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Join Date: Jan 2004
Location: Pittsford, NY
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Rebuilding a 3.4 996 motor
I will be doing my first M96 rebuild of a 996 3.4 motor that had a suspected cylinder failure. The borescope shows something near the side of the piston that shouldn't be there!
Anyway, the question I have is, that since I'll be tearing it all down anyway, and I can't rotate the engine at all, does it matter if I don't use the cam hold down tool when I remove the valve cover to get the heads off? My plan is to examine everything and then have the cylinders relined. I'm sure I will have many more questions once I get going, but the removal of the engine is tomorrow and tear down to follow. I am grateful for any responses. Tony
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Tony G 10 Porsches come & gone! 1962 Morgan Plus 4 
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09-01-2023, 04:51 AM
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Sounds like its pretty borked so if you are doing a full rebuild it wont matter.
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09-01-2023, 05:23 AM
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Right then...a full rebuild is the plan. It had some sort of a rebuild 3000 miles ago, and part of the reason I bought it. I think the original cylinders must have been reused and just new rods, bearings, pistons etc. installed. Hopefully the heads were done, but we'll check that too.
I will magnaflux the crank and start from scratch. At least I'll know what I have when I'm done.
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Tony G 10 Porsches come & gone! 1962 Morgan Plus 4
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09-01-2023, 05:37 AM
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Use the cam hold down tools; they are designed to prevent cracking or breaking the cams due to uneven spring pressures when the cam cover is off.....................
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09-01-2023, 05:46 AM
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Thanks JFP, what if the slots don't line up? I saw an early picture of a shop made thread in tool in the 101 projects book. That would be handy! Not sure if my cams are slotted or are able to be threaded. Will know more when I pull the motor and take the cam plugs out and look. Motor is a '99 996 in a 2000 Boxster.
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Tony G 10 Porsches come & gone! 1962 Morgan Plus 4
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09-01-2023, 06:09 AM
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The proper cam holding tool and saddles uses bolts to protrude into the openings on the end of the cams regardless of their positions:
 
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09-01-2023, 06:33 AM
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Got it. I was thinking about the cam timing tool for the chains on the other end.
Thanks for clarifying!
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Tony G 10 Porsches come & gone! 1962 Morgan Plus 4
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09-01-2023, 07:25 AM
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Location: Dahlonega , Georgia
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Talk to LN Engineering about Nickies cylinders and bumping that 3.4 to a 3.8 . My 99 C4 bumped to 3.8 made 388 hp at the crank last year . That's almost 100 hp more than stock . You won't regret it . But I did have Len Hoffman perform some magic on the heads . Have fun
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09-01-2023, 01:30 PM
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