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Discussion Starter · #1 ·
Greetings from yet another backyard mechanic!

The engine in question is a Mexico(or maybe International Harvester?) block 24 valve from 2001.

I recently changed my front main seal. Needless to say I need to go dig in there again because I didn't realize that my 240 000 mile engine had a repair sleeve installed untill I was trying to fit a normal size seal on top of the crankshaft. Of course force was my first route of propblem solving rather than checking if there actually was a sleeve on there. I took my chances and was pretty easily able to pry the sleeve out to find a mint condition crankshaft under it. The sleeve had some noticeable grooves and the seal was completely blown on one part. The new seal fit very easily on the shaft after this but the whole ordeal took so much time that I just had to go with it. It leaks less now, but it leaks.

One of the first things I checked while I had the timing cover off was how the KDP was doing. The pin itself is buried deep in its hole and next to the pin is a Torx head bolt. Judging from some videos and pictures off internet I get the impression that on 12 valves the pin hole is pretty close or completely level with that bolt that is next to it. And the bolt is a normal 6 sided bolt head, not a torx like on mine. Also on 24 valve it looks like the pin hole is elevated considerably off the level of the bolt so making a backyard blocker isn't just going to be a flat piece of metal with a bolt hole in it. I've even heard legends that some 24 valves have a KDP blocker on the timing cover itself, but mine is flat.

Some DIY KDP blocker installations call for chiseling a piece off of the edge of the pin hole so you can fit a cam style blocker on the adjacent bolt. I don't want to go that route since I think there's a risk of causing a much larger crack on the timing case that would be intended for making a cam style blocker. And pieces of aluminum flying all over the place near the timing gears.

I have one of these on order:
https://www.amazon.com/gp/product/B07LB2QS88
Supposedly this piece would block the pin hole without chiseling and comes supplied with a replacement bolt that can't back out of it's hole/thread with the timing cover installed. I'll have to see when I actually get my hands on this if the lobe feels like it won't cause terminal damage if the bolt should ever some loose and allow the lobe to start spinning freely. Loctite on the thread is of course necessary.

I'd like to hear if anyone here has some knowledge about the KDP issue in regards of 12 valves VS 24 valves.

Personally I don't drive a ton of miles and by itself this truck will last me years and years. But blocking off the KDP in a clean fashion would add value to it, if even necessary on a 24 valve?
 

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I heard a long time ago it's not a issue on a 24v so I never worried about it.
 

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I'm fairly sure 24v's pin hole is tapered, solving the kdp.
 

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I did mine about 4 years ago and on my 98.5 the pin was just starting ti protrude.
 

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2011 Ram 2500 4x4 6.7 68RFE 4 inch lift
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Why is that pin in there after all the case bolts are tightened? It’s not a solid pin so it’s not there to stop oil from coming through.
 

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Shouldn't be a problem on a 2001, right?

Sent from my SM-G920P using Tapatalk
 

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During the 24 valve years, Cummins went to the rounded head torx bolts that did not have a flange under the head. The flange could drop into the recess between gear teeth and lock up the engine, breaking expensive parts. In about calendar year 1996 they also began using sealer on the bolt threads so they wouldn't tend to vibrate loose. During the 24-valve years Cummins also introduced a gear case with a deeper hole for the dowel pin, with a restrictor ring so the pin couldn't vibrate out all the way. Unfortunately there is not a specific date when the later case began being used exclusively. Your year "should" have the later case. You posted that the case is thick there with a deep hole for the dowel. That suggests that it is the late style with the restrictor.
 

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Discussion Starter · #8 ·
Cool information, thanks :)

Anybody know how long the pin is? I'm guessing the stepped timing case could also be tall enough at the KDP hole so the pin would hit the timing case cover plate before it can fall into the gears? As a form of overkilling any possibility of the other preventive desings failing. With all this in mind I'm not going to add anything into the cement mixer that could potentially get loose and interfere with the gears. But it is of course very interesting that there does infact seem to be different timing cases through the production of the 24 valve. Atleast judging by what I was able to dig up on the internet.
 

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dowel pin is 0.395" diameter, 0.625" long
 
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