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Completely rebuilding my Disco 4.6, have a bearing clearance question!
Hello all!
I have a 2003 Disco 2 with 104k miles, 4.6L Bosch injected motor, auto trans. So I just got my block back from Vance down at Q and E machine shop, all cleaned up, new cam bearings, had LA flanged sleeves pressed in, decked the whole thing, crank polished, etc . I had a very loud tapping/knocking sound so decided to tear it all down and redo the entire thing.
Anyways, on to my question. Flipping through the rebuild manual it states that for the main bearing clearances to be between 0.0004 - 0.002 in. and the big end bearing clearances to be 0.0006 - 0.0021 in. Maybe it's just because I've never built a Rover v8 before, but aren't those tolerances crazy tight? I can't even hardly find Plastigage that'll work down that tight! Lol!
I had my crank polished and just threw good standard bearings in , as long as the crank spins free with the caps tight should be fine IMO, not building a 1000hp race engine lol
Think I list stuff in my 98 thread, bearings were cheap on amazon and machine shop said they were supposed to be good brand
I had my crank polished and just threw good standard bearings in , as long as the crank spins free with the caps tight should be fine IMO, not building a 1000hp race engine lol
Think I list stuff in my 98 thread, bearings were cheap on amazon and machine shop said they were supposed to be good brand
Remember to use assembly lube
Yeah, that's probably why I'm having issues with this. This is the only motor I've ever built that wasn't a performance build. I just saw 0.0006" and immediately went "no way that can be a correct spec, big end elongates at high rpm, no more oil film at that tight, bam" So you'reprobably right, I just need to bring my thinking back in check hahaha. Thank you for the reply, and yes, I always use assembly lube with either comp cams or royal purple mineral break in oil
I mean you can probly mic the crank journals and put bearings in , torque caps with crank out and mic the id. Of the bearings, there may be a better way just not off top of my head lol
I mean you can probly mic the crank journals and put bearings in , torque caps with crank out and mic the id. Of the bearings, there may be a better way just not off top of my head lol
Well, that is the "correct" way to do it, I just thought for a non performance engine I could just Plastigage my way out of having to manually measure everything and do all the math haha. It just really comes back to I was just caught off guard by the manual saying less than 1 thousand was still a good spec, usually I've seen between 1-2 thousands is the range, plus maybe another half thousandth if it's going to be a higher rpm or a forced induction car.
03-15-2016, 12:43 AM
Completely rebuilding my Disco 4.6, have a bearing clearance question!
. I had a very loud tapping/knocking sound so decided to tear it all down and redo the entire thing.
