sump scarper 48 chief

[hairynob24]

G,day i have a 48 chief thats over oiled , rings are worn out , lots of carbon build up . The carbon has done damage to the rear bore .How do you know the position of the scarper pickup . Should it just touch the flywheel ? or a mick hair off the wheels . One half of the rear case baffle has been broken long time ago the rest are fine . Did a manifold check before pulling it down and it was ok .Carby is in good condition . The rings are 3 cast iron compression .and standard oil ring [ not a 3 x piece ]..this is why i am asking about the sump scarper , cheers Rob

[PaulCDF]

Hairy

I found this on Professor Jim Moshers Performance Indian cite:

http://performanceindian.com/Oil%20P...0Scrapers.html

Oil Pump & Scrapers

"A "scraper" as used in the 1947 Chief was a good upgrade from the original sump casting used from 1932
through early 1947. The scraper is a flat 1/4" plate with a contoured blade behind it that sits very close
to the outer edge of the rotating flywheels. It's job is to "scrape" off any excess oil from the flywheels
when the motor is running. It doesn't actually scrape the flywheels, but rather sits about .015"-.020" off
the edge (just enough to capture excess oil). The scraper blade is cocked at an angle, which helps to direct
the oil now sitting in the bottom of the crankcase toward an oil fitting that the sump tube connects to.
It is a simple system that works really well. The scraper is not restrictive, so an oil pump that has sat
for a length of time has no trouble picking up oil to return to the oil tank. I use a 1947 Scraper on ALL
bottom ends for Scouts, and Chiefs prior to 1947. In 1948, the Chief had this scraper cast into the cases,
and there is only the threaded hole for the sump line fitting. To install a scraper to an older Chief, or
Scout, there is a little trimming needed to the sump hole, and at the very bottom of the case joint, so the
scraper can make it over to the left side wheel. Be very careful to not trim out too much metal, or the
scraper gasket might leak!"

Hairy as your Chief is a 1948 the scraper should be cast into the cases

[hairynob24]

PaulCDF thankyou , if i had it to far away from the fly wheels do you believe this would create over oiling ?

[PaulCDF]

Hairy;

If the scraper is out too far from the flywheels could it result in over oiling?

I'll give you my 'weasel answer' on that one: Possibly.

How is your oil pump? Wet sumping?

[tfburke3]

Prior to 47 there was a pickup tube (no scraper )and broken or removed baffles are also common with no problems.
The return system all needs to be good.Clean screen,tight fittings and good return pump to prevent running wet sumping.
My guess is your worn out rings are the problem.Tappet/pushrod and valve stem/guide wear should also be checked.
Tom

[hairynob24]

tfburke3 cheers , i did take the pump off and went through it , looks ok , so i am going forward barrels are in getting bored and checked , valves , guides etc , so now a wait until i get them back . i have noticed when starting that bike on the side stand it would start to wet sump , but once i stand the bike up it returns better ?

[kitabel]

High perf auto engines have scrapers fitted with Teflon strips that touch the crank, then self-clearance by abrading away the plastic to get really close.

[tfburke3]

The motor doesnt wetsump when starting.The crankcase is most likely already over filled with oil from sitting and tank oil making its way past the oil pump to the case,then the return pump empties the case.
If it clears up thats a good indication that the return system is ok
Running wet sumping is when the return pump doesnt return as much as the supply and case level rises.
Tom

[PaulCDF]

FROM THE ARCHIVES: AMCA Forum

Gary Stark on Wet sumping:

01-03-2013, 12:14 PM
"(T)he plunger in the cast iron oil pump is the culprit for causing wet sumping. The plunger to wall clearance gets too great and the oil goes straight into the bottom end of the engine.
Although what frustrates people is it does not happen every time. This is caused due to the where the plunger stops when you shut off the bike. If at the middle, you have leakage. If at the ends of the stroke, little to no wet sumping.

Whats the solution:
We take your oil pump, hard chrome the plunger, and hard chrome the oil pump.
Next we grind the the plunger and hone the oil pump so both have a perfect clearance better than new. Since the hard chrome is harder than the original pump material and it's running in oil, you have basically fixed the oil pump for the remainder of it's life time.

The above process is not inexpensive, but it's the best solution to solving the wet sumping issue.

Your rebuild process is quite extensive, after the above we will have the body cad plated, then reasemble the pump.
We then place the pump on our test stand and run it for 1hr and then after it's warm check the pressure the pump produces.
While these pressure numbers are arbitrary, our experience has found that when a pump holds these pressures they seem to work perfectly on the bike.

On a cast iron pump with a 5/8" plunger we want:
at 1200rpm -feed side: 60lbs minimum, and 1 cup volume in 54 seconds with a bleed down not more than 20lbs in 60sec
return side - 30lbs pressure minimum. Our new return gears usually produce 60lbs + on the return side

What's the cost:"

Note cost were from 2013 (A different time and a different world)

Hairy;

I'm still thinking your 48 should have its scraper cast into the cases?

[GaryJK]

Hi, this is my 1st post here. I've been absorbing posters' info for years and finally can contribute some information of my own.
My '48 Chief, #1313B, has the removable steel scraper.
It also has a Motolamp headlight. I've always wondered if that was original or replaced by a previous owner.

Gary in Iowa

[T. Cotten]

We aught to define a term or two, Folks,...

"Wet sumping" most commonly refers to over-filling the cases while running.

Filling the cases while sitting, by draining through the pump, is often called "static sumping".

Just hope it don't do both.

....Cotten

[hairynob24]

Cheers everyone for your input, I think I will recheck the oil pump plunger