What Shells?

[mmt 15]

Hi guys,

 

I´m reshelling my mi engine but I don´t know which shells is in it.

 

I´m changing both the main and the big end bearings. I was hoping for not taking out the crank but the machin shop can not from the numbers on the old shells figure out which shells to replace them with.

 

Is there any way that I from the numbers on the backside of the old shells can tell what size I need the new shells to be.

 

Any experts????

[welshpug 1,657]

measure the journal and the thickness of the shell, would have thought the machine shop could have done that

[mmt 15]

Hi mate,

 

What´s "the jurnal"?

 

The machine shop was somehow reluctant as the engine is french.....old monkey!

[welshpug 1,657]

the part of the crankshaft that the bearing runs on

[mmt 15]

Thanks!

 

It might be best to bring the jurnals to the machine shop. I was hoping that it was possible to get the size from the numbers on the shell.

[Miles 331 1 Cars]

Never replace bearings without measuring them first, these wear more than the eye can see

[pug_ham 244 3 Cars]

If your machine shop don't know the basics about measuring the crank to find bearings to suit, I'd be taking it somewhere else that does.

 

It can be done with the crank still in the engine for the big ends but the mains aren't as easy although can still be done, just.

 

Best way to get accurate figures is to have the crank on the bench though imo.

 

Graham.

[DamirGTI 342]

If your machine shop don't know the basics about measuring the crank to find bearings to suit, I'd be taking it somewhere else that does.

Graham.

 

Quite right , doesn't sound like a professional shop !

 

For main bearings , most accurate way to measure clearances is by comparing outside dia. of the crank journals to the inside dia. of the bearing caps .. set of inside and outside micrometers are needed for this or better still - dial bore gauge .

Less accurate way - plastigage ..

 

For big end bearings , first need to measure crank journal dia. (with outside micrometer) , and then fit the shells inside the conrod/bearing cap , tighten to spec. torque and measure inside vertical dia. (with inside micrometer) - difference in between the two readings is bearing clearance ..

Again , less accurate way - plastigage ..

 

Damir

Edited November 9, 2010 by DamirGTI

[mmt 15]

Thanks gyus.

 

I think I after all will be removing the crank and take it to the shop. It also could do with a polishing.

 

Better safe than.....