New or Rebuilt Injectors
 

Half of my injectors are suspect. I know that there are several companies that rebuild them, but are they able to bring them back after they have 148,000 miles on them? Is it better to just buy NOS bosch injectors?

have them rebuilt, if they're not rebuildable I'm sure they'll let you know. It obviously costs a whole lot less and you will even get a set of flow matched injectors, good luck buying some new ones and getting the same result. If you're worried about down time, buy a cheap used set and have them sent directly to a rebuilder, then direct to you.

I would buy them new....they cost about $80 each and you are sure to have no leaks in lots of time.

I've always wondered how you rebuild an injector that has one moving part and is swedged together.

Exactly SoCal! What do they do to make it stop having post nasal drip, and then balance them? Do they have to glue them back together when they are done playing with the injectors guts? Inquiring minds want to know.

I have a set of NA injectors from my 86' that were cleaned/flow matched by rcengineering (comes with printout) all of them to spec. Make me an offer an they are yours. :)

How did they do it if they can't take them part?

SoCal, you, of all people should know that a carpenter's knife, super glue, and duct tape can fix an injector.;) Just kidding. No need for fires, fix it right. SmileWavy

The process is simple and straight forward. There are reputable shops and "home town hole-in-the walls" which can rebuild, flow test and match the injectors with good results. As with anything, do a little research and pick a good company. The company that did '69s injectors are a very well known outfit. I'm not aware of a need to
2 split the halves, but I have seen a stock bosch 951 injector that "appeared" to have been rebuilt which was leaking at the seam of the metal bod. The injectors are ultrasonically cleaned and the o-rings, caps, and filter is replaced. They work the crap out of the injectors on special equipment to clean them. Typically injectors just need to be cleaned, it's not usual for them to fail mechanically. They flow them before and after, and will repeat the process to achieve the desirable #'s and try to get them very close to each other. I remember Tony G getting some 951 35# injectors rebuilt and they got them flowing upwards to 43-45#'s! I don't know why having them rebuilt wouldn't classify as "fixing it right", but if you're worried about fuel rail fires, protecting or making full use of your new injectors, I'd highly recommend that you also add some things to your shopping list: If they haven't been recently replaced, you may look into a new fuel rail, dampner, regulator, fuel filter, in-tank screen filter and of course the fuel lines(when were they replaced)? you can spend $100-$125 getting all 4 refurbed or drop $80 on each one.

or for $50 plus shipping for the same thing as RC(in the High perf. injector market for 30years):
http://www.affordable-fuel-injection.com/fuel-injector-cleaning.htm

don't you think there would be some liability issues that they'd be worried about if rebuilding injectors wasn't successful and led to external leaks causing fires? I haven't heard any bad reviews about any rebuilder other than someone finding another source that would do it for less. I think I'd go with experience over price, but 1/2 price is pretty tempting, do some research on some others.

With out taking the injectors apart calling them "rebuilt" is erroneous.

Cleaning injectors is easy for any one with a piece of tubing, solvent and shop air. Would do it all the time at VW dealers.

Now how would you change the flow if you can't take it apart? Is there a set screw hidden somewhere that controls the flow of fuel?

Changing the plastic "hat" and o-rings is like resealing the front of the engine. I wouldn't call the engine rebuilt.

Now I've seen a bunch of injectors cleaned and matched for flow and spray pattern.

...well highboost explained how they clean them so I will leave it at that....

The printout that RCengineering sends out shows the flow characteristics of the injectors before and after.

on a side note: Its an interesting point highboost brings up in regards to Tonys injectors. I had a friend who saw the same thing from so called 55lb injectors. After having them put through one of these procedures he was able to increase the flow to ~72. I am not sure how some of these injectors are calibrated but it seems that you can definitely alter their flow characteristics........ Even accross different manufacturers you can get some interesting results.

Cleaned them. Not rebuilt as is claimed.

Yup thats right they clean them but they also test to make sure the injector is working as it was intended (the mechanicals, resistance in the coil, spray patterns). There may be rebuildable injectors? Not sure of that actually?

They explain part of the testing/cleaning procedures on their website.... www.rceng.com

I don't see your problem socal, if you're unhappy with the terms, talk to the companies that do the service. As the saying goes, if it ain't broke, don't fix it. If cleaning is all that's needed for them to be in "like new" or a "rebuilt" condition, then so be it. They have replaced the necessary worn parts to make it operate as or better than new. who cares what they call it, it's a good inexpensive service when compared to the cost of new ones and the results speak for themselves. It's basically an industry standard, remanufactured or rebuilt parts are sold all the time with only the necessary items replaced.

I checked several companies that do this and none of them call their service rebuilding.

The worn parts they replace are the same parts you can buy at Pep Boys for $3 per injector -- two o-rings and a plastic "hat".

They do use a high power ultrasonic cleaning bath while they are back flushed. Possibly a bit better than just back flushing them with solvent and shop air but still the same operation.

The injector can not be taken apart so any insinuation that these are "rebuilt" is totally bogus.

I've been cleaning injectors since 1970. How long have you been cleaning them?

...that were cleaned/flow matched by rcengineering (comes with printout) all of them to spec. ....

You wrote: How did they do it if they can't take them part?

"I've been cleaning injectors since 1970. How long have you been cleaning them?"

Wow, very impressive; So you've been doing this approach since 1970 eh? I'm sure it would work fine for mfi or cis injectors but are you saying you'd use this approach on a motronic car? the injectors need to be juiced to let fuel through, I'd love to see you go to town on them with an air compressor. Sorry but I prefer to see real #'s vs. a "ooh I think I cleaned it pretty well". I've got too much invested to use your approach, I'd rather spend the extra money and rest assured; especially with the euro spec 2.2S race motor or with the 95# injectors on my 951 when running 25+ #'s of boost. who gives a crap about the definition of them being rebuilt, for simplistics I was giving a recommendation about "rebuilt" injectors as asked in the post. As I said before, they typically don't fail mechanically, they just get dirty and need a good cleaning. Obviously you seem to be inclined to cleaning them too as this is what you've been doing for the last 30 years. I was recommending to have them done vs. spending the money for new ones. It's pretty lame to have such a strong opinion about the fact that they aren't "rebuilt". The term was just loosely used in the question and it was repeated. I really don't know what your trying to achieve other than foolishness; they take injectors which people think are ready for the trash and bring them back to better than new spec for less than a 1/4 of the cost of new ones but you can't generally call them "rebuilt" on the general principle that they didn't cut them open. They don't open them because they're capable of cleaning them w/o having to do that and the #'s prove it. I'd love to see what kind of improvements they could make on one of your "cleaned" injectors. Maybe I can talk a builder into cutting them in 1/2 and welding them back together, then it would be "rebuilt"...right?

My tuppence ha'penny.

If half my injectors were suspect I'd have a go at cleaning them all using the 'rocking' method and some injector cleaner as I've described elsewhere.

If that didn't work then (depending on the plumpness of my wallet at the time) I'd either buy two second hand injectors (figuring they'd be roughly the same mileage as the two survivors) or a full set of nice new units.

I wouldn't pay half-price to have them cleaned because they'd just be the same tired old items (but cleaner) at the end of the day. I would pay to have them serviced if they are of the rebuildable type because then they'be be essentially reconditioned to as new for half the price.

I noticed the debate getting a little heated on the subject or rebuilding. Depending on the external body design you can rebuild injectors relatively simply. I've done it a fair few times on my Z1000-H which has Bosche K-tronic injection. If you look at the pic of one mine you can see a little retaining screw just under the electrical connection. Unscrewing this allows you to unscrew the main injector body casing and access the internal mechanism.

A lot of bollocks is spoken about fuel injectors - like they're some kind of guru-mech subject. Essentially all an injector is is an electrical gate. It has a spring-loaded precision metering needle that lifts of it's seat when the electrical actuator comes into play. The fuel, already under pressure, rushes through until the actuator closes it. And that's all it does. Eventually the needle and the precision bore through which it slides will become worn with age allowing it to leak and throwing out the precision metering slightly.

I've attached a cutaway pic gleaned from a Kawasaki bike mech training course I did years back so you can see how little there is to it. It was supplied by Bosche (it looks like a diesel injector to me)

Sometimes you can access the components and replace parts (if you're in the know as to where to obtain them). Sometimes access is denied due to the casing design. I haven't looked at my Porsche injectors for a while but i believe they're the sealed unit type.

Either way they're nothing to get your knickers in a twist over.

http://forums.pelicanparts.com/uploa...1068035826.gif http://forums.pelicanparts.com/uploa...1068035851.jpg

Yes on motronic cars. This is a shop procedure recommended by Bosch and was taught at the Culver City VW-Porsche instruction center. Either the injectors worked or didn't. Back flushing "corrected" about 90% of the problems.

DK, that is not a screw. That is an opening in the plastic where you can see the metal of the injector housing. Here look at this cross section:
http://frwilk.com/944dme/injector.htm

The plastic is moulded around the metal of the injector.


I too would like to know how these can be "flow corrected" if you can't open them up. If you can open them then I would like to know how.

I'm sticking to my argument that rebuilt means the item is taken apart and mechanically wearing components are replaced or brought back to OEM spec. Changing the flow also means you have taken them appart and modifed the internal structure.

Cleaning means back flushing and possibly ultrasonic immersion to assist in cleaning.

I would imagine if you cleaned them that the flow would improve if the filter(mesh) inside was dirty and it was back flushed?

I would assume if after said cleaning/testing (or whatever we are calling it) and that the flow improved back to the injectors specs? Can't you assume that it is working fine? and thus we corrected the flow?

Good question on changing the flow of an imjector above the stated specs. The problem is that flow of an injector can be different. That difference is usually related to fuel rail pressure....... ex. 55lbs at 3 bar...... but that injector could flow much differently at 2.5 bar or maybe lock up at 4 bar.