Oil Pressure concerns

[Mr Comet]

Enginologists
First I'd like to say I hope I did not scare wsa111(Bill) off. The word on the street is he knows his sh** I hope he'll privide his opinion.

The second main reading is in and the first may have been better. I can send pictures of the actual readings to anyone who'll PM me their e mail. I already have Bubba and Stu's. Will the 20-50 idea get me 3k miles without any damage to any other parts? If I find a crankshaft with main diameters bigger than I now have is an option to have the crankshaft machined to match 10 over bearing and just replace my already over machined crankshaft with engine in car? Or should any machining be complete while the block is present to size it up or of speak? This is all quite new to me. I would like to use the car this season(thruOct) I usually only put a k or 2 on it a season. I've put alittle over 12k on the car the eight years I have owned it. The main bearing are fomoco bearings. Is it possible the mains were not swapped out? Would data on the back of bearing tell us so?

 

[bubba22349]

If you can send me pictures of the bearing condition and crank condition it would be helpful. FoMoCo bearings are the stock bearings from when it was new they would be standard size, it is likely they would also have quite a bit of wear, so a new set of main bearings (Clev. 77 to match) would help your low low pressure. Yes you could get a reground crank kit or have your crank turned to .010 under, but if it still mic's in spec a new set of main bearings should fix the low oil pressure. You would be better off to pull the engine out to do that job, wonder if they replaced the timing chain set.

 

[Mr Comet]

I'm working on the pictures. My computer skills match my mechanical skills.

 

[stu in wichita]

No reason to look for a different crank at this point. Yours sounds like it could be turned and polished - bearings are availbable in 10, 20, 30 and even 40 thousandth undersize. However you go about it, fixing the excessive clearances will be the best for long engine life.

If you do try running with 20w50 oil and the pressure comes up to a good level, the motor should easily make it through the summer without hurting anything else. I'd drive it a bit gently, though - the 50 weight won't flow quite as easily into the tight clearances. But that's probably just me being overly cautious.

I've run 10W40 in every engine I've rebuilt and have never had a problem, even after a lot of miles (100K miles on Mopar 318 and 180K miles on Chevy 327). I know a couple of guys who run 20w50 oil in freshly rebuilt motors with no problems.

-Stu

 

[Mr Comet]

How's the pictures? SB 6 total.

 

[stu in wichita]

I sent you a couple of emails. It looks like the several bearings have well over .003 clearance - out of the range that the green Plastigauge can measure. I'd use some red Plastigauge and get exact measurements.

I'm thinking that you've found the problem.

-Stu

 

[Mr Comet]

All of them? 6 looks like it's right on .002. Can I take it oil won't solve this much clearance?

 

[bubba22349]

I didn't get or see #6 but sent you an email back. I think the clearances can't be fixed with thicker oil did you pull out any other bearings and look at the back for size markings? Did you try the Red yet?

 

[Mr Comet]

six is the best of the lot looks to be close to .002. what's used for clearance above 6?

 

[Mr Comet]

Since I have been advised to remove the engine to get the best repair completed I will be doing that first before any further measurements. Thanks to all