Measured the cylinder bores - are they still good to go?
11-14-2016, 08:24 PM
#1
Pro
Thread Starter
Measured the cylinder bores - are they still good to go?
Finally disassembled the other engine I have. I got the bores, pistons and crank measured by the shop in the neighborhood. Before I go any further with this one I would like to have your opinion if it is good core for rebuild.
944 Turbo S engine, 200+ Kmiles, does not have any signs of previous machine work to bores and crank. In fact bearings are still factory ones. I'm planing it for street car, no mods except for A Tune, LR single port WG and custom KLR chip increasing boost to 14.5 PSI. It will never be tracked. I really would like to save this block as it has the matching number with my car...
Cylinder bores - excellent surface with no scratches that can be caught with fingernail. Tolerance group 1 (all 4). There is a ridge on top of each cylinder though. Measurements are 100.05 mm (all 4) transverse to the engine block, 65mm below edge (as per WSM method), 100.04 (all 4) longitudinal so out of round 0.01 mm (limit?). The measurement in the groove that 1st ring made on top of each cylinder is 100.1 (all 4 again). In general these measurements are identical throughout all of bores.
Pistons - tolerance group 1, measurements 99.99 mm 2, 3 and 4 piston, 99.98 piston 1. There are no damages visible, no deep scratches etc. They never got in contact with valves (thank you PO...). Wrist pins have no play at all.
Crank - conrod bearing journal 51.98 mm (all 4), crankshaft bearing journal 69.98 mm (all 4). Excellent surface, only one main bearing surface have barely noticeable scratch, machinist was not sure if polishing will be enough. Rod and crank bearings were still factory ones. Rod bearing #1 had strange worn out sign - see picture.
What do you think about it all? Sorry for long post but I wanted to give as many details as possible.
944 Turbo S engine, 200+ Kmiles, does not have any signs of previous machine work to bores and crank. In fact bearings are still factory ones. I'm planing it for street car, no mods except for A Tune, LR single port WG and custom KLR chip increasing boost to 14.5 PSI. It will never be tracked. I really would like to save this block as it has the matching number with my car...
Cylinder bores - excellent surface with no scratches that can be caught with fingernail. Tolerance group 1 (all 4). There is a ridge on top of each cylinder though. Measurements are 100.05 mm (all 4) transverse to the engine block, 65mm below edge (as per WSM method), 100.04 (all 4) longitudinal so out of round 0.01 mm (limit?). The measurement in the groove that 1st ring made on top of each cylinder is 100.1 (all 4 again). In general these measurements are identical throughout all of bores.
Pistons - tolerance group 1, measurements 99.99 mm 2, 3 and 4 piston, 99.98 piston 1. There are no damages visible, no deep scratches etc. They never got in contact with valves (thank you PO...). Wrist pins have no play at all.
Crank - conrod bearing journal 51.98 mm (all 4), crankshaft bearing journal 69.98 mm (all 4). Excellent surface, only one main bearing surface have barely noticeable scratch, machinist was not sure if polishing will be enough. Rod and crank bearings were still factory ones. Rod bearing #1 had strange worn out sign - see picture.
What do you think about it all? Sorry for long post but I wanted to give as many details as possible.
11-14-2016, 11:01 PM
#5
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11-15-2016, 12:22 PM
#8
Rennlist Member
If you are worried about the crank then have the machine shop check it to insure it is straight. As you have said this is a 200k engine, I would be happy with a bearing that looked that good.