BTW- I have ARP main studs.

 

are LQ9 and LS2 rods the same part?

 

from what I understand and have read but not 100%.

 

What kind of wear spots are you referring to? Copper showing on one portion of the diameter? Ever had a factory motor (with less than 100 miles - let alone factory crate motor (LS7) dyno break-in engines only) apart and look at the crank and rod journal, and especially cam bearings as installed by GM? Did you happen to check those bearing tolerances to GM specs before moving on with the build? When you say never... how many times in your experience does never mean? Once? Maybe twice? Or are you a machinest or an engine builder by trade? And how many times have you built a GENIII/IV motor thats not been honed and the crank will not turn after aftermarket main studs have been installed?

Bill

 

Bill, I understand where your coming from. I was under the impression that when you go from bolts to studs an align hone is needed, but again, it's been many years since I was "in the know" regarding machining procedures.

 

Wear spots I'm refering too is just high spots(shiny spots) Ones you can even see on a un-ran engine that has been turned over by hand a few times. Can you see .0005" of misalignment this way? Probably not. I have personally built around 25 engines with all of just a couple being 400-750 NA horspower engines; sbc,bbc,gen3,amc,&ford. I have built 2 Gen3 engines and both had ARP studs. But have been envolved in many others. I checked them for tolerance to be on the mid to high side of the factory specs upon reasembly. Neither of them had any problems what-so-ever with the crank not spinning freely, nor any engine build ever. All those problems have been associated with too little clearance on a bearing or thrust flange warped.
I am not an engine builder or machinist by trade. I used to do non-automotive manual & CNC work though. Just a gear head that usually gets nominated by family and friends when an engine project/build gets under way. I'm not trying to say that my opinion has more acredidation than yours, just stating my experiences. But I did stay at a Holiday Inn Express last night.

 

Bill, maybe you can teach us something. I have always heard that is what you "need" to do yet never had without issues. What is different about the threads that would cause the hole to change? Is the stud threads at a tighter tolerance in the hole and when torqued the hole swells more? Or is the extra torque you put on a stud (10-20lbs) distort the hole? What is the theory?

 

Went back and reread my posts last night and they definitely had a rather strong tone to them. I apologize for that.

I did this once before my machinest made me a believer...

I had my machinest (re)build a shortblock for a customer... all forged assembly. This particular motor had an Eagle crank, Eagle H-Beam Rods, and JE pistons. The shortblock was assembled with Clevite bearings spec'd for factory tolerances. Factory main bolts were used. We got the shortblock on an engine stand and started to finish assembly. The customer decided he wanted to change to main studs before the rest of the motor was put together. The motor spun OK when the cam was degreed. Changed out the main bolts for studs and the motor became VERY difficult to turn. Why? I could theorize or speculate but would probably be wrong. We wound up reinstalling the main bolts. I talked to the machinest about it and he didn't get into the reasons about why... it was more like "thats why I make sure the bolts/studs you supply are the ones that will be left in place after assembly." I left it at that. I have learned alot from him and started paying attention to his questions he would ask me, including his recommendations, when we would spec out a shortblock... questions regarding horsepower levels, race or street app, what kind of power adder if any, etc.

My machinest does it his way. Not all machinests are created equal and certainly have their own opinion based on their years of building engines. I too have home built engines...small block Chevy's. I never mastered a leak free 2-piece rear main seal. I hated Plastigauge... but it worked.

My bet is there are ALOT of home built GENIII/IV motors out there and most of them have not had any problems... yours being one of them. If Grippy home builds his shortblock will he have a problem? Chances are he will not. GENIII/IV motors are particulary sensitive to rotating assembly balancing... according to my machinest... another reason why I pretty much have left it to him for shortblocks.

Bill

 

I check each bearing tqed to spec with the bolts I am going to use by method of a dial bore guage and micrometers. Maybe that is why I have never had any issues. I attempted to use platiguage once and threw it away. But platiguage is much cheaper than a quality dial bore guage and mic set.

 

Some people are overly cautious IMO. Get the block checked and see what the shop says and go from there.