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Military DB4

Well I am trying to pick up a second truck as a test mule/sled pulling truck. Hopefully a military K30 if I can find one for sale near me. If I get one it will be a perfect truck to test it on since I wanna try a couple things with some high boost.
 
The big issue when going to a heavy fueler is, can the engine get rid of all the extra heat that all that fuel is going to make ????

The DB2 that was used in the early 6.5 can deliver enough fuel to produce a good honest 300 HP from a 6.5

This is of course with a good exhaust and a better turbo, plus a few other mods along the way for good measure.

The biggy though is cooling the beast after you build the BIG FIRE.


Missy
 
Thats why I want to try it in a older K30, you can fit twice the radiator in one of those suckers and a huge intercooler too.
 
The radiator size is the same,the one in my 97 is out of a 84 chevy that had a 6.2,and is the same as the one in my 92. The older trucks should have more room for an intercooler though.
 
I was thinking more like the avalibility of a BeCool with a thicker core and no oil cooler in it. But if that fits in my style truck with little modification I know what I am ordering soon.
 
6.2 turbo said:
I bought another one of these pumps on ebay. I would like to build one of these to sell . If anyone is serious let me know.
Click to expand...

still looking for a test mule? the Camaro is in need of a pump and I think she has all the necessary supporting mods and a nice flowing turbo. wouldn't mind bolting on your hand-built IP for some testing and reporting back.
 
Does the DB4 rotate the same direction as the DB2? I thought someone previously mentioned it was somehow reverse direction because it didnt operate off another gear or whatever, like ours does, but a chain that spun same direction as gear below it. Our IPs spin backwards essentially. and maybe it doesnt matter which way you spin it.
 
You can install the cam ring either way,but the housings have an arrow same as the cam rings.
 
I will have to check. Since I was planing on using a db2 housing I didn't really think about it . Another interesting thing I discovered is that the DS4 drive hub fits the DB4,but it would need a spacer to put the gear at the right spot. The bolt pattern on the DB4 is also wrong . To me it looks easier to put the parts in a DB2 housing,and use the DB4 or DS4 cam pin instead of the small DB2 cam pin .
 
I will need to build a pump fairly soon,for the Tahoe. It has a stock one for now. I'm open for any far out ideas on the DB2 or 4. Like to some how make the advance work better,maybe less,or more piston travel, or modified advance cam,or delete the advance arm completely, and somehow make it adjust with a bolt ? I have all ways been confused as to where the advance plunger is at full fueling. I think it might totally retard at full fuel,and is only needed for easier start up and part throttle . It does look like there is more fill time with the piston in the retarded position. I might start with the 4 plunger .270 just to get the feel of things again. It must have a working advance. The governor needs a very heavy spring or made solid. It probably will also get a DB4 cam pin. The plunger travel limiters will be left out.
 
Keep us updated.

I bought an almost new 4911 pump for cheap and I just sent the rotor out to have .410" plungers made and fitted. Hopefully my cam pin will be ok at this level, but I would like to see any ideas for getting a larger pin or bolt, whatever works.
 
Well, let me tell you a little story. I called Penninsular to buy a NEW "DB4 Race or Marine" pump, I was told that none were available but they had a used one that they would sell me after they "checked it out to make sure it was good". So after waiting about 2 weeks for this process I was told that it was good and reluctently paid 550.00 for a used pump. So I installed it and not enough fuel (low EGT's) so I called them and told them and they said go ahead and turn it up to get more fuel, so I turned as far as it would go still not enough fuel. So I called Peninsular and they told me to send it to there pump shop, so before I sent it back I had it tested at a local test facility and he said he had to back off the test because the drive started to wabble pretty bad. So I sent a pump with the numbers DB4831-5722 to there shop. After about 3 weeks and getting the run around I was finally told that the pump came apart on their test stand. Peninsular said too bad (I only put about 150 miles of test & tune time on it) before I sent it back. So I told them to send my blown pump and parts back to me which they did but the housing tag reads DB2831-5722. So I guess the DB4 housing was still good enough to keep. So then their pump shop said they could build me a DB2 that would put out more fuel for 1200.00. So I paid it along with 100.00 for them to test, blowup and keep some of my DB4 pump. So now I have $1880.00 in a DB2 that puts out only 90 cubic millimeters @3500 RPM. So 6.2 turbo I may or may not have some parts in my returned goody bag that you can use, but probably not. By the way what turbo is that in your avatar? Sounds like we have similar likes, I have 3 12 Vavles 1 CR Cummins and I want to build the 6.5 that is coming out of my Suburban and put in a 2 door 2wd tahoe after the P 400 gets installed in the Burb.
 
vdb11 said:
Keep us updated.

I bought an almost new 4911 pump for cheap and I just sent the rotor out to have .410" plungers made and fitted. Hopefully my cam pin will be ok at this level, but I would like to see any ideas for getting a larger pin or bolt, whatever works.
Click to expand...

Watch the head, the walls get a little thin with that big a plunger, also need the plungers hardened. Like I said just putting bigger plungers wont do it. You may find that you wear out rollers real quick. When you increase diameter rather than stroke you increase load because of the rate at which you compress the fuel over the area of the plunger.

if you get to much capability when the rotor goes past the slot you will still have pressure in the pistom with no place to go, Guess what that does to rollers and cams. ?

Yeah not just a vendor, go figure.
 
Slim Shady said:
Watch the head, the walls get a little thin with that big a plunger, also need the plungers hardened. Like I said just putting bigger plungers wont do it. You may find that you wear out rollers real quick. When you increase diameter rather than stroke you increase load because of the rate at which you compress the fuel over the area of the plunger.

if you get to much capability when the rotor goes past the slot you will still have pressure in the pistom with no place to go, Guess what that does to rollers and cams. ?

Yeah not just a vendor, go figure.
Click to expand...

Well what do you suggest is a good plunger size?Are the slots in the rotor larger between the .29, .31, and .33 inch pumps? I thought the only difference was the plunger size. What is the right spot then?

Also, you mentioned stroke over diameter, how would you increase the stroke? The only way I can foresee doing that would be a different cam ring, with larger lobes??
 
Now you are starting to see how complicated it is. Not as simple as just putting in larger plungers, Not to mention you change initial injection timing because you have greater capacity at a faster rate, then that also changes the time of the peak pressure rise in the line and the injector duration, If you timed or sized it right you could get the almost perfect injector spray at almost peak pressure for the full time that your transfer slot is lined up. (start thinking now in the big picture how all the parts fit together ) just the way I did when making the ATT, then you will have something that works.

Yep just another vendor selling product. Sorry if I seem reluctant to share.
 
Well then I think I might just go with something like .33 or .35 inch plungers. I know the "marine" pump has .33 inch. I couldn't see why plungers that size could be damaging unless the marine pumps run a completely different rotor with different injection slots.

I understand that you do not wanna share because you have money on the line here where most of us don't. Do you plan on selling a custom DB2?

Thanks for sharing what you did.

EDIT: 6.2 turbo, you mentioned putting the DB4 internals in the DB2 housing, would the internals from a DS4 fit in a DB2 housing? I am not familiar with how they look on the inside, does the rotor have the allen screw to adjust fuel like the DB2? I figured being electronic it wouldn't have this but I want to check. I guess the head is probably all different too since the fuel comes in at a different location.
 
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I had a .370 plunger head and rotor that was factory Stanadyne, it worked pretty good,and the cam pin survived. This is the biggest factory plungers I've seen,there might be bigger ones though. The rollers and shoes from DS4 will fit in the DB2,they seem to be made with a different material. Probably better ? The slots in the head are ok, my 1/2 inch plunger pump I had the charge holes in the rotor enlarged, plus added two more,don't know if it helped or not. Do not decide to slot one of the charge holes,it will not run. I custom ground lots of camrings, seems that the steeper lobes ran better, and did not over advance like a long lobe,I did go back to a almost stock lobe last. Increasing stroke farther than tossing the limiter spring, will not help untill you are conviced the plungers are getting filled. The metering vavle is a huge restriction,stock it only opens half way across its opening,and then the governor will close it even more at higher rpms,. Of all the things I tried a simple JB welded governor made the biggest difference in mid to top end fueling. To prove to myself that the metering valve is a problem I took a stock 6.5 pump and slotted the metering valve hole, and it made enough fuel to create 50 psi boost,would not idle though.
 
6.2 turbo said:
I had a .370 plunger head and rotor that was factory Stanadyne, it worked pretty good,and the cam pin survived. This is the biggest factory plungers I've seen,there might be bigger ones though. The rollers and shoes from DS4 will fit in the DB2,they seem to be made with a different material. Probably better ? The slots in the head are ok, my 1/2 inch plunger pump I had the charge holes in the rotor enlarged, plus added two more,don't know if it helped or not. Do not decide to slot one of the charge holes,it will not run. I custom ground lots of camrings, seems that the steeper lobes ran better, and did not over advance like a long lobe,I did go back to a almost stock lobe last. Increasing stroke farther than tossing the limiter spring, will not help untill you are conviced the plungers are getting filled. The metering vavle is a huge restriction,stock it only opens half way across its opening,and then the governor will close it even more at higher rpms,. Of all the things I tried a simple JB welded governor made the biggest difference in mid to top end fueling. To prove to myself that the metering valve is a problem I took a stock 6.5 pump and slotted the metering valve hole, and it made enough fuel to create 50 psi boost,would not idle though.
Click to expand...


Did it not idle because it was over fueled or couldn't maintain a steady fuel rate. Now did you slot the metering valve in a DB2?. The DS4 is another issue, try four larger plungers in that head.
If you figure fuel displacement based on bore can the DS4 pump be made to put out way more fuel (than we can use) and do it better with the electronics. BUT and this it the big but, can you make it reliable and if we get more fuel how much can we cool the heads since most of the combustion initiates and takes place in the pre cup (another thread sometime this winter). So do larger pre cups give you a faster burn and reduce heat transfer to the heads or do smaller pre cups give you a slower burn and more efficiency at the cost of more heat transferred to the head.? So how much fuel can we actually burn efficiently in an IDI diesel? Do we lose the efficiency from less advance since you see less drive energy for the turbo or do we gain efficiency by retarding the timing and getting more drive energy from the turbo, or is it someplace in between.

At what point does increasing the pre cup size diminish one point of the torque curve and increase the other. Does

Does increased EGT mean a problem when you have a free flowing exhaust and very little restriction. DO (NA) diesels run higher sustained EGTS than the turbo models?
 
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