I think grabbing the walls is exactly what happened to #5 piston, this time I will have properly gapped rings, lesson learned. Thats just what I`m going to do run it, beat on it, and enjoy it. Extra clearance just made me nervous for a bit, I`m over it now time to whine about other things, like no time to work on projects after waiting so long to get parts.

 

Are you measuring in multiple dimensions in the bore? If so, are the bores round, ie same measurement in all dimensions? I presume you are measuring from the top with main caps torqued and no heads?

Since the block was machined with a torque plate, measuring without the heads torqued the bores could be slightly distorted so you would get a oversized measurement in one dimension and an undersized in an opposing dimension. If you really want to get accurate measurements, torque the heads and mains then measure from the bottom. This will tell you if the bores will be completely round and of proper size when in it's assembled state. Even if they are round at 0.005 p2w, the extra 0.002 from Mahle's spec and 0.001 from your machinist's spec, would not cause power or longevity issues but may be a little noisy on cold start until the piston grows a bit.

Moving over to your main bearing clearance at 0.001, this seems a little tight to me. General rule of thumb is 0.001" for every inch of main journal diameter. IIRC, LS cranks are ~2.5" so that would be 0.0025" main bearing clearance.

 

^ the above is also correct

 

Thanks for the all the advise, finally have time to get out in the garage and take some measurments. Rod journals on crank have been polished to 2.0995, big end of factory gen 4 rods measure 2.226,stock size Clevite rod bearings measure .0611 thick per side. .0611 x 2=.1222.
2.226-2.0995=.1265
.1265-.1222=.0043 clearance on rod bearings to crank journal, confirmed this with ID mic with assembled rod and bearing torqued to spec. Plastigage I guess sucks or I suck using it. Trust the mic readings completly.
So now WTF, anyone make larger bearings to get back to .002 clearance? Clearance is measured on a diameter and not per side as far as I know. Crank is coming back out to mic it as well.

 

Can go real old school with it and use leather bearings

Do you want me to check my FSM tonight and see what the factory allows?

 

LOL leather is perfect I have an old belt I can use, not sure what FSM is but ya check it. Thanks Arthur.

 

Factory service manual.

 

Found Clevite rod bearings on Summit`s webiste for a .002 undersize crank, ordered them Saturday installed them today, all rods are right at .002 clearance now.

 

Sorry, I totally forgot to get you measurements from the FSM, been a very busy weekend here at the house with this boat and stuff

Glad to hear you got that issue resolved!

 

Got the engine back in and most everything bolted back up to it. Left the plugs out, pulled fuel pump relay and cranked engine to prime it. Now hve a severe oil leak out the back of the engine lost a lot of oil fast. Suspect the barbell but I know I installed a new one, quess I must have damaged the O ring tho. So frustrated I`m just gunna cry and drink beer the rest of the day. At this point I think it may be easier to pull the tranny out to get to the leak.