Honing Cylinder Walls for Rebuild?
01-31-2007, 07:30 PM
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Honing Cylinder Walls for Rebuild?
During 944 N/A Engine rebuild is it important to cross hatch hone the nikasil coated cylinder walls? This is a Race ONLY engine.
01-31-2007, 07:53 PM
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Do NOT hone the cylinder walls on a stock block 944 series engine. It is NOT a nikasil coating as found in 911 cylinder jugs. The 944's entire block has a silica impregnation that is only "unveiled" with a proper boring and polishing sequence. This is fully explained in the factory manual. Hone it with a NAPA (et al) stone and you're looking at a new overbore in the best case scenario (with new pistons too) or you could ultimately trash the block in the worst case.
01-31-2007, 08:17 PM
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Before you decide what to do make sure you check the cylinder wall taper top to bottom. Then as SeaCay said if you have to hone then you need to find someone in your area with the right stones and polishing paste. A lot of the NA engines don't wear the bores as quickly as the 944 turbos so you may be good. However if the taper is bad then the rings aren't going to last as long as you would want.
02-01-2007, 09:53 AM
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don't touch the bores.
The right process to hone is expensive and then you need oversized pistons. These are expensive too. Much more cost effective to buy another used block if there are problems. Even so the blocks don't wear much at all and unless there is major scoring usally don't need anything.
The right process to hone is expensive and then you need oversized pistons. These are expensive too. Much more cost effective to buy another used block if there are problems. Even so the blocks don't wear much at all and unless there is major scoring usally don't need anything.
02-01-2007, 10:28 AM
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You should find a guy who will re-lap the engine....the engine is alusil and if you do anything to the bores, you will have to bore and get first oversize pistons and you won't be lucky enough to get mahles any more.
Re-lapping is very specialized though not really expensive.
Re-lapping is very specialized though not really expensive.
