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Old 10-07-2019, 05:50 PM   #347
John V
No more BMWs
 
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Join Date: Apr 2005
Carmudgeonly Ride: Ram, MS3, CX-5, RX-8
Location: Glenwood, MD
Posts: 14,753
Moving slowly on all of this. I finally got the new (used) engine completely torn down, cleaned, honed and inspected. I'm happy that I got a good engine from the salvage yard, so now the buildup starts.

Cylinders honed with a ball hone, then the entire block was washed including every bolt hole, then blown dry with compressed air, then the cylinders oiled.



The new rods and pistons are just a little more beefy looking than the stock stuff.



Cylinder head was torn down to receive new valve springs, shims and retainers to allow a little more headroom on redline - 8,000 RPM vs 7,500.



Valve springs have more seat pressure than the stock ones.



Cylinders were measured to be round within the tolerance of my dial bore gauge (0.0005"). The piston to bore clearance is 0.0055" which is above Wiseco's recommended minimum of 0.0035".

All crankshaft journals were in spec, and every bearing clearance is on the large end of the spec at 0.003". The spec is 0.0009" (!) to 0.0039" for both the rods and the mains.

The oil rings and 2nd compression rings all were within spec out of the box, but the top compression rings will need filing. The recommended ring gap for a boosted application is 0.0055" times the bore diameter which is 3.5", so about 0.019", and they came out of the box at 0.014" which is too tight. I'm borrowing a buddy's rotary ring file so when that arrives this week I should be able to finish that up. The bottom end gets new stock main bolts from Mazda which are inbound. The cylinder head is getting ARP studs. Probably not necessary at the boost levels I'm running but if I ever creep closer to 500hp they will be welcome insurance.
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