383 Oiling issue

[OldMech]

OK Gents and Ladies.. this issue isnt as simple as it sounds..
We bought an engine out of a 55 chevy thathad been replaced, because they "couldnt make it run right"
I wont go into all the issues with that...
The rotating assembly was together, the heads off.., cam was out.. Eagle crank, pink rods with arp bolts, speed pro hyper pistons with coated skirts.. Took it apart looked everything over. measured the crank, ordered new rod/main bearings.. measured the bores, and ordered new rings. Pulled the cover off the melling 55hv pump and checked clearances... reused it, like new..
Bolted it together.. installed the canfield alum heads, roller rockers, used break in lube with zinc etc...
Engine fired in first two revs, and ran wonderfully... I set the idle screw to run at 2000 rpm to let it run and break in, walked aroudn the front to watch gauges. .. about the time I looked at the oil pressure gauge it said 70PSI... but started dropping.. I watcfhed until it hit 5 PSI and shut it off.. it never stopped or slowed. it dropped like the second hand on a clock without pause...
Pulled the pan, put a new punp and different pickup tube in it. changed the filter and bypass and restarted... same issue. Oil pressure held for about 1 minute, then started dropping.. watched until it hit zero and the lifters started to clatter and shut it off... It has a mechanical gauge on the stand.. I tried a second gauge with the same results.... Just to make sure...
Pulled the crank and sent it in to have it checked, ordered a new cam, installed NEW cam bearings. Machinist said crank was good, he polished it and got me another new set of bearings to match. I checked the block for the plugs in the galleries. Made sure no one had drilled a hole in any of the front plugs for oiling the gear drive etc... reassembled.. started it... same issue exactly.. I figured it had to have a harmonics crack in the block along one of the main gallery's...
I took another block, had it bored, swapped all the parts in... fired it yesterday, ran one minute and the oil pressure started to drop... and went to 0 after watching it slowly go down for several moments... I shut it off, threw a few things. Drank a few beers staring at it, trying to think of reasons it might be doing this... I am now at a complete loss.. I have built a LOT of engines in my time, and have never hit a SBC I couldnt figure out.. this one has me stumped.. Looking for help, ideas, anyone thinking outside the box... What can I check here?????
Frustrated beyond belief... Thanks for any ideas or help guys!!!

[jerry clayton]

I suggested way back in your original posts about doubling the amount of oil in the pan to see if it took longer to lose pressure and a few guys even suggested that you consider it,but evidently from reading thru all your posts you haven't tryd that---


Is your pick up still one inch off the pan bottom? Is the bottom of the oil pan sloped????
how wide and long is the bottom sump of the pan?????are the baffle doors in the pan installed correctly and move freely in the correct direction???????with the pan off and setting at the same level as when on the engine stand, pour oil into the side cavities to see how well it flows into the pickup area---------


With the pan off the engine and setting supported somehow on the floor(or bench--you can do this on a milling machine or drill press also) run the pump with your priming tool and the pickup immersed to the 1 inch level and see how long it takes to pump the oil out( you will want an old main cap and fix a hose or tube to it to route oil into catch can-----


Get a set of old valve covers and cut the top out so you can put on the heads on the stand and also remove the intake manifold so you can run your priming tool and see the oil flow to the top and return(or slow or no return ) from the top end----We have see many instances of aftermarket heads not draining back very well and with some of the aftermarket valve covers(big, fabricated,billet looking BLING?) will hold more oil that the pan causing a dry sump shortly after startup-----------


So good luck and I'm waiting------------

[rspears]

I'm with Jerry. If you haven't fixed the oil pickup you may be sucking a vortex on the bottom of the pan before the level even gets to the 1" level. Sounds to me like you've got an oil capacity/oil drainback problem - you've got all of your oil up in the valve covers and upper end, starving your pump. An easy way to know, but extremely messy would be to pull the bolts off of a valve cover, have someone hold it tight against the gasket to prevent leaking, start it up and run it until the oil pressure has dropped to zero and as you shut if down jerk the valve cover. I predict you'll have between two and three quarts of oil on the floor.

[pat mccarthy]

did you use your old lifters ? there has been a company thats made lifters for years had many bad sets of lifters out there will not say there name on here PM me i will . take valve covers off the engine, put primer back in the engine and just prime it . no need to run it . see what happens if oil shoots out of the lifters then just set covers loose on the engine . but i been told the lifter valving is so bad in the lifters that about a minute of priming will empty a stock sbc oil pan

[OldMech]

the oil pickup isnt a problem, I did check it as suggested, half a dozen times just didnt post it.. sorry, need to know information... I replaced the pickup itself just in case it wasnt sealed when it was assembled, and the oil pan was replaced with this block because the dipstick tube is on the opposite side. When the idea came up the first thing I did was check the oil in the pan, run the engine until it hit 0 pressure, and checked the oil level, it read full about three seconds after the engine shut down.. it has now had three pickup tubes on it and two different oil pumps... When priming the engine with a drill, I watched the flow from the lifters and down into the heads. No oil pooled in the valve covers at that time, though there wasnt the same amount of oil in them like there would be if the engine was running.
The cam and lifters came from Lunati, Hyd lifters, they adjust correctly (none collapsed) and it does not rattle when running until several moments after the oil gauge hits 0.. and I havent let it run long at that point...

I havent ignored your recommendations, just havent put enough detail in type..

I should also mention, when I first start it, it Does hold pressure for about two or three minutes, which would also lead me to believe that its running out of oil at the pickup, however, once it IS warmed up just slightly, it will not hold pressure at all, even when shut down and restarted. Pressure will jump on restart, Often only to 40 or 50 psi but immediately begins to fall. let it cool off, it will hold 70 psi for two or three minutes. The dipstick always reads right on the full mark.
I do have a set of old valve covers that were cut out, so will pop them on and check it while running just to make sure. Please keep it coming!!!!!!

[34_40]

Isn't there an area at the distributer that the oil passes by? The distributor has a seal??

I could be all wet... I avoid bowties at all cost! But it popped into my head.

[pat mccarthy]

........................lifters

[pat mccarthy]

Isn't there an area at the distributer that the oil passes by? The distributor has a seal??

I could be all wet... I avoid bowties at all cost! But it popped into my head.

yep no seal but can be O ringed.you have to roll the edge of the hole in the block with a lead in the block so not to cut the O ring just did a Big M 598 for this . MSD Dist have this O ring job done . but funny that this works very well with no O rings many BBC and sbc and v6 gm enginea are running fine .just no matter how dumb it seems just like some on the dumb thing ford has done as well and others .not all engines are built the way we like them some of us have done things to make a bad idea better the trick is knowing . the sbc has a ok drain back and oil system some thing is getting way over looked like a under size cam journals .or lifters. or small base circle cam and lifters are droping in to the oil band part of the lifter

[jerry clayton]

Since you have the engine on a stand---------remove all the pushrods so no oil will go to the top of the heads and use your prime tool to pump the oil to see if you get the same results-----if you don't you will have identified that its an issue of the heads not draining back (since the heads weren't changed)


Then, you can remove the back two lifters so all the oil is from the lifter galleys is dumped right back down into the lower end---------and you should maintain pressure as the oil will be on a very short circuit to return to the sump

[34_40]

Never said or thought it was dumb.. It was more a memory of someones motor who was losing oil pressure from that spot.

Just trying to help is all.

[pat mccarthy]

Never said or thought it was dumb.. It was more a memory of someones motor who was losing oil pressure from that spot.

Just trying to help is all.

no i said and in the past said it is. BUT i played with a 572 bbc that was low and did find that the hole in block was about 005 bigger then the oil rings could hold . played with it did find thicker O rings well that did not help much maybe 1.5 pounds was nothing the engine was set up loose that.s all that was over 10 years ago with many bottles of NOs thru it and getting the hell beat out of it in the muds pits. after the piston came apart crower billet rod cut threw the piston wall this block now back in the shop i did check lifter bores @ .0003.5 on the lifter to bores and the the rods and mains over 003.5 this did added to the lower oil presure. with this 383 two blocks doing the same thing ? yes checking the Dist size at that point may not be a bad ideal . have to start some were but 8 or 16 lifters will pass more oil

[34_40]

No harm / No foul Pat! As I said, it was a memory that flashed through and I thought I'd share is all. Might be something for him to check,, even if it isn't the complete problem.

Strange it would affect 2 blocks but maybe it's the distributor more than the block?

Anyway.. great minds think alike! Have a good weekend if we don't chat sooner.

[OldMech]

hmm... the dist is an msd billet unit... I need to measure it... The only thing I can say is that my primer guide is an old dist housing cut down, and it does the same thing with the drill on it as it does with the engine running.. pressure comes up good, hits 70, and shortly after starts dropping...

ran with cut down valve covers. DID notice that some of the lifters oiled more than others, but have noticed that on many other small blocks int he past. all are getting oil, none are dry, and the oil is flowing back through the heads fine.
The only correlation I have between the two engines is cam/lifters, and the crankshaft.. at least that have to do with oiling. I am going to "once again" check the pickup tube and oil pump. If no difference is found, I am going to pull the crank back out of it.. is it possible that it was drilled wrong? While there I will check end play again, rod side to side clearance etc... I just have difficulty believing those things can cause the problem to be so severe.. I have pulled worn out engines apart with massively excessive clearances that still held SOME oil pressure... Please gents, keep thinking, I'm taking the advice and checking on it all at this point, even if I have done it before.

[jerry clayton]

In some of the aftermarket cranks the rod throws are bored out to lighten the assy---------if the oil groove from the main to the rod journal isn't in the correct place it can come out in that cavity---if its f'd in one its probably a total orgy in all four-however, that would return the oil to the pan almost instantly---------this engine combo you have is doing something with the oil------------

[techinspector1]

Is it possible that much oil is roping around the crank? Have you tried different oils?

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