Lmarth

Brian-- I'll try to be brief. My sense is that you're adjusting the valves properly, have good lifters and the correct studs,girdle parts,etc on top. Most on this thread are suspicious of oil flow/pressure. My experience with a problem like this that has resisted SERIOUS troubleshooting by numerous experts is that you assume something is ok that isn't. Is the oil pressure really OK with a known good guage to eliminate the oil pump/by-pass valve as the culprit? Are you absolutely sure all the oil galley plugs are in?I just looked at the oil flow diagram for BBC's to jog my feeble mind and need the help of the really knowledgable wrenches on the board. If oil pump is good, oil goes up around rear cam journal to feed lifter oil galleries. Isn't the rear cam journal and rear bearing grooved to facilitate oil flow? Could someone have pressed in one of the non-grooved cam bearings in the back? I don't want to go off deep end, but something we think is working correctly apparently isn't. Don't laugh, but we all needed those little clips for the rocker arms to keep from burning ourselves adjusting valves with a feeler guage as that oil was flying all over the place. Just trying to help.--Lou

martiniboat

Formula31- This dist. is one that I had ran in a previous boat motor so it can be eliminated from the suspect list. (I'll bet that defective dist. of which you speak was a bugger to track down) The flow is consistent from one side to the other, actually, the pressure drop/flow is noticeable from the rear to the front cyls. I did compare the MSD to my GM dist. just for kicks.

Blue Thunder- The cam was installed 'straight up', no degree action. I too thought the lifters were defective until the fourth and final time of setting the valves statically (using a couple of different methods), becoming frustrated when it was the same ol' s**t, and then utilizing the tried and true method of adjusting while running. It was only then when I could actually 'see' the flow (or lack thereof) that I realized something must be wrong with the supply to the lifters.

Sutphen30- The block is good ol' GM iron, brand new.

Lmarth- You're absolutely right Lou about those damn 'little things'. They can sometimes easily be overlooked by the best of us! My only proof that the guage is accurate was from it's relationship with a 6.5TD just one week previous. In fact the guage virtually peeks at startup as expected but then tames right down (or a touch higher) to where the previous pressure/motor was. This by no means proves anything, so I will put a 'real' guage on there tomorrow and see what she says. All of the galley plugs and plugs behind the cam gear are in place. The cam bearings haven't been touched since I bought the motor.

I have to pick up some parts tomorrow at the high performance candy store and will ask the old drag race engine builder (hope he's not reading this, LOL) what his thoughts are on the matter. At this point I'm thinking a deliquent oil pump or related part...

A BIG THANKS to everyone who has been on this mission with me so far. I believe it takes nothing less than this outpouring of ideas to conquer this or any problem for that matter. You guys rock!

B

martiniboat

This is strange, Mbam had some great ideas in a lengthy post made yesterday but now it's gone?

I spoke with a high performance engine builder yesterday who builds a lot of drag racing engines. I asked him about the flow characteristics of the BBC oiling system to the top of the motor and he said what some have also said on this thread...should be very messy! He made mention of some oil restrictors (as did Mbam) that may have been put in the block to reduce flow to the lifter galley. DING DING DING! That was enough to jog my memory! The new 502 short block was not purchased directly from GM but through a fellow who said he was 'about' to prepare it for his drag car. It was one of those 'hurting for money distress sales' and I got it for a song. He said it was untouched except for some cosmetic grinding on the external flashing. The whole package appeared stock to me and I felt comfortable with the purchase. Perhaps he got a little further than he let on or simply forgot.

So anyway, here I am with a 502 in my shop truck that was scheduled to be broken-in/ dialed in for several weeks while I build up my 'ultimate' 6.5TD. The problem here is: Unless I miss my guess, that engine has to be removed to remove the restrictor plugs. (if in fact that is the trouble) SOMEBODY PLEASE CORRECT ME IF I'M WRONG since I have very little time to be messing with this during the busiest time of the season for my new biz. (sometimes I wish I wasn't so anal about others working on my stuff)

Is there a way for me to positively (physically) verify the existence of the plugs without removing that motor or am I looking at some more late nights?

Thanks guys!

B

Mbam

The restrictor can be incorporated in the 2 rear oil galley plugs, which means they will probably be aluminum. What we used to do is tap the feeds behind the rear cam bearing and put in 1/16 pipe plugs that were drilled.