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injector cup failures??


fjh

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So have any of You guys that have been seeing repeat failures on cups and injectors  been trying anything different to hold the dam things in?

Don't want to start any wars here how ever the installation procedure could be part of our issue?? just fishing for some thoughts here! 

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11 hours ago, fjh said:

So have any of You guys that have been seeing repeat failures on cups and injectors  been trying anything different to hold the dam things in?

Don't want to start any wars here how ever the installation procedure could be part of our issue?? just fishing for some thoughts here! 

Usually find failures to do with procedures and tooling on the replacement side. From new, Most needing to be done at least once in 600k miles. We've had OEM (Mack/Volvo) reman heads with failed /poorly installed cups. 

Edited by bbigrig
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We discovered the cure for injector cup leakage. Don't ask the engine to put out more than *400 horsepower. Four D13's, no injectors replaced to date, 330 horsepower. Shooting for 25,000 hours without a cup or injector failure on the oldest machine, it's starting to get an audible injector "pock" under load, but still performing on original 6.  

Edited by Mack Technician
Needed asterisks @ 400HP
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12 hours ago, bbigrig said:

Usually find failures to do with procedures and tooling on the replacement side. From new, Most needing to be done at least once in 600k miles. We've had OEM (Mack/Volvo) reman heads with failed /poorly installed cups. 

 

Please describe what  Procedure and tooling issues are you speaking of Bud I'm interested in your incite here! 

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Use to replace injector cups once a year and some more often on the same trucks it seemed until the most recent install tool came out (88800513).  But, I think its also very important that the injector bore, tip bore and conical seat area is clean and pit free (seat area). Proper torquing technique is very important as well. I've seen some techs in our shop zip right through injector replacements only to see them come right back several months later. 

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Turckster, I have watched techs here do the same thing. They've done one set and don't think they need to look at procedures any more. I just did a set that was 18 months old, maybe 15,000 miles. Had air in fuel bad and leak down/no start over night.

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On 5/1/2019 at 10:34 AM, fjh said:

Yup we just did another set the other day 6 months in  checked the torque while removing them( mid to low 30's on the bolt coming out) I'm sure the tech followed the torque procedure in his mind it was correct ! I could be wrong but These bolts should have seen at least 50-60 ft pounds coming out! Quite honestly  Its a piss poor way to hold the injectors down to start with and  to add to the already compromised situation the bolt is in my opinion Maxed out for its size and  for what engineering is asking it to do .That is why they have all these torquing procedures that may or may not be helping the situation  to start with trying to get by with a design flaw that that should have been addressed years ago! they have us applying magic paste then not applying the paste And so on  !Bla bla 

FIX the f*king thing! These engines has decent potential if not for the flaws they seem to be unwilling to redesign!  JUST KEEP  Patchin!  

When I worked in auto racing. when ever a new car design was produced, failure of parts was a given.  It was quite normal for us to find cracks or failures at the first race or after the first few tests early in the season. These parts when built were designed in CAD and the only testing was done with computer generated stress tests. When the parts were put under real work vibrations / stress things happen differently. It was not uncommon to pull those parts off the car, crack check them and re engineer them so they could mileage out before they were considered junk.  I remember at Long Beach Grand Prix we had the whole Formula Atlantic's series on brand new shock absorbers. 3 cars had signs of leaks at the end of the weekend. We found that the aluminum "Bridge" that held the air canister to the main body of the shock cracked on all 3 cars and leaked oil. Within a few days we had a new design made and the series asked all teams to send back the shocks to us to have the parts replaced. Wen they started coming in we found a few more that were cracked. The next race was 3 weeks away, my self and 2 others had the job to replace about 150 of these parts. This was not just a simple bolt on and go. We had to tear the damper apart and then install the new part then bleed it with fluid then test on a machine to show they were matching and as good as new.    

That being said Mack has had years to solve this somewhat simple issue of cup failures. It may be a huge task to re design the head so this stops but what they are doing by band aiding the issue has caused them more harm than good. Anyone that knows mack knows about this issue. I know bolt torque is a important assembly process but if the bolt is to small or the pressure that is pushing on the injector is to great you will just end up with torque specs that don't maintain regardless to what you set them to.  I suspect them asking to have this "magic paste" used was another band aid to allow the injector to move around a little with the vibrations that again proved to do nothing but made it last another 10-20 thousand miles. It sounds to me like the head or the injector has a serious flaw that nothing seams to help it. the time is now to stop dancing around this issue and address the problem correctly.  they really need to improve on their well known reliability issues. its killing Mack at the moment.

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On 4/29/2019 at 10:19 AM, fjh said:

 

Please describe what  Procedure and tooling issues are you speaking of Bud I'm interested in your incite here! 

Using worn swedge tools, improper torque procedures, using stretched hold down bolts, not sucking oil out of the injector hold down bolt bores, techs in a rush, oh....and just a poor design that really has yet to be updated. 60series had a similar combustion gas to fuel system issue so meh....

Job security 

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On 5/1/2019 at 10:34 AM, fjh said:

Yup we just did another set the other day 6 months in  checked the torque while removing them( mid to low 30's on the bolt coming out) I'm sure the tech followed the torque procedure in his mind it was correct ! I could be wrong but These bolts should have seen at least 50-60 ft pounds coming out! Quite honestly  Its a piss poor way to hold the injectors down to start with and  to add to the already compromised situation the bolt is in my opinion Maxed out for its size and  for what engineering is asking it to do .That is why they have all these torquing procedures that may or may not be helping the situation  to start with trying to get by with a design flaw that that should have been addressed years ago! they have us applying magic paste then not applying the paste And so on  !Bla bla 

FIX the fucking thing! These engines has decent potential if not for the flaws they seem to be unwilling to redesign!  JUST KEEP  Patchin!  

Yes...about 60lbft coming out on the hold downs is about right. 

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41 minutes ago, bbigrig said:

Yes...about 60lbft coming out on the hold downs is about right. 

When you torque the inj. hold downs to 15 ft/lb, 180 deg, back off to 7-8 ft/lb, torque to 18 ft/lb and torque turn to 90 deg that averages 45-50 ft/lb. Therefore there is no way when backing off a bolt that you are going to get 60 ft/lbs. Several years ago there was a recall that require retorque/check of MP8 injector hold downs and the torque spec was 45 ft/lbs.

It may be that is the problem, not tight enough. But, what do I know, I'm not an engineer, just a dude that fixes their mess ups. 

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53 minutes ago, turckster said:

When you torque the inj. hold downs to 15 ft/lb, 180 deg, back off to 7-8 ft/lb, torque to 18 ft/lb and torque turn to 90 deg that averages 45-50 ft/lb. Therefore there is no way when backing off a bolt that you are going to get 60 ft/lbs. Several years ago there was a recall that require retorque/check of MP8 injector hold downs and the torque spec was 45 ft/lbs.

It may be that is the problem, not tight enough. But, what do I know, I'm not an engineer, just a dude that fixes their mess ups. 

About, close to, around, whatever.....we have fooled around with a few and found some have been torqued as high as just under 60ft lbs. Like it or not that's what we have seen. With age, temps,materials, mating surfaces and heavy versus light use duty cycles/applications of the engines, it almost seems the cup design is just not meant to last. 

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Finally s

6 hours ago, bbigrig said:

About, close to, around, whatever.....we have fooled around with a few and found some have been torqued as high as just under 60ft lbs. Like it or not that's what we have seen. With age, temps,materials, mating surfaces and heavy versus light use duty cycles/applications of the engines, it almost seems the cup design is just not meant to last. 

Finally someone thinking what we’re thinking!! 

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The injector yokes are beefy & cup basement is thick. Find a fed-up guy who has an old engine that burns a little oil and has chronic cup leakage. Drill yokes a size up and tap the cap screw one size up? Install a 12.9 bolt and lay into that prick just short of injector distortion. Worse case would be bore shoulder collapses dropping injector into the cylinder and it's reman time. Best case he never has another injector cup leak and Mack sends a hitman to kill you for all the injector sales you cost Volvo.    

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4 hours ago, Mack Technician said:

The injector yokes are beefy & cup basement is thick. Find a fed-up guy who has an old engine that burns a little oil and has chronic cup leakage. Drill yokes a size up and tap the cap screw one size up? Install a 12.9 bolt and lay into that prick just short of injector distortion. Worse case would be bore shoulder collapses dropping injector into the cylinder and it's reman time. Best case he never has another injector cup leak and Mack sends a hitman to kill you for all the injector sales you cost Volvo.    

Ha ha I’m stoked now ! love that idea but remember you thought of it !  I ll  send their hit men after you if I get caught 😂 He told me to do it. No worry’s thou Revenue will be way down by that time they wouldn’t be able to afford. A hitman.🤔

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Modify the valve covers to act as a hold down clamp. The attached picture is a 1970s Honda cb750 valve cover. The rocker arm holders were prone to failing so the racing community welded and drilled threaded bosses to the valve covers so a bolt could thread through to apply additional holding force on the rocker arm holders.

Never seen an MPwhatever in person, let alone with valve covers off. Don't know if the injectors would be compatible with a fix of this sort.

PC150001.jpg

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Volvo must have the same issues. No? Keep it under 400 HP. No wonder they are out of heavy haul. It sounds like increasing bolt cross section might be the answer provided there is enough head meat to allow this. Selling more injectors/cups/labor vs loss of market share is a no should be a no brainer. It used to be that field testing new products should take about 18 months to correct design defects. May bee Volvo thought it was 18 years.

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18 hours ago, james j neiweem said:

Volvo must have the same issues. No? Keep it under 400 HP. No wonder they are out of heavy haul. It sounds like increasing bolt cross section might be the answer provided there is enough head meat to allow this. Selling more injectors/cups/labor vs loss of market share is a no should be a no brainer. It used to be that field testing new products should take about 18 months to correct design defects. May bee Volvo thought it was 18 years.

18 years and counting! Having said that we have a  Volvo loader at the shop at the moment just put cups in that puppy Not even a 400 hp engine ! this issue isn't just confined to Trucks ! Just an over all  Volvo trash issue! (we got it passed the warranty  were AHH good enough! ) like earlier stated  job security for us guys  and ongoing parts sales for THE BIG V!    keeps the economy  going!

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Maybe this is part of how the top 1% keep the bottom 99% from making money. I'm a capitalist, don't get me wrong, but I prefer to deal with honest people. Don't plan on buying a Volvo or a molvo with this sort of crap going on this long 

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7 hours ago, fjh said:

 Volvo loader at the shop at the moment just put cups in that puppy Not even a 400 hp engine !

OH Snap!....hit Re-edit, I just added an asterisks to my previous post.

* My 400HP D13 theory hereby only applies to folks who don't huff ether in arctic Canadian regions. 

Edited by Mack Technician
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  • 2 years later...

How do you tell which cups or injectors are bad? Once you pull the old ones out are they damaged by the removal process? Might seem Petty but at several hundred a piece why do all six when one has gone bad in less than 100k? Is it usually the injectors or just the cups? Can you replace one without the other?

 

Am I mistaken or is it simply extreme pressure that holds them in until the injector is installed and torqued?

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