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Can I use a 6.2 DB2-4779 to replace a 6.5TD DB2-4911 injection pump?

NateDogg024

NateDogg024

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Hello,
I'm new to the site and am excited to be a new member. I hope to gather knowledge from everyone and try to offer my opinion, or experience, to anyone.

So here goes my first post.

Some background info to start.
I am currently doing a restoration on my 1993 6.5TD; the motor and nv4500 was originally in a GMC k2500 standard cab long bed. The frame was rusting out and had some moderate to major front frame damage. I picked up a 1990 Z71 that was in spectacular shape -I was told the truck was from Florida- and it appeared to be true, because it had absolutely no rust. This was great, until I wanted to test out the 4 wheel drive (oops huge regret). nevertheless, I have stripped the frame down and have finished the first coat of pain. While the frame is nearly ready for re-assembly, I want to start working on the motor.
Moving on,
and bringing me to my main question. I, along the way, have acquired a DB2829-4779 IP that is from a 6.2 diesel. This pump is visually in vary good shape, BUT it has been boxed up and sitting on a shelf for easily 5 years, so is it still usable? and will it work in place of my old -approaching 200,000 mile DB2-4911 6.5TD pump?- Now i know i would be taking a step backwards going to a 6.2 pump but will it work?

Thanks for any help
Nate.
 
From the part number list in Technical, 4779 is a 1990 c/k heavy duty 6.2 pump. From what I have read on here myself, the db2829 pumps can be turned up to supply plenty of fuel. The main question is are the plungers and head healthy enough in that pump.
 
Welcome to the Truck Stop Nate. :welcome2: I'm not one of the experts here, but I do know the 6.5 2831 series pumps have larger fuel plungers than the 6.2 2829 series DB2's. I believe you could turn the the fuel screw up 1/4-3/8's of a turn, and have it fuel your 6.5 in stock trim just fine. Rest assured one of the pros will give you more info eventually.
I look forward to hearing more about your project, and maybe eventually seeing some pics.

Matt
 
Thank you for the warm welcome Matt. I will be putting plenty of pics up soon. I agree with you and scottm. The turned up 6.2 pump could bring the fuel delivery, up to, or close to stock and that would be fine under load, but will it supply enough fuel during start up? Right now that is the problem with the 4911 pump. It's having the hard hot start issue. The 4779 pump looks nice and I'm sure it could handle being turned up, but looks can be deceiving right? It has been stored for over 5 years, I'm guessing. I was told it has low miles. I bought it shortly after I bought the truck and had no knowledge of the differences, but now after doing some searching on the cost differences, between the 4911's and any 6.2 IP; I got a good deal on the 6.2 pump, now I'm just not sure if it's compatible.
 
One sign of a worn out IP is hard starting, especially when hot. Hot fuel is thinner, and a pump with excessive internal clearances can't generate enough pressure. I have read of people pouring cold water on the IP to get it to start when hot.
 
Welcome to TTS!

The .29 vs .31 plunger size can be helped a bit by cranking the fuel screw as previously mentioned, I would guess 1/8-1/4 turn? Also figuring the 6.2 was probably natural aspirated and the 6.5 turbo= more fuel screw of 1/2 turn- this part I remember from researching when I added a turbo. So I would suggest 3/4 turn, minimum.

Now factor in the time of fighting it and not wanting to do it again just for practice, I would throw in another 1/4 turn to be sure. Too much fuel screw = having to not mash the go pedal at stop lights or you might leave some smoke, waste fuel, etc. So... 1 full turn.

That being said, check your area for a standyne approved shop and have the pump tested before going on if a bit of cash is easier spent than your time. More time than cash then dedicate a day and we will cross our fingers with you.
 
Pretty much spot on.

To give you some good history.
When Banks came out with their Turbo kits for the old Square body trucks, the recommended adjustment on the fuel screw was 1/4 turn, and this was perfect to get the turbo delivering the extra power desired.

Giving a 1/2 turn should be adequate for the 6.5

Here is a link to the Banks owners manual.
Page 14 has the instructions on adjusting the FUEL.

Read the entire run down on the procedure to avoid issues with the pumps functions.

Warning
Improper reassembly of the top cover to the pump can result in a RUNAWAY.



https://www.google.com/url?sa=t&rct...yIGgAQ&usg=AFQjCNHnpfAiVqfeDvmxX-1_uH0WX00EeA

Missy
 
There also a little odd shaped plate on the side of the IP that has two screws in it.

The little plate looks like a little mountain laying on it's side.

With the IP off the engine you can easily access the adjustment screw without tearing the top off.

Just remove the cover, then turn the IP shaft until the screw appears in the hole.
Turn clockwise to increase fuel.
 
5 years? I suspect the fuel in the pump is no longer fuel. Varnish is more like it. It may be better to simply rebuild your 6.5 pump and make sure they use a NEW head and rotor as well as steel sleeving the advance piston cylinder.

6.2 pumps could have different timing for EGR engines. BFD.

6.2 pumps have less throttle shaft rotation than 6.5 pumps. This only matters for automatics and I am not sure if you are going to keep the MT or go auto. You will get 0.5v to 4.0v out of the TPS. This results is low pressure in the auto trans at wot, different shift points, etc. More or less the ECM will think you are at less than full throttle for auto trans control. There is a 6.2 TPS, but, the plug is different than the 6.5 TPS plug. :rolleyes5:

I run a 6.2 pump with the fuel screw turned up all the way. It passes the smoke test on B99 without turning the fuel down. For a GM turbo it may be too much fuel. For the A Team Turbo I am down 6-8 lbs of boost over a 6.5 .31 plunger pump.
 
Thank you all for the responses. I will be weighing my options and will cross that bridge when the time comes. If I go with the 6.2 pump I will be sure to update this thread.
Thanks!
Nate
 
Cloyes is what I run I do the complete set with the sprockets. They go on guitar string tight and are sloppy at 30K miles. All chains stretch quick and then lead a long sloppy life. Max slop spec is like 0.8"... So figure on doing timing at 15K and 30K miles then forget about it for a few years.

Dealer may still be able to get the manifold bolts. Fleabay is always a good first look, but double check dealer price before buying.
 
Thanks WarWagon, So you're saying if I put on a complete new timing set, I should expect on adjusting the timing a couple times and this is done by moving the injection pump left or right? (Sorry if I sound like a complete newbie but I pretty much am) I've never been this far into the 6.5 motor. I'm still leaning towards using the 4911 pump until it's absolutely had it, than seeing if the 4779 pump will work. I was just going to put the IP right back in-line with the mark on the timing cover; but if I do that with a new chain will I have problems?

Everything has 189,000 miles on it: heads, bottom end, oil pump, timing gears, and injection pump.

Also if you could help me out with this, while I have the oil pan off what should I be looking for as far as cracking is concerned? Where are they mostly located? Are they found on the main caps, or in the block, the front, back etc.

This is a 599 block, from what I understand, they are one of the better castings. Is this true?
 
With a new IP and timing chain set, on the line is where you want to be. Then about each 30,000 miles, advance about the width of a dime. The new timing set will last until it's time for a complete rebuild.

Have you changed your Harmonic Balancer yet? If not I would jump on that while you do the timing chain. Get AC Delco not doorman on the HB, unless you can afford a Fluid Damper from Leroy. The doorman are good for about 35,000 miles, the AC Delco 125,000 (why you need a new one), FD good for ever-as in outlast multiple engines. If the balancer comes apart, so does your crankshaft and block.

The cracks are found (or hopefully not found I should say) on the main webs- the part the main caps bolt to.
http://www.thetruckstop.us/forum/showthread.php?20077-Cracks-and-chuncks&highlight=cracked+main+webs
 
Well I was optimistic, but I have confirmed my worst fear. Today when I removed the oil pan, I found two cracks in the block :nonod: The first one is about an inch long (on the diver side first main web from the front of the block). The second is on the passenger side second main web from the front, this one is about a half inch long.IMG_0901[1].jpgIMG_0889[1].jpg
 
Man that sucks. Let me guess, original harmonic balancer?

When I had to out my last engine, I looked at 13, yes thirteen, friggin blocks before I gave up and invested in the optimizer. I know the block is thicker and better metallurgy, but once I am into a timing chain or water pump, or anything in that area over 100,000 miles- that sucker is getting a fluid damper.

What's the game plan? You could lock and stitch what you have there, just get a fluid damper on there for the future.
 
First pic is a killer. Bad spot. Long crack. Second pic crack is a good candidate for a L&S but the register crack is a death knell.
 
I thought the 599 blocks were some of the best GM blocks as well. That sucks- scared to drop the pan on Big T now. Sometimes ignorance is bliss! :D

I have two what appear to be (never had them magnafluxed, no visual cracks) crack free blocks- a 929 from a 95 6.5 turbo and a 599 from a 93 6.2. Hanging on to them for spares though!
 
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