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> Type 1 oil pump revisit, For the last time
Chad911sc
post Feb 24 2026, 10:32 AM
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Finally put the short block back together this past weekend! (IMG:style_emoticons/default/beerchug.gif)
This is for the next guy who wants to put an o-ringed oil pump into their motor.
I purchased one from low budget VW and it had the correct circumference, but sat too deep into the type 4 case. It bottomed out against the cam, and the o-ring groove was inside the case instead of the case bore ( Pic 1,2). So I dropped the idea of the o-ring pump and just ordered a CB performance pump built for the type 4 engine. I once again measured the circumference against the case and it was good. But, after looking at it closely in the case I noticed that the oil intake once again didn’t line up properly, and it only had a pubic hair’s worth of metal riding on the case. It was sure to suck air, even though it was the correct circumference (Pic 3).
So I ended up going to the local water jet shop and took one of the oil pump gaskets with me for the shape. They cut out a spacer from 1/8 inch aluminum and it worked perfectly. Now the intake port lines up correctly and the o-ring sits inside the case bore as it should (Pic 4).
Forgot to take a picture of the spacer, but it looks like this one from the German Supply kit.….(Pic5)


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stownsen914
post Feb 26 2026, 11:12 AM
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Thanks for sharing. I had this question about using a type 1 pump in a type 4, and have seen various responses - some suggest just grinding the corners off the drive tang that mates with the camshaft. The spacer looks like a better option. I'm surprised no one makes one.

Did the CB Performance pump have an o ring (looks like not from your pic)? That seems like an important feature to ensure good sealing of the oil passages to the pump for proper oil pressure. The pics I see on their website don't show an o ring.
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Chad911sc
post Feb 26 2026, 01:28 PM
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No the CB performance one is not an o-ringed pump. It fits well in every respect via circumference and depth with the camshaft, but the oil inlet and exit do not. They sit too far back into the case and barely are sealed due to it having such a small sealing surface.
The o-ring pump I used was from Low Budget VW, and it was the 30mm pump. If you use a 1/8 inch spacer, it fits like a glove. But it has to be installed while the case is split apart. Due to the O-ring will be destroyed if you tap it into the case already assembled.
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stownsen914
post Feb 26 2026, 03:05 PM
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Thanks. When you say the CB pump has a smaller sealing surface, do you mean due to the incorrect depth of the oil pump in a type 4 case? I.e. would be addressed by a spacer similar to the one you had made?
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Chad911sc
post Feb 26 2026, 03:37 PM
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If you look at picture #3, you can see what I’m saying about the sealing surface issue. There is barely any metal on the case covering the oil intake port. I think it’s just a design flaw of the type 1 pump in the type 4 case. I don’t think a spacer would work for that pump specifically because everything else lines up perfectly on the CB performance pump. The circumference is correct, as well as the depth of the pump body to the camshaft. If a spacer was used, I don’t know if it would still engage the camshaft drive gear correctly. It might, but I haven’t investigated it specifically. The spacer worked so well on the Low Budget VW pump because it sat too deep in the depth of the o-ring, the body depth into the camshaft, as well as the drive gear. So the spacer fixed all three problems at once.
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Jack Standz
post Feb 27 2026, 11:40 AM
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Photo shows a cut-in-half old Type 1 oil pump housing. You can see how it fits in this Type IV "W" case, including the area where the oil pump/case oil passages align with each other.


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Jack Standz
post Feb 27 2026, 11:41 AM
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Photo shows a Type I oil pump with o-ring modified for a full flow system and use in a Type 1 motor (Gene Berg pump).

Shown here for illustration purposes only about how this Type 1 oil pump and o-ring fits in a Type IV "W" case. You'll note that the o-ring lines up just inside the case bore, which means a spacer (like the one water jetted by @Chad911SC for his project motor) might be needed to put the o-ring a little deeper into the case bore. It also shows how important it is to mock up your motor during the build process. Especially important when modifying things like using a modified Type 1 oil pump in a Type IV motor.

There are many options and possibilities when doing so, including modified oil pumps with 1, 2 and even 3 o-rings. YMMV.


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Superhawk996
post Feb 27 2026, 12:30 PM
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Love the thread title: Type 1 oil pump revisit, For the last time
(IMG:style_emoticons/default/laugh.gif)

Nice photos documenting some of the concerns.
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friethmiller
post Feb 27 2026, 01:58 PM
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I'm definitely going to be doing this type of "dry fit" on my pump very soon. And I now have somewhere to post the pics (IMG:style_emoticons/default/biggrin.gif)
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cgnj
post May 15 2026, 10:26 AM
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Unearthing this post. This may be one stop shopping, or you end up with the Schadek bore out of tolerance for the case. I recall that I measured a few of the Schadek pumps and they were outside of the tolerance. I was always chasing a leak I could not find till I ran the motor on my welding table. Type 4 Oil Pump Kit 26mm GearsType 4 Oil Pump Kit 26mm Gears
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stownsen914
post May 16 2026, 06:59 AM
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Ah so someone does make a spacer! Thanks for sharing this ...
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