HELP!! SR Engine Building

[240KAR]

So I bought the tools to put my Sr together myself, bore gauge, micrometers, blah blah..

Anyways, the question I have is this, I have measured my crank and my block with the bearings (ACL race series) in it and torqued to spec. Then I took my biggest clearance from the block and subtracted the crank measurement…

Here are my measurements and I've checked them multiple times… largest number is the block main journals and the smaller is the crank journals.


55.029 - 54.968 = 0.061mm Journal #1

55.031 - 54.957 = 0.074mm Journal #2

55.034 - 54.963 = 0.071mm Journal #3

55.031 - 54.956 = 0.066mm Journal #4

55.036 - 54.973 = 0.063mm Journal #5

Tolerances are suppose to be from 0.009mm - 0.022mm as you can see mine are way off!

What could cause my clearances to be this far off.. I've checked multiple times and got around the same numbers.

the only thing that was done to the block was align hone and the polished the crank..

[di-devol]

What could cause my clearances to be this far off.. I've checked multiple times and got around the same numbers.


Here is your problem. You should get the same numbers every time. I'd take it to a shop.

[Kingtal0n]

So I bought the tools to put my Sr together myself, bore gauge, micrometers, blah blah..

Anyways, the question I have is this, I have measured my crank and my block with the bearings (ACL race series) in it and torqued to spec. Then I took my biggest clearance from the block and subtracted the crank measurement…

Here are my measurements and I've checked them multiple times… largest number is the block main journals and the smaller is the crank journals.


55.029 - 54.968 = 0.061mm Journal #1

55.031 - 54.957 = 0.074mm Journal #2

55.034 - 54.963 = 0.071mm Journal #3

55.031 - 54.956 = 0.066mm Journal #4

55.036 - 54.973 = 0.063mm Journal #5

Tolerances are suppose to be from 0.009mm - 0.022mm as you can see mine are way off!

What could cause my clearances to be this far off.. I've checked multiple times and got around the same numbers.

the only thing that was done to the block was align hone and the polished the crank..

.063mm = .0024"

0.022mm = .0008"

Check your units and make sure the bearing are round (you are not just checking one direction) that the bearing is not egg shaped when torqued @ spec

from the FSM: ".004-.022mm (.0002 - .0009 inches)"

You may have the wrong bearings. Most people would just throw the bearings in and check if the crank spins free (which it would have) and go, which might explain all the disaster sr20 builds using those bearings.

Wrong as in "wrong size" not wrong as in wrong part #. Why not try OEM bearings? At least for mockup purposes to see if it's your bearing or your crank that is throwing everything off.

[240KAR]

When I say around the same number.. I'm talking like very very close.. like +- .002mm. So I don't think my measuring is the case..

Yeah, I'm trying to do it right and not just throw it together..

Okay.. the bearings were out of round.. I am going to torque them to only 65ft-lbs and try again..

and the crank is in spec.. the numbers on the main journals are 1 2 2 2 0.

When I measured the crank ( the third time) the measurements fell in the 1 2 3 2 0 category [ per FSM].. journal 3 was a little off but still within the operating limits..

1 - 54.970
2 - 54.963
3 - 53.961
4 - 54.966
5 - 54.975

rechecking the bearings now...

[240KAR]

at 65ft-lbs I took 3 measurements

10 - 4 = 55.057mm

2 - 8 = 55.046mm

12 - 6 = 55.064mm

thats 0.018mm out of round… way too much.. could the machine shop have messed up my line bore?