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Engine/Transmission (1998.5 - 2002) How many have seen kdp on 24 valve truck
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My boss fixed his. Theres someguy on the internet that has a jig you use to drill a hole into the case and then you insert a bolt or screw into the case and this blocks the KDP from backing out. If you drill into the case and hit steel (case is aluminum) you know the pin is backing out and you'll have to pull the front cover off and fix it. This is just another option if you don't wanna pull the front of the engine apart. But I guess the guy doesn't charge anything to borrow the jig, it just gets passed around from person to person. I'll try and remember to ask my boss about it tomorrow if anyone is interested in it. This is how he took care of his.
Engine build date on my 2000 is 7/99, and it is stepped so the pin can't come out.
You have nothing to worry about, your truck was built after 7/99. I am not sure exactlly when they changed the front gear case but for sure from 7/99 on.
Look at DCreed's pictures above. Between the two gears and the side of the gear case is a small dowel that is starting to migrate out. That's the Dowel Pin of Killer Dowel Pin (KDP) fame. The purpose of the DP is to align the gear case with the block during assembly, providing a very accurate, positive location.
On all the 12V's that dowel pin was straight and over time worked it's way completely forward. If you're real REAL lucky it will fall to the bottom of the case and maybe into the oil pan and do no damage. The standard result is that the pin gets in between the gears and KKKRUUUNNCCH, bang, boom, etc. See the first pics in the post.
It was my impression (and many others more in the know than I) that this was revised with a stepped pin. The stepped pin has a larger diameter in the block and smaller pin diameter in the case, effectively trapping it behind the case. (relative diameters, I don't know the exact variation from the straight pin) This revision, I was told, started with the 24V engines. Apparently that is not true. My 24V is a 12/07/98 build, FWIW. That's from the ENGINE data plate, not the body data plate.
What we need now are the Cummins build serial numbers and dates where the stepped pin revision started and then all we have to do is check the metal tag on our engines to know if we have the KDP or not. I know a couple of retired Chief Engineers from Cummins, I'll rattle cages and see if we can get an answer. I am relatively certain the engineering change record database would have a record of when this happened. It may take a while, so be patient...
OK, I stand corrected. Interesting approach on Cummins' part. What I was told sounded particularly plausible since I would have thought it would have been cheaper to go the stepped pin route with a floating free end dimension and just reduce the diameter of the hole in the case, rather than drilling a shallow, flat bottom, blind? hole. Well, you know about assumptions.
Sounds like a step in the case and shorter dowel was cheaper than a stepped or journaled dowel. I'll run with this info tomorrow and hopefully I can get a good explanation from at least one of these guys.
OK, I stand corrected. Interesting approach on Cummins' part. What I was told sounded particularly plausible since I would have thought it would have been cheaper to go the stepped pin route with a floating free end dimension and just reduce the diameter of the hole in the case, rather than drilling a shallow, flat bottom, blind? hole. Well, you know about assumptions.
I'll run with this info tomorrow and hopefully I can get a good explanation from at least one of these guys.
Dowel is the same as before thats why they stepped the case
Here is your answer.
When I had my 99, I went through all of this to the level of speaking with Cummins Engineers on the phone. A couple of friends of mine from my college days work at Cummins in Columbus so I was able to talk to who I needed to. Plus... I pulled my engine apart to double check mine and went through all this. All of your questions are familiar. There is no answer to any of them carved in stone. Here's why.
With the introduction of the 24V engine... Cummins designers decided to address the timing case dowel pin issue. They were aware for some time but it wasn't frequent enough of a problem to worry about until a new revision of the B-Series was due.
Historically there were two styles of cases for the 12V engines. One had a relatively flat area around the pin bore and this one made the tab method a viable option using a case bolt nearby. Another version had more metal around the pin bore opening and didn't really allow for the tab method per se. If the tab method is used on these cases, the tab washer needs to be "stair stepped" to cover the hole. IE: The opening where the pin comes out is not at the same elevation as the surface under the head of the bolt. Its "higher".
Later the case was further improved such that the new bossed pin bore case included a "lip" edge in the inner bore at the end of the line. The pin could move out to the edge but never fall out or stick out. This was a revision to the later case with more metal around the bore. Called the improved bossed case.
Herein lies the problem. Cummins never changed the part number of the cases. Further when the 24V was introduced, many bins of old style cases existed that could still be used if drilled for the VP44. Thus Cummins decided to use up all stock. But meantime they were producing the new cases and bins of the 24V new cases were being used. At the same time.
No rhyme or reason was given to which engine got which. No notes were kept as to what serial number engines got what case. So there is no magical cutoff date or serial number.
My 99 which was built in 10/98 HAD the improved cover with the lip edge. So I didn't need a fix. My pin moved 0. 0005" using bore depth mic. So no real movement anyhow. But 24V engines up to 2000 had been seen with the problem. If memory serves me correct... there were even reported failures.
So don't assume that all built after 99 are safe. OR even 2000. OR even any of them in my opinion if it were my truck.
I dislike the drill method of pinning. This is because of the various types of covers involved. There is one jig and two types of pin bores out there in non improved cases. In one case the bolt will block the hole fine. In the other case your drilling into thick aluminum bossed pin bore metal inside and all the shavings are going inside the engine. Not my favorite thing to ponder on lazy afternoons. Even if different jigs for the two styles of covers existed... you'd have to remove the case cover to figure that out. Then you're already in there. So why drill then? I had photos somewhere of the different cases including mine... but couldn't find them. If you go in the case with a fiber optic scope to determine... it would be difficult at best if not impossible to see. The lip edgs is not exceedingly obvious. Its more of something you feel with a hook or awl tool. But definately enough to stop the pin from vibrating out.
It sucks... but take the fan off, remove a pulley, remove some bolts and get a new crankshaft seal and cover gasket (Or triple bond Cummins sealant). Some trucks didn't use a gasket. Either way is fine.
Its a one afternoon job. Jig fixing isn't much faster if you've never done either. Oh... while youre in there, tighten the case-to-block bolts. They loosen over time and can do same or worse damage than a KDP.
Thats the 24V KDP issue as I see it.
When I had my 99, I went through all of this to the level of speaking with Cummins Engineers on the phone. A couple of friends of mine from my college days work at Cummins in Columbus so I was able to talk to who I needed to. Plus... I pulled my engine apart to double check mine and went through all this. All of your questions are familiar. There is no answer to any of them carved in stone. Here's why.
With the introduction of the 24V engine... Cummins designers decided to address the timing case dowel pin issue. They were aware for some time but it wasn't frequent enough of a problem to worry about until a new revision of the B-Series was due.
Historically there were two styles of cases for the 12V engines. One had a relatively flat area around the pin bore and this one made the tab method a viable option using a case bolt nearby. Another version had more metal around the pin bore opening and didn't really allow for the tab method per se. If the tab method is used on these cases, the tab washer needs to be "stair stepped" to cover the hole. IE: The opening where the pin comes out is not at the same elevation as the surface under the head of the bolt. Its "higher".
Later the case was further improved such that the new bossed pin bore case included a "lip" edge in the inner bore at the end of the line. The pin could move out to the edge but never fall out or stick out. This was a revision to the later case with more metal around the bore. Called the improved bossed case.
Herein lies the problem. Cummins never changed the part number of the cases. Further when the 24V was introduced, many bins of old style cases existed that could still be used if drilled for the VP44. Thus Cummins decided to use up all stock. But meantime they were producing the new cases and bins of the 24V new cases were being used. At the same time.
No rhyme or reason was given to which engine got which. No notes were kept as to what serial number engines got what case. So there is no magical cutoff date or serial number.
My 99 which was built in 10/98 HAD the improved cover with the lip edge. So I didn't need a fix. My pin moved 0. 0005" using bore depth mic. So no real movement anyhow. But 24V engines up to 2000 had been seen with the problem. If memory serves me correct... there were even reported failures.
So don't assume that all built after 99 are safe. OR even 2000. OR even any of them in my opinion if it were my truck.
I dislike the drill method of pinning. This is because of the various types of covers involved. There is one jig and two types of pin bores out there in non improved cases. In one case the bolt will block the hole fine. In the other case your drilling into thick aluminum bossed pin bore metal inside and all the shavings are going inside the engine. Not my favorite thing to ponder on lazy afternoons. Even if different jigs for the two styles of covers existed... you'd have to remove the case cover to figure that out. Then you're already in there. So why drill then? I had photos somewhere of the different cases including mine... but couldn't find them. If you go in the case with a fiber optic scope to determine... it would be difficult at best if not impossible to see. The lip edgs is not exceedingly obvious. Its more of something you feel with a hook or awl tool. But definately enough to stop the pin from vibrating out.
It sucks... but take the fan off, remove a pulley, remove some bolts and get a new crankshaft seal and cover gasket (Or triple bond Cummins sealant). Some trucks didn't use a gasket. Either way is fine.
Its a one afternoon job. Jig fixing isn't much faster if you've never done either. Oh... while youre in there, tighten the case-to-block bolts. They loosen over time and can do same or worse damage than a KDP.
Thats the 24V KDP issue as I see it.
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Excellent post, ncostello. Thanks.
I spoke with Mark at TST today and he indicated that even if the Engineering Change Records existed that getting an indication of exactly when the change actually took place would be pretty difficult. Mark would know as he spent many years as a Chief Engineer at Cummins.
Another tidbit he communicated to me was that the 12V engines with the P7100 pumps were thought to be the main cause of dowel pin migration. The idea being that the longer and heavier P7100 constitutes a significant moment arm load that flexed the back of the case. Thus a significant enough movement of the the case against the block to 'work' the pin out. So, with the smaller lighter VP44, the occurrence of a dowel pin failure should, logically, be lower. A caveat on the VP44 pumps; the first design iteration of the pump support was prone to failure, so if the support fails, the pump would move around more on the case and could contribute to a higher likelihood of pin migration. Depending of course on how long the support was broken before it was repaired. Geeze, talk about variables.
Maybe we can feel better about having a VP44 and the likelihood of failure over a P7100 equipped engine being somewhat less. Well, from a practical standpoint, those thoughts don't help us pinpoint anything without removing the cover and inspecting. Seems to fit with what several folks on this forum have said all along, "Pull the cover and fix it, or pay severe consequence".
And from what you just posted, ncostello, it wouldn't matter one wit if we found out when the ECO for the cover went through due to the mixing of old and new stock.
And as for possibly being upset with Cummins for mixing the cases, well, easy to say, but it is difficult to operate in an automotive environment with considerable cost reduction pressures. Likely on the ECO, it was noted that the old inventory was ok to exhaust. Sometimes, if this is NOT done, there will be NO inventory to maintain production in this Just In Time world we live in. Been there, done that.
In my engineering career, I have worked for companies that have supplied various aircraft manufacturers, Ford, GM, and most recently Chrysler and can tell you that before the ink is dry on the supply contract, cost reduction goals are being discussed. Just a fact of life. I am not being an apologist for Cummins, just simply stating that this is the way things tend to be in the pressure cooked automotive environment.
I left a message today with the second retired Chief Engineer that I know, but that now seems pointless with the known mixing of old and new stock. So, it appears to me that, sadly, the ONLY safe and smart option is to get a dowel pin 'fix' kit, pop the cover and check status. #@$%! And the second thing to do is to check the support mount on on the back of the VP44 and make sure it is ok.
That will be my plan. If I hear of anything else that would be helpful to us, I'll post here. And MANY THANKS to ncostello for seeing the thread and taking the time to post the "inside story".
I spoke with Mark at TST today and he indicated that even if the Engineering Change Records existed that getting an indication of exactly when the change actually took place would be pretty difficult. Mark would know as he spent many years as a Chief Engineer at Cummins.
Another tidbit he communicated to me was that the 12V engines with the P7100 pumps were thought to be the main cause of dowel pin migration. The idea being that the longer and heavier P7100 constitutes a significant moment arm load that flexed the back of the case. Thus a significant enough movement of the the case against the block to 'work' the pin out. So, with the smaller lighter VP44, the occurrence of a dowel pin failure should, logically, be lower. A caveat on the VP44 pumps; the first design iteration of the pump support was prone to failure, so if the support fails, the pump would move around more on the case and could contribute to a higher likelihood of pin migration. Depending of course on how long the support was broken before it was repaired. Geeze, talk about variables.
Maybe we can feel better about having a VP44 and the likelihood of failure over a P7100 equipped engine being somewhat less. Well, from a practical standpoint, those thoughts don't help us pinpoint anything without removing the cover and inspecting. Seems to fit with what several folks on this forum have said all along, "Pull the cover and fix it, or pay severe consequence".
And from what you just posted, ncostello, it wouldn't matter one wit if we found out when the ECO for the cover went through due to the mixing of old and new stock.
And as for possibly being upset with Cummins for mixing the cases, well, easy to say, but it is difficult to operate in an automotive environment with considerable cost reduction pressures. Likely on the ECO, it was noted that the old inventory was ok to exhaust. Sometimes, if this is NOT done, there will be NO inventory to maintain production in this Just In Time world we live in. Been there, done that.
In my engineering career, I have worked for companies that have supplied various aircraft manufacturers, Ford, GM, and most recently Chrysler and can tell you that before the ink is dry on the supply contract, cost reduction goals are being discussed. Just a fact of life. I am not being an apologist for Cummins, just simply stating that this is the way things tend to be in the pressure cooked automotive environment.
I left a message today with the second retired Chief Engineer that I know, but that now seems pointless with the known mixing of old and new stock. So, it appears to me that, sadly, the ONLY safe and smart option is to get a dowel pin 'fix' kit, pop the cover and check status. #@$%! And the second thing to do is to check the support mount on on the back of the VP44 and make sure it is ok.
That will be my plan. If I hear of anything else that would be helpful to us, I'll post here. And MANY THANKS to ncostello for seeing the thread and taking the time to post the "inside story".
Yes Indeed!
This stirred my thought though. Were the "old" cases drilled for P-pump aready? Then there would be extra holes?
I imagine they'd be covered enough that no amount of inspection could find them without removing parts, which would defeat the purpose... .
It's a glimmer of hope, but after a decade of 24V's possibly having this problem, shurley someone else has thought of looking for two sets of pump mount holes (if they are there... )
Actually, I'm wishing for a fiber optic borescope for Christmas. :-laf:-laf NOT.
Mark and I talked about this as it would be helpful to diagnose a myriad of issues and not just engine issues. Straight borescopes are rather expensive and likely only justifiable as a business expense, but the use is quite limited. With miniature camera technology increasingly available and inexpensive, I wonder if anyone has such an animal that would be of diagnostic use?
A bit off thread but worth the question. Anybody?
Mark and I talked about this as it would be helpful to diagnose a myriad of issues and not just engine issues. Straight borescopes are rather expensive and likely only justifiable as a business expense, but the use is quite limited. With miniature camera technology increasingly available and inexpensive, I wonder if anyone has such an animal that would be of diagnostic use?
A bit off thread but worth the question. Anybody?
I've been working on my radiator and intercooler on my 91. 5. So this morning I decided to check my dowel pin and tighten up the front cover bolts inside.
I have the old style case (obviously not the improved one since its a first gen) but with the extra metal around the bore. So I'd need a stepped tab to fix. I'll post a photo to show what I mean.
Instead... I'll tap the pin back in and use green loctite. Additionally I'll take a punch and peen my own lip edge inside the bore. Called the stake method.
It looks like my pin has moved out somewhat. But I'll report back when I hit it a few times with a hammer.
I once thought to use the borescope. But if you look inside there's not much room and to get to the pin... you'd have to make some twists and turns around the gears. Unless the scope has amazing directional control... it would be difficult at best. And with the oil covered parts... the light might reflect like crazy making good visibililty impossible. You'd have to go into the oil fill port/VP44 gear nut cover. My oil fill is on the front cover unlike the 24V engines.
I'd have to say raw cases were not drilled until needed. Thus there should be no extra holes for a P Pump or whatever. Drilled on an as needed basis?
Cummins used many different pumps all through the years. I think industrial engines still used VE pumps when the VP's were being used. So the cases could be drilled for whatever whenever. I don't work the line... so I'm no expert. But thats how I would do it. Make one case... machine as needed.
I have the old style case (obviously not the improved one since its a first gen) but with the extra metal around the bore. So I'd need a stepped tab to fix. I'll post a photo to show what I mean.
Instead... I'll tap the pin back in and use green loctite. Additionally I'll take a punch and peen my own lip edge inside the bore. Called the stake method.
It looks like my pin has moved out somewhat. But I'll report back when I hit it a few times with a hammer.
I once thought to use the borescope. But if you look inside there's not much room and to get to the pin... you'd have to make some twists and turns around the gears. Unless the scope has amazing directional control... it would be difficult at best. And with the oil covered parts... the light might reflect like crazy making good visibililty impossible. You'd have to go into the oil fill port/VP44 gear nut cover. My oil fill is on the front cover unlike the 24V engines.
I'd have to say raw cases were not drilled until needed. Thus there should be no extra holes for a P Pump or whatever. Drilled on an as needed basis?
Cummins used many different pumps all through the years. I think industrial engines still used VE pumps when the VP's were being used. So the cases could be drilled for whatever whenever. I don't work the line... so I'm no expert. But thats how I would do it. Make one case... machine as needed.
drag racer
TDR MEMBER
Ok, examining my truck for the KDP situation became high up on the project list, since my extended warranty expired last year, and the reports that 24V engines are not 100% immune. I started disassembly last night, and just now got the gear case cover after running around for some other parts and tools today.
Here are my particulars:
Model Year: 1999 24V engine
Engine Build Date: 09/10/1998
Truck build date: October 1998
Dowel Pin Inspection: all the way in! who-hoo! Oo.
Tapped on it with a punch and it did not noticeably move in any further.
Gear Case Situation: Reading "ncostello" posts (which are awesome BTW), it appears I have the "second" design where the hole is still straight (I do not feel a change in ID while probing with a scriber), but with a raised rib of material running adjacent to the hole bore. Therefore, the straight teardrop-shaped washer in the KDP repair kits will not work.
QUESTION: For those that have this style of case, is staking the best action to take as "ncostello" suggests, or are there other actions to do???? For those that have staked, I'm assuming it can be done by doing a couple of hits of a punch on the ID of the pin bore to try and raise a little metal, or might it be better to do the stakes on the outer face of the pin bore???
Any suggestions or clarifications welcomed, but please hurry - I want to get the cover back on soon.
.
Here are my particulars:
Model Year: 1999 24V engine
Engine Build Date: 09/10/1998
Truck build date: October 1998
Dowel Pin Inspection: all the way in! who-hoo! Oo.
Tapped on it with a punch and it did not noticeably move in any further. Gear Case Situation: Reading "ncostello" posts (which are awesome BTW), it appears I have the "second" design where the hole is still straight (I do not feel a change in ID while probing with a scriber), but with a raised rib of material running adjacent to the hole bore. Therefore, the straight teardrop-shaped washer in the KDP repair kits will not work.
QUESTION: For those that have this style of case, is staking the best action to take as "ncostello" suggests, or are there other actions to do???? For those that have staked, I'm assuming it can be done by doing a couple of hits of a punch on the ID of the pin bore to try and raise a little metal, or might it be better to do the stakes on the outer face of the pin bore???
Any suggestions or clarifications welcomed, but please hurry - I want to get the cover back on soon.
.
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Issue 128 – Digital Version
Digital Magazines
FREE!
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Renew
Subscribe
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Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
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The Perfect Collection Vol. II
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What Makes Us Tick?
Product Showcase
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