I have a 93 6.5 Turbo with a bad injector pump. I have a good pump from an 81 6.2. can I use the 6.2 pump on my 6.5? Or, failing that, is the rotor & head assembly interchangeable?

an '81 6.2? H&R is quite different. Your 6.5 pump has bigger pumping plungers, accumulator pistons in the head, much improved advance device and governor...the list goes on, pumps changed a lot over the decade+ span your talking about. Could you make your 6.2 'work' in your 6.5, sure, you wouldn't be the first.
But to do it atleast close to right, you'd have to send both pumps to a fuel shop and have them build your 4911 pump using the head from your 6.2 pump. And if your going to spend that kinda money why wouldn't you just get your 4911 rebuilt?

What's the matter with your's anyway?

i put the 6.2 pump off my 85 into a 6.5 that i built and put in my 85 and as far as i am concerned it runs great decent power no smoke smooth idle easy to start

I think I gave you pretty much the same advice too didn't I?
It will work, no doubt about that, your's is naturally aspirated though isn't it? His is turbo, so he'd really have to crank that pump up, and it still wouldn't make rated fuel quantity.

Late model HD 6.2 (ie 4979), and HD N/A 6.5 (ie 5088) specs are identical, same rated HP, fuel delivery, advance, everything, and are all but interchangeable.

tdg read my sig

My bad :o:
Would you honestly say that it runs great considering, or great period?

and yes you gave me the same advice i am just one of those people that if im told it can't be done ill do it or if it does not work i want to know why then figure out a way to make it work:p:

great period blows my old 6.2 away by miles

i put the 6.2 pump off my 85 into a 6.5 that i built and put in my 85 and as far as i am concerned it runs great decent power no smoke smooth idle easy to start
What did you do to make it work?

I ran a 6.2 pump on my first 6.5 conversion and it ran well. I opened the fuel all the way and it was respectable, but in no way did it run as strong as a stock fuel setting 4911 pump! Until you try it you won't know the difference. When I was all done playing with 6.5's that 4911 was wide open):h :cool2: and you could do some real good smoke outs!

i just turned the fuel all the way up which in my case was only about 3/8s of a turn on the allen screw and then put it on

4911 pump stock will deliver almost 70mm fuel max, and if you crank it all the way you can get 80+! A 6.2 pump on the otherhand will max out in the 60s.

so TDG the 6.2 can deliver around 60 mm and the 6.5 stock motor on the valve cover says it is 63 mm of fuel so as a stock motor it should be comparable. not good for trying to build it up past that . that is ok with me if i want to go faster i can jump in the camaro that one can really rock!!!

TDG,

IYHO, how long does it take to "turn up" the fuel pump? I have a 93 per my sig. So I have the DB2 which I guess is what you are referring to as the 4911? SO just a rough guess from start to finish? I know there have been a few threads on this, and honestly, they confused me more and are why I haven't done it yet. Anyways, thanks for your help.

Dan

depends on your method, I usually do it by removing the top cover and it can be done in 10-15 mins. Diesel-Pro offered up a different method or removing the inspection plate on the side of the pump (2 1/4" bolts) and rotating the engine until the pin on the driveshaft is in the (I think he said 10'oclock) position, and that will put your leaf spring adjusting screw in the window and you can give it an 1/8th turn with a 5/32" allen through the inspection plate. I guess you could also use a mirror and have someone roll the engine over while you watch for the screw head to appear too.

The advantage to this is preventing mis-reinstallation of the governor components and top cover.

Half hour I would guess, if its your first time.

my 4974 is set to stock delivery at 81mm, how much will it deliver if i turn it up?

10-15% of 81mm3 is + 8.1-12.15mm3 at half a turn if my extrapolation is valid.

How much does that pump cost? Also, I'm sold on getting a better crank, what's a billet crank going to cost?

grape i know you worked with a fuel shop to come up with that pump but i was wondering what it originally came on if any thing and where i could find one and what kind of $$ i should expect to pay for one i am building a motor for my 77 blazer going to be a van motor with a centre turbo 12" lift 39.5" super swampers 700r4 373 gears

having the pump built was expensive, head rotor, everything is different with the 33cc plungers. with that pump number TDG should be able to tell us what all is in it, it's listed in the stanadyne book as the 250hp marine pump. The rev limiter is also like 4200, but i'm not sure. As far as having a crank cut from billet, about $3600.

that is a pricey crank what exactly are you building what kind of hp are you hoping to acheve

i dont' know that i'd ever spend the money on the crank, that's just what our race truck stuff costs and it would be built the same way, big chunk of steel. I think it would be a waste in the blocks that you can get your hands on. Not to mention trying to get the heads to not go through the hood could be a good trick. As far as power......as much as i can, there is a different pump that my pump shop found that was listed as a 300hp marine but they said the operating pressure was way higher, but still it was a 2 plunger pump. We've been looking for almost 3 years off and on trying to find a 4 plunger 8 cylinder head and rotor and there is none that we've found yet.

As far as having a crank cut from billet, about $3600.Out of my budget, I'll guess I'll look into who could make a forged steel crank.

having the pump built was expensive, head rotor, everything is different with the 33cc plungers. with that pump number TDG should be able to tell us what all is in it, it's listed in the stanadyne book as the 250hp marine pump.
Expensive is a good word for it, new head/rotor, new camring + small parts and whatever your core needs for rebuilding. Probably be better off buying a whole new pump and selling them your core.

We've been looking for almost 3 years off and on trying to find a 4 plunger 8 cylinder head and rotor and there is none that we've found yet.
Thats right, there are no 4 plunger 8cyl DB heads. DS's all have 4 plungers though, I'm toying with the idea of boring out a DS4 831 head to make it an 833.

Thats right, there are no 4 plunger 8cyl DB heads. DS's all have 4 plungers though, I'm toying with the idea of boring out a DS4 831 head to make it an 833.
i asked about the ds head and rotor because of the 4 plungers and they said no way to put it in my mechanical pumps, but maybe they just didn't want to mess with it. Hell 4 31cc plungers should pile the fuel in if you can adjust the leaf spring right? The only issue with 4 plungers they told me was having to have two adjusting screws, which meant without a test stand if i was cranking on the screws i could have half the engine make more or less power than the other half.

i asked about the ds head and rotor because of the 4 plungers and they said no way to put it in my mechanical pumps, but maybe they just didn't want to mess with it. Hell 4 31cc plungers should pile the fuel in if you can adjust the leaf spring right? The only issue with 4 plungers they told me was having to have two adjusting screws, which meant without a test stand if i was cranking on the screws i could have half the engine make more or less power than the other half.
No they're right, there's about 20 reasons why a DS head won't work in a DB pump. And they ONLY problem with dual leaf springs is you have to adjust them to get the same eccentricity on all 4 rollers, even if you don't, all 4 plungers pump on every stroke, so its not going to make a balance problem, just longevity and overall fuel output.