TheSamba.com :: View topic - Oil pump replacement. T1 26mm. Gaskets, O-rings, oh my!

Sat May 26, 2012 4:26 pm

78 Camper 2.0 EFI, valve cam and lifter upgrades 4 yrs about 30k ago. The camper had slightly low OP on a long trip last summer (Brad Penn 20/50) and since I had to replace the trans and axle seals I wanted to replace the oil pump while the engine was out.

I got Scott's Schadek 26mm pump with blueprinted cover. The studs are correct and the old pump came out with some gentle persuasion. The new pump has an interference fit. Tight, but starts with a smear of lubriplate. I'll freeze it before install.

When I rebuilt the engine, I used paper gaskets on both sides of the pump body, tan between the case and red between the cover. No O-ring. Thin case sealant on the case side, Loctite 518 on the cover.

Bentley shows a gasket between the pump body and the case and the O-ring. No gasket on the cover.

Scott recommends no gaskets and makes no mention of O-ring.

I had no leaks from the previous set up and one of the paper gaskets with the pump covers the O-ring groove. They'r both very thin gaskets.

What's Sambanistas take on the situation? O-ring and no gaskets or just sealant and torque to specs?

Sat May 26, 2012 4:45 pm

There's no O-ring on a Shadek pump. The grove you're looking at is there for some other technical reason. I think it maybe helps prevent the oil pressure from extruding the gasket.

Sat May 26, 2012 5:38 pm

I wondered as much looking at as direct comparisons as I could find.

Now the narrowed question. Gaskets? None? One? Two? and againt which surface if any?

The one on the cover seems like a good bet if I used only one, but the cover has been machined and polished flat.

In that case a lot depends on the sealant.

Sun May 27, 2012 3:41 am

Maybe their pump uses a red gasket of their choice under cover, whichever one is used this is a very thin gasket, putting a stock red gasket in an eng kit (by accident??) is too thick and will loose some oil press as it bypasses sides of pump gears.

Sun May 27, 2012 7:28 am

I had purchased a 30mm shadeck oil pump and my engine case is now together. My new cam came with dome head internal wrenching bolts that were taller than the rivets used on the original cam gear. They would touch the back side of the pump before it was seated. One samba person posted to me pictures showing a slight countersink on the cam gear at each bolt( He used hex bolts) and the bolts heads were were milled down a bit. Then a bit was removed at the back of the pump. While the engine was in half the pump was installed to verify .060 clearance from back of pump to cam gear hardware. Then you could remove the pump and proceed with engine assembly. Since my case is together I went with a stock pump.

Sun May 27, 2012 7:53 am

rcnotes wrote: I wondered as much looking at as direct comparisons as I could find.

Now the narrowed question. Gaskets? None? One? Two? and againt which surface if any?

The one on the cover seems like a good bet if I used only one, but the cover has been machined and polished flat.

In that case a lot depends on the sealant.

Normally you use the thin gasket for the pump cover and the thick one for the pump to case. That's what I did.

Other people just use a bit of Loctite 518 on the cover with no gasket. Probably works fine also.

I used the gasket because I figured that little bit of clearance, .004 or so was known to be correct and would be consistent whereas I had not idea how much clearance the Loctite would provide.

I also sanded down the pump body with gears installed using a known flat surface. This way I knew my pump body and gears were at the same height and all the clearance would be provided by the gasket.

Sun May 27, 2012 8:36 am

When I built the engine I used the thicker paper gasket against the case and the thin red one on the cover.

I think I'm going with sealant only between the cover and the pump because the cover is blueprinted for that pump. Why use a gasket when the cover is blueprinted for the pump?

Using the thin tan paper gasket (came with the pump) between the pump body and the case shouldn't make much difference on the clearance of the cover to the pump and could prevent a leak.

Sun May 27, 2012 1:19 pm

Sanding pump body to same level as gears a no-no. Most or the Bently manual will tell how to use feeler guage to measure this clearance, will have to use gasket now. Been awhile but i think that clearance 3tho. Someone here has done it recently and verify the clearance.

Sun May 27, 2012 9:30 pm

morymob wrote: Sanding pump body to same level as gears a no-no. Most or the Bently manual will tell how to use feeler guage to measure this clearance, will have to use gasket now. Been awhile but i think that clearance 3tho. Someone here has done it recently and verify the clearance.

I'll just quote the bible here... Tom Wilson:

"Reducing end clearance all the way to 0.000 is not mandatory, but greatly improves the pump's efficiency. End clearance is not actually zero because the gasket provides the necessary clearance for the pump to work properly."

Sun May 27, 2012 10:28 pm

What's this "blueprinted" pump cover jazz? The most a cover can be done is precision ground flat. Same thing many of us do using a slab of glass. The pump and gears can be ground with a determined clearance if that's the desired result. Or no clearance if it to be used with the correct gasket. Regardless if a gasket is intended to be used under the cover it is the thin one. Grab some precise flat item and check for yourself what the gear and body clearance is set at. It may be clearanced and it might be flat.
Pump body to case gasket is only there for sealing. Thickness is not a factor. Wheras cover to pump body obviously is. I don't remember in detail about Shadek gaskets but in addition to the thickness it seems like they also were configured differently. There is no press leakage point between pump body and case so a plain gasket is suitable. But between the body and cover it's different. Study the special groove on the pump body. It seems like it was there to let leakage from the pressure side return back to the no pressure suction side instead of leaking to the outside. There is no pressure involved with anything ported to the negative pressure of the suction side of the gears. The body to cover gasket might reflect that design feature also. I have a big pile of gaskets and don't remember which went with the Shadek.

Have no Idea about your pump but generally beware whenever you hear the words blueprinted, billet, or CNC. Frequently they mean absolutely nothing except marketing B.S.

Sun May 27, 2012 11:47 pm

you use the thick gasket between the case and oil pump. The thin red one with small holes goes in between the cover and pump. I can't tell you all the reasons why but I believe it gives you the proper clearance between the cover and gears. It also lets oil flow in the groove around the end of the oil pump so that the gears aren't just metal on metal where they touch the cover. Even Wilson mentions using the thin gasket. Page 130.

Mon May 28, 2012 5:08 am

Oh well. That didn't take long. I see the Samba hasn't changed. Sigh. Sometimes people look for info and not an online humiliation to get it.

Thanks for your contribution to the discussion DB, you are the effin' best! :roll: but here's the info on the pump I purchased. http://www.germansupply.com/home/customer/product.php?productid=17241&cat=&page=1 Call it what you want, but Scott describes it as "blueprinted". Whatever it is, so be it.

Desertbusman wrote: What's this "blueprinted" pump cover jazz? The most a cover can be done is precision ground flat. Same thing many of us do using a slab of glass. The pump and gears can be ground with a determined clearance if that's the desired result. Or no clearance if it to be used with the correct gasket. Regardless if a gasket is intended to be used under the cover it is the thin one. Grab some precise flat item and check for yourself what the gear and body clearance is set at. It may be clearanced and it might be flat.
Pump body to case gasket is only there for sealing. Thickness is not a factor. Wheras cover to pump body obviously is. I don't remember in detail about Shadek gaskets but in addition to the thickness it seems like they also were configured differently. There is no press leakage point between pump body and case so a plain gasket is suitable. But between the body and cover it's different. Study the special groove on the pump body. It seems like it was there to let leakage from the pressure side return back to the no pressure suction side instead of leaking to the outside. There is no pressure involved with anything ported to the negative pressure of the suction side of the gears. The body to cover gasket might reflect that design feature also. I have a big pile of gaskets and don't remember which went with the Shadek.

Have no Idea about your pump but generally beware whenever you hear the words blueprinted, billet, or CNC. Frequently they mean absolutely nothing except marketing B.S. [url][/url]

Mon May 28, 2012 7:00 am

I don't read that as an attack on you, I see it as questioning fancy words used as possible advertising gimmicks. I imagine the only way to achieve true zero clearance in a pump would be to mill the gasket area on the body to compensate for the gasket thickness.

Plastigauge is cheap and available at most FLAPS, lay a strip across the gears and bolt on the cover with no gasket (don't turn the engine), then remove the cover and observe the clearance. If it squishes the sh*t out of the gauge you need a gasket, if it's still showing a few thou you don't.

Mon May 28, 2012 7:46 am

Great suggestion.

busdaddy wrote: I don't read that as an attack on you, I see it as questioning fancy words used as possible advertising gimmicks. I imagine the only way to achieve true zero clearance in a pump would be to mill the gasket area on the body to compensate for the gasket thickness.

Plastigauge is cheap and available at most FLAPS, lay a strip across the gears and bolt on the cover with no gasket (don't turn the engine), then remove the cover and observe the clearance. If it squishes the sh*t out of the gauge you need a gasket, if it's still showing a few thou you don't.

Mon May 28, 2012 8:33 am

When I did mine, I did as Jake and Scott recommended. No gaskets only loctite 518.

Mon May 28, 2012 8:43 am

Hoody wrote: When I did mine, I did as Jake and Scott recommended. No gaskets only loctite 518.

Any leaks so far?

Mon May 28, 2012 5:41 pm

Quote: What's this "blueprinted" pump cover jazz? The most a cover can be done is precision ground flat.
Sorry that offended you. :wink: I hadn't read Scotts description of it.

Blueprinting a part is one of those ambiguous words that doesn't have a definite meaning.
Prints of drawings used to be blue because of the old ammonia printing method. No longer used but that's of no concern. But it does refer to the original manufacturers design and manufacturing requirements. VW's pump cover manufacturing drawings had flatness and surface finish specs and dimensional specs always have a specified tolerance range. Anything within that tolerance range is acceptable and meets that parts design requirements. And VW supplied parts would meet those requirements as compared with much/most of the aftermarket junk.
When someone (such as VW) assigns a manufacturing tolerance it is based on their most ideal requirement and then how far from that ideal can be tolerated. Technically it's probably impossible to meet that ideal spec. so a variation is allowed. When someone "blueprints" a part they try to get it closer to the ultimate target spec. which is a good thing. But some so called blueprinters can harm a part by getting it to good based on what they think is good. For instance surface finish on some of our engine parts need a certain amount of roughness to provide oil pockets for optimum lubrication and minimal wear.
In some cases they just make sure it meets the original spec., in other words that it does meet the spec. and nothing fancier but the fancy word "blueprinted" gets thrown on it. Out of a batch of original manufactured parts the quality will vary and some will be on the loose end of the specs and some much closer even though they all are good parts. Some might even be more accurate than later blueprinted covers.
What Scott says is good and probably a real good option. He has a great reputation. "Specify if you want the pump cover blueprinted. Stock covers are heavy duty but may not be as smooth as some builders will want. Blueprinted cover is honed flatter and is smoother than factory supplied part".
Sounds like you did good on your choice.

Tue May 29, 2012 11:13 am

[img]http://www.thesamba.com/vw/forum/album_page.php?pic_id=931865[/img]

I fitted the German Supply pump body into the case but the drive gear is too tall and sits above the edge of the pump body by a couple mm when tight in the cam slot. Needless to say that is a problem.

This picture is a comparison of two oil pumps.

The one on the left is from CB Performance Maxi Pump 1.

The one on the right is the modified T1 from German Supply with a little assembly grease on it.

Both are 26mm pumps. Both have Shadek mfgr cast marks. The CB on the inside of the pump body, the GS pump on the outside.

The GS pump driven gear measures 56.1 mm from the end of the tang to the face of the gear.

The drive gear on the CB pump measures 54.6 mm.

The thickness of the GS pump from the face of the pump body where the cover fits, to the round shaft extension for the drive gear measures 45.5 mm.

The thickness of the CB pump body taken from the same points measures 43.9 mm.

The inside depth of both pump bodies are 25.1 mm

The od circumference of both pump bodies are 69.05 mm

The CB gasket set is a fairly thick paper, 1.4 mm between the pump body and the case and a very thin custom made paper gasket for the cover.

The GS gasket set is the thin tan gasket for the pump to case and the very thin rd for the cover. There is debate on the gasket and sealant arrangements for the GS pump

The CB drive gear is pinned. The GS gear is not.

The GS pump has the stock T1 steel cover with custom machining.

The CB cover is some sort of hardened aluminum with a smooth polished inside surface.

The CB pump has some inner machine differences with a deeper and wider circumferential groove, the cavity areas appear larger due to more extensive machining with what appears to me to be a little better flow thru the pump chamber. There is also a machined hole that CB touts as a "pressure chamber" to maintain constant oil flow.

All in all, from appearances and a few comparative measurements, the CB pump looks like a good product with a bit more engineered inner machining.

The big differences are that the CB pump drive gear is 2.5 mm shorter which would account for the GS pump drive gear being too long and extending above the pump face.

The total thickness of the pump bodies from the face to the end of the round drive extension is also different with the CB pump being 2.45mm shorter which would bode well for not making contact with the cam.

I'm going to experiment with these measurements and the fit of the CB pump body with drive gear into the cam slot.

Tue May 29, 2012 11:20 am

Tue May 29, 2012 1:14 pm

I'm considerting grinding down the tang on the GS pump gear.

The question is.

Does the pump gear "float" in the pump body?

Is it contained by the pump body and the cover with the length of the drive gear tang only be long enough to make good contact in the cam slot?

If so, then the length of the tang is only relevant to the contact it makes with the cam slot, and

The height of the actual gear as it fits between the pump body and the cover is only critical to the interior clearances for pumping efficiency?