Lone nut camchain port removal
 

Hello everyone

I’m rebuilding my 74 2.7 and I’m having difficulty separating the cases due to that lone nut in the camchain port left side cyl 1-2-3. The nut I suppose is just stuck to the stud and the whole thing just turns and turns, I’m getting nowhere. Any ideas? :eek:

Thanks in advance



65 912
66 912
67 912
70 914
71 914
74 911
81 911SC

Try to get a sharp chisel or a bent tip screwdriver under the edge of it and back it out at the same time. As it lifts get the chisel under a bit more, keep the lifting pressure on it till you get it out. PITA as it will try to walk off the chisel tip.
Don't forget to timesert it before you reassemble the case.

Ok Mark, I’ll try that tomorrow. Another question. This case is the 7R. When I disassembled it there were no broken head studs. I have new P/C and head work done. I took the engine apart because of a hugh oil leak which I think from maybe from old gaskets etc. Timecerts are expensive along with all the other machine work. Do you think I can just get away with out any machine work. I am unsure of mileage but I’m estimating 70,000.

Mark

Forgot to mention, it looks like the oil leaks also came from the o-ring that seals the case throughbolts. I drove the car through the summers here in Arizona, 115+ degree temps here.

It's not very likely that you'll get away with no machine work. Possible, but not likely. If the crank doesn't turn freely when you reassemble, you'll need to have that fixed (some variation of a line bore). And yes, by all means, fix any stud problems now. The studs don't break as much as they pull out of the case on 2.7's. Case savers are a better bet than timeserts. Has the oil bypass mod been performed? And with that heat, make sure that the cooling tin mod is done, too. Some spot face the through bolt holes, too. That'll help with the leaks.

Why would you risk an unsuccessful build on this Mg case? We won't build a Mg motor without getting it properly machined. Send it out and get it prepped properly, it already has one obvious issue you were asking about.

We have had good luck using Ollie's but I am sure there are other good suggestions out there.

Cheers

I’ll try that tomorrow. Another question. This case is the 7R. When I disassembled it there were no broken head studs. I have new P/C and head work done. I took the engine apart because of a hugh oil leak which

Mag cases don’t have broken studs, they have steel studs that the expansion of aluminum cylinders have pulled the threads out of the magnesium castings.
Much like the bolt you can’t remove.
Bruce

It turns out it was not a threaded nut, just an alignment pin. Both case halves are now separated.
I read that mag cases get such a bad rap, are all mag cases doomed? That every time you rebuild them you have to have 2-3 grand in machine work done? I’ll take one of the posters advice and put the case back together with new bearings crank and rods and we will see what happens.

I'm sure the pro's are correct it must be machined but if you proceed otherwise you can try what has worked for me.

If the crank gets pinched when you button up the case, experiment with the tightening sequence.

I've found that can free the crank.

Part of the reason I am in the business of making new aluminum cases are crappy mag cases.

I have first hand experience with this. When I built my 2.7 for my 914 it needed close to 7K of machining to get the case right. I thought that was normal.

As soon as you unbolt a mag case, it assumes whatever shape it wants and rarely goes back together again in a manner that makes the crank spin right.

Another poster suggested playing with the tightening sequence, but the only problem with that is that Porsche specs only ONE tightening sequence, so altering that sequence might make the crank turn but will certainly not create a leak free environment that has the proper torque specs.

If you have the budget, source a decent 3.0 aluminum case. Lots are out there.

At this point I would only consider rebuilding a mag case if it was a) important to have matching numbers on a historically significant car or b) an almost perfect mag case as a starting point.

Sounds like there may be a market for new replacement 2,7 cases.....

Mag case
 

Catorce

I have several 3.0, 3.2 extra cases lying around. It’s just that I have a new set of 2.7 P/C and newly machined heads I picked up for cheap. I’m not a member of the Hoidy Toidy Porsche club and just going to pack up this 2.7 mag case, pay 3-4 hundred dollars to ship it to Kalifornica, then pay another $2K plus bucks for machine work just because people of the Hoidy Toidy club says that’s the thing to do. This engine ran fine after the oil leak. Old gaskets, o-rings and everything else that seals this engine will fail after 46 years. I hope some of these “ famous” machine shops that cater to the Hoidy Toidy Porsche club made enough money for their retirement cause when mag cases are all gone so will be their cash flow.

First of all, it's "hoity toity" SmileWavy

Second of all, I own a machine shop, and I don't rehab old Porsche cases, I build new ones.

You need to understand the amount of work that goes into rehabbing one of these old cases. On average, they need to:

- Make spigots round
- Make case parting surfaces flat
- Make spigot deck flat
- Install case savers
- Clear out and clean oil passages

That's just to start, and that alone, on average, takes 15+ hours of machine time or more, usually billed at 125 per hour. Again, those things are needed even if the case looks good to the naked eye.

So what you are trying to do is take quite literally the ****tiest case Porsche ever made and fix it up on the cheap and expect it to last. You can sprinkle sugar on a turd, and that doesn't make it candy.

Take your fancy 2.7 heads and sell it to some fool, then build up your 3.0 or 3.2. You'll be much happier and it will probably be cheaper.

Where I come from that’s how we spell it. You are exactly right, only fools send those mag cases to the machine shop. That’s why I’m not doing it.

I'm about to be in the same boat with my 7r case I'm building for my 914 and I'm not willing to spend 7k on machine work on a 2k case. For half of that that price I'd buy a used Bridgeport Mill and do it myself. My pain threshold is about 1500-2000 for machine work and even then it'd hurt.

Catorce, how close are you to producing your cases and what's an estimated cost for one?

Tony

Please explain.


If I read this correctly, you think the wise choice is to just re assemble as is? Because you got a deal on a P/C set and a set of heads? OK.

Wish you all the best. Please keep us updated after you have more than a few miles on your build.

Cheers

How did removing a suborn nut turn into this???

Have a day lumping around aluminum cases, you soon beg for Mag cases.

And yes I'm one of those guys wishing I made more money so I could retire. Really …..??

I also do not call my customers fools!! I'm extremely grateful for their business. Without them, I have no business.

And go out an buy a use bridge port and do it your self. Don't forget all the tooling that needs to be made to hold the cases and the machine tools needed. I wish it was that easy. If I added up all of the money I have lost in deprecation my machines have taken, the cost to keep them running in top shape, and the value in tooling we have made over the years, machine tools you need, I could retire and retire really well. But alas, that's fantasy land not a machine shop.

I believe the Mag cases have their faults. I also believe that when properly repaired with added strengthening along with years of seasoning, they still have a life to live.

My concern with aftermarket cases is all about weight. Its really hard to get the weight out of machined part. However, the fact they are coming available is great news.

You know something, you can fix mag cases but you can't fix stupid.

We're waiting on the foundry to cast us the last two prototypes. One of them is going in my test mule within 3 weeks or so. I have already sold 41 cases. The wait list goes into late August.

Price is $6495.

Thanks Neil.

My case halves are within 3 pounds of factory each. I refuse to dig deeper to save more weight. In fact, there are places where I did not extract all the weight I could have. As an example, look at the deep recesses by the air guide bosses. We didn't mill ours that deep at all.

Why not go for ultimate weight savings? Because at 3 pounds per case half, or 6 pounds total, the strength trade off is not worth it. I'd rather have the meat in those areas so that my cases can be ultra strong and no one ever needs to worry about how much power the case can handle.

A 6 pound difference is easily negated by the driver skipping the Big Mac for lunch :eek:

My concern about weight was not directed at your cases, as we have spoken in private about them. There are full billet cases that I was referring too. Billet parts are always heaver in general.

You have my respect for what you are doing as you have mentioned to me the amount of investment you have. Machine tools to do this work are not for the faint of heart. 100's of thousands gets them on the floor but not tooled.

We will talk soon as we are currently involved in design for a project for these cars that has only air cooling in general as its connection to the original engine.