alu case machining question

Peterfrans · 05-02-2009, 10:55 PM

I have an early aluminum case coming in which I want to use for a 2.7 MFI engine. I am currently listing these things to do to the case:

- machine case to accept 90mm cylinders
- weld on bosses for the MFI pump
- machine the case for the use of intermediate shaft bearings
- machine the case to accept the later chain boxes
- add piston squiters
- oil bypass upgrade

Do I miss something?

I am also looking for recommendations for a machine shop to perform this work, preferably with a not to long turn around time.

tref · 05-15-2009, 04:26 PM

I'm in the same situation, who in Canada could do this. The other options in the US are good but shipping and custom gets in the way.

F.

rvanderpyl · rvanderpyl's Garage

There is no one in Canada that I could find. Everyone seems to just send them down to the states.

As for machine work, you can also clearance the case to use a later, larger oil pump.

304065 · 05-18-2009, 03:38 PM

Send it to Ollies in Lake Havasu City, Arizona.

Those are very expensive upgrades you are proposing. Have them check the case for line bore, the aluminum cases are usually pretty good but once it's there it should be checked.

Peterfrans · 05-19-2009, 12:35 PM

mine is currently being disassembled and will then head over to ollies.

blue72s · 10-06-2010, 02:24 PM

Sorry to bring an old thread up, but in what way the late chain boxes are different to the early ones? What kind of machining work does the case require to accept the late chain boxes?

Is there any other possibility that a MFI pump can be used without having to weld on bosses? A detachable bracket for instance?

jcge · 07:07 PM

935 relocated the pump by using a bracket on the rocker cover...

blue72s · 10-07-2010, 05:15 AM

Wow! that looks good. Thanks for the pic. Do you have the part numbers please? (send me a PM)

jcge · 10-07-2010, 01:35 PM

Sorry - I don't have a PN for the rocker cover - maybe one of the 935 guys will chime in

aws · 10-09-2010, 08:25 PM

The early 911 case will need to be welded for the lower bolt on the late model chain housing, it then needs to be drilled and tapped and a locating dowel installed for the late case. It is a time consuming job and the last several times I have farmed it out to George at Ollie's. It has been years but I welded two dowels on top of the case to mount the MFI pump on, another time consuming job--- I would ask George on that one too unless you are pretty handy. I would not use the 935 set up--- Too much of a problem to adjust the valves and I doubt it will fit in a stock engine compartment. aws

blue72s · 10-10-2010, 04:19 AM

But what's the difference between the late model chain housing and the early one (besides lower bolt)? Why is it an upgrade?

Walt Fricke · 10-10-2010, 06:14 AM

I assume that the extra bolt helps prevent oil leaks. Like the 6 vs. 11 bolt lower valve covers.

stownsen914 · 10-14-2010, 01:15 PM

I have an early aluminum cased 911 engine running MFI. I did not my case welded. Rather there is a bracket that was carved out of a chunck of aluminum that mounts to (I think) on of the case half bolts. Then I had to drill two holes in through the case near the bell housing, and screwed two 6 mm bolts into the bracket to attach it there as well. I've been running this setup for many years without issue.

Scott

blue72s · 10-16-2010, 02:25 PM

Is it true that there were two types of early 2.0 aluminum crankcases? The last two digits .01 vs .0R ?

What's the difference between them two?

blue72s · 10-17-2010, 11:40 AM

Are the following modifications required to update an early alu crankcase to accept the post-'68 chain boxes? 150 man hours?? For what?

Late Chain-Box Modifications Photo Gallery by 914-6 GT at pbase.com

Peterfrans · 10-17-2010, 01:13 PM

no, that's for replicating in detail a RSR engine case based on an early engine case. Clearly an example of form over function. Ollies did mine for $240. Can't imagine they spent 150 hours for that money. Just give them a call, I was very satisfied with their work. Unlike some other companies I have been doing business with over the last year, they were a pleasure to deal with, everything as discussed and delivered on time.

blue72s · 10-18-2010, 09:55 AM

Thanks. But I still don't know the difference between pre-67 and post-68 chain boxes. AFAIK, the late version had the same number of bolts as the early one. Anyone got pics of both side by side?

Peterfrans · 10-18-2010, 10:53 AM

before: 3 studs, 2 dowels

same case after modification: 5 studs (2 with a locating collar)

blue72s · 10-18-2010, 12:56 PM

Thanks.