Oil pump modification question

[BigLakeBob]

Duke, I always value the information you share, but I believe this is what a '51 pump should look like not as in your post #8. No hole by idle shaft and oil return gully.
DSC06997.JPG

[dukekleman]

Bob,
You are correct!
The oil pump body I photo'd ( actually an early knuckle head version) was for conversation regarding the galley's I marked up (A, B &C)on the correct Panhead crankcase . I did not have his year oil pump disassembled on any engines in my shop at the time. Possibly should have gotten an Internet image ...was in a hurry at the time, laughing...

Duke

[paddy]

D, Thanks for all the insight..Much Appreciated!!!
What ya think about using JB Weld to fix that tiny hole?

[dukekleman]

Paddy,

I was wondering how long until that product got brought up in this conversation... laughing

Harley Davidson uses Maxlok MX/T6 Acrylic Adhesive part number 11100088 inside the primary drive systems along with a retaining clip with out issue.

If all things were prepared on the surfaces properly, it will probably work. It's just not something I'd typically recommend.

Duke

[paddy]

Right I was thinking about what you said about even having enough room to get a tig head in there. That hole is pretty far back.

[dukekleman]

Paddy,

If a person can't get the tig torch back into that area:

You could try inserting a brass or stainless steel rod into the gally from the gear cover gasket end.

Then proceed to solder the hole shut and remove the brass or stainless steel rod...


Duke

[paddy]

D, So I went the JB weld route. When I was cleaning out that oil gally the air cameout of that tube that is above the screen. Is that supposed to happen?

[dukekleman]

Paddy,

Yes, they are connected so air coming out of the stand off tube is normal.

Hope this helps,

Duke Kleman

[paddy]

D, Ok trying to understand this ...The hole in the oil galley is pressurized return oil or feed oil??? I am looking at this pressure oil drawing and trying to figure out were the oil is coming from. Were the pen is is the gallery that terminates at the cam cover.... and with the hole i found in it....Thanks for the education..

[dukekleman]

Paddy,

On your engine, the oil is pressured oil on the feed side which is bleed off from the bypass circuit.
It works in conjunction with a properly timed breather gear when active on the piston downstroke.

The timing of this is crucial along with piston ring & cylinder bore correctness. If not correct, combustion pressures enter the crankcase causing many issues often brought up by others on this forum.

It is equally important the gear cover gasket seals properly around the area shown in the photo below. Oiling issues arise if this isn't sealed properly.
IMG_20250105_102047110_HDR.jpg
Let us know if you have any other questions.

Hope this helps,
Duke Kleman

[paddy]

Great! Thanks for explaining that!!! I have used the JB Weld.. Gonna be in the 20s and 30s here for the next week so I will report back once I can get it out for a spin and get that oil back up to 200 F. Thanks for all the clarification and help.!!!

[dukekleman]

Paddy,

It would be good to know the answers to my questions in post #5.
Knowing those numbers would allude to what you are probably going to see once you ride it.
IT would also be useful comparative data, before and after the JB weld fix.
There could be tolerance issues that all stack up to low oil pressure. Hopefully this will cure your problems.
Keep us posted.

Duke

[paddy]

D, I had wrote this down but forgot to post.
Oil pressure @ 2,000 - 2500 rpm below 150F:... gauge maxed out at 30lbs
Idle oil pressure @ 175F: 0 oil pressure light is on
Oil pressure @ 2,000 - 2500 rpm @ 175F:
about 7lbs light is out
Idle oil pressure @ 200F:.. 0 oil pressure light is on
Oil pressure @ 2,000 - 2,500 rpm @ 200F:
0 oil pressure light is on.
like I said I don't believe I have the best gauge but it is the same Marshall 0-30 that I have on 3 other bikes here.
same. Builder has done 6 other motors for me and I have never seen that oil pressure reaction after oil heats up before after he sent me another pump and had same results I had figured it had to be internal leak. As I said this motor I inherited. It was freshly build by another builder long gone now and when I ran it last year I could never get any pressure after it got hot. So I had my guy go through it he did find tolerance issues along with a very tight rod crank bearing it was so tight scored blue and eaten up. He also changed out the 3 hole crank pin to a 1 hole. He did tell me a little here and a little there will result in low pressure. But flow is most important. However the light if working correctly should go out after you crack the throttle from Idle. I am guessing when he heat cycle this motor after the build he gets motor hot not necessary the oil. He said he had 7-8 lbs and would not have given me the motor back if it wasn't right. Probably why he wanted to put his own guages and sending switch on it after I told him I had 0 pressure but had flow.
I am very appreciateive for your help and hoping this casting defect hole was the problem all along and just looking to move forward and enjoy the bike. Get some breaking miles on it before putting the sidecar back on and hopefully to the Road Run in Kentucky this year..

[dukekleman]

Paddy,

Yes, I doubt he got the motor oil up to full operating temperature.
It takes a long time on the chassis Dyno or the street to get the oil up to proper temperature. You wouldn't want to try and do that on an engine run stand.

Hopefully your discoveries will yield proper results.
Keep us posted.

Thank you,
Duke