First air cooled Porsche..engine (no car..yet)

[stitch2k1]

So, I made an impulse purchase today, and now I have a 1972 911T engine, the 2.4L (that's actually a 2.3L) flat six.
I have absolutely zero idea what my end goal with this thing is, but at the price I couldn't really say no.

I plan to take it apart here soon -- after my next project is complete -- and I'm going to try to rebuild it and run it on a stand. I have some of the MFI parts, but not all of it. The main distributor pump is gone (it was $$$$ sadly). I have the intake stacks, injectors, and throttle body parts I believe, I have not inventoried everything. I will probably be converting it to carbs due to cost.

In the meantime, my real reason to start this thread, does anyone have any good books they can recommend for early 911 motors? Old school stuff, I plan to make this motor stock -- no performance mods -- with resale value in mind in case I cannot find a car to use it in. Some kind of roller long hood 911T, a 914 to swap, or something else similar.

Shoutout to my E91 328i wagon, this thing has been a total champ hauling it's second Porsche motor.

[Tom]

Now THAT sounds like something I might do. Now to find the VW bus to put it in.


There are a ton of 911 rebuild books/sites out there, but if you don't have this one, it's a seriously good/clear guide...

How to Rebuild and Modify Porsche 911 Engines 1965-1989 Paperback – Illustrated, May 9, 2003
by Wayne R. Dempsey

[stitch2k1]

I’ve got that book on my radar, the goal is a stock rebuild. Tragically most of the MFI is gone, I have both throttle bodies, intake plenums, and the fuel lines but the rest is gone. I am ISO for those missing parts or a whole MFI, but I’m not willing to sell my left nut for it, ITB carbs would be a lot cheaper (and more logical).
But that’s a long ways away! Searching for a yoke for it currently, and I’ll be tearing it apart starting in June/July when I have the time.

Will add an Imgur album with more pics, but here’s one in the back of my hangar with the throttle bodies and plenums on it.

[Tom]

Honestly, unless you get a car where you want it to be stock, I'd look to install some kind of electronic fuel injection -- either an after market stand-alone or maybe adapt a Porsche DME from a 3.2 or the like. The PMO carbs are super nice too, but you may need to sell several body parts to buy them.... https://www.pmocarb.com/products.htm

[stitch2k1]

My goal is to keep the motor stock, simply because the value will be the highest. Installing (used) carbs in the temporary til I can restore the MFI to working condition is a very non invasive way to get a running motor. But I'm still far away from that. I'm calling up a friend's dad's buddy who might have an engine yoke so I can try to get this on a stand.

I was going to do an Imgur album, but that site is completely useless nowadays -- I miss when it was just a site for uploading images to Reddit. Anyway, I'll say that hopefully spamming attachments here instead will keep the longevity so we don't come back in 20 years and find a bunch of missing images.

You can see on the bottom of the motor that it probably had a salted life, I'm guessing the car this came from was a northern one. Luckily 80% of the bottom has had oil leaked over it. The magnesium corrosion is concerning, so disassembling the motor to be able to clean and treat the case with mag coat and then leaving it in my house until I can get it to a shop. Need to see if I can find somebody within reasonable cost to line bore it out and other stuff.

Reliability mods I've seen discussed is doing the SC 3.0 4 rib oil pump conversion along with changing a route I believe, and then updating to Carrera 3.2 oil pressure based cam chain tensioners. Would love to do this motor right, but I think some things will be cost prohibitive. I'm thinking if anything doing anything in the crank case is justifiable today, but maybe do the upgrade tensioner another day, especially when I have a car for it (if I get one, that is).

[stitch2k1]

Additional images

[stitch2k1]

So I finally paid some attention to the engine.
Serial # is 6130680
Engine code is 911.51
So, it's a 73TE engine, not a 72T. E for Einspritzer or something meaning it's old MFI not CIS injection.

The magnesium throttle body on the right side, I was hoping ultrasonic cleaning could save it but it's far gone. I could clean it good (maybe), and JB weld it to fix the cracking and the corrosion pits so there isn't a bunch of turbulence where there's giant divits in it.

But, since I want to make the original MFI work, and I think I have help to find the right dizzy for it, I'm going to look into possibly designing my own ITB's for it, because the fuel nozzles (more like a fuel nozzle on a jet turbine than an injector imo) screw into the head itself.

@Tom, vibe check my crackpipe idea here. 3D printing individual ITB's with stacks, and make my own or copy the original throttle cable system.

My only other option is carbs, and I'd rather have MFI especially if I keep the engine.

[Tom]

So I finally paid some attention to the engine.
Serial # is 6130680
Engine code is 911.51
So, it's a 73TE engine, not a 72T. E for Einspritzer or something meaning it's old MFI not CIS injection.

The magnesium throttle body on the right side, I was hoping ultrasonic cleaning could save it but it's far gone. I could clean it good (maybe), and JB weld it to fix the cracking and the corrosion pits so there isn't a bunch of turbulence where there's giant divits in it.

But, since I want to make the original MFI work, and I think I have help to find the right dizzy for it, I'm going to look into possibly designing my own ITB's for it, because the fuel nozzles (more like a fuel nozzle on a jet turbine than an injector imo) screw into the head itself.

@Tom, vibe check my crackpipe idea here. 3D printing individual ITB's with stacks, and make my own or copy the original throttle cable system.

My only other option is carbs, and I'd rather have MFI especially if I keep the engine.

Vibe confirmed. The issue with engine parts and 3D printing is strength and heat resistance. Throttle body stacks don't need to be particularly strong, but anything under the hood needs to be good to well over 200F. You might get away with ABS for throttle stacks, but you'd be better off with a high temp plastic. You can draw up the model and use a normal 3D printer to confirm fitment, then do the final in a high-temp plastic or even a metal print. My formlabs printer can print their high temp resin (good to 460F) but the set up cost is about $350 for the resin and tank, so you would want to be very sure you have the model the way you want it before you jump in. 3D print services can offer even more material options, including "metal," but I'd assume 6 throttle bodies would cost some multiple of $350.... Either way, if I can help, I'm in.

[stitch2k1]

So I finally paid some attention to the engine.
Serial # is 6130680
Engine code is 911.51
So, it's a 73TE engine, not a 72T. E for Einspritzer or something meaning it's old MFI not CIS injection.

The magnesium throttle body on the right side, I was hoping ultrasonic cleaning could save it but it's far gone. I could clean it good (maybe), and JB weld it to fix the cracking and the corrosion pits so there isn't a bunch of turbulence where there's giant divits in it.

But, since I want to make the original MFI work, and I think I have help to find the right dizzy for it, I'm going to look into possibly designing my own ITB's for it, because the fuel nozzles (more like a fuel nozzle on a jet turbine than an injector imo) screw into the head itself.

@Tom, vibe check my crackpipe idea here. 3D printing individual ITB's with stacks, and make my own or copy the original throttle cable system.

My only other option is carbs, and I'd rather have MFI especially if I keep the engine.

Vibe confirmed. The issue with engine parts and 3D printing is strength and heat resistance. Throttle body stacks don't need to be particularly strong, but anything under the hood needs to be good to well over 200F. You might get away with ABS for throttle stacks, but you'd be better off with a high temp plastic. You can draw up the model and use a normal 3D printer to confirm fitment, then do the final in a high-temp plastic or even a metal print. My formlabs printer can print their high temp resin (good to 460F) but the set up cost is about $350 for the resin and tank, so you would want to be very sure you have the model the way you want it before you jump in. 3D print services can offer even more material options, including "metal," but I'd assume 6 throttle bodies would cost some multiple of $350.... Either way, if I can help, I'm in.

We'll see, I first have to find the pump. Hoping my buddy pulls through. I also could just clean out the corrosion with a brass dremel bit (or similar), and JB weld the cracks. I saw a video on YT of a guy sleeving it with aluminum, so maybe JB weld the cracks and bore the throttles for that? More options than I though, 3D printed parts on an old air cooled 911 would definitely be cool.

[stitch2k1]

Spent a bunch of time reading about the MFI in detail. I think there's some serious opportunities to 3D print replacement parts for these. Especially with how DISGUSTING the prices for replica aluminum parts are. I've bought Porsches for LESS than what they want for aluminum throttle bodies? WTF?

It seems all that matters is that the throttles on each body are linked exactly, so I would use the original effectively but I would split it up into individual throttle bodies (instead of one mold), and use the old plenum. The plenum is also relevant to this, as it links both throttles together, and manipulates the MFI pump/dizzy.

But that being said, I saw a video last night and I think some JB weld, and mill should be able to fix my throttle bodies and make them usable. So maybe 3D printing won't be necessary.

Slowly this is turning into my schizo experience into overhauling a 911 engine with zero prior knowledge or experience. I like this.