niacc
Member
Blinking oil light at idle sent me looking for a cause.
We completed the plasti-gage project this morning and found bearings that were not the prettiest, but not terribly worn either. Clearances were as follows:
All are in inches.
Rod Bearings
.0027
.0019
.0012
.00195
.00198
.00199
It seems only the first one was somewhat loose, pushing the allowable tolerance. The others seemed within tolerances. Condition of the bearings was generally okay, with some minor dirt scratches, a pair of interesting grooves in number one. Other bearings ranged from some quite nice, others showing a bit of wear.
Main Bearings:
.0014
.0014
.0018
.0014
.0020
.0014
.0014
The first main bearing shows some serious signs of wear, somewhat like wiping, but tolerances were within tolerances. Again, condition varied from very nice to a bit shabby.
I would like some help to confirm if these bearings are standard or oversize. Here are the markings I found on the rear of the bearing shells:
Rod Bearings: 3061 Um
UO .25
85 377 610
Main Bearings: 2970Xe
UO .25
74377610
When I miked the bearing shells, I think I confirmed that they were .25mm oversize.
The Crankshaft looked quite good everywhere. Only the most minor of markings.
The oil pump gap (between the inner rotor and the outer rotor) was right at .006 inches, within the allowable .0079 upper limit. The radial gap between the outer rotor and the housing was also within the allowed .0039. There was some significant but not catastrophic scoring on the housing, indicating some axial wear issue. The gap measured .004 axial play on the outer rotor and .005 on the inner rotor, both a bit out of tolerances if my data is correct.
We plan to replace all the bearings, We are not sure whether the oil pump or its internals need replacement, but I am inclined to do so.
What is the difference between the old and new style pumps listed for sale other than about a $100 difference (the old style being more expensive)? And, can someone suggest a good source for the oil pump, parts, and these bearings?
Thanks,
Dave Buettner
We completed the plasti-gage project this morning and found bearings that were not the prettiest, but not terribly worn either. Clearances were as follows:
All are in inches.
Rod Bearings
.0027
.0019
.0012
.00195
.00198
.00199
It seems only the first one was somewhat loose, pushing the allowable tolerance. The others seemed within tolerances. Condition of the bearings was generally okay, with some minor dirt scratches, a pair of interesting grooves in number one. Other bearings ranged from some quite nice, others showing a bit of wear.
Main Bearings:
.0014
.0014
.0018
.0014
.0020
.0014
.0014
The first main bearing shows some serious signs of wear, somewhat like wiping, but tolerances were within tolerances. Again, condition varied from very nice to a bit shabby.
I would like some help to confirm if these bearings are standard or oversize. Here are the markings I found on the rear of the bearing shells:
Rod Bearings: 3061 Um
UO .25
85 377 610
Main Bearings: 2970Xe
UO .25
74377610
When I miked the bearing shells, I think I confirmed that they were .25mm oversize.
The Crankshaft looked quite good everywhere. Only the most minor of markings.
The oil pump gap (between the inner rotor and the outer rotor) was right at .006 inches, within the allowable .0079 upper limit. The radial gap between the outer rotor and the housing was also within the allowed .0039. There was some significant but not catastrophic scoring on the housing, indicating some axial wear issue. The gap measured .004 axial play on the outer rotor and .005 on the inner rotor, both a bit out of tolerances if my data is correct.
We plan to replace all the bearings, We are not sure whether the oil pump or its internals need replacement, but I am inclined to do so.
What is the difference between the old and new style pumps listed for sale other than about a $100 difference (the old style being more expensive)? And, can someone suggest a good source for the oil pump, parts, and these bearings?
Thanks,
Dave Buettner