series bolts torqued to 45lb-ft very, very rarely gets you within the recommend stretch for this particular bolt. On the motors I have built, this generally takes 55lb-ft or so. This number will vary based on the type/amount of lube used, condition of the threads, and the calibration of the torque wrench.

critter

iTrader: (9)

So how many have measured their rods with stock bolts to find out whether they are out of round??? Oh wait. You can't because the bolts can't be reused.

Someone would have to demonstrate personally to me that Arp bolts cause the rod big end to go out of round while the stock bolts don't. Us engineers like to see proof of something that doesn't make any sense.

8POTS

Call me old fashioned and untrusting of stock components but if I was reving past 6500, I would be thinking of doing a specific build with tough components top to bottom....all mic'd up and balanced. Still no guarantees here but you have something built for the job.

7000rpm on stock components is certainly on the ragged edge of what stock components will put up with..bolts or no. The serious punters get a motor built and inspect an intervals. Nothing is left to chance.

There won't be much left of your motor should something substandard let go at those revs. Might even take out some other gear in the engine bay.

If you don't have the folding to do a build, you won't have it to pay for a repacement motor when it finally 'lunches' itself.

Scalpel

iTrader: (4)

Based on the volume of these engines produced and the reputation GM engineers must keep I'd be willing to bet that their design and installation of the stock rod bolts in the stock rods have been thoroughly tested to not deform the rod end bores.

Someone has already demonstrated that the ARP rod bolts can cause rod big end distortion.

All we need is someone to get a stock rod and use a set of new stock bolts to test it out.

That's the only way we'll know for sure.

However, to test well it'd be ideal to have several hundred individual stock rods in two categories, one with stock rod bolts and one with ARP rod bolts.

Install them to spec and measure the rod big end bores out of both groups and analyze the data that way.

Will that happen, nope. But it's nice to dream.

Cal

iTrader: (1)

I'm resurrecting an old thread here, but an important one.

How about installing the ARP bolts on each rod, but without the crank, just to measure the roundness. If round, use the ARP's. If not, reassemble with new GM rod bolts. Would that work?

Lostpatrolman

iTrader: (3)

I remember reading that the katech rod bolts were the same length as stock bolts. Would this mean that if torqed the same, they wouldnt deform the rod end since they would have the same clamping force?

Mike94ZLT1

iTrader: (3)

Very good point, I would like more info on this!

gnx7

iTrader: (28)

Take a look at Katech rod bolts also. The resizing problem doesn't seem to be a problem with them. For $140 I should hope not....

I run them as well as many others.

Cal

iTrader: (1)

Where do you buy them? Any of the sponsors have them? ====>

dug

iTrader: (10)

If sponsors dont have them you can get them directly from Katech Engineering.