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Registered
Join Date: Apr 2006
Location: Fairfax Station, VA
Posts: 56
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Engine Rebuild Question
Making progress on my 944. Getting ready to take the engine to the machine shop, but I'm not sure what to tell them about boring the cylinders. Engine has 185,000 miles on it, but cylinders appear in great shape. No scoring and you can barely feel a ridge at the top of the cylinder. I've found a couple different sets of pistons on-line.
Piston Set, .50mm Oversize, 2.8L Stroker, 944 (1983-88), 1 set per car Also found: Factory European Spec Piston, size is 100.5 +20 over standard, wrist pins and rings included I guess part of this decision depends on the measured diameter of the cylinders and whether they are worn out of spec. What's normal for boring out an early 944? Any alternatives to spending $1500 for new pistons? Is it necessary to replace the head studs? 
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'83 944 '87 951 |
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06-10-2006, 05:59 AM
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You don't need to resurface the bores when doing a ring job. Just stick the rings on with the gaps in the right places and stick the pistion-rod back in the hole it came out of. Predicated on no deep gouges.
Should you want to bore the block the bore surfaces have to be etched. This will remove the aluminum and leave the silicon crystals exposed that the iron plated pistons and rings actually ride on. Caution on the cylinder walls; boring makes them liable to crack. In most cases that an NA block is bored it is also iron sleeved and "regular" aluminum pistions are used.
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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06-10-2006, 08:51 AM
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Join Date: Mar 2004
Location: Virginia
Posts: 35
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SoCal Driver I have read nothing but the same instructions for ring replacement. Can you elaberate on what you mean by "deep gouges." Also can you direct us to the best resource to get information on the ring gap placement and other block rebuild information and or proceedures. I did not see complete engine rebuild details on Clark's garage. I have done front end rebuilds on my 84' 944 and had the head off and rebuilt but never a complete engine rebuild?
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83-944 84-944 91-944 S2 Cab |
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06-13-2006, 06:36 AM
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Join Date: Oct 2005
Location: San Diego
Posts: 703
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Here's a post I read that had some good info.
2.8 L Stroker conversion Also look up info at Lindsey Racing. Good People to work with. http://www.lindseyracing.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=LR&Category_Code=944PISTON I believe that you need a 3 litter Crank if use the Stroker Kit, but not sure. Previous post had good info on if to sleeve for bore sizes. I Would recommend new head studs if old gasket blew or if running boost. When my old head on my Acura blew gasket and got Red hot in a hurry, it caused the head to warp a bit. Thus needed a slight honing to ensure flatness.
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1987 924S with 968 Drive front to back, Bilstein Insert on mod/stock Struts, 450# Hypercoils, 28mm Torsion Bars, Weltmeister Adjustable Sway Bars, Lindsey 968 Light flywheel, Spec Stage II Clutch, ToYO RA1's, Auto Power Cage & 6 pt Harness, KLA Strut Brace, Greasy hands, heavy foot, and lots of smiles |
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06-13-2006, 07:27 AM
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1983 Porsche 944 2.5 liter
