Main Bearing Clearence Differences

[ahh 33 s2]

hey all,

did some double checking of my main bearing clearences today, i was aiming for .002" but after checking twice with plastigauge i had a bit of a mixed result

RB26 with ARP mains and was tunnel bored,

tourque up in three stages then went back thru each bolt and loosened then tightened again in 3 stages again. ARP lube was used

i got .001" on the 1st and 7th journal

and .002" with the rest.

infortunatly i dont have a have an internal mic. to be able to check with out the crank in,

and i did have redline assembly lube on the majority of the bearing,

where do i go from hear?

i was hoping that it was all going to be perfect

[The Dan]

they need to be checked dry

[ahh 33 s2]

ahhhh shit!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

back to the shed tomorrow it is then

elite i think it was you that posted a diagram of this being done just a real simple 2d diagram, i cant find the thread it was in, do u have that picture to put up, if it was u

Edited March 31, 2011 by ahh 33 s2

[T04GTR]

if in doubt swap out the studs for sock bolts and check it. also ring the machinest and ask what EXACT torque the did when they tunnel bored it.

[ahh 33 s2]

ok so i been back at it and still a disappointing mixed bag of results, i am yet to speak to the machinest but will head there tomorrow, although its been a very long time since they had it in there possesion, been a very long and slow process this one

this is what i have got,

journal clearence

1 1thou

2 2 thou

3 1.5thou

4 2 thou

5 1.5thou

6 2thou

7 1thou

so as you can see there is a bit of a pattern but why

they way im doing it it 30 pound on all then 50pound on all then finally 70pound

then undo and retighten one by one,

why cant modify be easy

[Adriano]

Have you tried swapping the bearings around from the loose jornals to the tight ones?

[ahh 33 s2]

Hadnt thought about it, might be worth a crack

[r31 25t]

Any machining on the crankshaft?

Maybe check the journal size, they can vary from factory.

[rob82]

ok so i been back at it and still a disappointing mixed bag of results, i am yet to speak to the machinest but will head there tomorrow, although its been a very long time since they had it in there possesion, been a very long and slow process this one

this is what i have got,

journal clearence

1 1thou

2 2 thou

3 1.5thou

4 2 thou

5 1.5thou

6 2thou

7 1thou

so as you can see there is a bit of a pattern but why

they way im doing it it 30 pound on all then 50pound on all then finally 70pound

then undo and retighten one by one,

why cant modify be easy

Silly question - are you using the appropriate torque order?

[ahh 33 s2]

Yeh both the crank and journals were machined to match under size bearings, i paid extra for them to do extra checks, as I'm a super novice,

And yes I am tightening in the right sequence,

Will be going to machine shop, see if the keep some record of what the did, or just put em on the spot of what torque they would use