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81 931 Turbo Rebuild
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Scislowicz  
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PostPosted: Tue Jan 01, 2002 11:56 am    Post subject: Reply with quote

Hi all,

Anyone have a recommendation on selecting a rebuilder for a 81 924 turbocharger? My last rebuild was done by Turbo Power.

thanks!
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Nick Neves  
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PostPosted: Thu Jan 10, 2002 7:42 am    Post subject: Reply with quote

I don't know where you're at, but Charles Brown at Turbo Data in San Luis Obispo does excellent work with the kkk turbos. I highly recommend the shop. I live in the Bay Area, but when the time came to rebuild, i sent my turbo to him because he has great integrity, does excellent work, and turn around time is quick. I used to live in SLO and work at Precision Engineering Automotive, a Porsche speed shop, and we gave him all our bussiness. Never a complaint. He rebuilt my wastegate as well. My new turbo is a 944/924 hybrid that should flow better, spool quicker, and last a long time. I don't have it installed yet(need a head, anybody got one!) but I am anxious to see the improvement. He is also very affordable.
nick><>
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wdb  
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PostPosted: Thu Jan 10, 2002 2:42 pm    Post subject: Reply with quote

http://www.atkengines.com/catalog/porsche.htm
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Nick Neves  
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PostPosted: Thu Feb 14, 2002 6:43 am    Post subject: Reply with quote

dear Scislowics,
I preveiously posted on a great turbo rebuilder. Well, i had him rebuild my spare turbo recently and the work was exceptional. unfortunately for me, before i installed it, I had some head problems that waranted an engine teardown. it appears my old turbo, rebuilt by turbo city- a different company, started to lose pieces of its compression blade. these pieces chunked up the combustions chamber surface of my head, rendering it useless. Guess i shouldn't have waited so long to replace that old turbo. I've decided to try putting a 944 engine in the car, so i now have this beautiful turbo, a series 2 K26 upgraded with blades from a 944 turbo and completely rebuilt with zero miles on it. If you are interested in buying it, e-mail me at sevenup@rocketmail.com
nick><>
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friskynibbles  
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PostPosted: Thu Apr 18, 2002 2:54 pm    Post subject: Reply with quote

i'm just beginning my rebuild on saturday and somebody said i should have the turbo done professionally... how much do you think this would cost?
and any advice about rebuilding my engine would be appreciated. sadly, all i have is a mechanic and the haynes manual...

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Rick MacLaren  
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PostPosted: Fri Apr 19, 2002 4:09 am    Post subject: Reply with quote

Engine Rebuild:

- I'd balance everything. Doesn't hurt.

- Shotpeen your rods

- Debate exists over piston coatings amongst rebuilders. Question: If you have to coat your piston, why are you coating it? Didn't it get made strong enough?

- New rod bolts, seals, rings, etc.

- No need to knifeedge the crank. You need oil to fly around down there.

Good luck
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friskynibbles  
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PostPosted: Fri Apr 19, 2002 5:48 am    Post subject: Reply with quote

what is 'shotpeen' ? 'knife-edge' ?
i.....am.......dumb..........

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Benski  
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PostPosted: Fri Apr 19, 2002 5:58 am    Post subject: Reply with quote

Shotpeening is a process to harden/strengthen metal. I think it basically involves pounding the metal with glass beads to get the irregularities out of the metal.

Knife edging if when you cut the counterweights on the crankshaft so they glide through the oil rather than splash it around. The splashing reduces horsepower, but also spreads oil around the bottom end.
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Rick MacLaren  
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PostPosted: Fri Apr 19, 2002 6:01 am    Post subject: Reply with quote

Shotpeening is a mechanical technique designed to harden the surface of a metal. Typically the 'shot' is like glass or metal shotgun pellets blown at high speed to the surface of the metal. They hit, cause a rounded indentation in the metal, and these rounded indentations help to relieve the stresses on the metal. It results in a stronger metal.

The description given above for knifeedging the crank also applies. But it's a process typically used by dragsters on North American cars. Unlike our North American counterparts, our old fart cars require more oil bouncing around underneath. IT's a choice. I chose to have MORE oil rather than LESS oil. You choose. Mine blew up because of (among other things) lack of oil down below.

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friskynibbles  
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PostPosted: Fri Apr 19, 2002 6:04 am    Post subject: Reply with quote

ok then i think i'll keep the oil sloshing around. as much as i like blowing things up, there are only so many 931s kicking around. and i want to keep mine!

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numbers  
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PostPosted: Fri Apr 19, 2002 9:36 am    Post subject: Reply with quote

Keep the extras to a minimum. These are very well built, stron little engines right from the factory. You do not need to do a lot of improvements to them. Save your money.
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Rick MacLaren  
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PostPosted: Fri Apr 19, 2002 11:32 pm    Post subject: Reply with quote

Numbers is right. I was even questioned by the guy who installed my engine as to whether or not even balancing was needed cause he thought it was done in the factory.

I think it was right to do the balancing. The QA on these engines was not the same as the QA done for Porsche. The balancing and flywheel work was worth the money.
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Geddy T  
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PostPosted: Fri Apr 26, 2002 10:07 pm    Post subject: Reply with quote

I'm blowing oil through my intake which should mean bad seals in the turbo. I plan to rebuild it, but don't have tons of cash to have it done for me. Everyone says that it's just totally impossible to rebuild the turbo myself, but how hard could it be? Replacing bearings and seals?... Would I be biting off more than I could chew? And if I do need a rebuild, what kind of price am I looking at?
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Rick MacLaren  
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PostPosted: Sat Apr 27, 2002 1:35 am    Post subject: Reply with quote

I think the issue with the turbo is this:

If you rebuild it and you've made one little mistake, and the turbo runs at like 30,000 to 100,000 RPMs, then, like, the question becomes, can the metal hold up against even one little mistake at that speed?

So the reason we take these to pros is so we don't blow up the turbo with our little mistakes.
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numbers  
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PostPosted: Sat Apr 27, 2002 6:55 am    Post subject: Reply with quote

You can buy the rebuild kit and install it yourself. It is relative simple. However, the issue is cleaning and balancing the turbine wheel. If you do not clean it, and just leave all of the deposits in place, it should stay in balance. But, if you don't remove the deposits, you loose a lot of the benefits of a rebuild.
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