Case Oil Screen bit me

[panpered]

Has this happened to anyone? I had taken the witches hat oil screen out and had ordered the replacement seals and washer. I carefully studied various manuals and parts guides and it clearly shows that for 1962 and earlier, there are two seals that go first, then the screen, then the witches hat, then the cap with a new washer. The seals in the kit were cork. Putting things back in I notice the cork is fairly tight, but I keep wrenching on the cap and it sealed fine. I start it up and my oil pressure gauge that is on the pump reads fine, oil is returning to the oil tank fine. Good to go.

Not! I just stuck an intake valve on the rear cylinder. I pulled the rear head off and inspected and clearly oil is not getting to the head. Out comes the case screen assembly and the damn seals are swelled and over-compressed and the hole is closed off in the center. No or little oil to my heads.

I can't tell you how frustrating it is to carefully study all the books and feel confident it is going in right, and then be looking at freaking valves and valve guides that I just replaced last year.

What did I do wrong?

[VintageTwin]

Vol. 1 pg. 75, has a pic and some words that say use (1) washer down in the screen hole. "Witches Hat" is a Stett term. The repop screen (witches hat) has a molded washer at the base which accounts for one washer. Putting two washers and a repop hat in there is one too many washers. Usually you can't even get the cap on with two washers down in there.
The OEM manual and Clymers are wrong for today's world if they suggest two washers.
Some of that literature doesn't translate to today's parts.

Yes, the screen is only for hydraulics, but if you're going to have a screen, it has to be a correctly installed assembly of:
One washer, the repop screen w/plastic base, and the spring, and the cap. Spring fits over the screen and bottoms on the screen base.
I use to have a little debris in my screen at oil change time, but I also had hydraulic tappet bodies w/ the Colony solid conversion cups sitting in the bodies.

witchhatfl3.jpg

- '41-59 M&O Guide, Vol.1 © Kirk Perry, Mark Stettler T.A., 2000
Many times the repop version of the OE part has been upgraded to the post 1965 era design, often requiring fewer parts or better engineering.

[PanPal]

I thought this screen was only for oil to Hydraulic lifters???

[fourthgear]

The oil also goes through the screen & up to the rocker assem., nice to keep crap out of there too .

[hjans]

VT

Would it be to much to ask to post the pic of the Vol.1 ??

Hans

Edited jan.10 :
Sorry, seemed to have missed a picture !!
It was right there !

[panpered]

The witches hat is the original NOS type and does not have the plastic at the base as described. My setup looked exactly like the original manual except they don't really say anything about the specs of the two seals.

I think the only purpose of the seal was to make sure oil went up from the bottom, through the screen, through the little holes on the side of the witches hat, instead of seeping past the base. I think the lesson learned is that you only need enough pressure on the cap to slightly compress the seal and that is all. Anymore can compress the seal so that it closes off the hole in the middle.

It also appears that all the changes going on over the years in this assembly had to do with trying to meter the oil to the hydraulic lifters. I am running solid lifters anyway, but still like the idea of having the screen there. So.....

Is there any reason I can't just use a later style screen, no witches hat, a spring (the spring goes completely around the screen and holds the base of the screen down) and the cap to hold it all in under spring tension. The only issue I can think of is that by not going through the little holes in the witches hat, more oil will likely make it to the heads than was originally intended, but I am not sure that is a bad thing either.

[PanPal]

Is there any reason I can't just use a later style screen, no witches hat, a spring (the spring goes completely around the screen and holds the base of the screen down) and the cap to hold it all in under spring tension.

I am running the later style screen in 2 pan motors now. It appeared to help flow to the front exhaust lifter on my 59 that would tap after an hour of riding. The screen is not as fine on the newer style but the original design seemed to be too restrictive.

[wreck74]

clymers manual shows (late 1952-1962) with two seals under the screen, then it shows (1963-1965) with one seal under the screen. in my nosparts catalog it shows the tappet oil screen kit for late 52-62 with two seals under the screen

[panpered]

wreck74 is looking at exactly the same sources I did when I put the two seals in without thinking much about it.

All I can say is be careful. If the cap is resisting, then don't keep tightening much more before pulling the whole mess out and studying it a while (I am assuming a two seal setup). I am going to go with the later style setup using the spring over the screen.

Thanks for the comments on this. I fixed the one stuck intake valve on the rear head. I did not remove the front head to inspect and plan to just fire it back up and see how it goes for a while.

One positive thing is that the pistons don't get their oil from this part of the system, so my bottom end and pistons had plenty of oil the whole time the heads were being starved of oil. The rocker arm bushings also had enough oil to keep them from scuffing or burning, so I think I am ok on those as well. If one stuck valve is all the damage then I will be lucky. Time will tell.

[concrete guy]

So is there a big down side to not running any of these parts at all? My pan came with none of these as I found out when I was chasing some oil leaks. I am running solids.

Thanks,
Scott

[hjans]

The oil also goes through the screen & up to the rocker assem., nice to keep crap out of there too .

I agree with this.

Read the posts above !!

Hans

[biker_k]

So is there a big down side to not running any of these parts at all? My pan came with none of these as I found out when I was chasing some oil leaks. I am running solids.

No....there is no problem not running the screen or any of the associated parts. I've got a 60 pan that I've just rebuilt with the help of a master harley machinist who's been wrenching and rebuilding pans for over 30 years. He suggested I leave them out. I trust his opinion on every question I have.... he's always given me straight up advice and has never been wrong. If yours are out, leave em out.

[john HD]

i haven't had mine in for years, i run stock hydraulics

i figure with a clean oil tank and a oil filter it is ok. i think it was originally ment for oem bikes without a filter.

john