'46 chief oil pump

[PaulCDF]

Omar
Thanks for the feedback and THANK YOU for helping that gent out.
God Bless him. Hope if I make it to 90 I remember what a motorcycle is!

[Omarttentmaker]

Take a look at Jerry Greer's web site. You can see the difference in the cast iron oil pumps, the sump valve assembly and the difference between the early '46 and the later style sump valve assemblies. If you look at the '47 sump valve assemblies, you can clearly note the differences. Take note, there are several differences... sump valve assy, plunger size, more.

Many Indian owners have opted for the '47 style sump, with the scraper, likely for the perceived advantage of a larger plunger AND the scraper. Alot of the 39-46 Chiefs have been converted to the later '47 "improvements". Bigger plunger means more volume returned to the oil tank. The scraper is intended to eliminate the maintenance of pulling the sump valve and the necessary work to avoid the failure.

I completely agree with Harry about pouring oil down the return line to prime the pump, to see if there is air, or leakage back through the sump valve disc. But, that won't tell you if the pump barrel is worn and the oil is leaking past the plunger. Sure, on occasion the sump disc will get a piece of debris or somehow leak. However, if you have to continually have to prime the return side, there's a good chance the pump is showing signs of further wear. BOTH the sump and the pump itself are separate components, but each MUST be addressed when problems occur. Cheaper to fix BOTH, rather than take short cuts and end up with a major overhaul, trying to "Cheap out". There is no easy way to success.

My suggestion, start with the "priming the pump", then if you still have no oil return, after your bike sits for several days, repeat the "Prime process", do this step a couple of times, so you eliminate "false positive" tests, continuing bleed-offs indicate more work is needed. Step two... pull the sump valve assembly and repair it with care and attention to detail.

If, after re-assembly, there is a weak oil return through the line returning to the oil tank, then you will have to decide if you want to overhaul the pump body and plunger assembly. The later is a much bigger issue. Oversize plungers are available, but must be fitted properly, NOT just putting in an oversize plunger and calling it good.
Some simply replace the return gears, these are also a tolerance fit. However, if the pump still bleeds off and the "pump loses prime", then the return gears are may not be the problem.
Could also be the plunger side. BEST is to overhaul ALL the components, with attention to every detail.

There are three main issues with a cast iron pump... the sump valve, the return side, and the plunger tolerances. ALL of it matters, if you want a trouble free oil system.
IT is all VERY different from a Harley. Like Pisten Bully noted... its all in the details. No short cuts allowed.

Sorry about the long answer, but Indians are so much different than Harleys, it can be a daunting task for sure. Even for the most experienced.

Roger Herbison aka C2K

Thanks to all who replied. And yes, indeed, the return line was airbound. He filled it with oil and things are now right again. BTW, my first suggestion to him was to get a manual and read abut the pump, but this guy is really old-school (he's 90).

[PaulCDF]

Omar

You may find Jim Mosher's discussion of Indian Oil pumps and sumps useful:

Oil Pump & Scrapers (performanceindian.com)

Performanceindian.com

[PaulCDF]

Here are my 'search' steps:
AMC Home Page
Features (Right hand side)
Vintage Motorcycle Library
Search term: "1948 Indian"


1948 Service Manual.jpg

Good Luck.

[ChiefTwoKicks]

Take a look at Jerry Greer's web site. You can see the difference in the cast iron oil pumps, the sump valve assembly and the difference between the early '46 and the later style sump valve assemblies. If you look at the '47 sump valve assemblies, you can clearly note the differences. Take note, there are several differences... sump valve assy, plunger size, more.

Many Indian owners have opted for the '47 style sump, with the scraper, likely for the perceived advantage of a larger plunger AND the scraper. Alot of the 39-46 Chiefs have been converted to the later '47 "improvements". Bigger plunger means more volume returned to the oil tank. The scraper is intended to eliminate the maintenance of pulling the sump valve and the necessary work to avoid the failure.

I completely agree with Harry about pouring oil down the return line to prime the pump, to see if there is air, or leakage back through the sump valve disc. But, that won't tell you if the pump barrel is worn and the oil is leaking past the plunger. Sure, on occasion the sump disc will get a piece of debris or somehow leak. However, if you have to continually have to prime the return side, there's a good chance the pump is showing signs of further wear. BOTH the sump and the pump itself are separate components, but each MUST be addressed when problems occur. Cheaper to fix BOTH, rather than take short cuts and end up with a major overhaul, trying to "Cheap out". There is no easy way to success.

My suggestion, start with the "priming the pump", then if you still have no oil return, after your bike sits for several days, repeat the "Prime process", do this step a couple of times, so you eliminate "false positive" tests, continuing bleed-offs indicate more work is needed. Step two... pull the sump valve assembly and repair it with care and attention to detail.

If, after re-assembly, there is a weak oil return through the line returning to the oil tank, then you will have to decide if you want to overhaul the pump body and plunger assembly. The later is a much bigger issue. Oversize plungers are available, but must be fitted properly, NOT just putting in an oversize plunger and calling it good.
Some simply replace the return gears, these are also a tolerance fit. However, if the pump still bleeds off and the "pump loses prime", then the return gears are may not be the problem.
Could also be the plunger side. BEST is to overhaul ALL the components, with attention to every detail.

There are three main issues with a cast iron pump... the sump valve, the return side, and the plunger tolerances. ALL of it matters, if you want a trouble free oil system.
IT is all VERY different from a Harley. Like Pisten Bully noted... its all in the details. No short cuts allowed.

Sorry about the long answer, but Indians are so much different than Harleys, it can be a daunting task for sure. Even for the most experienced.

Roger Herbison aka C2K

[Omarttentmaker]

Omar

Hopefully your friend has a manual

I would start by reviewing Kiwi Indian Tech Videos:

Kiwi Indian Motorcycles "Oil Pump Timing"

Kiwi Indian Motorcycles "Ignition Timing"

Available FREE KiwiIndian.com or Youtube

A 46 should have a timing hole similar to HD on the left crankcase.

From what little I know; most of it from this Forum,
The Indian oil pump produces very little pressure, but there SHOULD be return visible in the oil tank when running.

PS

Just checked the Club has Overhaul manual in the Library for 1948 Indian Chief "74" cu in and Oil pump repair section (page 18)
does speak to pumps prior to 48.

Went to the document library for the first time, but I don't see anything in there relating to manuals.

[pisten-bully]

Gotta friend with this chief, and the oil pump seems to have quit on it. Being a Harley guy, I know next to nothing about this motor, but I see that the timer is hooked into the oil pump internally. Anything I should pay particular attention to when removing the timer to get at the internals of the pump? Would the lack of oil pressure be something as simple as sheared key, or should I be looking for something particular? Guessing it would be wise to somehow mark the position of the motor before removing the timer, unless this motor has a timing hole and mark similar to a big twin motor. Any help or pics appreciated.

...the devil is in the details! For example, the return oil line to the tank may have become airbound for some reason, we don't know how long the Chief sat, was there an oil change and the return line wet sumped, etc.? Maybe, just maybe the oil pump needs priming by pouring oil down the return line and that will fix it. These Indian oil pumps don't build pressure, they simply return oil from the sump to the tank and feed it back to the sump and the splash/misting does the rest.

[exeric]

ALSO, I think you might be well served to pull the sump pump first, the screen could be blocked as well as the small flapper inside it could be worn, its possible to repair this and might be the cause of your problem?

Very good advice. I just went through the sump valve assembly on my '41 SS and it was a mess. Can't hurt to take a look, and easy to access, and clean.

[NiteOwl]

ALSO, I think you might be well served to pull the sump pump first, the screen could be blocked as well as the small flapper inside it could be worn, its possible to repair this and might be the cause of your problem?

[exeric]

The Indian oil pump produces very little pressure, but there SHOULD be return visible in the oil tank when running.

If you're wearing white pants, and the motor is running, and you want to see if oil is returning; use caution Paul gives good reference to the Kiwi tech videos.

[PaulCDF]

Omar

Hopefully your friend has a manual

I would start by reviewing Kiwi Indian Tech Videos:

Kiwi Indian Motorcycles "Oil Pump Timing"

Kiwi Indian Motorcycles "Ignition Timing"

Available FREE KiwiIndian.com or Youtube

A 46 should have a timing hole similar to HD on the left crankcase.

From what little I know; most of it from this Forum,
The Indian oil pump produces very little pressure, but there SHOULD be return visible in the oil tank when running.

PS

Just checked the Club has Overhaul manual in the Library for 1948 Indian Chief "74" cu in and Oil pump repair section (page 18)
does speak to pumps prior to 48.

[Omarttentmaker]

Gotta friend with this chief, and the oil pump seems to have quit on it. Being a Harley guy, I know next to nothing about this motor, but I see that the timer is hooked into the oil pump internally. Anything I should pay particular attention to when removing the timer to get at the internals of the pump? Would the lack of oil pressure be something as simple as sheared key, or should I be looking for something particular? Guessing it would be wise to somehow mark the position of the motor before removing the timer, unless this motor has a timing hole and mark similar to a big twin motor. Any help or pics appreciated.