fjh Posted February 17, 2008 Share Posted February 17, 2008 Guys we have had a problem truck eteck 460 which has choked down a valve on #2 cyl for the second time.The valve yoke pin was broken in both instanceschicken or the egg??Is there a roller / h ring issue causeing this? or just a bad luck with reman parts?I checked and the push tube is still straight !First head lasted just over a year, this head 7 months or so.Engine was a total rebuild 2-3 years ago due to a valve failure as well.The guy is not very happy and nor are we over this BS. This engine has a long history of problems. And good maintance.This customer has been a solid Mack guy for years this truck has been a sore spot for him.Any input or thoughts?Buying a PETE not aceptable! Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted February 17, 2008 Share Posted February 17, 2008 Guys we have had a problem truck eteck 460 which has choked down a valve on #2 cyl for the second time.The valve yoke pin was broken in both instanceschicken or the egg??Is there a roller / h ring issue causeing this? or just a bad luck with reman parts?I checked and the push tube is still straight !First head lasted just over a year, this head 7 months or so.Engine was a total rebuild 2-3 years ago due to a valve failure as well.The guy is not very happy and nor are we over this BS. This engine has a long history of problems. And good maintance.This customer has been a solid Mack guy for years this truck has been a sore spot for him.Any input or thoughts?Buying a PETE not aceptable! If it has happen two times on same cyl. then may have a exhaust brake problem. I dont know about the eteck but 60 series DD can have a exhaust brakehanging the valve open too long and hitting the piston and one of their units was hanging due to the piston having a wear ridge in the housing and it would hange on it just for a little bit. By the yoke pin being broke that sounds like a side ways force to do that but if one valve hangs down then that may do it. glenn Quote glenn akers Link to comment Share on other sites More sharing options...
fjh Posted February 17, 2008 Author Share Posted February 17, 2008 If it has happen two times on same cyl. then may have a exhaust brake problem. I dont know about the eteck but 60 series DD can have a exhaust brakehanging the valve open too long and hitting the piston and one of their units was hanging due to the piston having a wear ridge in the housing and it would hange on it just for a little bit. By the yoke pin being broke that sounds like a side ways force to do that but if one valve hangs down then that may do it. glennThanx GlenThe engine was sitting aa loading dock idling when it broke!The jake was notin use at this point the driver claims it was bumped up to 800 rpms or so the valve pin that goes thru the screw looks fine the yoke pin simply snapedoff flush I didnt have time to look at much else yesterday will look deeper monday just fishing for ideas at this point.as I said this engine has been bad news for quite some time for so reason. Quote Link to comment Share on other sites More sharing options...
Mackpro Posted February 18, 2008 Share Posted February 18, 2008 If it has a jacobs engine brake, we see this all the time. The floating jake pin in the valve yoke is worn out. Mack has come out with a new improved floating pin that we use. part #421GC41CM These pins wear down and then the yoke starts to wobble and then breaks off the valve yoke pin in the head. Most of the time we can drill and slide hammer the pin out of the head. Good luck. Quote Link to comment Share on other sites More sharing options...
m5040 Posted February 19, 2008 Share Posted February 19, 2008 If you see these break all the time with a Jake, is there anyway to check to see if the problem is about to happen without disassembling much ? I have a EM6-300 with a Jake. Quote Link to comment Share on other sites More sharing options...
fjh Posted February 19, 2008 Author Share Posted February 19, 2008 checked that today ,the valve pin that goes thru the screw looks fine !the yoke and pin look to have no funny wear! Quote Link to comment Share on other sites More sharing options...
Mackpro Posted February 19, 2008 Share Posted February 19, 2008 (edited) Heres a pic of a good/new pin. The floating part should be around .008 past the the threaded body. If its flush or up inside the body its really bad. If one is bad change them all. On the new style ones the floating part is silver. Edited November 1, 2019 by Mackpro Quote Link to comment Share on other sites More sharing options...
Mackpro Posted February 19, 2008 Share Posted February 19, 2008 these are only on the etech engines and some Asets engines 1999-2005 Quote Link to comment Share on other sites More sharing options...
m5040 Posted February 20, 2008 Share Posted February 20, 2008 So then the 1983 vintage EM6-300 should be safe regarding this issue and the Jacobs brake ? Quote Link to comment Share on other sites More sharing options...
fjh Posted February 20, 2008 Author Share Posted February 20, 2008 So then the 1983 vintage EM6-300 should be safe regarding this issue and the Jacobs brake ? yes its a diffrent set up! Not to worry.Anyway more to the story coming to a theater near you. The pins in the above pic are eteck !Theses pins are OK ,I beleive the slave that operates the on top of these is the direct cause of this failure we investigated further today and as soon As I saw these slave pistons and there condition I remembered orderng them back when the first failure occured ,apon further investigation it seems our parts people never notified us or the customer parts had come in and the customer was never notified to bring the truck back to have them installed . We went down to the parts dept, no one seemed to have a clue (this is quite normal).So we went over to the holdshelf where parts are kept on hold for jobs and sure enough 3 slave pistions sit with no tag or work order number or anything ,all lonely on the shelf !THEY'VE been sitting here for THREE MONTHS and no one asked any questions???.!I think the ball has been dropped here US DUMB mechanics just order in specilty parts in JUST for somthing to do I GUESS. This is a non stocking item surely you should be asking some questons? .I'm just a tad pi$$ed off at this! Quote Link to comment Share on other sites More sharing options...
David Posted February 20, 2008 Share Posted February 20, 2008 How much is the owner going to pay for this learning experience? Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted February 20, 2008 Share Posted February 20, 2008 yes its a diffrent set up! Not to worry.Anyway more to the story coming to a theater near you. The pins in the above pic are eteck !Theses pins are OK ,I beleive the slave that operates the on top of these is the direct cause of this failure we investigated further today and as soon As I saw these slave pistons and there condition I remembered orderng them back when the first failure occured ,apon further investigation it seems our parts people never notified us or the customer parts had come in and the customer was never notified to bring the truck back to have them installed . We went down to the parts dept, no one seemed to have a clue (this is quite normal).So we went over to the holdshelf where parts are kept on hold for jobs and sure enough 3 slave pistions sit with no tag or work order number or anything ,all lonely on the shelf !THEY'VE been sitting here for THREE MONTHS and no one asked any questions???.!I think the ball has been dropped here US DUMB mechanics just order in specilty parts in JUST for somthing to do I GUESS. This is a non stocking item surely you should be asking some questons? .I'm just a tad pi$$ed off at this! That is what that was happen on one model of the 60 series DD the pistonns was hanging in the housing just for a little bit and the valve would smack the piston but some kelp saying that it was the jake brake staying on and that can happen with a leaking or bad selnold but i said that is not going to make the valve stay open when the piston comes to the top and starts down so we got to checking then a service letter came out and told us to watch for the worn ridge in the piston housing.Some times you would finf metal in there from a piston failure and i think that caused alot of valves to drop.I have pulled alot of heads off of the DD and found valve marks in the top of the pistons and some times it is from the cam timing being off one tooth. glenn Quote glenn akers Link to comment Share on other sites More sharing options...
fjh Posted February 20, 2008 Author Share Posted February 20, 2008 How much is the owner going to pay for this learning experience? DavidThe owner will llkly pay nothing! The head is under warrenty for one year ,the jake piston thing i just speculation on my part, but I'd bet dollars to donuts this is where the problem lies. Quote Link to comment Share on other sites More sharing options...
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