Peter M Posted 4February Report Share Posted 4February I've got a stubborn mate with a tired SC. I helped him pull the engine out a year ago and he's been repairing the 915 on and off since then, including machining and repairing the mainshaft where the shoulder that holds the 3rd gear in place fractures and allows excess play and creates an unwillingness to stay in gear. While the engine was out he discovered he had some broken headstuds of course. However being a stubborn (but a very bright geneticist) bugger he declared he wasn't going to pull the top end of the engine like everyone else does and then get caught up in the "while you're there" slippery slope. "No" he said, "I'm going to make a tool that allows me to remove those broken studs from the top of the heads!". A few months later he asks me to come over and help him remove the broken studs. I look at his grubby old engine and start laughing, "I can't even see the studs with air deflectors in the way, you really think we can remove them???" We start heating the case near where I think the stud is with a heat gun and then a LPG torch. After much grunting the first one comes out. More heating and grunting, the second one comes out. Yet more heating and no grunting this time, the third releases it's grip on the crankcase easily. One more to go. Surely we can't be lucky again! Surely the extraction tool will give out? Surely I'll hit his thumb with the hammer he has entrusted me with? More heating, more grunting, curse words too now as this one is hanging on! It made us work all the way but came out in the end. I've never seen broken dilvar studs removed from an assembled engine before and would never have believed it unless I was there. JWM, 911, tomo and 1 other 4 Quote Link to comment Share on other sites More sharing options...
WB997.2GTS Posted 4February Report Share Posted 4February He is a genius,, someone who thinks outside the square, Well done. Peter M 1 Quote Link to comment Share on other sites More sharing options...
OZ930 Posted 4February Report Share Posted 4February Put a patent on the tool…quick. Sell the patent to Porsche and sit back. tomo 1 Quote Link to comment Share on other sites More sharing options...
Peter M Posted 4February Author Report Share Posted 4February 1 hour ago, OZ930 said: Put a patent on the tool…quick. Sell the patent to Porsche and sit back. That's what amazed me. Just a conventional deep nut extractor that he welded to a 3/8" long extension that he then turned down to 10mm diameter so it would fit down through the heads. Given how thin the walls were on the extractor after machining and seeing how much torque being applied I thought the extractor would simply split. But it didn't! tomo 1 Quote Link to comment Share on other sites More sharing options...
Buchanan Automotive Posted 5February Report Share Posted 5February Got to give him credit for that to work, We have had some studs stuck in so tight that even with heat they have taken thread material from the casing. But why? you said its a tired SC, it must be ready for chains and chain guides, the valve guides would be well beyond their best and why isn't he removing all of the Dilavar studs and replacing them, surely soon enough he will have another old broken stud and the engine will need to be pulled again. Im always a fan of do it once, do it right. Unless his plan is to flog it on the market asap Regards Sean Harsh, Mike D'Silva and OBRUT 3 Quote Link to comment Share on other sites More sharing options...
Peter M Posted 6February Author Report Share Posted 6February On 05/02/2024 at 15:48, Buchanan Automotive said: Got to give him credit for that to work, We have had some studs stuck in so tight that even with heat they have taken thread material from the casing. But why? you said its a tired SC, it must be ready for chains and chain guides, the valve guides would be well beyond their best and why isn't he removing all of the Dilavar studs and replacing them, surely soon enough he will have another old broken stud and the engine will need to be pulled again. Im always a fan of do it once, do it right. Unless his plan is to flog it on the market asap Regards Sean Sean, Sorry I don't know the answer. He certainly intends to keep it and fixing 3rd gear, the original reason to pull the engine, was to allow it to be driven more often. The car's only done about 120,000km. 911 1 Quote Link to comment Share on other sites More sharing options...
Brian P Posted 10March Report Share Posted 10March I just found your post Peter! Well the engine was dirty, on the outside, but not so tired I think. Here is the oil coming out of the engine, before we pulled it. And the gearbox/diff was shiny clean on the inside (but not the outside!) "surely soon enough he will have another old broken stud and the engine will need to be pulled again" ... After the engine was back in the car, I had a look at clearances. I reckon you could do this job with the engine still in the car. You discover the broken stud problem when you check the tappets, so you will have the left-hand muffler /converter off anyway, and maybe the oil line(s) on the RHS, giving enough room to get a suitable tool in there. Having a car hoist will help of course. Not as comfortable as having the engine out, but with patience and a friend or two it should be quite do-able. If a nut-twister tool fails, you could try plan B or plan C, as described here: https://www.youtube.com/watch?v=KQyXD_deDWA The gearbox job that includes a repair to the mainshaft is here: https://www.youtube.com/watch?v=czrCthVcktw That was also good fun! A few hundred km down the road and it is all holding up. Cheers, Brian K reedminor, Peter M, tomo and 1 other 4 Quote Link to comment Share on other sites More sharing options...
Peter M Posted 10March Author Report Share Posted 10March Ingenious work Brian! I was impressed with the work you did with the head stud removal but what you achieved with the main shaft repair was just at another level! Really well documented in your videos as well. Quote Link to comment Share on other sites More sharing options...
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