D6c Injectors

[D6c10K]

Now that I'm just about done working on my blade I can turn to a couple of other repairs......

The 3306 in my 10k D6c (pre-comb) is a little hard starting and I'm wondering if a set of injectors might be in order. I get minimal blow-by from the oil filler tube so I don't think I have terrible compression loss and it doesn't use much oil.
It's in the shop now at 55° and won't start without using glow plugs or ether (never both). Right now I've got a couple of bad glowplugs with doesn't help.
Even in warm weather I usually hit the glow plugs for about 20 seconds, which usually does the trick.
Not real sure how easy I should expect it to start.

Are aftermarket injectors any good?......really inexpensive.

 

[kshansen]

I would first get all the glow plugs working, Cat did not put them in those engines just to get them off the shelf! Been a bit of time since I worked around a 3306PC engine but I would not be surprised if one needed a warming up for a few seconds anything below 60º.

Just for your info here is what Cat said right in the operation manual, and remember this was for a new machine straight from the Cat House so for an engine with a few years on it you might want to drop down one line in the chart.

 

[DoyleX]

Even on a 80 degree day I need a quick 5-10 of preheat to get it to pop easily. It is just the way they are. Fix the glow plugs. When was the last valve set done?

 

[old-iron-habit]

I agree with the replies above. If you feel after fixing the glow plugs and using them while starting per the Cat specs that you still have issues, Bill Walters on the ACMOC site has all the factory injector rebuild equipment and will test and rebuild your injectors as neccessary for a fair price.

 

[Metalman 55]

My D6C is a little older than yours & has the D333C engine. I do not know if mine is PC or not? Anyhow after we had the hyd lock problem earlier this winter we changed out all the injector nozzle tips & I think they were just over $100 ea CDN. Mine always starts real good in cold weather. Anything over about 60f I use no heat like the chart says. When it is say around 15f out I only heat for about 1 minute on a cold start. I remember years ago running a D8K which was new at the time, with the D342 engine in it & it needed heat right up to about 70f out for a cold start.

 

[D6c10K]

Sounds like I might just need to get the heaters fixed. There is some confusion about which heaters are correct. The head was replaced not long before I got the tractor, and presumably valves refreshed at that time.
A couple of heaters weren't working when I got it and the others burned out not long after that. When I went to get new ones the heaters they came up with were a different style. Thinking that perhaps the replacement head used different heaters, I bought heaters matching what I had. The problem is, if I run the heaters more than half a minute or so the new ones started burning out too. Now I'm thinking the heaters are the wrong ones. They are a little longer than the ones that Cat came up with so possibly they stick in too far and get hotter than intended and burn out quickly. ( and for some reason, when a heater burns out it dead shorts and pops the breaker)
I can't see a p/n on the pre-comb chambers and have been putting off pulling one to see if I can figure out the correct heaters.....guess I need to go ahead and do it.

 

[Old Magnet]

What is the tractor s/n and head casting #? D333c or 3306 engine?. Makes a difference as to what chamber is used.
Are you running 12v or 24v glow plugs?

 

[D6c10K]

Old Magnet,

Edit:

It's a 3306..s/n 3n35163 Arr. 4N7365..
Head casting marked NWP 2W656 -3-
24v glow plugs
Is the NWP the supplier or aftermarket maker?

 

[D6c10K]

It's very possible I have mix-matched head / precomp / glow plug parts from when they replace the head.

Edit:
For my arrangemnet the parts book shows
8S7930 Pre-comb chamber
4N7466 head assy
Two glow plugs listed:
1P7324 (24v) and
4N360 (voltage not listed)

 

[kshansen]

It's very possible I have mix-matched head / precomp / glow plug parts from when they replace the head.

Edit:
For my arrangemnet the parts book shows
8S7930 Pre-comb chamber
4N7466 head assy
Two glow plugs listed:
1P7324 (24v) and
4N360 (voltage not listed)

I'm getting somewhat confused, not hard for a 66.7 year old!
You list a head number of 4N7466, I'm finding a 4N7446
Then on the Pre-chamber you have 8S7930, I'm seeing 8S3970

Now for some more "Fun With Numbers"

Took the two different Glow plug numbers you listed 1P7324 and 4N0360( had to add the place holding "0" to get things to work better.

I'm finding that the 1P7324 is used in a pre-chamber 5S6795 with a Classic part number 2423437
Then working with the 4N0360 I'm seeing it used in a pre-chamber 8S3970 with a Classic part number 2423438

I do not have access that I know of that will tell me the differences between the two pre-chambers but am just guessing there is something important there to be found. Is there any chance you can see a part number stamped on the pre-chambers? Maybe right on the top? With my luck the numbers are stamped on the side so you would need to remove them to find numbers.

By the way I did determine that both of these glow plugs do show as being 24 volt versions.

 

[Old Magnet]

From hard copy manual...
Head assy 4N7446
8S3970 original chamber also interchanges with 5S6795 and 7S7142
1P7324 24v glow plug (long with spark plug type terminal)
4N0360 24v glow plug (short with small diameter stud type terminal)
2W656 is a late 3306 cyl head.
I don't know what the NWP stands for but I suspect it has something to do with the importer (china)

 

[D6c10K]

I transposed the number....4N7446 is correct

I'm going to have to pull the hood off and see if I can see any numbers. If not I'll have to pull a chamber out.
Supposed to be raining/ snowing tomorrow so maybe I'll get after it then....nice today so it's kind of an outside play day.

 

[kshansen]

I transposed the number....4N7446 is correct

I'm going to have to pull the hood off and see if I can see any numbers. If not I'll have to pull a chamber out.
Supposed to be raining/ snowing tomorrow so maybe I'll get after it then....nice today so it's kind of an outside play day.

Just to be sure you can not pull the chambers with coolant in engine or you will fill cylinder with coolant. Also it takes a special tool and you will need seals and gaskets(sealing washers at the bottom).

 

[Old Magnet]

Some chambers have part numbers stamped visible (small) without removal.
The 2W656 casting number replaces 7N8516, 7N8526, 8N1446 & 8N1187.
Injector service group is 7S9891 and the included nozzle is a 7S8772.
Optional nozzles are 8N8796, 8N1831, 8N1584

 

[D6c10K]

Just to be sure you can not pull the chambers with coolant in engine or you will fill cylinder with coolant. Also it takes a special tool and you will need seals and gaskets(sealing washers at the bottom).

I've got the spline tool....I had the head off several years ago because the last guy got the head gasket out of place on the outside of the push rod galley....leaked lots of oil.

 

[56wrench]

Are the pre-cups indexed properly for correct glow-plug orientation? The correct indexing is achieved by using the correct thickness of washer under the pre-cup. There is a specific range for the glow-plug orientation but I don't remember it off-hand. It will be in the manual.

 

[D6c10K]

I indexed them when I had the head off doing the head gasket. Can't see a p/n on the pre-cups so I'll be pulling one when I get a chance.

 

[D6c10K]

I pulled the front pre-comb. chamber and found it to be p/n 8S3970 which matches what my parts book lists for my arrangemt #4N7365.
The glow plugs I have are 3T8706

The parts book shows I should have 4N0360 glow plug and when I check Cat online for that part it shows it's replaced with 3T8706.....so far so good.

The odd thing is, if I use the SIS parts site and put in my S/N & Arrangement it says I should have pre-comb. chamber 8S3970 and glow plug 1P7324.

.




In a couple of pics I found online the two glow plugs do look different . The plug connectors I have fit the small stud on the 3T8706 glow plug but I don't know if it will also fit the other one with the "spark plug" end.
I'll have to stop by Cat and see what they think.

 

[D6c10K]

Is there any problem re-using the shim washer under the pre-comb. chamber? They seem to be hardened washers.
When I had it out before I think I bought an assortment of washers to be sure I could index them all and used some old ones and some new.
I may have put some never-seize on the threads and washers.
I'll replace the o-ring for sure.....

 

[thepumpguysc]

Nothing like hands on.. Take ALL your #'s & see what the old hats have to say.. I would even take a couple of Gp's from your engine w/ you.. Take a burnt one AND some that works.. Hell tak'um all, they'll test them real quick..
I'm sorry I'm no real help but this is precisely why I don't mess w/Cats that start w/ 33 or Cummins PT systems..
To easy to mix & match parts & just because you have a SN.. it doesn't mean squat.. in both cases..
I'm sure the guys here will give you the best path to follow. Good luck..