Hi all is there anybody out there with pictures of their failed lb7 injectors? any help Is greatly appreciated trying to get together where most cracks happen at on the injector for research reasons. I have access to a very good machine shop and cnc shop and if its just a matter of making the bodies out of stainless instead of a cast or whatever they made these pieces of junk out of I might could possibly give it a try. thank you very much.

 

Now this would be fantastic.

As far as I know, the cracking only occurred in the first batch of injectors from bosch. The redesign seems to have completely eliminated it.

What I believe should be done is make the ball seat out of a better maternal. Perhaps tungsten carbide? The pintle can probably be made out of a harder material too.

The biggest issue seams to be the check ball seat erosion. Then leaking nozzles.

Do you have the ability to make nozzles and jets?

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I took apart a failed injector once that was suffering from a high return rate. Couldn't see anything wrong with it. No erosion.

I believe that more of the failures are likely due to a small contaminant getting in and preventing proper movement of the internal parts and if the injector was removed and cleaned it would likely work fine for many more miles. The issue is who wants to take this risk

Anyways, I look forward to any part you make

 

Its going to take more than a typical machine shop!

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a skilled machinist should be able to make another check ball seat with just a lathe

 

if its even a couple thousandths of it will not work and you will not know until you put it in your truck and possibly burn up your $8000 motor.

BTW it was GM fault about the non-hardened seats. Bosch recommended hardened seats and GM wanted to save $0.03 an injector... somehow Bosch ended up on the hook for it anyways.

Rumor is that GM remans are not done by Bosch any more. You know the quality you are getting from bosch= excellent. who knows what 3rd party GM has turned to to save a $.

 

A little birdy told me the "fine" folks at flight service might be building GM's paper weights after 3/13 . Have no way to know if that's true.
Any machinist can make the peice but there's quite a bit more involved than putting it on a lathe and spinning it out. Not to mention a test stand from hartridge. Their not cheap machines and you would HAVE to have one in shop for this process.

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how about taking known good parts and re-heat treating them? there are some expert heat treaters that could harden then seats, etc for minimal cost.

what about cryogenic hardening? take the injectors apart and throw them in liquid nitrogen for so many hours and reassemble them

 

Very good idea, expensive I would vote. A new injector, disassembly, reassembly and bench testing. But its still seems better than constantly replacing injectors.

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based on these guys (Cryopro Cryogenic Tempering Processing Center) and the price of bench testing (+-$50 each), if they end up lasting only 50% longer then you are still saving money

and if you are using new (bosch remanufactured) injectors then some will probably argue that retesting them is un-nessasary

i wonder if you could just drop the whole injector in the bath and not have to take it apart. the only thing i would be worried about would be the solenoid (plastic) and loosing some ductility in the body. will plastic survive the process?

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oh ya, got to remove the springs, so disassembly will be required

 

Any changes including disassembly will require a bench trip. I almost think I remember some type of mechanical shim or something like that in the solenoid. Last time Rob ran a set for us he mentioned something to the tune of a solenoid shim or adjustment. That may be way off base, we're not an injection shop so unless its mine personally we don't take it apart!

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