I am stumped and hope someone can shed some light. I installed a SBC 350 that sat around for about 12 - 15 years and fired it up and had 65# of oil pressure. Everything seemed to be normal until I noticed there was no oil coming out of the rockers. I pulled the right bank pushrods and rockers to blow them out and noticed there was oil in the pushrods - most were clean. The hyd. lifters pumped up and I watched the pushrods rotate while cranking engine over. I even ran it for about 20 minutes by manually oiling the rockers to no avail. I substituted another distributor thinking the base may be too small and oil leaking by there - never started it but just cranked it and watched the rockers - nada! Doubt all the lifters went bad sitting and thought if the oil galley was blocked, at least some oil would come out of some of the rockers. Any ideas???
sitting for that long u just may have plugs in the lifters from dirty oil or something... sometimes u really don't get oil squirting 3 ft out the rockers... i to have about 70# pressure and i don't have a ton of oil coming out. i think i can produce more tears from peeling an onion. u don't need alot of oil just nuff to oil the rockers. u may need to pull the intake and pull the lifters and tk them apart to clean.. very easy to do..
Thanks Bill for your input. I realize you don't needa lot of oil but I'm not getting any... except for three that barely dribbles out. It's not even enough to lube the rollers (Crane roller rockers) on the valve tips. I may end up pulling the lifters out and checking them. I was even thinking about trying a new set of lifters but hate to do that to the cam/lifter match. Getting desperate here... :sweat:
Have yiou tried adding/subtracting lifter preload to see if there a 'sweet spot' where they oil better? If you could adjust on them w/the engine running, that would show you pretty quickly if that was gonna help.
If the geometry is off (like Richiehd said), that might cause it.
Obviously a missing gallery plug could do it but I wouldn't have expected to see good pressure.
I'd be a little worried if you heard a noise then the pressure dropped. Any idea where in the engine the noise came from?
Just an idea, and maybe someone can help me here, but did you check pushrod length. Maybe the oil holes are covered up on the rocker end. You said they had oil in the pushrods.
Thanks guys but this engine ran okay when I pulled it out years ago. Spun a cam bearing? Possible but don't know why it would or would cause that. I guess short of taking it apart, I won't really know. Man, this is confusing and I've talked with some pretty knowledgable people and they're stumped too. Thought I'd put the word out and see what I come up with. Never before in my life... Thanks again.
Yesterday I tried something someone suggested - shoot oil down the pushrod into the lifter to reverse flush it. Upon reassembly and cranking engine over, I heard a "clank" and now oil pressure is only 35# - down from 65#. Rev. flushing had no effect. I'm beginning to think a galley plug may've worked loose possibly behind the timing cover. Think I'll try and locate a stock pair of pushrods and rockers and try what you suggest before pulling the timing cover off... or engine out! Get back to basics!
Hi,i would add 2 qts of trans fluid,( to engine oil)and run it for awhile (keeping an eye on temp guage) it is HI-Detergent oil,will clean up MOSTLY all crud,and it will oil lifters good...
there is a very small check valve at the bottom of the lifters . so back pushing oil i don't feel would have any effect.. IMHO...
your gonna need to dig deeper now..
The lifters have a metering plate just under the pushrod cup, whether passages or bleed holes or both (several design approaches are used depending on the manufacturer) are very small and easily plugged. Oil left to sit actually will resin cure or the passages/holes became plugged with suspended dirt that settled.
With care these can be cleaned. The lifter body does not need to be removed just the inner plunger. Remove the bail from the top of the lifter after removing the push rod. Take the plunger out putting it on a clean towel take the top apart (remove the push rod cup) typically there will be a disk with 1 to several tiny holes in it. The bottom of the push rod cup typically has a very small protrusion that the dist seats upon this may have an equally small passage in its side. Inspect all of this under magnification and clean carefully with a solvent like lacquer thinner. If there is a wear pattern in the disk reassemble it in the reverse position so any wear faces into the plunger's reservoir. Lubricate the parts with fresh oil and install them back into the lifter body they came out of.
This process leaves the lobe and lifter match intact, but you must be careful not to mix internal parts of the lifters as well.
With all due respect to Bogie's excellent dissertation (I'm a fan too), another option is to remove the lifters for cleaning one at a time, replacing each one when done cleaning before removing the next.
The reason I say this, is I have sent the circlips flying off into the ozone on several occasions when disassembling/reassembling them- and that was w/the lifter out in front of me on a towel w/good lighting. If that happens and you're working on the lifter still in the engine, losing the clip would be easier to do and could even find its way into the hole at the end of the valley, the distributor hole or into an intake port, etc. Obviously those holes could be plugged up, but the whole thing is too much bother compared to simply removing them one at a time IMHO. This also gives you the opportunity to inspect the lifter foot for abnormal wear.
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