Connecting Rod Nuts/Plastigage

[VOTS89]

My engines out of the car and I'm changing the rod bearings.

Since we don't reuse the old rod nuts, do I check the bearing clearance with the old rod-nuts or the new rod-nuts?

Torquing the new nuts to spec and then removing them to inspect the plastigage seems odd.

Thanks...Bruce

[thomasryan]

Use the old ones.

[VOTS89]

Thanks

[thomasryan]

Right behind you on doing the connecting rod bearings.....a little preemptive at 93k but the kit was on sale))

Did you have the crank polished?

[VOTS89]

I didn't have the crank polished or replace the main bearings and I don't know if I'll regret it later. The bores look sweet so I'm hoping I'll get lucky.

I know I'm so close to rebuilding the whole engine, I go back and forth in my head about taking the short block to the machine shop.

How about you?

Bruce

[thomasryan]

Most ppl that I know with these cars get 250k out of the rings so better left untouched unless there is oil consumption.

The car had the upper balance shaft off a tooth when I purchased it and the hall sensor wires where shot from heat. Resealed the front and oil housing and I have replaced the mounts with some very cheap ones...$17 clearance item cheap so I bought 4. Car is very smooth after the pistons warm up a minute.

Hot oil pressure is good but not perfect and most professional mechanics on these motors notice cylinder wall issues if the con rod bearings are allowed to get too shabby. I like the Lindsey racing improvements to the oil pick up and my plan is to go this route.

[Bradical]

Back up... The rod nuts need to be replaced because a service bulletin came out to order the replacement of the smooth-face nuts that the engines were shipped with with replacement ridge-faced nuts.

The nuts are not one-time use and they can be torqued and removed. They are not egged or oblong.

[thomasryan]

He is just temporarily using them to check clearance.

[Bradical]

Originally Posted by thomasryan

He is just temporarily using them to check clearance.

Yes that's fine, the point is that it doesn't matter which ones you use for the plastigauge.

[thomasryan]

Good catch though))

I am a doubting Thomas by nature and the number 2 rod bearing thing, I feel, is a combination of many things. Aerated oil or lack of oil at the pick up is probably the main offender but other things come to play in my mind. The force/inertia vectors in the balance weights are pretty close to same plane as number 2 on the crank. I am really to lazy to do the math on the primary or secondary harmonics but due to packaging, there has to be a compromise to lessen the first order and let the lessor vibrations fall where they may.

And why does the oil return dump next to the pick up? If you pour a Guinness stout, it takes a good ten minutes for the head to go down. There is no way to rephrase that...I feel like Leslie Neilsen and just farted before the camera rolled.

[Bradical]

Here's the page I was talking about, just to further clarify. I was under the impression they were one-time use when I did mine, too.

[VOTS89]

Thanks for the additional info, I'll be replacing the bearings this weekend.

Bruce