Porsche 911 67S - engine case repair and rebuild

[redrobin911]

As you may have remebered the original enigne in my 67S (nearly finished!!) suffered an engine failure that badly damaged one of the case halves. Up to now there have been various methods of repair invloving some form of recasting part of the case and then welding. The success rates from what i've seen are not that good, because of the heat generate in the welding process which can then lead to case distortion, hence why I've done nothing about it until now. Firsly the cases as I got them i.e. badly damaged - see below.



A mssg from fellow DDK'er Tin69S put me in to contact Alan Barker from EMP engineering and following a phone call and a few email he's agreed to take on the project to repair the cases. Damaged cases plus a good undamaged case half were set over. The good case was digitally scanned and below you'll see the CAD drawing which will then be used to make the complete replacement part. Damaged case is being trimmed down as we speak to allow the new part to fit. The process will then involve lazer welding the new part in to the case half, laser welding uses no heat. Once finished the cases will machined to original spec. Pics below showing the owrk on the case halves and CAD part. must say I'm impressed with teh work so far - its only been with them for a week.

[willbrown]

Love it. Found a solution to a problem a lot of people would have told you was basically impossible ;o)

[tim69s]

This is a picture of one of their laser welding machines doing a test weld on one of my damaged mag case halves.
Having been shown round the facility and seen the work they do for all the big names, pretty sure your case is in good hands.


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[maxakarudy]

Very interesting, are they making the new part or using another case for the sections?

[redrobin911]

Very interesting, are they making the new part or using another case for the sections?

Hi Martin - I originally bought another case to replace the damaged one but never wanted to use it as wouldn't be orignal. I sent the good case half over and thy scanned it to make a 3D drawing from which they will make the new part/section - green photo above. Hoping its going to be a great job!

[maxakarudy]

Even more interesting!

Are they casting the new part of can they 3D print it?

[tim69s]

I expect they are CNC milling it from a block of metal. They have lots of hi tech milling machines but no 3d printers as far as I am aware.


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[210bhp]

How do they analyze the original material to get a molecular match for the new piece?
In the later cases there is a percentage of silicon and possibly a small percentage of magnesium and copper but not sure about your 67 case.

Regards
Mike

[redrobin911]

How do they analyze the original material to get a molecular match for the new piece?
In the later cases there is a percentage of silicon and possibly a small percentage of magnesium and copper but not sure about your 67 case.

Regards
Mike

Not sure how they get a match but know that I had to send the cases to them before they could order the material for the part to be machined, so assume that they will have taken this into consideration? I'll be asking the question and getting some pics of the new part hopefully before and after CNC machining, and before after welding into place.

[MikeB]

One way or another, you’ll have made the original case whole and useable once again, Robin, job done

[redrobin911]

One way or another, you’ll have made the original case whole and useable once again, Robin, job done

Thanks Mike - but getting cases "done" is only half the story. Need to then check all dims the line bore and start a rebuild - one step at a time - but confident I'll get the original engine back in the car.....some day.

[redrobin911]

So, in relation to the choice of material to use for the CNC'd part Alan uses the knowledge he's built up over the past 20+ years to determin what to use, he's reluctant to be more specific and I get that giving away "trade secrets" would not be benificial to his business. I'm happy to leave it at that .

Please see updated pics from a few days ago and I'm very impressed, not only with the quality of what's being done but at the speed - i.e. the caes have onyl been away 3-4 weeks, I'm used to the same in months and years.

Let me know what you think....part is to be laser welded then machined back to factory spec....

[redrobin911]

Some photos of the welding work completed, now just to bore in a few places and tap for some studs. i've very impressed with what I've seen so far and the service I've recieved, good comunication and all work done in a matter of weeks.

[MikeB]

Looks the business

[911hillclimber]

Very smart!
In the past I've used a spectrograph analysis to determine if a material is 'alloy A' or 'alloy B' etc. You spark the parent metal and the elements are analysed as gases and their % determined, so you can find the alloy make-up and find the best match in today's stock (which could be very different to alloys of 1968).

I am interested in the laser welding used. Is the part added welded 'deep down' to the case or is it fillet welded on the surface?
Will they crack test the case to see if there are any holes and test for fluid leaks via the joint lines?

Lovely bit of tech on DDK!