DB2 information

[ak diesel driver]

I have a hard time believing some parts won't interchage the look pretty similar

 

[Acesneights1]

4 plunger vs 2 plunger. Can't see much being the same actually.

 

[turbovanman]

So what does running a larger plunger do? I will be running a .31 plunger on my n/a 6.2 for now until I get the turbo on.

Can someone tell me the specs of this pump?

DB2 831 5209? Thanks.

Thing I don't get is Heath diesel was pushing like 330HP(IIRC) or something like that out of a full custom mdded 6.5 but yet Peninsular is building 400+HP 6.2s What am I missing ? Is it the cooling factor availible to marine engines vs truck? That is the only sense I can make of it.

Yes, its the cooling. On a supercharging the 6.2/6.5 thread, someone linked to a marine site and they said they can get more power due to watercooled exhaust manifolds and other watercooled items.

 

[Acesneights1]

Yeah I mean really as long as you can keep the heads bolted to the block, the only other real issue is getting rid of heat.

 

[randomid25]

I can tell you the DB2 833 4974 "Marine" pump uses the same (small) size fuel inlet as the 829 & 831 pumps. The 4 digit number on the end of the DB2 model numbers are the specs of the pump. This includes the advance, max rpm, etc., basically the characteristics of the pump. A Stanadyne dealer can look up the number and find the relevant specs of the pump. You are pretty much stuck with the plunger size, but a good pump rebuilder can change the other perimeters to match the pump to your engine. I ran a DB2 831 5088 , which is the 6.5 NA pump and I thought it did fine. I have never been really happy with my 4974 pump, I never thought it delivered what it should. I'm not saying it was bad, just not a huge difference to the standard 6.5 DB2. I just got my 4974 pump back from a certain well known pump rebuilder (in the Florida panhandle) that is a regular poster on another website and he made a few tweaks so it should be better. That and my genuine Bosch 311 Marine nozzles were toast after only 10,000 miles, so I have a set of injectors from him that are matched to my pump. I'm installing a GM-8 turbo as well. I'm hoping the new combination will be deliver a little more power.

As far as the Peninsular intake it is a new upper intake that bolts to the stock 6.5 turbo lower. So they didn't cast an entire manifold, just the top.

That is great info Bobbie, Thank you. TD and myself are thinking about modifying the pump inlet to flow more fuel into the pump so there might be some improvement in fueling afterwards.

 

[redshift96]

Curious if anyone has made any headway on this. I finally got as far as removing the inlet cone to check the screen filter, and it appears that increasing the size of the inlet fitting wouldn't be particularly challenging.

However, given the comment above concerning the same exact fittings being used on the marine pumps as well, I begin to wonder if flow is not so much the problem, but rather maintaining stable fuel inlet pressure under load. Obviously, a slightly larger fitting, line, and post-filter volume would help avoid a dip in pressure at the IP inlet, but perhaps not enough for the factory to have bothered, even with the bigger pumps...

So now I'm wondering what the ideal inlet pressure is at the IP, and what the acceptable hi/lo range would be... maybe a simple pump upgrade and a high-quality fast-response regulator might be a more effective approach?

Thoughts from anyone who's invested more time and thought in this than I?

 

[3500GMC]

Curious if anyone has made any headway on this. I finally got as far as removing the inlet cone to check the screen filter, and it appears that increasing the size of the inlet fitting wouldn't be particularly challenging.

The material Stanadyne uses is pretty much as hard as carbide. I tried to get a Cobalt drill through and just scratched the surface. It's HARD. Let alone even thinking about passing a pipe tap through it...

If I were to pursue the FTB type mod on a DB2, I'd probably make a whole new inlet cone. Who knows?

 

[6.2 turbo]

I drilled and tapped mine to 1/8 pipe thread,and used a 3/8 push loc barbed fitting . I used a regular drill bit, just had to sharpen it about 20 times . I might have started with a small bit and worked my way up ,can't remember. I do remember it was very hard steel . I didn't notice any increase in power either,but I had a 1/2 line feeding it before,with an adapter fitting. I figured the 1/2 inch line was pointless and switched to 3/8. A 1/4 inch compression fitting with the nut removed fits the factory threads. I used one of these that had pipe thread on the opposite end and then had a hose barb fitting on top of that. Eventually I broke the fitting flush with the pump,trying to remove the hose. If any one comes up with a fitting that would thread into the factory threads and goes to 3/8 hose let me know.

 

[Acesneights1]

I put pics of the inlet cone on another thread. I don't see any benefit to drilling it out. I think the opening in the cone is sufficient for the amount of fuel the DB2 uses. Also the cone preload affects the clearence/preload on the transfer pump in the IP so I don't think I'd be f'in with that unless I had the proper tools. it requires a special socket and needs to be torqued and then locked in place. Thompson Tool sells the socket. it is 19$. I may order one jus in case I ever have to take one apart.

 

[just a number]

apart is easy. a 3/4" wrench works. now to torque it back down that when the fun happens.

 

[6.2 turbo]

I never knew there was a socket.

 

[Acesneights1]

Yes, it is required to properly torque/preload the transfer pump in the IP. I was unaware until Just a number asked me to take a junk one apart for pics. Then when the transfer pump was in my hand and I saw the lock for the cone which was sealed, I thought I beeter inquire about that...

 

[just a number]

can you post a link for that socket ACES?

 

[dragogt]

Can anybody explain what the differences are between a regular and military 6.2 6.5 pumps?

From what I understand the milspec ones have 'hardened" internals so they can run whatever fuel is available; I've also heard the 24v thing, but then I've also heard that "just" the starter is 24v and everything else is 12v.. Also will the injector lines mix and match? I understand that DS4 and DB2 lines won't, and that you have to use a full set from whatever pump I.E. all from a 6.2 or all from a 6.5; But other than that is there any reason why they wont?

 

[redshift96]

can you post a link for that socket ACES?

Here's the link.

http://www.thompsondiesel.com/Stanadyne.htm

Search the page for "TP" (as in transfer pump). Not sure if this is the same outfit Aces had in mind, as there's nada on there for $19. I see a whole end-cap-specific torque wrench for $86, and a "TP ADJ TOOL KIT" for a paltry $712 clams. Not encouraging either way.

Now I'm wondering if that's why my truck seems so down on power after the pump and injectors were replaced, even with the fuel screw turned up slightly. Pretty sure I'm at least in the neighborhood of the 30 - 40 ft lbs spec., having hand tightened with a 3/4" wrench. Guess I could try tightening another touch, and see if it improves anything...

 

[turbonator]

heres the progress we have made so far with the larger fuel inlet... the original size was .165'' that is the inside diameter of the inlet pipe.... without destroying the threads, we were able to bore it out to .250''... the fittings were a union from 1/4'' compression fitting threads to 3/8 pipe which was bought at canadian tire... after a simple push-on type 3/8 female adapter was used.... here are some pics... also to add something else to this, a 2831-5088 in fact is the same pump as an 4911, it is just detuned for use on the n/a motor... so usually being detuned they dont wear as much, thus they are in better shape than 4911 and can be had alot cheaper than the "mythical 4911"... following in the footsteps of 6.2turbo, we are discussing mods including larger plungers(.400"max) and different lobe hieghts in the cam ring....300hp here we come...

 

[3500GMC]

Did you grind or drill?

 

[Acesneights1]

Can anybody explain what the differences are between a regular and military 6.2 6.5 pumps?

From what I understand the milspec ones have 'hardened" internals so they can run whatever fuel is available; I've also heard the 24v thing, but then I've also heard that "just" the starter is 24v and everything else is 12v.. Also will the injector lines mix and match? I understand that DS4 and DB2 lines won't, and that you have to use a full set from whatever pump I.E. all from a 6.2 or all from a 6.5; But other than that is there any reason why they wont?

DS4 lines no worky on a DB2. Some DB2's are 24v some are 12v depends on what it came off of. The The 2829's are CUCV IP's and are 12v. The 2831's are Humvee and are 24v.
DB2 lines don't mix with DS4 and also with DB2 the lengths are different depending on the application. An older 6.2 with the angled injs will use differnt lines than a later 6.2 or 6.5 with a DB.

 

[turbonator]

Did you grind or drill?

we had it drilled out at the machine shop, we tried with titanium drill bits but to no avail... after the work was done, the machinist told us that the cone is only case hardened, he drilled with a carbide bit, and as soon as he broke through the case hardening it was soft metal... it cost us $17.00 to drill the cone and around $5.75 for the fittings, so for the price of the mod if it works great, and if it is a marginal improvement so be it.....

 

[3500GMC]

You know I almost chucked my cone in the mill and tried a carbide end mill but I chickened out. I first started to drill with a Cobalt twist drill from the back side so as to leave myself room for error, and the bit immediately smoked and dulled.

Cool deal on the fittings you have...