4 inch bore engine

Passatman · Post by **Passatman** » Sat May 07, 2016 8:20 am

Ok guys i have seen where it was mentioned here that the oxyboxer retains it's stud location when going 4 inch bore.
Has anyone done this engine as a daily driver and how was the performance, did the engine cool well? I am thinking about doing a 4 inch bore daily driver.

Post by **Marc** » Sat May 07, 2016 11:29 am

It's my understanding that if you want to run 4" cylinders with decent wall thickness the studs still need to be moved out a little. One of the modifications Rocky Jennings is set up to do (he moves 'em .050"). I'd definitely ask for his input, he's probably seen more oxyboxers than anyone.
http://www.rockyjennings.com/

Passatman · Post by **Passatman** » Wed Jun 15, 2016 5:14 pm

I will be contacting him in October.

ecksrash · Post by **ecksrash** » Thu Sep 15, 2016 12:09 pm

Any more info Passatman??

Passatman · Post by **Passatman** » Thu Sep 15, 2016 5:21 pm

Ecksrash no info yet i haven't approach rocky as yet. I should have some info in october.

Passatman · Post by **Passatman** » Sun Apr 16, 2017 1:08 pm

I approached rocky and he isnt too fun of the idea. You might be lucky in checking with brothers machine shop, spoke to those guys sometime ago and the guy on the phone said they had done a 4 inch bore oxyboxer for a customer.

I will be doing a 94mm bore engine instead as the options for a 4inch head is costly. My choice of head was JPM 230 heads.

Chip Birks · Post by **Chip Birks** » Sun Apr 16, 2017 9:09 pm

Rocky didn't like the 4 inch bore idea? I thought that was half the benefit of using the wbx case for these oxy builds...why doesn't he want to do it?

Passatman · Post by **Passatman** » Mon Apr 17, 2017 5:41 am

It's my guest that the cost of machining would be prohibitive. What i wanted to do was use a waterboxer head on the oxy engine bottom half, something similar to the porsche 959 engine.

Chip Birks · Post by **Chip Birks** » Mon Apr 17, 2017 7:53 am

Like a water cooled head with aircooled cylinder.

Passatman · Post by **Passatman** » Mon Apr 17, 2017 8:35 am

Yes that's it.

Passatman · Post by **Passatman** » Mon Apr 17, 2017 8:35 am

Yes that's it.

tmbryhn · Post by **tmbryhn** » Sun Aug 28, 2022 2:35 am

Revitalizing this one. What kind of combo did you end up with?

Im considering building a street Oxy with 4" cylinders, MS230 and one of my 84mm WBX cranks.

These kits from AA seem quite nice to get the job done, and they have the option of running a 6-stud pattern.
Has anyone checked these out?
Is the bolt pattern in these the same as stock WBX/Type 4?

https://aapistons.com/products/101-60mm ... -be-edited

Chip Birks · Post by **Chip Birks** » Sun Aug 28, 2022 8:54 am

Do type4 and wbx share a stud pattern? I didn't realize that.

Steve Arndt · Post by **Steve Arndt** » Mon Aug 29, 2022 2:38 pm

Chip Birks wrote: ↑Sun Aug 28, 2022 8:54 am Do type4 and wbx share a stud pattern? I didn't realize that.

They do not. T4 has a rectangular stud pattern.

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