SBC Guys - top end oiling issue qns.....

Hey guys....

I just fired a nice little 283 SBC, and all is good. Broke in the mild cam all went well I then dropped it into the car and it runs well, no probs.

However when I went to relash the hyd lifters/valves, I found I had no oil to the pass side rockers. Ran it up, nice n warm, no dice !!

After some online searching/scoping, I found that SBC lifters receive pressure from the back of the block where the distributor intersects with the galleries in the block. Commonly, some engines have had issues getting oil to the pass side rockers because the groove in the bottom of the distributor was not machined all the way round to allow oil to the pass side rockers.

So I removed the dist tonite and had a look - a std sbc single point dissy and yes, it has the correct groove machined in it so that can't be the problem.

The other thing is I checked the lifters and they have pumped/primed up OK as the engine is running quite well - so I surmise that the lifters are being pressurised by pil coming from the lifter galleries. It just appears that the oil ain't getting thru the pushrods to the rockers via the lifters. Pushrods have been checked and are clean !! The oil pressure is good so no issues there around 15lbs hot, 45-50 @ cruise.

So the question is - do I have bad lifters or is there something Im missing here?

Any thoughts....

Rat

 

The early 283s had a groove in the rear cam journal for oiling. You have a aftermarket cam, none have that oiling groove. Might look into that.

 

Yeah I know about that one too ....by mines a 67 283. I dont believe the later 283s required a ntohed rear cam journal like the earlier ones did.

My old 57 283 had that grooved rear cam journal though so this cant be it.....

BUMP

Rst

 

The chances that you had 8 bad lifters out of 16 and installed those all on the passenger side are kind of slim.

15 psi sounds low to me. Do you get oiling at 40 psi at cruise speed? You had oiling at break in but now you don't or you just found out that you never had passenger side oiling?
I'm no sbc guru just an observation.

 

I agree it would be rare ofr 8 lfters to ALL not be able to sned oil up the pushrods. 15 sp at idle is plenty imo. 40-50 psi at cruise hot. I had oil at the drivers side rockers when preoiling the engine but didnt check the pass side rockers as well otherwise id have picket it up. Kinda new to SBCs so i figured id have oil on both banks of rockers hehe.

The pushrods and rockers all look great...no blueing or smoking them out so no probs there. What is stumping me is that the lifters are all pressurised yet the oil wont travel up the pushrods to the rockers tips like on the drivers side rockers.

Weird....

Rat

 

Very strange. You sure the oiling holes in the rocker arms are not obstructed? How long did it run without oil getting to the rockers? I'd be kinda concerned about that. Are they the stock rockers or, roller? This just doesn't make sense.

 

15 PSI is passable but not good by any means. I got a stock 'late 283 that has never even had a head off that holds 30 @ idle and 60 at speed until it warms up then the idle pressure drops to between 20 and 25. A fresh engine should at least compete with a 45 year old engine.

I initially was going to say that you need to make sure you got the early distributer and had it clocked correctly or that you probably don't have the rear cam journal notched. But then you pointed out that it is a late 283 so that should not be an issue.

You could have a plug out of the back of the block or one not properly sealed. That should become evident pretty quick if you pull the cover off of the bell housing.

Did you replace the cam bearings? Loose cam bearings can affect top end oil pressure, also when I do replace the bearings I am real careful to get the oil holes lined up. I have had people tell me that it is not real important but it does make a difference in my experience.

You may also get youself some bottle brushes and try passing them through the oil passages that feed the top end, you can do that at least without a complete teardown.


Have you run it without the rocker covers on yet? it should look like a fire boat with the rocker covers off. If it does then I am going to suggest that your oil problem is not an oil problem at all but a set of bad lifters and murphy's law kicking in.

 

What oil pump are you running? i've had a few bad ones before.

 

Rat, I'm not sure how the rockers could operate for any length of time with out smoking the pivot balls;that was usually the first to fail with any kind of spring pressure. I have had problems with the interface of the rocker oil hole with the pushrod on some replacement rockers but the chances of that happening only one side are slim ...stranger things have happened so you might check that (one way to do that is to put about .005 clearance at the valve and see if flow improves, temporary running wont hurt the lifter). The block hasn't had restrictors installed behind the rear cam bearing has it???; it was common to install 5/16 allen set screws drilled to .060 when running rollers. If the block has been raced its a possibility;if one was plugged with debris and the other was not the situation you describe would occur....fats

 

Darn chevys and their top end oiling problems, never would have happened in a Y-Block Ford.

 

Thanx PB,

I did'nt assemble this mill so cant vouch for the cam bearings lining up - the clearances checked out OK on the rods/mains and the sides were within spec.

If the cam bearings were'nt lined up, then I should'nt be getting oil to the drivers side rockers either should I ? The rockers are stock/factory and the oil holes are clear. it was'nt run long this way no so the rockers/pushrod tips looks OK.

Oil pressure could be a tad higher but all the lifters have filled and I have no clattering t all. All the plugs were removed by me and re-sealed with Permatex sealer so this engine does'nt leak a drop of oil, not even from the rear main or timing cover.

One thing i did'nt mention is that Im running a Weiand WC4D intake and as the block/heads have been decked and i did'nt want to mill the intake as its a super nice original piece. I ran .120" intake gaskets to enable it to mate up/seal to the heads properly. At first I thought that this would this lift the dist too high thereby uncovering the gallery in the dist bore enough to cause leakage to the oil galley on the pass side?

But then the lifters seem to be full of oil/juiced up and the engine runs nice - they are simply not pumping up the oil thru the pushrods to the rockers as they are on the other side.

This is why I'm stumped....

Rat

 

The "soft plug" behind the timing gear on that side might have poped out. If you have a high volume pump the oil pressure would still be what you have now. I can't think of anything else.

 

This is the first thing that comes to mind also. Rat, is this a completely fresh rebuild? Did you remove ALL of the galley plugs front and rear? Were the cam bearings replaced? Was the block hot tanked or blasted? Are you confident on your final assembly cleaning of the block and the oil passages? On the front plugs behind the timing cover, did you tap them or at least stake them? TR

 

I had a plug pop out on me once, didn't take long and the valve train started making lots of noise, also oil pressure on the guage went to crap. Good luck

 

Tongue in cheek,, I presume

 

Here's an early ( with gear) and a later one (without)
The early one has a typical groove all the way around.
The later one has a grove that varies in size that goes all the way around. Note the "x" in the casting, this smaller grove is in about 90* of the casting.
They will both fit either engine.
If by some chance the later housing is clocked incorrect on the body the holes in the block could be partially blocked. Those holes in the block are located at 12:30 and 5:30 when viewed from the front.

You said you checked it but here's a pic any way.


I still think 15 psi is low and especially low on a new engine. I would suspect an internal oil leak. The oil would follow the past of least resistance which is apparently not to the push rods or rockers on the passenger side.
Hope you find the cause of trouble.


If this is riding a touch high because of your shiming and extra thick gaskets, it could be leaking right there.
It definitely has a taper to it. \ / best I can measure is about 0.010 total at the bottom.

 

it mite be your lifters i just did a 455 olds for a guy last summer he had the same problem i checked it out and got him a set of new lifters and it worked, the cam & lifter kit was comp cams.

 

rat, if you ran that engine for the 20 minutes for cam break-in at the very least, you will need to closely examine all the rockers on that side and the balls for wear. If your running rollers, pull each one and feel how well the fulcrum rotates and the roller tip, and if there is any sign of heat from lack of lubrication. Tips of the valve stems too and the rocker arm end of the pushrod tips to be safe. TR

 

It seems to me, if you are dead certain that the lifters are getting juice, but it isn't getting to the head, that you would have to have something wrong with the pushrods. To confirm this, or eliminate it, swapping the pushrods side to side would tell you if they could be plugged or not drilled clear through. My thought on it is this, you say you did not do the rebuilding, and therefore you cannot count on any information from the builder. Even the best of builders have a bad day. I would say, blow out the push rods on the right bank. Every engine that I have ever had, the oil pressure was greater than 15 psi. I would think 20at a very minimum, as Beaner said, his 30+ year old engine still holds 20 at idle. It only takes a little piece of dirt to clog up an oil passage, and I agree you should try to "rod out" the passage that goes to that right bank. My other question is this, this is not meant to insult you. Did you get a little too much sealant on the plugs when you installed them? A little sealant goes a long way, and a little too much goes a long way toward causing issues with such a small passage.

 

little bit

 

31 Vicky, My dist is similar to the one on the left of the pic - although the groove seems to be more uniform in width than the one you have in the pic.

I might try reinstalling the dist without the gasket and see what happens.

Just for shits & giggles, what is the OD of the raised section on either side of the groove just above the dist gear? I measure mine and its at 1.200".....if mine is too small, there may be leakage there thus not allowing enough pressure to build in the affected lifter gallery to get oil UP the pushrods to the rockers.


Willy, the pushrods are super clean inside and I can see right thru them when held up against the light. Re the plug sealant, I only used enough Permatex to coat the threads to seal the plug properly.

TR, the rcokers are stock and they look fine as do the pushrods. In fact, no galling or heat blueing at all. I used a real good moly lube on the rockers/pushrods tips at fire up.

Stu 55, if a gallery plug had popped then I wouldnt have any oil pressure at all correct?

Got to admit, Im stumped.

BIUMP for the mornin crew...

Rat

 

rat, I'll answer that question " if the front galley plug fell out you wouldn't have any oil pressure", that's INcorrect. You would have a internal leak and low oil pressure, or pressure bleeding off at low RPM's. Now, lets say that it is true that galley plug vame out or was left out, AND you removed all the lifters on that side, then you would have little or no oil pressure. The pump couldn't keep up with that amount of internal loss.

Remember if you ever see a oil flow schematic, you can understand better how the pressure is developed. On your SBC if your gauge or sender is at the back of the block you are just above the rear main bearing feed. Oil leaves the pump, goes thru the rear main cap and thru the crank mains and rod journals. The clearances and tolerance is primarily where you pressure is established. Your sender is just above this route in the oil system. Now the plug at the end of the lifter galley or in the cam cover is at the end of this stream. This is why too why you will have pressure, but not a normal reading at idle. At higher RPM's the pump will keep up much better, still leaking internally, but keeping a better reading in PSI on your gauge. I kept the explanation very simplified on purpose to shed some light, not quarantee this is the cause. Hope that helps, TR

 

Did you stake or thread the front galley plugs ? Just for poops and giggles, the bump, its for the nightime crew here in the U.S.

 

GM oil psi was stated as 30 psi @ 30 mph and one quart consumption every 700 miles.

 

He has NO oil flow up thru any of the pushrods at all on one bank of the engine. Hope that helps. I'm without a project right now, you wanna donate one since you have too many? <grin> I'll be right up buddy, TR

 

TR, That galley plug under the timing cover is the end of the line correct?
I'd be willing to bet a gauge there will read zero or close to it. Any way to check for a leaker there with out taking the front of the motor apart?

 

Thanx for the input fellas....

TR the front plugs are threaded and I made sure they were sealed properly when I had the cover/chain off to relube the cam/lifter prior to fire up.

Guys this isnt an oil pressure issue imo. It MUST be an oil FLOW issue - to me it kinda stands to reason that IF the lifters are pressurising and getting oil then that must mean the lifter is NOT flwoing oil THRU it to get thru the pushrod to the rockers, esp when any other potential blockages appear to be clear.

Or looking at it nother way, if the lifters were'nt getting oil the engine would run like crap as the lifters would'nt over come the valve spring pressure and open the valves properly. Engine runs fine....

Thus the lifter must be the limiting factor?

Lifter/gaskets are cheap enuff - so I guess there's only one way to find out....

Anyone else have any thoughts?

Rat

 

31, I dont know if he has that small square plug above the front of the timing cover or not. That one angles off into the valley to the main cam feed, so not sure how that would read. I would say it would read lower than the reading from the back of the block if he was bleeding off from the lifter galley, I'll have to think about that for a minute.

 

yes, flow and pressure are related.

Tricky here I know:
as flow increases, pressure must decrease.

Those lifters will pump up in a coffee can with no oil pressure at all.
They are getting oil flow, too much flow and not building pressure because of an internal leak.
If it was a flow restriction, or blockage the other side would be shooting oil accross the yard and your gauge would be much reading higher.

if it was pump problem there wouldnt be oil up one side, it would be too little on both or none on both.
Thats the angle im looking at from anyway.

 

I still have a problem with the 15 PSI at idle, and to top it off its a fresh build, something doesn't add up.