Oil pump problems

[55suicidepan]

Description: My 55 has 20-25psi of oil, when cold. Then after it gets hot, the oil pressure drops to zero.

Well I got another problem. My 55 has 20-25psi of oil, when cold. Then after it gets hot, the oil pressure drops to zero. I was thinking bad pump? I am going to take the oil pump off to check for damage. I did not here any knocking or other strange noises. Should i worry about other damage, if a new oil pump corrects the problem?

[panhead]

Have you checked if oil returns to the oil tank?

[55suicidepan]

No i haven't checked if oil is returning back to tank, How do i check that?

Okay i figured out how to check oil return. And yes oil does return back to tank,when pressure has dropped to zero. so what is that telling me? That my oil pump is working, but the pressure is not?
I am confused.

[Cotten]

I think this has been covered on this forum before, but,..
Pressure and flow can be quite independent of each other. You can have outrageous pressure and still starve for oil. Flow is what our motors depend upon.

So take that damn gauge off. It only makes you worry. That's what women are for; Among other things.
(It shoulda nearly pegged when it was cold, so do not trust it. Your eyes need to be on the road anyway.)
If you still have hydraulics in it, they will quickly alert you if there is a problem!

[55suicidepan]

So cotten are you telling me that as long as the motor is not knocking, then it is ok?

[Cotten]

IF you are running stock '53+ hydraulics, they will knock before the 'idiot light' will come on.

Of course, that can cause damage itself, but at least it alerts you quickly to a problem.
The HD OHV pump is very durable, and the motor does not require the overkill that it delivers.
There are three common catastrophic malfunctions: A sheared feed and/or drive key, where the light comes on immediately; A sheared return key, where the motor fills and smokes, and eventually bogs down; Or a lack of supply from the tank, either by blockage, or out-and-out stupidity. That, of course, isn't really a problem with the pump itself, but it is by far the most common!
Sheared keys can be diabolical in that they may initially 'catch' at low speeds, but spin on the road.
I have personally encountered a sheared feed key, when a tiny chromed screw, still with some chromer's wire on its threads, came out of my Paughco tank. (Lesson one: rinse and shake out new tanks!)
The single sheared drive key that I inspected might have been caused by excessively heavy oil.
My own experience with blockage was indeed my own stupidity, as I found an oil bottle cap at the bottom of the tank!

[VintageTwin]

If you're running the original cast iron oil pump, the oil pump shaft has worn the bushing-less body of the pump. Oil pressure is 20 lbs or more cold, then drops to what looks like zero on the test guage. It's because the thinned, hot oil is bleeding past the shaft/body clearance. Don't worry about it. The only part of the motor that's not getting gobs of oil are the rocker arms. That's the reason you need to snap the throttle off periodically, so it will force oil up to the rockers.
If you still want a new pump, don't just take the other one off and bolt-on a new one. The oil pump gears need to be meshed without binding, which involves removing the cam cover, gears, free-spinning the pump with your thumb, etc.

[mbskeam]

hello,
I also had the feed gear key shear. that was from the oil restrictor backing out of the oil pressure gage and droping down into the oil pump when shut down,as in the oil press. did not keep it out of the gears and when I went to start it oil light came on and gage said zero.on to the trailer it went. Surprised

mbskeam

but I do wonder if the 90mph to the hospital for the 1 1/2 month early baby birth had any thing to do with it. Surprised

[Cotten]

Kirk!
Where did you get the idea "That's the reason you need to snap the throttle off periodically, so it will force oil up to the rockers."??

[PanPal]

Now this thread has me wondering. My front exhaust pushrod starts tapping hard after 45 minute of riding. Tonight I noticed my oil light flickers in when riding in high gear at low idle after about 25 minutes (on a cool evening). I'm running 20-50 HD oil now. My buddy's first suggestion is stick a solid rod in there, next he said tighten the pushrod 5 turns after zero backlash. I don't think the tappet would have enough travel to pump up after 5 turns, and I'm not ready to give up and stick a solid rod in yet! He also says pans don't like the multi grade oils. I'm going to try straight 60 weight first but I think this is what I started with last year, same problem. I've replaced the tappet with no luck.

Cotten,
Does this sound like a slipping oil pump gear? Where does the oil come from before it gets to this tappet? How long should I be able to ride before she's yelling for a cool down cycle? The motor is not worn and loose. It cools down and the tappet makes noise then pumps up and I'm knees in the wind for another 45 minutes. Seems every where I want to ride is an hour and a quarter away.

[sleeper]

PanPal-

Hyd. lifter has .250" cushion in it. Correct adj. is 1/2 of that. U want to be in the middle of cushion. or .125"
So depending on TPI=threads per inch, that dictates
your adj. needed.. You can be a tad +/-
Look in your manual, it has a great schematics of oil & it's circulation routes...

[Cotten]

PP!

The front is of course the last of the units to get oil, meaning that something might be starving it upstream.
Most commonly this is excessive clearance between the tappet and the block, but it could be other things, like a "full-oiling" pinion bushing or a plugged tappet screen.
The Manual has a very good schematic of the oiling system.
I do not suggest 60wt oil, unless your machine is a very tired warhorse, or you live in a very hot climate. Heavier oil builds pressure, but restricts flow.
I shy away from multigrades, so try straight 50 wt. (I prefer non-Pennsylvania brands).
Note that the hydraulic units themselves can be temperamental!

[PanPal]

Thanks for the info. I'll look closer at my flow diagrams tonight.
Billy,
I do have the setting in the middle. I've tried 3 turns after and 4 turns on the rod adjustment. Same Sh*t.
Cotten,
I'll go with 50W and see what happens. I guess The tappet blocks need a good inspection. The tappet screen looks OK, Pinion bushing?? Is this the bushing that can get scared when pulling out the oil pump shaft in the case? I think it's more than temperamental Hydraulics. Very consistent time cycles before the gut wrenching knock begins.
So how long are people riding before their Hydraulics start tapping?
I hear theres a way to install Evo tappets in a Panhead resembling tappet block. Anyone have any input on this?
I guess I've gotten a little off topic here. I like this spell check option. I kind of wonder why it doesn't recognize the word Panhead though.

[VintageTwin]

Cotten, By snapping off the throttle (running an iron pump) for about three seconds, you use piston created suction to bring oil to the top of the motor. Not necessary when using an S&S pump, since oil volume is not a problem with their pump, and not something you'd do much of in a motor breakin period (first 2,000 miles).
Once again, high oil pressure on a cold motor. Zero on a hot motor? Oil pump shaft bore in the body is worn. No fix, except a new pump. Sounds coming from the motor mean trouble. Hydraulic tappet (failure) clicks are not heard as knocks. Don't let anyone but an expert touch the internals of your motor. Someone who works on Pan motors and has their wall plastered with letters of satisfaction for Knuckle and Pan.

"Very consistent time cycles before the gut wrenching knock begins".
Pinion shaft running crazy. Flywheel taper to pinion shaft taper not matching. Happened to my first motor. Any metal trash in the oil filter? Look for aluminum. The pinion shaft will start carving pieces of cam cover pinion shaft boss. Motors should not knock, ever.
If you put in a solid lifter kit and solid pushrods, throw all the Harley hydraulic tappet adjustment info printed in their book out the window. Solid lifter push rods adjust the same as early Sportsters...."spin pushrod with one finger and feel no trace of bind." Somethings seriously wrong with your motor. The only place to find solid lifter adjustment is in the Knuckle service manual, Clymers Pg. 155, and the early Sportster manual.
You said your motor was recently rebuilt? By whom?

[Rainjester]

55,

I had the same concern with my 53' when I first got it and found that it was common with these bikes. Mine was also around 25 pounds cold and it'd go way down to close to 0 (under 5 pounds) when warmed up. After some tinkering around, I found that I was indeed getting oil flow.
It's been said in the past that if the oil pressure is suddenly staying up and not dropping down when it's warm, be concerned, since there may be blockage in the oil passages.

jester-