Shim your governor springs

The cool part, this mod will work on other trucks with a P-pump. The 6CT(8.3), DT466, some Macks, Ford(New Holland) 6.6 & 7.8, usually 93 or newer.
 
smokin binder said:
Caution notes:
-Some pumps will hang up at 1000-1100rpm with the washer mod.
-the best shim seems to be with a 18mm OD, 13mm ID, 1.55mm thickness washer(some trimming required).
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I'm the one who tested and found out these measurements. Works VERY well on a 160 pump (1995 auto). Posted them to Cummins Forum from where they have been copied here. The next shims that I will try will be 18mm OD, 13mm ID, 1.9mm thickness.
 
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JariV said:
I'm the one who tested and found out these measurements. Works VERY well on a 160 pump (1995 auto). Posted them to Cummins Forum from where they have been copied here. The next shims that I will try will be 18mm OD, 13mm ID, 1.9mm thickness.
Click to expand...

:thankyou2: Thanks for finding this freebie... I've had mine shimmed for almost two years now. I found it on DTR actually. I thought I had put in here somewhere that I couldn't take credit for this. Maybe it was in another post.

That sounds about right on the measurements... Shouldn't be hard to find them with those measurements. I just like that an M12 washer works perfect :D

EDIT: I did post not taking credit on the bottom of page one :p Anyway thanks for the original post years back on this :Cheer:
 
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JariV said:
I'm the one who tested and found out these measurements. Works VERY well on a 160 pump (1995 auto). Posted them to Cummins Forum from where they have been copied here. The next shims that I will try will be 18mm OD, 13mm ID, 1.9mm thickness.
Click to expand...

I actually found your post on DTR, plus I wasn't trying to steal any credits away. I've done shims to only 2 Dodges, and the first one didnt like it and went to GSK. I made my own article based on the one on DTR, on another forum, but used your measurements.
 
Rest assured,
I'm not accusing you of this. I understood already from your previous posts that you didn't take credit. In my opinion the main thing is to distribute information to help other Cummins users. So you did a good thing by distributing. All OK, keep on truckin'
 
I found some M12 washers local that are 0.944" in diameter, but they are 0.094" thick. Can I use them, would that little extra thickness make that much of a difference even if I backed things off say 1 click?
 
As mentioned before, some pumps will hang up around 1500 if the washer is too thick. That's pretty much what your risk is. For the price, it cant hurt to try!
 
OK, I found mine at Ace Hardware. Any ideas on places that cary a washer that is M12 and in the .060-.070 in thickness?
 
Not really, is that all the thinner you could find them? I mean did you go to the store with your calipers and dig for a while? I would say fastenal, but their washers are all about .060... I just got lucky that our bolt bin had washers that were all sorts of different thicknesses. It was just a bugger to find a set that were the same :doh:
 
I did take my calipers and measured every one in the bin and grabed the 2 thinnest ones. I'll check fastenal later today.
 
So, all I could find was more M12 washers that are all .090+ in thickness. I did find some 1/2" washers with about the same overall diameter, about .063" thickness, and the hole is about .054" smaller. Will those work ok?
 
Rodram2002 said:
So, all I could find was more M12 washers that are all .090+ in thickness. I did find some 1/2" washers with about the same overall diameter, about .063" thickness, and the hole is about .054" smaller. Will those work ok?
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Those should work, worst thing you will have to do is ream out the holes with a drill bit. You will see why once you get the pump opened up. Good luck with it :Cheer:
 
So I used the 1/2" washers and made the hole a little bigger. They work great! I did use them on a 4K GSK and the truck pulls way past 4K rpm now. It did make the throttle more sensitive, but it's still nothing compared to a VP truck with a smarty.
 
Rodram2002 said:
So, all I could find was more M12 washers that are all .090+ in thickness. I did find some 1/2" washers with about the same overall diameter, about .063" thickness, and the hole is about .054" smaller. Will those work ok?
Click to expand...

Kind of off topic, but I wonder why a 1/2" washer would have a smaller hole than an M12 washer? Aren't a 13mm and 1/2" supposed to be nearly identical?
 
imelmo said:
Kind of off topic, but I wonder why a 1/2" washer would have a smaller hole than an M12 washer? Aren't a 13mm and 1/2" supposed to be nearly identical?
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Yes, I do believe 1/2" is something like 12.7mm. Not sure why the 12mm washers have a larger ID than the 1/2" washers, but it is mostly the OD that you have to worry about and that shouldn't be more than .990" IIRC Most 1/2" washers are more like 1.25" whereas the 12mm I have (and most I've seen) are .980".
 
i posted the washer mod years ago on dtr. i used 1/2 inch washers that i reamed out if i remember right. i can't remember if i did it on a 180 pump or a 215 i had in my 98 reg cab short bed. made a pretty good differance for the money. i must have had a million private messages on dtr after i posted it up.
 
Fwiw, a 7/16" flat washer was the correct thickness and outside diameter. I just drilled it out with a 1/2" drill bit, going up in steps. You have to "over-drill" it some with the 1/2" bit too though. Works great!
 
imelmo said:
Fwiw, a 7/16" flat washer was the correct thickness and outside diameter. I just drilled it out with a 1/2" drill bit, going up in steps. You have to "over-drill" it some with the 1/2" bit too though. Works great!
Click to expand...

It seems to vary by location for what washers are available that have the right thickness and OD. So long as the OD and the thickness are right it seems any washer will work (which there's no reason why it wouldn't).

FWIW I'm about to hit the dyno before I switch to true 4k springs (if I'm gonna spend money it's gonna be for more rpm than I have now). We'll see how the curve looks and maybe compare them to graphs from bosch 3k springs :Cheer:
 
BlackSkyRacing said:
It seems to vary by location for what washers are available that have the right thickness and OD. So long as the OD and the thickness are right it seems any washer will work (which there's no reason why it wouldn't).

FWIW I'm about to hit the dyno before I switch to true 4k springs (if I'm gonna spend money it's gonna be for more rpm than I have now). We'll see how the curve looks and maybe compare them to graphs from bosch 3k springs :Cheer:
Click to expand...

As promised, here's the link to my dyno sheets (finally) Hit the dyno for the first time... - Competition Diesel.Com - Bringing The BEST Together didn't want to post them all over... There's links to the two videos I managed to get on post #9

Anyway, looks like I had decent fuel all the way to 3100rpm, so I'm gonna just come out and say that Bosch 3k springs are a waste of money IMHO
 
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