[kkrofft]

Repairing a blown head gasket and I want to assess the condition of the bottom end by plasti-gaging the rod bearings.
What is the specified torque to retighten them to and what is the allowable clearance?

Thanks,

KK

 

[drvITlîkUstôlIT]

I wouldn't recommend plastigauge although sometimes you gotta do with what you got.

I'd use either (in order of preference)

1.) An inside micrometer (aka "dial bore gauge") in the big end and a outside mic on the crank journals

2.) A snap gauge in the big end and check it with a mic, then mic the journals

3.) A snap gauge in the big end and check it with a dial caliper, then use the dial caliper to check the journals.

Any of those would be better than plastigauge.

The bearing clearance service limit (the max allowed) is .0032"

Optimum is between .0009"-.0017"

The torque spec is 16-19 ft.lbs on all caps, then tighten and additional 90*.

You may as well check the side clearance of the rods with a feeler gauge while you're at it.

Side clearance service limit is .0160"
Optimum is between .0070" - .0130"

 

[kkrofft]

THANKS! That is just what I needed. I actually have the snap gauges and mikes but I am trying to do it with the engine in the car and thought Plasti-gage was OK.
I will be pulling the pistons to re-ring anyway so It won't be that hard to check per your suggestion.
Is it possible to do the mains while in the car? I have not tried to "split the case so far. I figure if the rods look OK I will infer the mains are OK too but i would really like to be sure.

KK