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Topic: Injector Removal- Cummins C8.3 and Isuzu 3LB1 (Read 2041 times) previous topic - next topic

Injector Removal- Cummins C8.3 and Isuzu 3LB1

I'm just over 99,000 miles and 2400 hours on the Cummins C8.3 so it was time to have the injectors tested as part of the belated maintenance schedule (or could be termed nonexistent maintenance program from the previous owners). 

The injectors on the Isuzu 3LB1 are supposed to be tested every 1000 hours and I'm at 1100 so I figured I would take them in for testing at the same time I do the Cummins.  The Isuzu Zexel injectors are extremely easy to remove and just thread out with minimal disassembly required.  This can be done in 15 minutes once you familiarize yourself with the fuel lines and remove the jumper strips from the glow plugs.  Do be aware that there is a spacer at the bottom of the injector bore that may pull out with the injector itself.  I will post pictures when I do the reassembly process but it is easy enough that anyone can do it with minimal tools. 

The Cummins injectors however are not nearly as easy to remove.  I would say that it is a huge PITA that requires the removal of quite a bit of stuff not directly associated with the injection system such as the AC compressor.  I would gladly leave this job to a shop in the future but due to the amount of labor involved, I would want to see all 6 removed injectors to ensure that the tech didn't skip a couple of injectors that are more difficult to remove such as cylinder 1 and 3 starting at the back of the coach. 

I would also like to take this moment to complain about the genius that decided to make everything within the engine compartment, including the insulation, a flat black color that doesn't reflect any light and seems to be too dark to see much of anything regardless of how many shop lights you put in the engine bay.  When I finally get around to replacing the insulation, it will be with an aluminized foil insulation to allow for more reflected light.  I tried to get pictures of the removal but they all turned out too dark to really see anything to be helpful. 

The Cummins injectors are a slide in type that are held in place by a bracket installed on the injector body itself.  This bracket comes off and is not visible in the pictures.  Despite the slide in nature of the injectors, you are not going to be able to just pull it out by hand, an injector puller will be required.  I created my own from an airbag removal puller bought at Autozone.  The puller was able to remove #5 without modification but was just too large to pull #1,2,3,4 and 6.  I modified it with a grinder to look like it does below.  If anyone wants the actual dimensions, I'll get them. 

I'll post the results of the injector testing after I get them back from the rebuilding shop. 

Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #1 –
On many diesel injectors, there is a small washer like part that goes between the injector and cylinder head. It may be hard to see but look closely. Part of it's job is cooling the end of the injector through conduction into the head. If it has one, you need to replace it with a new one as they flatten out and won't do their job used. Make sure to install correct side up. Have seen some people install a new one on top of the old one.

EZ to make an injector tester. I just used an old truck cab tilting hand pump, installed a fitting for a gauge and then installed the gauge (liquid filled so the needle does not jump around) along with an extra injector pipe. Once you have taken the injector apart and cleaned it and put it back together, you can see what pressure it opens at and what the spray pattern looks like (filled the pump with diesel). They make a buzzing sound when they open and close many times a second so is the reason for a liquid filled gauge. Do one injector at a time so parts are not mixed up. I have used a vice to hold the interior injector body and then used an electric drill to spin the pintle after I put a tiny bit of valve grinding compound on just the tip. Any on the pintle body would ruin the both of the parts.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #2 –
Quote from: Pierce & Gaylie Stewart –
On many diesel injectors, there is a small washer like part that goes between the injector and cylinder head. It may be hard to see but look closely. Part of it's job is cooling the end of the injector through conduction into the head. If it has one, you need to replace it with a new one as they flatten out and won't do their job used. Make sure to install correct side up. Have seen some people install a new one on top of the old one.

Pierce

The Isuzu Zexel injectors had the washer on them.  I thought the first one I pulled out was broken when the washer was sort of barely hanging onto the injector.  You could clearly see which side was the top and which was the bottom due to the deposits on the bottom.  That is a good point about replacing the washer though and I will have to ask around about a part number for it. 

Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #3 –
Had some time after being on the tractor this PM so brought up a good DIY site for cleaning Bosch injectors used in many vehicles and generators. The heat shield washer is shown on one of the last photos toward the bottom. You can see what I was talking about in the good closeup of the pintle and the surface where it seals. As I remember, the release pressure is about 3000 psi and each injector should be within 50 psi. You can buy new nozzles for $30/ea so not the end of the world if you need a set. They should be hospital clean when you put them back together.

Mercedes Injector Nozzle Replacement

Here is a injector tester like the one I made. Looks a bit better than mine but does the same job.

Universal IDI Bosch Diesel Fuel Injector Tuning Kit | Slick D.I.Y. Hardware

There is a small copper flat washer located under the fitting the injector pipe screws onto on the injection pump. Poor power or rough idle may mean the washer is seeping some high pressure diesel. If you don't have a new one, I get a flat piece of stone (graveyard footstone works well) put 1500 wet or dry on it with water and use a back and forth motion turning 90 degrees every few seconds. Once any lines are gone, I replace the wet or dry with crocus cloth to finish it with. If the pump is seeping here, replace the rubber O ring. Ken did that on his generator at Quartzsite.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #4 –
Google 'copper crush washer'

They are soft initially. The Perkins book says if you can't get new olds heat then to re-anneal.
Elliott & Mary Bray
ex. 1996 36' U295 - Build 4879
ex. 2018 Coachmen Leprechaun 319MB
 

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #5 –
Pierce, that is great information from the Mercedes site. 

Elliot, thanks.  Found the 80 piece kit from HF. 

Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #6 –
So I got back the injectors from the testing/rebuilding service. 

The Cummins injectors all tested out fine.  They were cleaned up very nicely and returned with new hardware.  They look nearly brand new.  $99.00 for 6 injectors.

The Isuzu injectors, which I only sent in for testing for the hell of it because I was already having the Cummins injectors done, all needed new tips.  These were also returned looking basically brand new with all of the silver paint removed.  $204.00 for 3 injectors.

I asked about the tips and they asked whether I had a fuel/water separator on the generator, which I had not yet installed at the time.  This could have been the problem or solid particles reaching the engine, they couldn't say for sure.  I don't know what everyone else is using but my generator fuel filter was not a water separator type.  Just a heads up .

Pics of the prettied up Cummins injectors-
Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #7 –
 is there not a water seperator for Gen  behind it , sort of under the stair area. I have one on the 2000 295??
JohnH
Coachless, now use aircraft. 2003 Ford Travelair TC280 class C. Super shape. Just for 1 yr .
1994 Ford E350 ClassC,total renovation inside and out. Now sold.
2000 U295  36' Cummins 350 c/w Banks Stinger, Resonator upgrade,Solar, LED lites.Residential fridge with slide out pantry. Build 5674. Sold
ex 92 GV 022C ored Cummins. Sold
ex 95 GV240 cat 3116. Sold
2017 Mini cooper s & 2016 land Rover LR2 HSE  LUX.
jhaygarth@aol.com    SKP #130098
treat everyone as you would like to be.

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #8 –
Quote from: John Haygarth –
is there not a water seperator for Gen  behind it , sort of under the stair area. I have one on the 2000 295??
JohnH

No, not on my FT anyway.

It might be that it was based on model and the U270 didn't get one or that it was based on model year and 1998 didn't have them.  Either way, I didn't have one until I added one, just the engine mounted filter.
Robert
Build # 5304
1998 34' U270 Cummins 6CTA8.3

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #9 –
I wonder if the fuel tank acts as a separator since the pickup tube is elevated to the 1/4 full mark?
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho
 

Re: Injector Removal- Cummins C8.3 and Isuzu 3LB1

Reply #10 –
Quote from: JohnFitz –
I wonder if the fuel tank acts as a separator since the pickup tube is elevated to the 1/4 full mark?

That and the fact that any water would go to the bottom of the spin-on generator filter. I have seen diesels run fine and water in the  spin-on secondary filter rust through the bottom. Good practice to replace as recommended by the mfg. If any algae shows up in the engine filters, change the generator filter also. Easy to install an extra filter/separator with a see through bottom in the generator compartment or even bolted to the engine.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)