Panhead oil pressure problem - please help!

14952 Views 15 Replies 7 Participants Last post by Panhead Jim, Aug 5, 2006

Panhead Jim

Discussion Starter · Jul 29, 2006

This all started when I tore the pan down a year ago, maybe more, to replace a leaking base gasket. It's a 1959, unmodified. Found the rear cylinder and piston scratched beyond repair. Bought new V-Twin cylinders (gulp), sent the heads, cylinders, pistons to Accurate for bore and rebuild, all new, and went back up. Put a pressure gauge on it this time, for good measure. I was sure the failed base gasket was the source of the ruin, as it failed on the pressure feed hole to the top end (common failure).
As it warms up to full hot, takes about 20 minutes, the pressure gradually falls off to zero with the stock, cast iron oil pump. Me and the wrenches I hang with eventually settled on tired pump, so new S&S pump, installed last weekend. Guess what, exactly the same deal, exactly, no change. 40-45 psi on cold start, holds good pressure early then just graaaaadually fades to nothing at full hot. I'm talking about nothing here, not even a blip when I jack it. One interesting fact, that may be important, is that when the lifter screen stops up, which it's done three or four times since the build, it holds great pressure, 25-30 psi, in the bottom end, even at full hot. Clean the screen, same deal, pressure good early, then fades to zero.
S&S is stumped, I'm stumped, my wrench friends are stumped. S&S suggested I go back to solids and plug off the hydraulic feed holes, which I had already decided to do, but what do you guys think about this? Any help or opinions would be greatly appreciated.

1 - 16 of 16 Posts

Trent

· #2 · Jul 29, 2006

Are you getting oil to the top end?

Panhead Jim

Discussion Starter · #3 · Jul 29, 2006

Trent said:
Are you getting oil to the top end?

Yes, but no idea how much. I collapsed a lifter the other day in traffic, so I know the pressure is low, just as the gauge indicates.

hatch

· #4 · Jul 29, 2006

I ran solids with plugged oil galleries....oil pressure galore....it was leaking EVERYWHERE from the pressure. What does the oil return stream look like when you tach it up a bit? My mentor told me..."these motors need very little pressure when idling....don't worry about it".....(but you do need some while riding and twistin the grip).

bigassbike

· #5 · Jul 29, 2006

sounds like you are running an oil guage off the oil pump, when the screen clogs up, it shows pressure....because the guage is before the "clog"

sounds like loose fits in the motor's top end(lifters,rockers). if its still returning, its pumping.

Jurneyman

· #6 · Jul 29, 2006

I agree with bigassbike if you haven't done so already get an adapter fitting and run it off the lifter screen opening,where in the hell is all that crap coming from that keeps cloging up the lifter screen? Oil will follow the path of least resistence,so if you have a loose fit in your lifter to lifter block fit the oil will
just dump back into the cam case,instead of being pushed into the lifters and
up the small feed lines to the top end.Unless you have a later designed hyd.
lifter,by jim's or of equal oualtity or design,replacing the hyd's with a good quality solid adapter is a good choice,blocking off the lifter feed holes with
set screws designed and sized for that purpose is the best way to do it,put
grease on the tap,to trap as many of the shavings as you can,then blow air thru the top most hole in the lifter screen cavity till you feel the air flow, if
you don't some of the crap could have gotton past the screen and blocked the passage.It also won't hurt to use the lifterblock gaskets without a lifter feed hole.So as was was stated in the previous threads the oil will be flowing
the path to the top end.If not we will try again in the process of elimination.

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PONY

· #7 · Jul 29, 2006

I had a similar problem years ago and a local engine builder pointed out a threaded hole in the cam cover end of the pinion shaft. He said that, while it's the oil passage to the pinion bearing & crank pin, their is already more than enough oil splashing around the lower end to provide oil there. He put a screw in it and promised me it would be ok and give me more oil pressure to the top end. It's been over 10yrs & 100K and he has been spot on so far. I ran an oil pressure gage off a custom front rocker adapter for a long time and had a min. 5lbs oil pressure. I would check with some engine builders to see what they think. It worked for me but I'd hate to see someone else tear up an engine by trieing this...

Panhead Jim

Discussion Starter · #8 · Jul 30, 2006

Jurneyman said:
I agree with bigassbike if you haven't done so already get an adapter fitting and run it off the lifter screen opening,where in the hell is all that crap coming from that keeps cloging up the lifter screen? Oil will follow the path of least resistence,so if you have a loose fit in your lifter to lifter block fit the oil will
just dump back into the cam case,instead of being pushed into the lifters and
up the small feed lines to the top end.Unless you have a later designed hyd.
lifter,by jim's or of equal oualtity or design,replacing the hyd's with a good quality solid adapter is a good choice,blocking off the lifter feed holes with
set screws designed and sized for that purpose is the best way to do it,put
grease on the tap,to trap as many of the shavings as you can,then blow air thru the top most hole in the lifter screen cavity till you feel the air flow, if
you don't some of the crap could have gotton past the screen and blocked the passage.It also won't hurt to use the lifterblock gaskets without a lifter feed hole.So as was was stated in the previous threads the oil will be flowing
the path to the top end.If not we will try again in the process of elimination.

J, I think you are right on the money. I'm sure the lifters and blocks are shot and gone. Sifton makes a nice complete solids kit. Has everything, one-piece rods, blocks, fitted solids, screws, gaskets, all there. Available J&P Cycle. I'm gonna do it, will let you all (ya'll, where I come from) know.

Panhead Jim

Discussion Starter · #9 · Jul 30, 2006

PONY said:
I had a similar problem years ago and a local engine builder pointed out a threaded hole in the cam cover end of the pinion shaft. He said that, while it's the oil passage to the pinion bearing & crank pin, their is already more than enough oil splashing around the lower end to provide oil there. He put a screw in it and promised me it would be ok and give me more oil pressure to the top end. It's been over 10yrs & 100K and he has been spot on so far. I ran an oil pressure gage off a custom front rocker adapter for a long time and had a min. 5lbs oil pressure. I would check with some engine builders to see what they think. It worked for me but I'd hate to see someone else tear up an engine by trieing this...

Would you believe, I'm a relative expert on this topic, and I may have screwed mine up while I was there. When I started hunting for the right S&S pump for my pan, I started asking a bunch of questions, cuz the wrenches I hang with started talking about DRILLING MY CASES. Welllllll, Ol' Jim wasn't about to DRILL CASES without knowing why, which freaked everybody out (I found it funny, cuz they didn't know shit about why, just you wuz spoz to), but I started digging. I'll just say, if you want to talk old shit and S&S, call a guy named Al at the company. He knows his shit, and will talk to you as long as it takes to make you comfortable. I started this reply out by saying I may have screwed mine up: I verified mine was correct for the '59 model year, a true "side-oiler," but failed to verify the plug. It's usually up in there a ways on the later pans, so not readily obvious looking at the end of the pinion like the older ones. I simply did not pick up a punch and ram it up in there to verify. Now I get to wonder about that shit for a while...

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bigassbike

· #10 · Jul 30, 2006 (Edited)

trying to find oil pressure on a vintage pan is a bit like a fool's errand.

it's pumping, as shown by the pressure buildup from the clogged screen.

dont mistake pressure for volume.

stratocaster

· #11 · Jul 30, 2006

What's in the screen? Seems like that's the whole problem. How abut draining the oil and putting it through a paint filter? -Strat.

PONY

· #12 · Jul 30, 2006

Hey Jim.. Take a look at my post on the next page and see if you have any ideas. The engine was wore out but fine before I fixed it!!

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Panhead Jim

Discussion Starter · #13 · Jul 30, 2006

bigassbike said:
trying to find oil pressure on a vintage pan is a bit like a fool's errand.

it's pumping, as shown by the pressure buildup from the clogged screen.

dont mistake pressure for volume.

I got ya, bud. I'm not tryin to find Evo pressure - 4 or 5 psi would be nice, though!

bigassbike

· #14 · Jul 30, 2006 (Edited)

usually when s&s pumps are installed on an old motor running hydraulics, a passage is blocked with a setscrew, this passage determines whether the top or bottom end gets pressure first, ideally you wanna supply your top end, and only the bottom end after the top supply has been met. it sounds like this wasnt done.

but an old motor wont always generate any pressure, even though tons of oil is being pumped. either way...clogging the tappet screen is most likely what toasted the hydro.

front exhaust?

Panhead Jim

Discussion Starter · #15 · Jul 30, 2006

bigassbike said:
usually when s&s pumps are installed on an old motor running hydraulics, a passage is blocked with a setscrew, this passage determines whether the top or bottom end gets pressure first, ideally you wanna supply your top end, and only the bottom end after the top supply has been met. it sounds like this wasnt done.

but an old motor wont always generate any pressure, even though tons of oil is being pumped. either way...clogging the tappet screen is most likely what toasted the hydro.

front exhaust?

Yep, front exhaust. Oh, and I KNOW the screen dumped the hydro, just clean it out, and the lifters pump up immediately. Man, the drilling and plugging procedures vary widely depending on the case set and the pump body / pump cover combo. You gotta know I got it straight from S&S (twice) before I even purchased my pump. It all depends on your pinion shaft, end-oiler vs. side-oiler, and whether hydros or solids. I'm SURE we did the appropriate install with no drill and plug, and at the moment, I'm SURE my tappet to block bore fit sucks, several thousandths at least. I'm just gonna go back to my trusty solids, all NEW in new blocks, and let the ragged edge drag.
I know it won't go 30 psi hot, but a few pounds dependably will give me the necessary piece of mind to get gone again.

Panhead Jim

Discussion Starter · #16 · Aug 5, 2006

Just a quick update, guys. Tappets and blocks on the '59 are shot and gone. Sloppy loose. Found a Sifton solid kit complete at J&P. Blocks, lifters, screws, gaskets. Gonna block of the oilers to the hydros and go back to my trusty old solids. Don't know what I was thinking on the hydro thing, quiet I guess. Screw it, pans are spose to tick like a clock! I'll post back with the oil pressures after the install. Anybody want to buy a perfectly wonderful original panhead oil pump?

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