Hi Everybody, Happy new year etc.,

As you can see I was busy working on a 96 3500 4X4. I did the 3 GSK, a 14cm non gated housing, tabed the KDP (which was 1/2 way out) and brakes, both rear with the big cylinders and fronts with new slotted rotors.

The brakes are AWSOME compared to the stockers, the KDP is piece of mind. The 3GSK was a PITA, I'm **** when I do vehicle work and the lack of "solid" info on how many spacers etc. that needed to be removed drove me nuts. I even removed the big spring to see what was going on. But it is in and works well. The one little "problem" is that it will rev right passed 3,000 RPM. My idle was spot on-real nice.

The 14cm housing?? not sure - took a ton of "pep" out of the truck unless you are above 25lbs boost and a lot of RPM's. Did not really notice an EGT reduction but it is not a problem unless towing. Did not have the boat available to hook up to and test. While towing and pulling a big hill 1500* was relatively easy to hit. The boat weighs 17,500 lbs on the trailer.

The truck is a 1996 4X4 3500 with an auto. It has the 4" turbo back, a number 6 plate, the AFC kit, the AFE intake, along with a "valve body kit"

Won't know if the housing is gonna stay until some towing is done.

 

Mcmopar. Don't ya feel better knowing that the dowel pin is dead!? How did you do with the crank seal? This was the one item that gave me a tough time.

Yes, I just did the 3k springs recently as well. I love the improvement, and as far as I am concerned, should be the very first mod that should be done. Reasonable price, do't have to worry about egt's (no need for gauges with just the GSK kit), and far better than just sliding a plate or turning the star wheel.

I was the same as you, I even pulled the large spring to look up in there with a mirror. I had no spacers on the springs that you remove for th kit. I did have a thin washer and a spacer (I guess) on the largest spring that you leave in. I have to admit, I played with mine a little, and ended up adjusting the springs one click tighter than my stock setting (even though each spring was a little different in adjusting nut depth). This gave me a tighter throttle, felt better, more responsive, less mushy to the pedal. I like the way the tranny acts.

Can't comment on the turbo except that I bet you will see an improvement in temps when you tow.

How's the tranny. Are you running the valve body kit from srw? Glad it all went well. Kevin

 

no "problem" going past 3000rpm... keep at or below 3400, and you're fine.

Forrest

 

I'm awaiting the report on the towing with the new housing as I have been thinking about upgrading/changing mine.

 

I think you'll see EGT go up.
That #6 plate fuel profile doesn't compliment with a GSK. Swap for a #10 and that should help the low rpm lag, too.
Are you going to bump the timing to 15-16°?

 

Fueling around,

Please give me some insite on your remark about the #6 with the GSK???

Forest,

I thought 3200 was the 12 valve limit unless you upgraded to the 60lb springs?? Any thoughts on the 3400 RPM's would be great.

 

I've got stock 240k mile valvesprings, and I've gone over 3400 more than a few times

the #6 has such a big nose on it, and it takes a while to get into the real fueling... not as bad w/ the 3k GSK... it was a PAIN w/ my 4k GSK. the stock turbo covered it up, but when I put a bigger turbo on, it was more pronounced.

I'm worried that a non-wastegated 14cm housing won't flow as well as a 12cm wastegated housing on the big end

Forrest

 

A few of the "good" diesel people recommended the 14 to cool off the EGT's that we were seeing with the 12 cm housing.

 

The best way to describe the governor lever motion with GSK is by using the Piers Diesel tech page. http://www.piersdiesel.com/TechLeverAdj.htm

The governor lever rises less than ½ inch up the plate before speed limiting.
Look at the stock plate. The lever really defuels as the rpm climb.
Look at the #6 plate. With stock springs, the lever would drop into the big fuel curve above the nose at about 2000 rpm GSK slows the rise of the lever so it takes 2,700 rpm to hit the same fuel curve. (These rpms are based on the starting position of the governor lever and used for illustration only.)
By the time you hit 2,700 rpm a stock 12 valve is already breathing pretty hard. If timing isn't advanced you put a lot of heat out the exhaust and your EGTS will probably rise.

An inside source at Cummins told me a stock spring 12 valve is good for about 3,600 rpm.

-John

 

I've seen 4k rpm before

but only once... I try to limit it at about 3400-3500

Forrest

 

Mine speed limits at 3,600 rpm with 3k springs.
I changed to 60# vlalve springs when replacing the head gasket last spring.. I haven't added the small spring (4k), yet.

-John

 

John, depending on the rest of your mods (plate, turbo, etc) you might just leave it as is... might not like the fueling curve if you do the 4k...

Forrest

 

Yep, that's why I haven't adding the small springs. A different plate is first on the list of many items.
Buddy of mine with a 96 manual is thinking to pull his (4k) GSK. Winter conditions do bring out the bad side of GSK.

-John

 

3,600 RPM on a stock 12 valve spring?? I thought 3100-3200 was max. That would totally change the way to drive this thing.

 

yup, wind it up!!!

the 4k makes the throttle touchier, but a stiffer throttle return spring cured that for me... my only other complaint was the fueling curve... took for EVER to get into the fuel w/ my #6 plate. so I yanked it out and ground it flat!