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Kawboy's restoration/conversion of a 1980 KZ13 8 years 5 months ago #9940

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aus_z1300 wrote: Love the 928 I had one a few years ago and have always regretted selling it though it was an auto and i'd prefer a later series in a manual.


This one's an '85. First year for the 32 valve engine. Worst job I've done on it so far is the timing belt. Porsche wanted 1800.00 dollars to do the job. The price of the belt is $58.00 and the rest is labor. Took me 10 hours to change it and retime all 4 camshafts. Purrs like a kitten and roars like a tiger when you step on it. Does 60 miles an hour in first gear @ 7000 rpm. and the icing on the cake, it's a 5 speed manual. Only 10% of the 928's were made with manual gearboxes.

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Kawboy's restoration/conversion of a 1980 KZ13 8 years 5 months ago #9945

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Good stuff that's the model to have. I remember the handling on one for a stock car was fantastic mine was an 81.
I remember buying a thermostat and it cost me $80 aftermarket.I had picked it up from a mechanic for $1000 that couldn't figure it out and done some stupid things like removing the thermostat wich stopped the flow of coolant to the radiator altogether.the problem was a dodgy connection on the ignition switch wich cut the power for the fan .He had put a 20w oil in and the lifters wouldn't pump up and were noisy.Went back to the 0w and it was fine.

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Kawboy's restoration/conversion of a 1980 KZ13 8 years 4 months ago #10239

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It's been a while (again #@$%$#%) since posting any progress on my project. I've been waiting for the last 3 weeks for "deer season" to be over so that the camshaft grinder would get back to work. I stopped in last week to see if my camshafts were done and found that they were behind 45 other camshafts waiting to be done. (I should go into business)

FINALLY got the cams back and started to fit them up. What a mess!!! There are a few different ways to get cams reground. One way is to build up the lobes with the proper weldment and then grind the new material. The other is to regrind the existing lobes and then parkerize the lobes. Megacycle wanted $800 to build up and regrind and that was more than I cared to spend here so lets investigate option #2.

I told the machine shop that I wanted to bump up the lift by about .025" to somewhere around .350"- .360" and stretch the duration out from 270 on the intake to 280 deg. and stretch the exhaust duration from 280 deg. to 285 deg. The machine shop said they would call me once they found profiles for the cam grinder and let me know what they had to work with. NEVER GOT A CALL !!!

Called early this week and the cams are done. they gave me .357" lift and 287 duration on the exhaust and .350" lift on the intake with 280 duration, so a nice little bump in duration and lift. That ought to perk the Kaw up.

Made arrangements to pick the cams up but he wasn't going to be at the shop. He'll leave the cams at the side door and I could leave the money in the mail box.

So I grabbed the cams which were all wrapped up in newspaper and trundled off back to the house. Unwrapped the cams this morning and what the F**K ?? He's ground so much off the base circle the the base circle is lower than the material beside the base circle. I told him I could afford to loose about .025" off the base circle and he's taken off .060" Shit!! One of the lobes is .030" smaller than the base diameter of the cam.



I also noticed that the lobes have been ground just ever so slightly off from the original lobe and there's a sharp edge along the entire lobe. Now he should have caught these mistakes and in a phone conversation with him today he told me that he thought the cam followers were smaller than the lobes. (You know what they say about assuming, assuming- you make an ass out of you and me)

Most people would say at this point the cams are garbage but they can be fixed. It will require grinding down the material beside the lobes (undercutting) so that the shim buckets don't interfere and he'll do this for nothing. I just really wish he had discussed the whole grind with me because I now have other issues to deal with.
With a 2.5mm shim in the shim bucket I measure .060" clearance. Then I need to reduce that by the clearance .008" so I need to make up .052". A 3mm shim will bring that .052" down by .020" so now I'm down to .032" I need to take up. By grinding the seats and valves I might be able to make up .015" - .020" . I don't want to cut the seats more than .020 and I don't want to cut the valves by more than .010". My next mission is to see if there are shims available around 3.5mm thick. Not fond of that option either but the only other option is custom valves and if I have to go that route I may as well buy a set of camshafts and send them off to Megacycle to the tune of $800 US which is $1040 Canadian.

Going to go cry in my beer now. Screw it, going to go have a few Bourbons (better than beer!!)

Pick of the lobe ground slightly off center SHIT!!


So mad I can't even think of why I took this one. Oh, now I see it, the knife edge on the side of the lobe.

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Last edit: by Kawboy. Reason: more info

Kawboy's restoration/conversion of a 1980 KZ13 8 years 4 months ago #10258

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l feel your pain, its always a crap shoot when you have to farm stuff out. l have a few talented people that do the stuff i cannot do. l got a couple of H2 cranks to be refurbed, got the name of a guy who comes highly recommended, its still a worry.

Dr Mark prescribes a bottle of JD, you can have the beers tomorrow to get over todays prescription
'They never see you coming, do they Bob''
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Kawboy's restoration/conversion of a 1980 KZ13 8 years 4 months ago #10262

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sorry to hear this.i have never had good luck with machine shops. i think every project i have taken in has been messed up by the shop. you never get to visit with the one doing the job.hope you can work it out. pat

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Kawboy's restoration/conversion of a 1980 KZ13 8 years 4 months ago #10266

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You have my sympathy. What a saga of one screw up built on another. If it is any consolation, your misfortune is typical of having almost any type of work done in the U.S.

My best advice is to buy a set of camshafts and send them to Megacycle (assuming they are true experts at cam grinding). At $1040 Canadian, you will be time and money ahead.
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