Thread: Concerned with ACL Race main bearing clearance.

Nope, you're not reading the chart correctly. You're mixing up the metric with american standard inches. The above chart is stating .014 mm = .0006".

To give you a better idea of the proper main bearing clearance, the FSM call for .0002"-.0009" as standard and the limit is .002".

Dont mix up the metric and SAE measurements. It gives you a range on the clearance according to the chart

Rod bearing clearance: .0008-.0026 in " Plastigauge uses both " and mm dont confuse them and dont confuse your decimal places either. .0006 and .006 is a huge difference lol.

On rod bearings i shoot for .0015 to .002" Main bearings .002-.003" Youll never have issues in those spec ranges.

Im using the .001" extra clearance bearings on my motor to compensate for the 20w50 race oil.

your right, I was looking at it wrong. Either way, I tried two cranks and they were both the same measurements.

I have plenty of experience measuring tiny things.

So I guess my next question is how I can get .006 using two different cranks?

Well, how did you measured the squish plastiguage? What were the steps did you take?



First, put bearings shell inside the main and bearing caps, install the crank.

Place the plastic/bugger across the main journal (front to rear engine).

Install the main bearing cap.

Torque to spec, very important. If you don't have a good torque wrench, and don't follow the torqueing steps, you won't get an accurate measurement.

Next, remove main cap and measure the squish plastic with the supplied gauge.

editted ....

Did exactly this, with the green first, then the red.

Another questions that is bothering me is how can plastiguage be used to measure one-ten thousandths of an inch if the plastigage only allows for thousandths measurement.

You seem to have arrived at the same conundrum I did way back when.