91sonomast

You won't break the rod bolt and send a cap flying around inside the engine.

streetknight2

iTrader: (10)

I had my engine apart and put ARP bolts in. 2 of the 8 rods "ovaled" and needed to be resized, the other 6 mic'd fine. However, I had them all re sized so I can use the same bearings.

ALWAYS check, no matter what brand bolts you're using. It's just the right way to do it.

Thanks for the info OP

Marc 85Z28

iTrader: (8)

I didn't present any theory, or make a dedicated thread either, YOU DID. All I stated is that I, along with MANY others, have had no problems doing what you claim should never be done. If the ARP bolts cause the rod to distort with eventual bearing failure, it would show on every rod on every engine that they were installed in. Too bad theory and real life don't always align Other factors are likely at play here if a 100% failure rate doesn't occur. Cheap or inaccurate torque wrenches, using 10mm socket instead of a 3/8", removing both bolts on one rod at the same time, etc etc.

And no, I don't have the bearings out of my engine so I can provide "data" to you! Why disassemble a good engine that was built properly?

KCS

iTrader: (20)

If you think of clamping force as a preload to oppose the forces trying to rip the bearing cap apart, then it makes sense that you would first want to increase clamping load as those forces increase (ie increasing RPM, bobweight, etc). Not enough clamping load can allow the rod bolt to stretch, ovaling the bearing bore, and if you don't spin the bearing first, you then cause a fatigue failure of the bolt itself.

So I don't think preventing a rod bolt failure is an accurate answer.

KCS

iTrader: (20)

In my opinion, ARP rod bolts absolutely will distort the bearing bore in every application, but with manufacturing tolerances typical of mass produced products, the consequences vary. I saw .0005" variance putting ARP bolts in a set of LS3 rods. That's .0005" more/less bearing crush or .0005" more/less bearing clearance and that was the beefier generation of rods.

Bearing clearances in OEM engines vary greatly, some have as little as .0009"!!! In an instance like that, where bearing clearance is tight, and the ARP's make the bearing clearance tighter, then you WILL have issues like we see here. If the bearing clearances are looser, the engine may survive.

Again, just a theory...

s346k

iTrader: (4)

i have had a hand in multiple katech swaps on stock shorts varying in mileage from 50k to fresh rebuilds. none of those blew up from rod bearing failure...in fact, none of them blew up at all. for whatever reason, the katech bolts seem to work just fine without resizing rods. i don't really see the advantage to an arp bolt unless the big ends already needed resized to begin with. even at that point they are overkill for 99% of the engines. i've seen stock bottom cars that stretched rods with stock bolts in them. year indiscriminant.

noskcaj

iTrader: (2)

All these threads make me nervous, haha.

I have LS1 rods that have the basic ARP rod bolts installed. I brought them to a decent machine shop that specializes in ls1's near me and he said they are all within 0.0003 OoR, which is within spec. I don't have a way to measure a bore that accurately in my garage, so I trust his blessing, but still makes me nervous. Rods only have about 3k on them if that makes a difference.

I guess I'll keep my rod clearances on the looser side with the new bearings.....

ohioz

iTrader: (9)

That makes no sense...How are both bolts stronger yet only one increases clamping force? Because Katech says so? Im not trying to be bias, i just wanted to know if I was the only one that thought this. Oh btw I have had arps in my car for over two years making 580 wheel through a turbo400

gMAG

iTrader: (1)

anyone else have that stinkin' Family Dollar ad blocking their view of this thread?
Anyway, I changed over to ARP's, without resizing. Many people here haven't resized, and claim that everything is fine with their engines.
My engine had a couple of complete bearing failures, combined with an ongoing oil pressure issue.
After tear-down, there was more than one issue which could have contributed to the failures. I'll never know for sure.
One thing I have learned....when the directions call for resizing, or any other protocol, do it!
While putting the engine back together, I followed directions, to the letter.
BTW, I'm now using the upgraded LS6 OEM rod bolts.

badazz81z28

iTrader: (6)

I'm curious about that too! Apparently Katech knows something that ARP and others don't.

Maybe Katech is really just a stock bolt

BrntWS6

iTrader: (7)

Are the torque specs differens on the ARP vs Katech?

studderin

iTrader: (28)

ya, I think the GM stock LS1 rod clearance is .0009 to .00027 or something people think is really tight. They run fine with that. How many people know of a failure form the stock rod bolt? Stock engines don't have rod bolt problem, its oiling issues, tuning, and unstable valve trains that take them out.

FYI the GM endurance test on a stock LS3 is under load varying 8,000 rpm for 23 hours

quik95lt1

iTrader: (7)

glad i could help out those that know what i was presenting here for the ones that disagree......hey no sweat off my back

quik95lt1

iTrader: (7)

glad to see someone that understands what actually happened here.....do all motors do it? no.......do some? yes.......this was one of the "some"......i treat every engine like a 9000rpm race engine regardless of street intentions or race intentions.....keeping the attention to detail is what builds good engines......and this is something that is a detail.....again personal preference if you call it....opinion if you may.....or fact.....take it how you may



if you go visit a good machine shop with a good racing background they will agree with what i am saying......will all "big" machine shops agree.....no........but many experienced in the racing area will........the shop that does my boring and balancing regularly machines and builds 2000+hp tractor pull motors as well as top fuel motors.......he agrees with me on this topic 100% and will not install rod bolts in a motor without sizing the housing bores.....i wonder why?


anyways...........i resign from this thread.......have no need or want to argue or try and defend something that i know is right in the first place........no hard feelings.....

bww3588

iTrader: (49)

In my experience, I installed arp bolts without resizeing 4 years ago when everyone on here did it...after 1k miles I had oil pressure problems, so I tore it apart and found the rods averaging .003 o-O-r and every bearing trashed...brand new bearings at that.

In katech's defense, I am under the understanding they use alignment dowls that prevent the cap from shifting under a higher clamp force.

Does this mean a hill of **** to me? No. I would never use katech bolts to avoid resizing...the initial cost is stupid and there is still the "what if" factor.

I couldn't care less how many people have done it and got away with it...it's still not smart esp when you consider the money invested in an engine build.

RezinTexas

if its the same clamping force, there would be absolutely no advantage to using Katech. It means that rod-cap flange face separation would happen at the same load point as the OEM bolts, resulting in failure.

The Alchemist

iTrader: (19)

I'm having a forged shortblock built right now, and with new rods, new bearings, new arp 2000's, my machinist measured rod bolt stretch, then resized the rods to make sure the bearings would be perfect. Is it overkill, maybe, but it's either worth doing right, or not doing it at all.

Can you toss in some different rod bolts, sure, you will eliminate rod bolt failure, but you may induce rod bearing failure. It might buy you some more time, and reduce the overall damage done, but it's still bandaiding a problem.

Just my opinion.

speedtigger

iTrader: (16)

I see some folks use the argumement: I got away with it, so it must be right. Or: I knew a guy who did that and it was fine.
That is just not definitive. There is no test period and there is no tear down for inspection to verify wear differences.
I will say, that I am also influenced by real world results of others in my choices too, but I try not to be prejudice on the information presented based on what I want to be true. With that said, you will notice that in every rod bolt thread there are some who have had no problem and others that have had failures. If you just look at those reports from the community, you will come to the conclusion that swapping the bolts without resizing is likely a poor procedure and comes with risk.
This conversation reminds me of somthing a CFO I used to work with said: Just because you made it to the grocery store alive without wearing your seat belt does not mean seat belts are unneccessary.............

wytry

iTrader: (6)

I don't want to hi-jack, but I have a question pertaining to rod bolts, and there are several people here that know what they're talking about.

I have an '02/'03 LS6 shortblock that I'm swapping in for my '98 LS1. Does anyone know if the rod bolts used in the LS6's are any stronger than previous year LS1's? I would prefer to not even touch the shortblock unless absolutely necessary. It'll be appx. a 450hp heads/cam car and see 6500-6700 occasionally.

Allen

Che70velle

iTrader: (6)

OK, I can't resist...you can take ANY connecting rod that has been previously torqued to SPEC, loosen the rod bolt, RE-TIGHTEN the SAME fastener too far, meaning OVER TORQUEING, or OVER STRETCHING the fastener, and you WILL have a rod that is out of round. It does not matter what fastener. Stock, arp, katech, diamond, pro-comp, etc, etc.
This is not a bolt manufacturer issue, this is a installation issue. Got an ald rod lying around? Try it yourself. I didn't believe it until I tried it myself, 20 years ago.