Connecting Rod Bearing Clearance????

[wildo]

I've finally got access to my connecting rods, and sure enough- running with only 1.7 qts oils is not good on them.

New bearings are here, but I need to measure the clearance. I can't find this spec in the manual. Anyone know?

 

[dandan2]

machine shop

 

[wildo]

machine shop

What? I can measure myself. My question is what the clearance is supposed to measure to..

 

[dandan2]

if u damaged a bearing u most likely did alittle damage to the crank. u have to repair that or the bearing will just fail again.

 

[justanothermp5]

yea your gonna have to get the crank turned and get oversize bearings if you scarred the crank too much

as for the clearances, i dont have them on me unfortunately, if i was at home i could help you out..

 

[wildo]

yea your gonna have to get the crank turned and get oversize bearings if you scarred the crank too much

as for the clearances, i dont have them on me unfortunately, if i was at home i could help you out..

The crank is fine. No scoring, and I plan to measure for out of round as well... By chance, does anyone know the torque specs? If I can't find them, I think I will torque to 85 ftlbs. Or maybe I can find the torque spec for a VW of Subie engine...

(How is this not in the manual!? Is there a section I am overlooking? There appears to be no info on crankshaft, connecting rods, or pistons...)

 

[wildo]

Wow- 85 ft lbs would have been too much, apparently. I found this chart:
http://www.campbellenterprises.com/...ng-rod-bolt-torque-stretch-assembly-specs.php

Edit- At least for their connecting rods, they do *not* recommend measuring with Plastigage (which is what I was going to use- not sure why they don't recommend it...), but recommend using a bore gauge + micrometers to get the clearance. They recommend .001" clearance. I don't know if that's factory, but I do know that VW air cooled engines call for .0008" - .0028" for connecting rod clearance. Seems like this is probably an acceptable average...

http://www.aircooledtech.com/plastigage/

 

[wildo]

Here is some more interesting reading:
http://www.hotrod.com/techarticles/steel_connecting_rods_tech/index.html

Specifically: "Oliver points out that typically you need 0.001-inch clearance for each inch of crank pin diameter."

My measurements:

#2 - 1.8875"
#3 - 1.8890"

Following Oliver Rod's formula, that should yield a clearance of: .00189"
______________
I have yet to find the stretch spec for our connecting rod bolts... That's going to be an issue.

 

[wildo]

Score: http://www.msprotege.com/forum/showthread.php?t=99158

Main bearings: 12.7 - 16.2 lb ft + 85-95* rotation
Connecting rods: 16.3 - 19.8 lb ft + 85-95* rotation

 

[flash75]

The FS engine manual has the information.

Rod bearing oil clearance, standard (.001"-.0026") Maximum (.0026")

Rod bolt torque is done in a sequence of steps.
1. Tighten in 2-3 steps to 16.3-19.8 ft.lbf
2. Put a mark on each bolt head.
3. Using the mark as a reference, tighten the bolts by turning each 85-95 degrees.
Note degrees not ft. lb.

The engine manual does suggest using plastigauge to check oil clearance.

Clifton

 

[wildo]

The FS engine manual has the information.

Rod bearing oil clearance, standard (.001"-.0026") Maximum (.0026")

Rod bolt torque is done in a sequence of steps.
1. Tighten in 2-3 steps to 16.3-19.8 ft.lbf
2. Put a mark on each bolt head.
3. Using the mark as a reference, tighten the bolts by turning each 85-95 degrees.
Note degrees not ft. lb.

The engine manual does suggest using plastigauge to check oil clearance.

Clifton

THIS is the info I've been craving for the last four hours. Many thanks to you! I'm going to have to locate myself a copy of that fs engine manual. Thanks again!

(By chance- does it give the crankshaft rod journal measurements?)

 

[justanothermp5]

http://www.trademotion.com/partloca...catalogid=4778&siteid=214264&categoryID=92295

for the overhaul manual Part No. 9999-95-193d-98

 

[wildo]

$42.50- had I'd known it existed, I would have bought it prior to starting. Thanks for the link!

 

[flash75]

Main journal diameter. standard 2.2023"-2.2029"
0.01" undersize. 2.1924"-2.1931"

Crankpin (rod journal) diameter standard. 1.8874"-1.8879"
0.01 undersize. 1.8776"-1.8781"

I found my book on eBay for less than $15. I haven't checked recently but a year ago
there were some sellers that must have purchased books from dealers who went out
of business. If you find someone selling manuals look in their other listings, you never
know what you may find.

Clifton

 

[wildo]

Thanks again!