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rocker arm oiling problem
Posted: Sun Jul 26, 2020 2:06 pm
by Greg Long
The problem I am having is some rockers are flooding and others getting very little oil. the engine is an AMC 405 bracket race motor, fresh build.
It has an external oil pump, the additional oil line in the intake valley, which seems to be used in most racing AMC engines, solid roller Morel lifters, bushed lifter bores. The rocker arms Harland Sharpe, correct length pushrods with 210 * tips, . 700 lift cam.
Priming and slowly rotating the engine, just a few degrees at a time I get oil to all rockers but very uneven amounts, some are not even oiling the valve side of the rocker, others will fill the recess for the adjuster and run over the side of the rocker.
This is a new problem for me and I am about out of ideas. The only thing I suspect now is incorrect bushing clearance.
The man who installed the bushings said to go ahead with break in, the man who honed the bushings offered other ideas, which I had already tried, the cam grinder said it might oil when running. So I am pretty much at a coin flipping moment, run it or not?
Any advice or helpful ideas would be appreciated. Thanks, Greg
Re: rocker arm oiling problem
Posted: Sun Jul 26, 2020 6:27 pm
by Walter R. Malik
Greg Long wrote: ↑Sun Jul 26, 2020 2:06 pm
The problem I am having is some rockers are flooding and others getting very little oil. the engine is an AMC 405 bracket race motor, fresh build.
It has an external oil pump, the additional oil line in the intake valley, which seems to be used in most racing AMC engines, solid roller Morel lifters, bushed lifter bores. The rocker arms Harland Sharpe, correct length pushrods with 210 * tips, . 700 lift cam.
Priming and slowly rotating the engine, just a few degrees at a time I get oil to all rockers but very uneven amounts, some are not even oiling the valve side of the rocker, others will fill the recess for the adjuster and run over the side of the rocker.
This is a new problem for me and I am about out of ideas. The only thing I suspect now is incorrect bushing clearance.
The man who installed the bushings said to go ahead with break in, the man who honed the bushings offered other ideas, which I had already tried, the cam grinder said it might oil when running. So I am pretty much at a coin flipping moment, run it or not?
Any advice or helpful ideas would be appreciated. Thanks, Greg
With Morel lifters, they are complete edge-orifice design so, the individual lifter bore clearance mostly determines the amount of oil they allow unless an oil hole in the bushing will at some time align directly with the hole in the lifter body.
Re: rocker arm oiling problem
Posted: Sun Jul 26, 2020 8:40 pm
by amc fan
What size hole is in the bushing? Does the band in lifter line up with the hole in bushing somewhere in its travel up and down? I have seen holes not in right place lube rockers ok due to lots of lifter to bore clearence.
Re: rocker arm oiling problem
Posted: Mon Jul 27, 2020 9:49 am
by Greg Long
Walter, amc fan, thank you for the replies. Both comments lead me to think it may be a clearance or incorrect hole position. Amc fan, the man who installed the bushings did not remember exactly but thought .032 hole size. Thanks again, all advice welcome. Greg
Re: rocker arm oiling problem
Posted: Mon Jul 27, 2020 10:34 am
by Walter R. Malik
Greg Long wrote: ↑Mon Jul 27, 2020 9:49 am
Walter, amc fan, thank you for the replies. Both comments lead me to think it may be a clearance or incorrect hole position. Amc fan, the man who installed the bushings did not remember exactly but thought .032 hole size. Thanks again, all advice welcome. Greg
With only a .032" hole size, I would not use a true edge orifice oiling lifter without slight modification.
Re: rocker arm oiling problem
Posted: Mon Jul 27, 2020 6:38 pm
by gmrocket
With that small of a hole in the bushing , and depending on the location of the oil band height during lift...plus if the lifter is slightly more loaded/cocked in the bore..you will get differing flow through the lifter with the edge orifice style
During running, the lifter should be running true in the bore, not the same as what your doing to check it.
Re: rocker arm oiling problem
Posted: Mon Jul 27, 2020 8:43 pm
by allencr267
spec .032 orifice means nearly unlimited bevel/chamfer/radius.
Re: rocker arm oiling problem
Posted: Tue Jul 28, 2020 9:14 am
by Greg Long
Thanks again guys. The intake is coming off today for a closer look.
Walter, what modification are you speaking of, a small vertical groove?
Re: rocker arm oiling problem
Posted: Tue Jul 28, 2020 9:39 am
by Walter R. Malik
Greg Long wrote: ↑Tue Jul 28, 2020 9:14 am
Thanks again guys. The intake is coming off today for a closer look.
Walter, what modification are you speaking of, a small vertical groove?
With a true edge orifice oiling lifter the oil hole is above the annulus of the lifter. We surface grind a .002" - .003" flat on the side of the lifter body to slightly connect the two. However, lots of people have simply used a file to do the same thing. though not as accurate, it seems to work just fine with a lifter bushing.
Re: rocker arm oiling problem
Posted: Tue Jul 28, 2020 7:18 pm
by gmrocket
allencr267 wrote: ↑Mon Jul 27, 2020 8:43 pm
spec .032 orifice means nearly unlimited bevel/chamfer/radius.
I use the same .032” feed
With edge orifice design SR’s...no problems even with big RPM and High lbs springs.
Checking the stuff your worried about acts a million percent different at 8K than manually tuning the crank over by hand
Re: rocker arm oiling problem
Posted: Wed Jul 29, 2020 11:04 am
by amc fan
I run a .080 diameter hole in the lifter bushings in my 418 cube A M C. 4.185 X 3.8 stroked engine. I use comp S B C lifters with Ford FE link bars. The area of .080 hole is .02 sq. inches.Assuming the the amount of oil coming out pump is 7 gallons a minute,the amount of oil coming out of each hole is 1.28 oz. per minute, but you also have the flow hitting the area annulus of the lifter in the bushing. If you figure out the area annulus of the lifter in the lifter bore you will know what size flat to put on side of the lifter.I was not aware they have edge orifice roller lifters. back in the day when we ran Fuelie cams on the street we used Piddle valve lifters not the edge orifice with the stamped rocker arms that had the O's ,not the Triangle's marking on the rocker arms.
Re: rocker arm oiling problem
Posted: Thu Jul 30, 2020 10:20 am
by Greg Long
O.K. what I found was the hole in the bushing is .060, the hole in the lifter is .085 which is at 12:00 and 6:00 when looking down at them installed. A few of the bushing holes are at 6:00, but most are at 5:00 to 5:30 causing less visible flow. Some also seem to be missing the oil passage in the block.
With an .058 wire I can insert into the bushing I fond the wire will not go in the same amount. With an .047 wire I can get it in more of them deeper. With .030 wire the same results, a couple more work. It appears to be an installation error.
I tried Walter's advice and put a small notch in the lifter as he described. I installed that lifter in the worst hole and instantly got oil, so I think the problem can be solved.
I am noticing too that the lifters and bushings are scuffing a little, top and bottom, possibly a clearance issue ? I can't get the small bore gauge in the hole with the heads on.
The helpful hint for today, don't drop the wire in the hole, guess how I know? Thanks, Greg