shimming Injectors?

[slim072590]

I have read on here and some other site a a time or two.. about when you replace injectors sometimes you have to shim, or move them back up to adjust the fuel spray, i think...

and searching has taken me no where on this... does it always have to be done? is it just for extreme perfection?



im starting with injectors because when i read my temps coming out of my exhaust manifold the passenger side cylinder closest to the radiator was running about 30-50 deg colder then the rest, and it has a slight knocking all the way through the RPM range.. and lots of white smoke

the job looks easy, just pull lines, pull injectors, use oil to set the O-rings, top first then bottom, then reconnect and fire up.. unless im missing something

if you have advice, that would be awesome.. or if you have a link to these questions already answered, again, awesome

Thanks,
Nick

 

[icanfixall]

Hello Nick and welcome to the forum. To shim an injecter you need 2 items. The injecter pop tester and the shims. Many that will pop test an injecter have bought the Rotunda pop testers off ebay. I actually have 3 of them. Now finding shims is impossible. Many of us have tried all over this country and no shop will sell us any. So we rob them from other used injecters we hopefully have laying around. When I shimmed mine a few years back I went to a shop that still works on our engines asking for used injecters. They had just a week before thrown out 2 five gallon buckets full of them... Really the only time we tend to agree on shimming is after about 5000 miles on a new set. Thats because the springs have usually taken a set by then. Now as the injecter continues running in the engine the pressure will sag or drop. We can remove and shim but once you have done it you wont want to do it again. Its plenty of testing and shimming to get what you want. Cleanliness is a must here too. any dirt will ruin a good injecter fast. I use clean rubber gloves so I can watch for dirt. When I see it on the gloves I change them. Figure around $300.00 for a good useable Rotunda pop tester. If you find one please pm me and ask if all of its there. Many of them sold on ebay have missing parts. Some members have made their own pop testers from hydraulic jacks and a little welding.

 

[OLDBULL8]

Welcome to the OB Nick.

I have read on here and some other site a a time or two.. about when you replace injectors sometimes you have to shim, or move them back up to adjust the fuel spray, i think...

In order to shim injectors, you have to take them apart in an enviroment that is hospital clean using white latex gloves. The shims are not readily available, even if you could shim them, then you have to have a pop tester to check them out. You cannot adjust the spray, the injectors must be in and seated on the copper crush washer.

and searching has taken me no where on this... does it always have to be done? is it just for extreme
perfection?

The injectors should pop at 1850+/- 50 PSI for efficient operation. You can build your own pop tester, check out the IDI tech articles.

im starting with injectors because when i read my temps coming out of my exhaust manifold the passenger side cylinder closest to the radiator was running about 30-50 deg colder then the rest, and it has a slight knocking all the way through the RPM range.. and lots of white smoke

That #1 injector could be leaking and give you that knock and possibly contribute to the white smoke.

The cylinders are numbered 1-3-5-7 on the passenger side and 2-4-6-8 on the drivers side.
White smoke is usually the results of retarded timing, you would have to get the engine timed to check that out, timing is set at 8.5* to 9* BTDC at 2000 RPM.

the job looks easy, just pull lines, pull injectors, use oil to set the O-rings, top first then bottom, then reconnect and fire up.. unless im missing something

If you replace any injector, read the HALL OF SHAME first. New injector cost is very little more than rebuilt. Most rebuilt injectors from many rebuilders are defective and are not pop tested as a set. Most all of us use BB code injectors. If you replace any, be sure and use antisieze on the large body threads.

if you have advice, that would be awesome.. or if you have a link to these questions already answered, again, awesome

Thanks,
Nick

 

[slim072590]

Thank you guys...

Is it like shimming a rear end where you set and check and pull and reset and check again... or are all the shims the same thickness? And do you shim all the injectors or just ones running different?

And if I buy injectors from the moose guys on here (I forgot his name, sorry) they poptest injectors before sale so do I still need a injector tester?

Thanks a million guys

Sent from my C811 4G using Tapatalk

 

[icanfixall]

A pop tester is nice to have but not a mandatory tool. All injecters need to be pop tested because you have no idea which running injecters are below the level of the others. Mel will pop test for you. So will Rus aka typ4 in Oregon. Some kind of pop tester is needed if you choose to pop test any injecter. Ideally you want every injecter poping at the same pressure no matter what pressure you choose. Say an injecter pops at 1500 lbs and all the others pop at 1850 lbs. The low pop injecter will be sending fuel into the cylinder much earlier than the others. So you chance a knock sound from early injection and lower power from the cylinder and engine. It also causes engine vibration. Say all the injecters pop at any pressure from 1500 to 2200 lbs. That poor engine is being told to speed up the crank and slow down the crank pulses from the combustion. Crazy things will happen like vibration breaking things. If all the injecters are within 50 lbs of pop pressure the engine will produce even power and give better fuel mileage too.

 

[mblaney]

+1

I pop tested eight brand new Delphi's after running them for 5000 and they were anywhere from 1600 - 1850. I did shim them myself and it is very time consuming (but fun if you like that kind of thing!). If you don't have easy access to a pop tester I would suggest buying them tested.

I forget the numbers but 0.001 shim thickness results in ?? psi difference. This means that you have to mix and match shims to get your pressures to match. I did not have a shim kit, I salvaged some and made others. Lathe, drill, deburr, hone for thickness, ultrasonic cleaner... Still not sure why I went through all that! Oh ya, it was fun!

 

[Mulochico]

I pop tested eight brand new Delphi's after running them for 5000 and they were anywhere from 1600 - 1850.

Were they tested and matched when you put them in?

 

[slim072590]

That's why I was gonna buy from the moose guys, they sell them pre tested

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[icanfixall]

A 1 thousands thick shim equals 55 lbs increase or decrease in pressure. Using old shims works fine because they are a none wear item in the injecters. About the only thing that wears in them is the spring, nozzle and pintle.

 

[mblaney]

Were they tested and matched when you put them in?

I installed them as 'brand new' as supplied by Pensacola Diesel. They are not pop tested (or at least matched) from the factory. My guess is that before assembly, the spring height and force is checked, a calculated shim is added and they are assembled. I got a great price on them but I bought them knowing that I was going to test them.

The point of doing them after some use is to let them wear in.

 

[77f250diesel]

This will help you understand what's involved....................
http://www.thedieselstop.com/contents/getitems.php3?6.9L%20Injectors

Dennis

 

[icanfixall]

I made several videos some few years back. someone might be able to direct you to them. They are on utube too.
http://www.youtube.com/watch?v=CKBvOuTBddk

 

[slim072590]

Thank you guys... I'm ordering injectors tomorrow and will hopefully have my truck running like new by next week... I'll post up a thread of injector install even tho I'm sure it's been posted 1,000 times... I just couldn't find them, haha

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[icanfixall]

Heres another video.
http://www.youtube.com/watch?v=XcSuxjmzEcI

 

[icanfixall]

how to easily remove the pump with the lines on it trick.
http://www.youtube.com/watch?v=DyhgOhS1OhY