batmantech Posted August 12, 2011 Share Posted August 12, 2011 04 late build 6.0 Customer drove low on fuel then had a miss continued to drive it until no start. Icp low found IPR not changing replaced IPR valve starts up runs rough misses. Power balance #3 low relative comp.#3 10% low. Man comp #3 low. Check crankcase press. 15 psi. Visual injector looks ok.vale train ok. Looked through injector hole hard to see the whole piston. My question with that high crankcase press can that only lead to one thing piston/ring damage? Is ther anything else to inspect before teardowm? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 12, 2011 Share Posted August 12, 2011 If you have low compression (physically measured) on one hole and high crankcase pressure, it's almost impossible for it to be anything else but a piston/wall problem. It may look acceptable even with the head off until you have the piston out. It sounds like you're paranoid, if you want to verify it you could put that cyl on TDC firing and apply shop air to the injector hole with a rubber tip blow gun, it should be leaking considerably out of the crankcase. Good Luck! Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 12, 2011 Share Posted August 12, 2011 Something I seem to use often yet others might never use.... A little more time consuming that a compression tester to use, it is, IMHO, more accurate and more conclusive than a some other tests. Just a side note... and just my own opinion. Non-contributing cylinders are non-contributing because there is no or low cylinder pressure. Without "squeeze" - there is no "bang"- without "bang" - there is no "blow" - and without "blow" there wont be any crankcase pressure. I've seen a lot of techs chase engine misses with marginal crankcase pressures only to find that the motor they just dumped a bunch of the customers money into is worn out once the formerly non-contributing cylinders start adding to the crankcase pressure. Since Gary's patient is at 15 (I'm assuming inches rather than PSI), it is safe to say that there is a concern with cylinder seal, anyway. Quote Link to comment Share on other sites More sharing options...
batmantech Posted August 12, 2011 Author Share Posted August 12, 2011 opps I did mean 15 inches of crankcase press,man comp. in bad hole 50 psi good hole 400psi. And yes I am slightly paranoid about this, I torn down my share of these and done plenty of oil-egr coolers, cab off headgaskets. I think its more the servive manager giving that look and the customer giving his ideas of what it could be or what I might be "overlooking". We have all been there I know. Thanks for the input. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 12, 2011 Share Posted August 12, 2011 What I was trying to get at... let's say you replace a bunch of injectors ... maybe change a bent push tube or a broken rocker arm or similar... Bringing more cylinders "on line" is only going to increase crankcase pressure. 15 inches.... IIRC, the spec is 12 on a 6.0 with the small orofice tester? (suddenly, I have the urge to compare engines using both tools....)... 15 inches would (if I'm right) have me calling for an FQR (Ford Quality Repaint.... The Ford rebuilder in our area seems to dip these rebuilts in paint rather than spray them... Quote Link to comment Share on other sites More sharing options...
batmantech Posted August 12, 2011 Author Share Posted August 12, 2011 this thing will actually make the tester tube whistle Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 13, 2011 Share Posted August 13, 2011 I'm not sure I'd spend too much time on a "teardown". Unless your shop is into putting lipstick on pigs, this thing deserves a long block. Quote Link to comment Share on other sites More sharing options...
joshbuys Posted August 13, 2011 Share Posted August 13, 2011 The Ford rebuilder in our area seems to dip these rebuilts in paint rather than spray them... I just figured that was a requirement, that's how they come out here, and that's how we got them when I was in Wyoming. I'm gonna have to agree with Jim on this one, this thing needs a motor. Quote Link to comment Share on other sites More sharing options...
batmantech Posted August 16, 2011 Author Share Posted August 16, 2011 Jim you were correct. The piston is melted grooved the cylinder walls and hit the head. Well at least now the customer can see the damage that is there. Thanks for listening and the input. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 17, 2011 Share Posted August 17, 2011 Like the sign in the mens room... "We aim to please - you aim, too, please". Quote Link to comment Share on other sites More sharing options...
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