feasability of swapping diff make diesel injectors

[columnshift]

This isnt really auto general, even though it may seem a little outside the normal maintenance...


First up I haven't worked at all on diesels, other than understanding basically how they work I only know gas stuff so far and only what i've put my hands on to work on. So i'm trying to understand something...

How feasible would it be to try and make a different make of diesel injectors work in an engine? The specific case in point - the oldsmobile diesel 5.7L/350 v8's of the early 80's which were much maligned and such are as close to "no parts available" as you can practically get. I haven't checked much in person just heard this from others who went looking. (My interest being mostly wanted to toy around with one as a beater for things like waste oil fuel and stuff/wouldn't want to damage a good engine I mean.) Injectors specifically sound impossible to find... but I was wondering why different injectors couldn't be used like from a GM 6.2 or ford 6.9 or something?

I'm aware you'd be doing some metalwork on the head, potentially welding up parts of a hole and drilling/tapping slightly different to position things properly, but would it be radically more than that or would it mostly be a machining trick?

I've wondered the same thing about diesel injector pumps as well, hearing things about the Cummins Ppumps that are durable tanks still available vs say the Stanadyne stuff for the IDI v8's that are now super-expensive like $1700... no i'm not talking about putting an inline 6 pump on a v8 or confusing IDI pressures with DI pressures, i'm just... wondering how much more complicated it would be to try and reengineer fuel systems on the older IDI v8's. If it's as "simple" as some machinework in the head, and physically mounting some other diesel pump even from some import or marine engine or whatever, and trying to make it work. I mean i'd think both those problems are more solvable/no worse than all the other crazy machinework i've heard of being done at all.

I'll admit my judgement on things is clouded by how apparently easy it is to put a custom engineered fuel injection system on gas engines - where guys weld up mounting bosses on manifolds, drill holes, install injectors, then cobble together a Megasquirt system or old Chevy TPI setup or whatever and the computer figures it all out. If I don't consider those kinds of builds unfeasible, what additional problems would there be trying to reengineer diesel injection?

 

[Chris142]

The 6.9 injectors are no longer made.I assume the 6.2 are no longer available new either. But there's many shops that still rebuild them. I guess any mechanical injector can be made to work with enough labor to modify things

 

[Olas]

Unless you can find NOS somewhere it's probably going to be much easier to send them for rebuild.

On the other hand;

Anything will fit if you know how.

 

[A_Harman]

Maybe the GM 6.2/6.5 injectors and pump could be adapted to fit, since they were also engineered in the late-70's, early-80's. The military still has a lot of 6.2's in Hummers, so there must a certified quality supply of fuel system components. Maybe you can adapt the pump and injectors from a 6.2/6.5 to bolt onto the Olds 5.7. At least you would be getting a fuel system made of components that were designed to work well together.

If you're going to play around with running waste oil for fuel, make sure that you have large filtration and de-watering capacity in the fuel supply system. That kind of thing can ruin an injection pump in minutes. Water in the fuel was what killed many Olds diesels when they came on the market.

You can't use a P-pump directly off a DI engine on an IDI engine. The injection pressure is much too high. Maybe you can call a diesel fuel injection specialist and pick their brains about the differences between DI and IDI systems. Scheid Diesel and Columbus Diesel Supply are two that come to mind quickly, but there are many others around the country.

 

[440Magnum]

Originally Posted By: A_Harman
Maybe the GM 6.2/6.5 injectors and pump could be adapted to fit, since they were also engineered in the late-70's, early-80's. The military still has a lot of 6.2's in Hummers, so there must a certified quality supply of fuel system components.


Oh, its better than that. The GM 6500 is still in production by the General Engine Products division of AM General, as the 'Optimizer 6500.'

 

[bullwinkle]

Stanadyne IPs can be rebuilt, look for a diesel repair shop in your area, and the injectors are available rebuilt, or the same shop can rebuild them. I would be very leery of pushing any more fuel through a GM 5.7, they need head studs to survive as it is, and the nodular iron cranks (a flaw shared with the 6.2/6.5) are crack & breakage prone, as are the earlier 5.7 blocks. My personal experience with pre-'92 GM IDI stuff has not been good-other than an '82 red 6.2 block, odds have having a decent one with any serious miles on it isn't good.

 

[440Magnum]

Honestly, if you want a cheap diesel vehicle to fiddle with and try alternative fuels on, an old Ford with an IDI Navistar isn't a bad choice. Heckuva lot more inherent reliability than any of the pre-Duramax GM products, including the 6500. The problem will be the body falling apart around the Navistar, same as with a first-gen Cummins Ram. Actually, the problem with the Ram will be that the demand for the engine alone keeps the price higher than the truck would be worth for your application. Another surprisingly cheap choice would be an 80s Benz sedan. Nothing special about them anymore at all, and they're stout enough that quite a few are still running.

You'll note that nobody has really talked about your suggestion of re-working old GM 350 diesel heads to take a different injection system... there's a reason for that. It would cost more than the end product would be worth, and there's a good chance the rest of the engine would promptly blow itself up under your new expensively built fuel system, even if you could come up with something workable. Welding up heads and then positioning an injector correctly in an IDI prechamber isn't in the "hack it together in your garage" category, IMO.

 

[ironman_gq]

You could always convert it to a gas engine. Not too difficult to swap out the parts and put a carb on it.

 

[A_Harman]

Originally Posted By: ironman_gq
You could always convert it to a gas engine. Not too difficult to swap out the parts and put a carb on it.


The diesel block was quite a performance piece when converted to gasoline. I remember there were some diesel-block Pro Stocks built way back when.

 

[artificialist]

One time I dreamed of trying to make a diesel from a VW 12V VR6. I thought about Benz style prechambers where the spark plugs would have been. If a 24V piston is flat on top, maybe a combustion bowl could be cut, resembling the combustion bowl of a certain Benz engine.

What I wouldn't know how to do is build all the diesel injection stuff.

 

[eljefino]

Originally Posted By: 440Magnum
Another surprisingly cheap choice would be an 80s Benz sedan. Nothing special about them anymore at all, and they're stout enough that quite a few are still running.



I was going to say the same thing. IIRC they toodled along with noncomputerized diesels well into the 90s. The controls run on vacuum, what a trip!