ARP main studs-crank won't turn
 

I'm putting together an LS-vtec. Block and crank are B18B1. I'm running ARP main studs for a B18C1 with an aftermarket aluminum main girdle. I'm trying to mate the crank and the block a this point. Problem is once all the main studs are all sequence tightened to the 80 ft/lbs ARP specifys, it takes a breaker bar to get the crank to rotate. Everything is very nice and clean, I have used assembly lube on the bearings & of course moly lube on the main studs. On the third attempt (kept having the studs turn in the block, as opposed to just the nut) I decided to make an extra tightening stage(if you will) at 72 ft/lbs, crank was a little tight but still spun by hand. Once at 80 ft/lbs, as it was with my two previous attempts, the crank needed a lot of incentive to rotate. I did plasti-gauge it beforehand and all of the journals checked out somewhere between the .025 and .038 specs. I do realize that this really only checks the clearance at the point where you place the plasti-gauge.

I've spoken with ARP and they told me I need to have the block line bored, because of the distortion caused by the ARP studs. Pretty sure that practice is not used on these engines. My guy at the machine shop is out for the day, obviously he is not able to give me advice right now. I'm considering swapping out the top halfs of the main bearings for one size smaller and trying again. What do you guys think?

Re: ARP main studs-crank won't turn
 

I've always seen everyone say switching to ARP studs for rods and mains requires line honing.

ARP does larger torque and it changes the bore over OEM. OEM was line honed at OEM torque with OEM studs/nuts.

Re: ARP main studs-crank won't turn
 

Guess I got lucky with my last two motors, or at least thought I did. Did not have this problem.

Re: ARP main studs-crank won't turn
 

Rebuilt a D16Z6 with ARP hardware and tighter clearances on those bearings. I too could not rotate the assembly by hand. Using a prybar, I was able to rotate and it was smooth. Stiff, but smooth. I was informed this is normal on a fresh build. Car is running like a scalded cat right now. **shrug**

Re: ARP main studs-crank won't turn
 

The difference in the factory torque spec and the ARP torque spec is dramatic... and that increased clamp force definitely distorts the main caps and saddle area. Thus, a line hone is required for optimal engine operation. "Really tight and expecting it to clearance itself" is a bad plan if long term engine reliability is important.

Re: ARP main studs-crank won't turn
 

JRCivic1-That's kinda what I was thinking(thank you as well tomcat). I think I just rolled with it before like Tx said. Those engines ran well, but my first ran for 15k and my second 10k. This is and has been a dual duty set up....street and time trial(road race). I doubt it will make much of a difference in how long it will last, of course I run the piss out of it on the track. My new plan/hope is to run it 3 seasons and rebuild. This motor will be pushing a bit more HP so I'm trying to dot all of the I's and cross all of the T's.

Re: ARP main studs-crank won't turn
 

anytime ARP main studs are used, line honing/boring will need to be done. mine was done, torqued to spec, and spins with ease. i build diesel engines for a living and even they dont require a prybar to be spun over. do it right the first time. just because you got lucky with not line boring previously, doesn't mean it was the right way to do it. would like to see how long the crank/bearing slast. if you cant spin it easily by hand imagine what is happening at 8,000 rpm. you can also measure "turning torque" (not sure if that is the technical term). that will tell you a lot.