Topic: Beans33's main bearing clearance catch all thread.

[Beans33]

Hey guys, im trying to check my rod bearing clearances and im getting crazy readings. I used a mike to measure the journal, zeroed my bore gauge to the mike, then measured the rod with the bearings in and stretched to spec. Im getting a reading of 0.0792 ... what could I be doing wrong. Ive re tried everything over and over and im getting the same reading.

[Mase-19]

I recommend using plasti gauge to get your main bearing and rod bearing clearances measured. It is the most accurate way.

[Beans33]

Ive heard the opposite..Its really hard to bolt rods onto the crank and bolt the block together with the crank in without moving the parts and messing up the plasti gauge. I tried doing the 1st rod on the crank and torqued it on fine without moving it too much but it was so hard to split the halfs and get the rod back off the crank and by the time me and a buddy put all our mite and pulled it apart the plasti gauge was totally uckfayed

[Beans33]

Hey guys im measuring up my bearing clearances  and so far ive got the following measurements

1 .0015
2 .0022
3 .0023
4 .0022
5 .0018

As far as ive been able to find, the factory clearance specs are
.0004-.0012
 
Now im using a mike and bore gauge to measure the clearances and I havent bolted the heads on and tried measuring that way yet. Im going to try that now to see if the clearances will tighten up a bit with everything together.

Curious what you professionals think about these clearances. should I look into getting a new set of undersized bearings. -.001 or would i be okay going with a 40 weight oil ?

My rod bearings ended up being
.0013
.0015
.0013
.0015

Would those be too tight to consider running a heavier weight oil ?

Thanks for the help guys, any is appreciated.

[Dr Beans]

Hey twin still uckfaying chapped you took that username,

Explain this in great detail (or better yet draw a picture) of how you are measuring your clearances. Once I see how your calculating it, I'll comment on your method. Torquing the heads won't effect bearing clearances, you do that for piston to dec or degreeing, ect. Since I'm assuming this is a subi engine, make sure the block is torqued to spec when checking your clearances.

Just from first glance your factory specs seem really tight. 0.0004 is ridiculous.... so I'd double check the spec on that. Are you sure its not 0.004?

Do you have plasti gauge? It's your friend if you want to double check your measurements.   

[Dr Beans]

I recommend using plasti gauge to get your main bearing and rod bearing clearances measured. It is the most accurate way.

It's the most inaccurate way lol.

Build something that can bolt onto the crank to keep it from moving if you're having problems from keeping the plasti gauge from smearing.

[Beans33]

Hey twin still uckfaying chapped you took that username,

Explain this in great detail (or better yet draw a picture) of how you are measuring your clearances. Once I see how your calculating it, I'll comment on your method. Torquing the heads won't effect bearing clearances, you do that for piston to dec or degreeing, ect. Since I'm assuming this is a subi engine, make sure the block is torqued to spec when checking your clearances.

Just from first glance your factory specs seem really tight. 0.0004 is ridiculous.... so I'd double check the spec on that. Are you sure its not 0.004?

Do you have plasti gauge? It's your friend if you want to double check your measurements.

Sorry about the name bud. I checked the journal with my mike, zeroed the db gauge on the bearing I was measuring then checked it on the mike. I did this for each journal and bearing separately. triple checked all the clearances and got the same readings every time.

I can't remember what the shop was called but I read an article about how they always mock up the block with the heads on before checking to get the most accurate measurements. I tested the theory by bolting my torque plate on and rechecking and there was little to no change. I could maybe see a variable of .0001 with both heads on but im only guessing.

Yes I did make sure the block was correctly torque 

 http://www.type-ra.co.uk/pdf/engine4.pdf this is where I got my specs from. It is specs for the 1999 sti uk model

I ended up getting a set of undersize main bearings and oversized rod bearings and mix n' matched
Now my measurements are

1 .001
2 .0012
3 .0013
4 .0012
5 .0013

Rods are now

.0017
.0018
.0018
.0018

They're all where I want them now 

[Delphiwrx]

Perfect! Those are awesome clearances for a seasoned block.

With your mix and matching were the mains pretty close to what I guessed through PMs? 2,3,4 using both halves undersized and 1,5 mix and match?