2.2E MFI rebuild

[zanderl]

About to start a rebuild of a 2.2E MFI Engine to replace the Weber-ed '72T Engine that was in my 1970 911E when I bought it. It's been a lifelong dream to do one of these myself, so my goals for the project are to end up with a silky-smooth, happy, revvy engine, while learning as much as I can from the process. Having built an EFI system "from scratch" in college (30 years ago :-/), I particularly want to celebrate the MFI system in all its intricate glory. My plan is to use the best of the usual suspects for the most important parts, and then DIY as much of the rest of it as possible (within reason).

This thread will be a combination of sharing lessons I've learned with asking questions/soliciting opinions from the collective wisdom of this forum.

Starting with this roughly complete "ran when pulled" engine (which happened to be a few # away from the long-lost original for this car):




First Question you might ask: Why did I start with a whole new engine versus rebuilding the '72T back to its original '72 T/E MFI format. @techweenie was kind enough to help me think this through (Thanks Bill!):

1. Wanted to be able to drive the car around while getting other things sorted such as body/paint an interior. Backstory is that my pristine '87 Carrera was stolen last summer, so I didn't have another weekend fun car. Back-backstory is that I decided the insurance $$ for that '87 should be funneled into this once-neglected '70E.
2. Despite having never driven any Short Stroke 911, I assume I'll appreciate a higher-RPM experience as an absurd contrast to the torquey grunt of my electric daily driver.
3. Sort of a lame nod to the originality - even though it's not number-matching, and this isn't a concours restoration.
4. 100% sure that as I got into the 2.4, I would that it needed everything done, so if I’m going to do everything to an engine, may as well be the 2.2 I want to end up with.
5. 2.2 being this narrow transition seemed kind of quirky and unusual.

That last point has been my first hard lesson. So far, almost everything that's already expensive and hard to find for any air-cooled 911 engine is sometimes doubly-so for the 2.2E because it's so much less common. For example: try to find the 7,100 RPM ignition rotor for the E, or the clutch kit and/or pull-type throwout bearing for this "911" transmission, or the correct green-shroud with the separate air channel which was unique to the 70-71E, actual 84mm "E" P&Cs, etc. T and S 2.2s are much more common, and 2.4s start to share so many parts with the later 2.7s that proper parts are so much more common.

Even more annoyingly, this early 1970 case has fewer of the updates which would have come "for free" in a 1971, or even a later 1970. For example: somewhere around 1970 they started adding the second shelled bearing for the intermediate shaft, but not this early. To say nothing of squirters (added in the 1971 2.2), it's got the oldest "0-rib" Oil pump, Electric MFI Fuel pump was mounted in the front for this narrow window of years, wide-boss tensioners with narrow-boss idler arms, etc. Conventional wisdom on all the forums would have been to start with a 7R Case or any number of other permutations which would be indistinguishable to all but the few thousand of us nuts who are semi-fluent in casting numbers and serials.

All this being said: I knew this was going to be expensive and illogical endeavor in the first place - and thankfully I can afford the learning process - but choosing to find a "close-but-not-quite" serial and wanting to *start* with original-ish parts, have both made things a little harder than they could have been had I been more sensible, without any of the benefits of actual originality/matching.

Which brings me to my second hard lesson. I was focused on finding a "complete" engine which had all the parts under the mistaken impression that having at least some form of every part would get me "part of the way there" with many things. However, I've since learned that to do it right, essentially "everything" needs to be worked in some expensive way, and that the "core" value of most of these parts is effectively $0. I can give dozens of examples, but take MFI throttle bodies as an one... I've come across recently-rebuilt bodies for roughly 1/2 the $3,400 it will cost to have my "originals" rebuilt. This is by no means a criticism of the masters who get paid what they do to restore an MFI pump or tumble/plate,cerakote and weld a chip in a magnesium cooling fan, but the cost of those operations has inflated so quickly that slightly older restored versions of those same items can be purchased *outright* for less than just the service would cost today. Again - I don't begrudge any vendor in this category, but just realizing the economic value of a "core" part is pretty poor, if not negative (see below).

Which brings me to my third related lesson. In many cases, there is a slightly later version/mod of each part which is better/safer/stronger/better enough that you'll want to "update" anyway - even if the one you've got is probably serviceable or restorable as-is. Take the tensioner/idler system as an example: (even without deciding to go to pressure-fed Carrera tensions)

What I started with:

1. (2) 930 tensioners (yay!), but with the "wide" bosses which require narrow idlers (boo).
2. (1)Left-side idler arm was monkeyed with, so trash
3. (1)Right-side idler arm seemed fine, but the steel boss definitely spalled on the pivot.
4. (2)Idler Gears seemed fine, but are an oddball solid casting and may be a little wobbly on their...
5. (2)Slightly worn shafts.

What I decided to do:

1. Find nice used narrow-boss 930 tensioners, and rebuild them
2. Find a nice used left-side idler, and then have the pair re-bushed/modified to the wide style.
3. Haven't decided yet, but likely to replace the idler gear wheels as the aforementioned monkeying was probably done to compensate for excessive chain stretch, so the worn original gears are going to chew up a new chain...
4. May as well

Given the 8 major parts of that system that I started with (tensioner, arm, gear, shaft), I will have replaced 3 (or 5 or 7), rebuilt 2, and had 2 re-manufactured thus replacing, rebuilding, or essentially re-engineering every part, and I didn't even change the underlying technology to pressure-fed. Admittedly, there were many ways to go about this, but very few of the strategies which had me simply refresh the original parts would have also let me sleep at night. In the end, I'm sure I would have come to a simpler/cheaper solution if I hadn’t started with the premise that I am "restoring", and would like to re-use what I already have. Furthermore, now I'm left with used-but-serviceable parts which will are likely to clutter my garage forever because I assume anyone else looking for a used part X is going to look for the "right" one, and not the slightly wrong one.

Therefore, knowing what i know now, I can much more clearly see the wisdom in starting "from scratch" with a case, and then tracking down a "ready" restored or new version of each part. That said, having never taken one of these apart before, I don't think I would have known which of each part I needed to find, so I couldn't have started "from scratch'. OTOH, buying an entire engine-worth of value-less "core" parts is a pretty expensive way to find a parts diagram.

That's all for now - I'll share more details of what I have accomplished so far, and will have some questions in my next update.

[dwa917]

Great post! Stick with it. It is a long and winding road, but worth it in the end for the experience!

[doswald]

Having just completed the rebuild of my ‘71T, I feel your pain. However, for me, having a complete engine to start with was invaluable.

dho

[Series900]

“ or the correct green-shroud with the separate air channel which was unique to the 70-71E, ”

70-72 E available at https://series900.wordpress.com/shrouds/

[zztot]

I also find this amusing, thorough and so true having embarked on similar journey recently. As an astute engine builder on this forum told me as I was whining the cost once said “ I can make money disappear faster than David Copperfield”.
A word of advice …..many good sources herein, but Supertec ( Henry Schmidt) has some very nice parts …..like reconditioned rockers and updated/modified arms for using Pressure fed tensioners….
Good luck with projects. ……that always helps.

[Rosco_NZ]

Beware WORDPRESS could be a SCAM

[blue72s]

Originally Posted by zanderl

Even more annoyingly, this early 1970 case has fewer of the updates which would have come "for free" in a 1971, or even a later 1970. For example: somewhere around 1970 they started adding the second shelled bearing for the intermediate shaft, but not this early.

How early is your case? What's the engine number?

[Series900]

⏰🔔⏰🔔. Roscoe , you might check up members of the forum before calling them out as a possible scam. The link is to my website where every shroud is available from 64-88 in each permutation and color. Compression molded as original texture. CNC trimmed for fitment and minimal fuss! Even ship to OZ!

Example of 70-72 E test fit before shipping

Or a stack of 70-72 long grey ducts check out post trimming

CNC TRIMMING…

[Rosco_NZ]

Apologies to anyone who is legitimate and doing the right thing.

My experience from another Wordpress vendor was offering very underpriced parts and attempting to collect payment .. which would not go through. The bank called within 24 hours asking about other attempted transactions.

Many honest folks out there, but I have been a scam victim before, consequently wary and cautious.