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CDD GM 6.2/6.5 DB2 Injection Pumps

Due to popular demand we now offer high performance GM DB2 builds, these pumps require no core charge and are built with all new components. Just as in our 130cc and larger Ford db2s, all of these pumps feature locked timing and a flat fuel curve, as well as the option to add our ICFC. Current...

classicdieseldesigns.com

 

Does your sig mean that you have the block bored .040" over with bigger pistons? Are they meant for turbo applications? This would be important in choosing how much to hop up the injection pump. Original NA pistons are not meant to handle the increased temperatures of turbo applications.

I have no personal experience with the CDD pumps, they seem well built and have a great warranty. However some don't like the locked timing feature. If you're looking to get a custom built pump for your application there's a great independent builder named Verlin Martin, you can find him on Facebook. He's built two hot rod pumps for me. If you don't use facebook send me a pm and I'll share his email.

If your pump is being replaced you should also refresh your injectors with new nozzles and get them all pop tested to be within 25-50 psi of each other. I had mine rebuilt and by Verlin's recommendation set to pop at 3k psi

 

Right, it is both block and pistons. I can find the part number if it helps. My dad and i built the motor, so I am kinda backtracking to get info.

Chevy 6.2 Diesel 1982-1991 Master Kit

We offer high-quality engine master kits and individual components for your Chevy 6.2 Diesel (1982-1991) at Northern Auto Parts. Shop now!

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This is the kit we used to rebuild the block. Got it from the machine shop as a short block and put ARP head studs on it, but no main studs.
I've heard the same about the locked timing, but no one ever really went into detail about why they don't like it. I've heard some stuff about a rough idle/ cold start, but all I've found has been Ford IDI stuff.
Ill look up Verlin Martin, though, part of why I was looking at CDD was because of the warranty and how much they put into the pump. It could be all just marketing buzz.
The injectors should be fine, there's just no fuel getting to them from the pump. How much did Verlin charge you to get your injectors to 3k? does that higher pop pressure just help efficiency for the IDI process? How high can they even run?
Sorry for all the questions. I've always heard that the limiting factor was the pump's low output, which is around 80cc or so.

 

Good that you have head studs and new rings. You're certain that the pistons are for a turbo application, yes?

How many miles has it been on head studs? There are certain wet holes that will leak if not properly sealed.

Verlin can explain the locked timing in detail. From what I can remember in asking him the same question essentially there is an internal timing advance built into the DB2 pump that adjusts timing under load. I think this leads to a less touchy throttle. A locked pump will behave more like an inline rack style pump, one of the most common ones being the P7100 pump on the 2nd gen 5.9. I think that locking timing on the DB2 makes it easier to hot rod/ push more fuel which is likely why CDD does it for consistency of production. Much harder to time a modified pump with the added variables of dynamic timing advance.

Lifespan on injectors is about 100k miles and you'll notice from searching on here that even new nozzles can be bad out of the box. A leaking injector will melt a piston and destroy your engine real quick. If you don't want new genuine nozzles you should still at the very least get your injectors tested and calibrated to pop off at the same pressure.

Verlin works with an injector guy named Jarod March who you can also find on FB. I can't recall exactly what he charged but it was around $500/$550 including shipping for genuine new marine nozzles and all injectors set to 3k psi. The higher pop pressure will wear out the nozzles sooner so all the more reason to get your injectors tested or rebuilt. I know some guys have gone as high as 5k psi but that's just from reading on forums like this. Not many folks doing their own testing and publishing results out there. Verlin has done a lot of his own testing and that's why I went with what he recommended for my trucks.

The stock 6.2 pump definitely put out a tiny amount of fuel. You'll likely need to upgrade to a .310 head and rotor over the stock .290

 

the motor was thrown in the truck back in 2018 and hasn't really been touched, aside from turning the pump up and turbo swaps (couldn't get the HX40 to light good).
I have gotten the motor up to 21 psi max boost before the intercooler (hindsight is 20/20) so i do believe that the pistons are up to the task.
Wet holes? I've never heard of them, at least when I've looked up head studs, it would tell you in a hurry if it was installed wrong. When I do the pump, I plan on taking the valve covers off and retorquing the heads to 115lbs instead of the 90lbs we did originally. according to what I've read, that seems like a good middle ground.
I used to have a 94 12vavle and loved the power output, so maybe locked timing is what I've been looking for all along.
the odometer on the truck hasn't worked and is far from accurate. Assuming 3~4 oil changes a year at 5k each id say that the motor has about less than or close to 40~50k miles on it (rough estimation)
I see the value of getting the injectors checked, though I'll call around my area to see if there is anyone who can.
I've looked a little into rotor heads and if I'm not mistaken, the biggest factory pump is .340 in the 93 6.5 4911 pump. everything I've seen, they can max out to 120cc, so would a .310 head be around 100cc?

 

@jrsavoie I've talked shop with Verlin numerous times, he says he won't go lower than 2700 psi on injectors and from his own experience/ testing 3k seems to be ideal. This mind you is for performance applications. I don't think he'd recommend 3k for a stock DS4. Both my engines are about 350 hp or slightly above and are work trucks so performance not economy is the goal. He still recommends non- marine nozzles if best MPG is the goal.

 

I am trying to get to the 350~hp goal too. I was wondering what pump you are using? I ended up pulling the trigger on the CDD pump, so I guess now I have a month to wait and ponder if that was the best decision.

 

@hawaiiantacos the hx40 can be a little laggy with its larger all around size which is why some run the 35/40 hybrid, smaller turbine side to help with spool up and larger compressor for more flow. There's a lot of factors that go into how well a turbo performs and I'm no expert but there's probably a better turbo for you if the rig is not meant for heavy towing and you'd like to see some better off the line performance.

If you haven't had any coolant leaks then whoever installed the studs did something right. Some of the studs are threaded into water jackets hence wet holes. Some use permatex the right stuff RTV to seal the threads while I've seen videos of people mixing ptfe paste with blue threadlocker to seal the threads.

I don't think the locked timing has anything to do with power per se, just the driveability/ throttle being touchy or not. Just different internal pump mechanics. An pump with dynamic timing can put out just as much fuel as a pump with locked timing.

The factory 4911 pump had a .310 head and rotor they never got anything bigger from the factory. Some upgrade to the .330 head and rotor. Other Stanadyne pumps had .350 and .370 and I think even .450 H&Rs but those were in tractor pumps and need machine work done to them in order to work in an 8 cylinder pump.

Both my pumps have .310 H&Rs and put out at least 350hp so a .310 should be more than enough for you. It's all in how the builder modifies the pump and what the rest of your air and fuel system do in conjunction with that fuel to make power. You'll need a good quality lift pump and a free flowing intake and exhaust to help everything play nice together.

 

@DieselAmateur from all the pump builders I've talked to the .310 head (at least the stock ones) are only rated at about 70cc of fuel output. If my rough math is right, at ~35hp per 1cc of fuel, then your pump should be maxing around ~250hp. Did Verlin machine out the pump in any way to help that fuel output?

 

@DieselAmateur
For a while I didn't like the hx40 mostly because of the lag. It may be because of the 3.08 rear gear that I had and the 4.10 axle swap it did help. Eventually, I ended up modifying a 6.0 PowerStroke turbo to work; it was fun, but a bit impractical. The hx40, probably, is a bit big with a 61mm cold side and 64mm exhaust. when talking to the CDD guys they seemed to like the specs of it for the pump.

When I take the injector lines off, I have a valve cover leak, so I'll get a better look at the rocker arms and the studs behind the valve cover to check for any evidence of coolant.

Ill have to call CDD to see what head they put on it to get a better idea. I am sure its pretty close to the .310 or maybe .330 Ill have to call and confirm. I have a 4in to 3in adapter for the hx40 that returns back to 4in pipe after it gets past the frame rails and 3in tubes for the intercooler so I'm hoping that's enough.

I do have a holley blue that pushes 110gph at 14psi, and I see 14psi at the feed side of the pump. I've heard operating from 5-7psi is good for this pump so I have a fuel regulator to keep it consistent wherever the pump wants to be.

 

@hawaiiantacos In addition to pumps Verlin also builds turbos. I'm going to have him design/ build one for my pickup. As you see everything from gear ratio to transmission type can affect how a turbo & engine performs so there's no one size fits all approach.

Look for oil in your coolant, that will be the most telltale sign of leakage or not. Did you or the machine shop install the studs? If the shop did ask them what if anything they did to seal the threads.

Your exhaust is good with the 3" to 4" sizing, are you running the 6.5 exhaust manifolds? I see in the picture you just have an air filter on the compressor of the turbo, which is not ideal as you're sucking in hot underhood air. A cold air intake that pulls outside air from/ through the fender like on the GMT400 trucks is ideal. Your intercooler is helping some but you have a lot to gain by having a true cold air intake.

Sounds like your lift pump is dialed in perfectly, 10-15 psi is what you want for a performance pump

 

@hawaiiantacos In addition to pumps Verlin also builds turbos. I'm going to have him design/ build one for my pickup. As you see everything from gear ratio to transmission type can affect how a turbo & engine performs so there's no one size fits all approach.

Look for oil in your coolant, that will be the most telltale sign of leakage or not. Did you or the machine shop install the studs? If the shop did ask them what if anything they did to seal the threads.

Your exhaust is good with the 3" to 4" sizing, are you running the 6.5 exhaust manifolds? I see in the picture you just have an air filter on the compressor of the turbo, which is not ideal as you're sucking in hot underhood air. A cold air intake that pulls outside air from/ through the fender like on the GMT400 trucks is ideal. Your intercooler is helping some but you have a lot to gain by having a true cold air intake.

Sounds like your lift pump is dialed in perfectly, 10-15 psi is what you want for a performance pump

Twisted Steel Performance has a very good tutorial on installing the head studs

I'm not sure where to find it.

 

@DieselAmateur
my dad and I installed the head studs. If I remember right, we used some sort of mix for the end of the studs on some of them, but I could be mistaken; it was some time ago now.

I've never seen coolant in the oil or vice versa, so I do think they are good. the limiting factor is the 90lbs we torqued them down to. studs are reusable from what I've read at least three times so I could always redo it, what a pain in the ass that will be.

as for the cold air intake with the intercooler, everything has gotten so tight around the turbo its hard to get cold air, i would like to eventually make a custom radiator support to help the air flow but that will have to come after my truck is running.

 

@hawaiiantacos there are many factors that go into modifying a pump and its fuel output not just the H&R. Your stock 6.2 pump with the .290 H&R probably only put out 70cc of fuel max and the .310 4911 only about 90cc in stock form.

Verlin does machine the pump to push more fuel. Exactly what or how that is done I don't know, but that is just one part of what goes into making a modified pump, changing stock components in one form or another.

Also with the math of cc to hp that will only get you so far as each engine is different. Lots of the Ford guys with the DB2 rate the pumps at a specific cc at a lower RPM which isn't necessarily transferable to the 6.5. Peak fueling for the DB2 happens in the lower RPM range and it is just a part of this pump's design that as RPM increases fuel output decreases no way around it. A modified DB2 for a 6.5 could be putting out 140cc of fuel at 1000 rpm but that amount of fuel at that rate is worthless to the engine. Peak HP for the 6.5 is about 3k rpm and for the pump Verlin built for my p400 engine it was putting out about 110cc at 3k rpm which he says is above 350 and pushing 400 hp.

I'm just relaying what Verlin has shared with me, he's out of town this week for a wedding but I'm sure he'd be happy to talk shop with you and give better answers to your questions when he gets back.

 

I love talking shop because it's cheaper than blowing up motors. lol