NightmareTA

iTrader: (20)

Recently cracked a ringland on cylinder 7 on my turbo 5.3 setup. I planned on pulling it out and throwing in one of the spare pistons I have, but upon teardown I found out it bent the rod on that cylinder as well. It's only a very slight bend, and I have a few extra rods laying around so thats no big deal to replace it as well.

My question is on the bearing replacement. Heres a few quick pieces of info on the setup...

Motor has 37K original miles. Crank journal is absolutely perfect with no marks whatsoever. The rod bearing I removed from that cylinder had a VERY slight "mushrooming" at the 4 corners on one half of the bearing where it would butt up to the other half. I don't want to re-use it so I ordered a replacement standard size sealed power bearing from the local parts store. How crucial is it to use plastigage first to check clearances in your opinions?? I can only assume that on such a low mileage engine and with using a standard size replacement bearing, it should be ok to just re-assemble.

Only reason I ask is because I'd like to get the car back together during the day Sunday, and I can't even begin to think of where to find any plastigage locally. Really don't want to have to wait and order it online...but if this is a pretty critical step, then I guess I could bite the bullet and hold off on re-assembly.

DropShipDave

I would assume your local napa or automotive store would have some for sure (My local napa says they have it in stock when I checked their website). Autozone says its eligible for 2 day shipping if you can't get it local. Call up your local machine shop/engine builder/speed shop. They would know how to get you some too.

If it were me I would want the piece of mind knowing that I have the proper tolerances on my rod bearings. That few dollars and a maybe a day or two wait could save you money and time in the long run.

SS2win

iTrader: (11)

Plastigage is not made of unobtainium. Any name brand parts house should have it. You definitely want to use it when replacing a bearing. Good luck.

Cam72aro

iTrader: (28)

You want to check the clearances. If not the motor might kill the bearings. It's like $10 or less. Like stated local parts stores should have them.

The Alchemist

iTrader: (19)

I don't know... I don't think plastigauge is that accurate, and what's it going to tell him? It's not like he's going to machine the crank journal to increase the clearances.

I'm not trying to argue here, but honestly, if the measurements aren't in tolerance what are you planning to do?

Cam72aro

iTrader: (28)

You can polish the crank, or polish the bearings to increase clearance. The only reason I suggested it is because I put a motor together without checking clearances and in 15 minutes of idle time all the bearings were gone. What if the replacement bearings are too thick? Micrometers are the best way to go, but plasti gauge will work better than not measuring at all.

NightmareTA

iTrader: (20)

I have a pair of very accurate digital vernier calipers that I was going to check the new bearing with and compare it to the old. May not be fool proof, but it's better than just "assuming." I guess if I can possibly find some plastigage at the local napa, maybe I'll pick it up.

Thanks for the replies guys. The forced induction section never fails to help out!

The Alchemist

iTrader: (19)

Please understand that I wasn't saying that it's not important to measure, but rather that I don't feel plastiguage is accurate enough to make corrections based off of the results.

The best way is to use a mic on both the crank journal and the rod end and figure out the bearing size needed.

Cam72aro

iTrader: (28)

I agree Alchemist. It's better than nothing I guess. I prefer the mics like you said. I definitely would check it though.