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I am just starting to build a 2.4L engine. Mock up while waiting for the crank to be balanced/assembled reveals the 30mm Schadek pump hits the bolt heads on the Webcam shaft. In doing some research it looks like the remedy is a combo of-
- grind down the bolt heads a bit
- eliminate the washers
- mill the back of the pump driven case/shaft by .095
- add a shim to push the housing out

I will take the pump in for the mod and the same time ask my machinist to install an o-ring.
I cannot find specs on the O-ring mod. How big? Groove depth?
Any help or comments on above appreciated

I don't think you need to O-ring an alu pump housing on a type 4. I never had a leak and never O-ringed any pump I used anyways, but I have never used a 30mm pump either I must admit. Maybe they produce more pressure the I'am used, which could make a difference in leak-testing, I dunno

I had issues .https://www.youtube.com/watch?v=YjRS4Ehms_4
It was the same with 2 different shadeck pumps . Just check the OD of the pump you have verses at stock type 4 pump . I made some shims and fitted the pump with the case halves apart .

The oringing isnt primarily to prevent external leaks, its to prevent internal leaks---low hot oil pressure due to sucking air and leaking pressure from/to the case due to the crap loose fit. The stock pumps were interference fit---Schadecks fall in the hole but they seem designed to drag on the studs so they feel about right when installing. pull the studs and it literally flops around by a several thou..

Totally not a fan of Schadeck, but there really isn't a reasonably priced alternative AFAIK.
Why they dont simply make them the right freaking size is a mystery.

CB pumps are apparently all Schadeck made as well, and the smallest pump Revmaster makes is 38mm, which is rediculous for most uses, although you probably wont ever have hot idle pressure issues with a 38mm pump...

The oring seal effectively redirects the leaking oil back to the inlet, and prevents sucking air.
I put inner and an outer oring on a 28mm melling pump, does not leak externally which is typically not a thing with iron pumps.
(melling pumps are the ~same wrong OD size as Schadecks, and the iron pumps dont expand like the case)

I dont recall the oring size, but I made the groove .100 wide to allow the oring to flatten out, ans used a .0625 nominal criss section oring, 2-1xx.
the groove as about 55 thou deep, I have moved but will see if I can track down the box of pumps I modded...

Thanks Pile
My machine shop is on it

FWIW,
My solution to the ‘too small OD oil pump body’ problem goes like this:

You pull the four oil pump studs from the case,
And replace with bolts.

To do this correctly,
The four threaded stud holes for the pump in the case need inserted.
I use Heli-Coils.

Then,
You install the pump in one case half before assembly,
Pinning it into place as the case halves go together.

This allows you to use an aggressive sealant,
Something like RTV or Dirko or maybe 518.
Around the OD of the pump body..

You will want to button up the case halves,
Torque, etc.,
Then move right to getting the oil pump bolted together with the cover and all,
And also make sure the goo didn’t squeeze into the main passages where the pump body meets the case.

This allows you to glue the pump into place,
Sealing everything up nice and tight.
Viola!
No more oil leaking around the pump body!