I have fried a couple of rod bearings apparently due to oil starvation at higher rpms(6k). I'm running the Z28 pan, windage tray, and pump with a standard spring. I did all the usual smoothing of the drainback holes, the area under the oil pump, and the passage from the filter to the pump, plus I painted the lifter valley with the Glyptal paint. I checked the pickup clearance to the pan as well.

Barring some problem I haven't found yet - this system should work great for the average hot street motor including an occasional blast to 6k. So, any ideas why I would run out of oil long enough to trash a couple of rod bearings? What's everyone else running that works better?

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

I have seen more than one motor clog the pickup screen with silicone. Sometimes it squeezes in from the intake or pan. Most of use have heard about engines pumping all the oil upstairs and leaving none in the pan, but we have also seen the pickupshift down and close on the pan at higher RPMs. I saw that once and it was enough to make me weld my pickups!

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Mark

1992 Firebird 355/Six Speed
1991 RS 350 / 700-R4
1987 Toyota Pickup 383 / 500 + HP 10.963 @ 119.95 Slicks / 11.997 @ 114.23 Radials
http://personal.lig.bellsouth.net/~racer383/

Should not have happened with the parts and care you used.
The Z/28 pump should provide all the oil you need.
check the pump and relief spring for anything that could make it stick open.
Check the screen as mark suggested.
Check the filter, cut it open and look inside.
Do you think the rods could have been off on the big end-lack of crush?
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

Maybe it only looks like oil starvation. Its possible that at those rpms you may have elongated a rod end. I have had that happen before. Time for beefy rods. Just a thought.

Thanks for the comments. I'm going to pack up the parts and go see my machinist. Hopefully, he can spot the problem and I'll share it here.

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Hey Scott,

Have you checked the oil gallie plugs in the front of the block?

Larry

Scott I got to say this ,back to basics!!

You wrote you have done allmost everything to take care oiling,but have you really measured rod bearing clearances? and done it useing micrometer?"Blueprinting" is more important than it sounds when building hi reving engine.6000 rpms isn a lot yet ,your stock oiling would work fine if everything is correct! hope you find it!

Larry - I checked the oil galley plugs - they look fine - the ones at the front of the block are the standard steel cups staked into place and they are almost flush with the front of the block surface so I don't think they're in too far. The rear plugs are threaded plugs and they also appear to be correctly positioned.

Joni - I checked the clearances with an inside/outside digital readout caliper (it was all I had access to) and then also double checked every rod and main with plastiguage. They were all right on. I checked the thrust bearing clearances with a dial indicator and carefully sanded the backside of the bearing until the clearance was correct.

It's been pretty cold here in Denver this week so I stalled a little on cleaning up the parts. Hopefully, it'll warm up a bit and I can get them into the machinist. I still need to check the filter and take a better look at all the passages as David suggested.

Thanks for the suggestions - I'll let you all know what I find.

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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Don't use the dial caliper for inside bore measuring.
Use snap guages for the rod bearing ID then read it with the outside caliper.

I think you may have some looser rod clearances than what you think you have the way you did it. The smaller the bore, the more the error using the caliper itself to read inside a bore. The edges are not sharp enough to read a bore that accurately.
The snap guages are curved and will do better.

Check your drain back passages from the cyl heads where the return oil goes through the head gasket hole. That's usually a restrictive area.
David
David

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Check my web page for First Gen Camaro suspension info:
David's Motorsports page (http://ourworld.compuserve.com/homepages/David_Pozzi/)
First Gen Suspension Page (http://ourworld.compuserve.com/homepages/David_Pozzi/first_gen_suspension.htm)
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer

David -

Good thought on the gasket. That's one area I didn't think of. I've also been having consistent valve cover leakage although I've changed gaskets a couple of times. Hmmm....

I will also find a way to get the right measuring tools when I reassemble it.



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Scott
'69 400SB, Richmond 5-speed; '99 HD Road King Classic
www.geocities.com/sdenning1 (http://www.geocities.com/sdenning1)

Scott, Could this problem and your cooked rocker arms problem be related? Oiling problems on SBC seem to be rare. Just food for thought.
Al.

302 - it's possible. I'm hoping to find something when I get a chance to look closely at all the parts. Unfortunately, it's colder than a witch's tit here right now - it's about 14 degrees and blowing snow. I just froze half to death snowblowing the drive and I'm done outside for today.