Premature Built Engine Failure
- Thread starter Mattsmax
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You didn't say whether the oil pump was reused or not.
IMO if the failure was due to the cam/ crank gear clearance he called you about, the cam gear should have showed some damage. What does the lube pump drive gear look like?
IMO if the failure was due to the cam/ crank gear clearance he called you about, the cam gear should have showed some damage. What does the lube pump drive gear look like?
Can you take some close pics of the cam gear and the oil pump drive gear please? Specifically the wear in the face of the teeth. Also has this shop built many duramax or diesel engines?
Were different gears installed since the block was align honed? To me this looks like the wrong gears were used since the block was align honed. When you do this, you bring the crank closer to the cam, and reduce the gear lash in the gears. If you use stock gears, you lose all your gear lash, and as soon as it gets hot, the softest gear gets chewed. Once it starts, it rapidly chews up until it takes all the teeth out. I know I've seen blocks get junked before after having machine work done because they couldn't get undersized gears/chains to obtain the correct chain tension or gear lash, so you have to get another block to get your clearances correct. Even a few thousandths of change can make a big difference in gear lash.
Not good!
Sorry to see a problem like this. I agree with what Ferm said. Someone needed to add clearance (lash) on the gears. I don't normally say a shop is at fault but my opinion is they should have not sent that out.
Sorry to see a problem like this. I agree with what Ferm said. Someone needed to add clearance (lash) on the gears. I don't normally say a shop is at fault but my opinion is they should have not sent that out.
Like I said, he moved forward after knowing it was off, and gave you the motor, he knows he ****ed up and now doesn't want to take care of it, I'd say your motor was a half assing experiment he was hoping would work
Wow, I'd be one unhappy person as I am sure you are. in my opinion, after a 2nd failing engine from the same guy, I'd be asking for some cash back! And get a different shop to do your work. No way would I be expecting him to build another one. Sorry to hear about your experience
probably not going to drag him through the mud in hopes that they can come to some type of resolution. in my opinion he should be refunding you all the money spent on labor and machining then you should be finding yourself a reputable builder.
This is true Steve.
Matt I hope your builder changes his tune as that one isn't on you, especially if you left the call up to him and he sent it out the door knowing it was hard to turn over
Matt I hope your builder changes his tune as that one isn't on you, especially if you left the call up to him and he sent it out the door knowing it was hard to turn over
you guys are speculating on clearances that no one knows about. we also only know one side of the story. if this shop did plenty of dmaxes before and had the concern to call the owner to explain to him that the aline hone tighten up clearance that much and the owner said "its in your hands", by no means would i think the shop wouldnt start with a new block. its possible they used the old block too but its not like that crank gear shredding apart hasnt happen before either with good clearances.
since we dont know before and after clearances from the hone, all we can do is guess based upon your story, OP. i also find it strange that you say they honed it and not bored the mains. if you honed it, you would be taking .001 to .002 at very max otherwise you would be sitting there all day and run a higher risk of not keeping the bores true. boring them out first keeps things truer when you need to start taking material out. i would also think that taking at or more than .002 out of the mains means your oil clearances would be sky high and you would at min need to run 20w50 oil to keep pressure some what up. i have yet to play with billet main caps and see how much distortion they make though. .002 out of the mains means the crank is only .001 closer to the cam though. not enough to cause this issue.
i cant help but think there is more to this story we are missing and not just in specs...
since we dont know before and after clearances from the hone, all we can do is guess based upon your story, OP. i also find it strange that you say they honed it and not bored the mains. if you honed it, you would be taking .001 to .002 at very max otherwise you would be sitting there all day and run a higher risk of not keeping the bores true. boring them out first keeps things truer when you need to start taking material out. i would also think that taking at or more than .002 out of the mains means your oil clearances would be sky high and you would at min need to run 20w50 oil to keep pressure some what up. i have yet to play with billet main caps and see how much distortion they make though. .002 out of the mains means the crank is only .001 closer to the cam though. not enough to cause this issue.
i cant help but think there is more to this story we are missing and not just in specs...
Looks like the line hone was wrong and the gears would fit but the block actually was not a good choice. If it's align honed too much the gears become closer than they are suppose to be and the clearance tightened up so much that the gears had no clearances when it hit up to temp. The teeth then broke and it went down hill in a hurry. That's why you use a guy that has the knowledge and proper tools to check it all out. Do not assume that the machining was right. Check it and make sure it is.
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