Oil pump Iron 1000 1979 bizarre.....

[jlv]

After complete rebuild of my engine, I blocked an admission valve after a few miles. The valve was easily rput back into its place with a little screw driver through the spark hole. Since I hate this type of behaviour of a brand new engine, I opened the top to realize that apparently oil never reached valves and cams, oil lines are perfectly clean' oil pump looks new, but after long inpection, I cannot understand how the oil could go to the engine if the place marked with a X on the below picture was not drilled. Before I drill it myself, i would like your advise re this blind element of pump. A factory mistake ? A model from later/earlier model (1979 had no oil filter).
Note that I never saw this engine in function before as I inherited the bike in cartons....



Thanks for your help.

[Hippysmack]

That appears to be an 86-90 oil pump.
At least the bottom cover is.
Here's an 86-90 cover:


77-E83 cover:



77-85 pump body has only 1 fitting on the body:


86-90 has 2 fittings on the body:


The feed lines are configured differently on 86-90 than 77-85 oil pumps.
Here's the oil pump sections with pics and info for:
Evo pumps:
http://sportsterpedia.com/doku.php/techtalk:evoil03

IH pumps:
http://sportsterpedia.com/doku.php/techtalk:ihil03

What does the front of the pump body look like?
It's either L83-85 or 86-90.

edit:
If you have the L83 body and drill the hole in the cover, it won't work properly and it'll wet sump from the jump.
The feed gerotors got bigger in 86.
The depth of the cover got bigger to accommodate this change.
That'll leave the clearances too loose inside using it on a L83 pump body.

[jlv]

Thanks alot for your help. By body pump has one hole only, withbthe brass connector where oil returns back to the tank. Without drilling, the only hole where the oil could go is the one tapped by the oil pressure sensor in the pumb bottom cover. With the hole drilled, the oil now can go to the side hole in the bottom of the case cover, and then go up to the upper hole in the sa8me case cover that feeds the cams pipe.

[Hippysmack]

If you use the 86 cover, your gerotors will be loose inside the pump.
They will probably deliver less oil to / from the engine.
Oil may also run straight from the feed side to the scavenge side starving your engine.
Just trying to help but you need the correct cover for your pump.

[Hippysmack]

I just tried to put the 86 cover on the E83 pump.
It just about doubles the tension on the gear to turn it.
The depth of the cover shows up on the top of the feed gerotors when buttoned up.
This squishes the (edit: scavenge) gears harder against the plates and will result in wearing down of the plates / gerotors.
This could warp the outer seal and oil can transfer between the pump sides..

[Hippysmack]

You should also determine which feed gerotors you have.
The scavenge gerotors are the same size 77-90.

77-85 gerotor app. dims:
http://sportsterpedia.com/doku.php/t...b#gerotor_dims
86-90 gerotor app. dims:
http://sportsterpedia.com/doku.php/t...j#gerotor_dims

This is how the feed gerotors should sit in the the proper cover.
Spec: .001"-.011" above the lip.


This is how the 77-85 feed gerotors fit in an 86-90 cover.

[jlv]

I really appreciate your detailed description. I have checked assemblies as per your recommedations. All this sounds OK and I really feel this pump assembly is made of homogenous parts.
The only issue is that this pump is made for a model where the hole I tapped with a pressure sensor is supposed to feed an oil filter that I do not have (1979 had no oil filter). Therefore since I drilled the famous hole, oil can co up though the check valve into the enfine, and I have observed that oil now goes up to my top engine.

But your comments caused some doubts. For example what is the purpose of the check valve if the hole I drilled does nox exist ?

Even if all seems to work now, I think I will look for a new pump !

[Hippysmack]

The 86-90 pump body doesn't have a check valve in the pump.
The check was moved to the oil filter pad.
The oil path goes out the cover fitting to the filter and back into the body fitting and into the bottom of the gearcase cover.



77-85 models have no filter pad (or feed oil route outside the pump) on feed side so the check had to be installed in the pump.
The check is essential as it keeps tank oil from sifting into the engine during shut down time and it creates back pressure to allow your low oil switch to work.

Your feed gears look taller to me than the 85 version but the pic could be skewed.
If you'll check the feed gear dims in the links I gave, that'll tell you if you have the 85 or 86 feed gerotors.

Even though you will get oil with the hole drilled in the 86 cover,
What I'm trying to say is it probably won't last long before tearing something up.

That cover is out of spec for 85 and prior model pump bodies.
If your gerotors fit low in the cover like the pic in my last post,
Oil will circulate through the pump until a certain pressure point.
From then on, any pressure over that is free back feed to the pump.
The pump is designed to transfer oil from the back cavity to the front cavity on the both the feed and return sides respectively.
If oil is allowed to be naturally shared by both cavities in the feed side, that reduces the effectiveness of oil flow from the pump.

If you have the 86-90 feed gerotors, too much pressure will be put on the return gerotors against the plate which will expedite wear in the return side of the pump and create excess heat up there as well.

Moral of the story:
Just because you can drill the hole doesn't make it a good idea.
My 2 cents.

edit:
I just checked the lip height on both covers and they appear to be the same (or close enough).
The gearshaft bore in both covers are the same depth (even though gearshaft lengths are different)
The shaft length is of no consequence as long as it sits inside the bushing.
(and the solid pin is fully inside the feed gears)
Measure this to be sure.

I put the 86 gerotors and cover on the 79 body and I have more resistance.
(but this cover was also made for the chamfered gerotors so that may be the reason for the extra resistance I'm getting)
If you have the 86 gerotors and the 86 cover with the hole drilled, it 'should' work.
The .001"-.011" measurement I mentioned earlier still applies however.
That would need to be measured.
But, be sure to check oil pressure with a gauge mounted in place of your oil switch to be sure you'll get enough oil from the pump.
See also Engine Oil Pressure and Testing in the pedia:
http://sportsterpedia.com/doku.php/t...re_and_testing

I still believe you need the right cover but if'n the gerotors are the 86 version, the right cover won't work.

Do the gerotors you have sit above or below the lip in the cover?

[Hippysmack]

Just keep in mind if using the 86 feed gerotors.
You'd be adding more oil into the engine but still scavenging the same amount with the taller feed gerotors.
86-90 engines are notorious for flooding the engine with oil leading to wet sumping during operation.
It's partially due to the MoCo using bigger feed gerotors without increasing the return side.
It'd be good to check the oil tank periodically for froth.
Occasional froth happens in all Sportsters.
But, too much oil in the engine churns the sump oil, mixes air in the oil return line and performance suffers.
But that's another thread.
You'd be looking for a constant froth which would not be good.

This is basically theory mixed with other XLF threads for me but it's something to consider.

[jlv]

Thanks again, I would never have found such details on the web. Since the engine has received new pistons, new boring, new valves, etc....I will avoid taking the risk and look for a 79 pump !
Here is a pic of the engine.