Injectors interchangeable?
 

My 603 has a knock I've isolated to cylinder 4, I want to swap out the injector to rule it out but don't have another one from a 603. I do however, have quite a few from 617 engines, which physically appear to be the same, and both have 135 bar stamped on the side of them. The other numbers on it though, are a little different.

Can I use the 617 injector or could the knock still be there afterward because the pressures could be different? Would I really need another 603 injector to rule it out?

It'll work. I've usually heard of people going the other way around though. The 603 has a smoother running engine partly as a result of it's injector spray pattern.

How about swapping the injectors between cylinders. If you know the knock is on #4 then the other five injectors should tell you if it is an injector or not.

No, it won't. They use the same injector body but the nozzle inside is different.

ok thanks guys. it ran the same and knock was still there. I'm going to swap 4 and 5 today.

It is a different nozzle. Many people have put 603 nozzles in 617s and it's worked fine. Actually better because the 603's nozzle is a little different to provide a smoother idle.

But this guy's wanting to go the opposite way 617's into a 603. I think it'll work.

As far as the physical difference, GSXR here on this forum (Dave from Idaho) has a MB Factory Manual picture somewhere posted of the difference and and explanation/reason they used the nozzle they did vs the old 61x nozzles.

It will work fine if he wants to switch all 6, but he is only wanting to switch a single injector, which will not work.

Not to argue with you for the sake of arguing (really sorry it's not an important thing to debate anyways) but it will work. Just won't be optimal if he has mix match injectors. The pop pressure is the same, just a slightly different spray. If I recall the newer 60x nozzles have an early mist followed by the main charge. I could be wrong about that but I think that's what they did differently for a smoother idle. Something different in the nozzle near the pintle and it's a very slight difference, that I am sure of.

The 603 has a small little tip sticking out and that seems to be the physical difference. the car ran pretty much the same with the single 617 injector in it.

I swapped 4 and 5 afterwards and had the same result. Car is sitting now untill I get time to mess with it again, I had the trans on my SEC grenade so I've been dealing with that.

So 'time' finally came today. Stuck another battery in the car in place of the other one that was now stone dead and fired it up. Fellow forum member 'brainlair' came by with his injector pop tester and ultrasonic cleaner and we went to work on the injectors from the two cylinders that the knock seemed to be coming from.

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Ok, I have to ask.
What were you using as a solvent inside the pyrex bottle while cleaning the injectors in the ultrasonic tank?

I've been thinking of tearing down my injectors and running them through my ultrasonic cleaner, but suspect that the water would be a bad thing to immerse the injector components in, if only for the potential of surface rust fouling the pintle.

its water mixed with alco-something, before they were reassembled, the parts were dried, then soaked in oil.

Ok, thanks for the info.

I'll have to see what I can find out locally, maybe through one of the lab supply houses.
I've tried just water on a set of CIS injectors, as well as the detergent additive that was sold with the ultrasonic tank at the odds and end store, but they don't seem to make too much of a difference.

Just got the word on the name, Alconox is the detergent that was used.

Ok, thanks. A friend just mentioned the Alconox as well, and offered to give me a few ounces to work with.