gmcmhdriver

I had a cylinder head gasket coolant leak under the t-stat housing on my 1999 24 valver so I replaced the head gasket with the latest and greatest Cummins upper engine gasket set #4090035 which includes the #3977063 head gasket. All is going well except I think I am having a problem with the injector installation - or perhaps not. After installation of the injector and after installing and torqueing the injector retainer, the retainer is sitting about 2-3 mm above the cylinder head. The injectors are being reinstalled into their original holes and I am confident the injectors are fully seated in their respective cavities because I can see where the grease on the copper washer has been "squished" away after installing and then removing the injector. I can also feel the injector "bottom out" in the cylinder head as I push down on it. This situation is occuring on each cylinder. It's almost like the injectors have "grown" a few mm since I removed them a couple of weeks ago - LOL! Is it normal for the injector retainer to stand above the cylinder head the 2-3 mm that I have happening to me or do I in fact have a problem? I have noticed the inside bolts with the double shoulder allow the injector retainer to "float" a couple of mm vertically. I am using the original injector o-rings that have been lubed with chassis grease. The fuel lines and fuel transfer tubes are removed from the engine so there is no interference to the injector from these parts.

The engine is in my diesel pusher motorhome so I have excellent access and great visibility from the halogen light stands. I have built a wooden scaffold that allows me to be directly above the engine. I can see everything and there is no debris or anything in the injector cavities in the cylinder head. Am I missing something here or is this a Cummins design intent - a normal situtation? Maybe I have lost some parts - like a shim assembly or something? Or perhaps not? I'm an old geezer and have been working on hundreds of car engines for over fifty years but is the first time I have been inside a diesel engine. Thanks in advance for your help. Ken B

Beast2B

original washers or new washers? new ones not deformed as much or different thickness?

gmcmhdriver

Thanks for the response. The washers are the original copper ones as are the o-rings. When removing the injectors, I wrapped them in a shop towel and put them into separate baggies that I marked for each cylinder. I did the same with the fuel transfer tubes and put them into the same bag with each injector. I am "reinstalling" the injectors back into their respective cavities. The injector retainer has a ridge on one side and I have installed the retainer with the ridge facing down into the corresponding groove in the top of the injector. Is this the correct way to install the retainer or do I have it upside down? With this retainer ridge installed into the grove in the injector and after tightening the screws, the retainer is standing proud of the head by perhaps 0.130 inch, maybe even a little more. Somehow this just does not seem right to me. Ken B

98whitelightnin

Is it just one of the injectors or all? If just one, try swapping them around as they are all the same. Would a head gasket with a different thickness have anything to do with it?

gmcmhdriver

It's every one of the injectors. They are all sticking up the same amount. I am missing something here and it is staring me right in the face. I guess what I need to know for sure is - - do the injector retainer plates get installed with the ridges up or down? It has been a couple of weeks since I removed them so I cannot remember for sure. It seem to me they should be installed with the ridges down where they fit into the top of the injector to keep the injector from rotating in the cavity in the cylinder head.

Beast2B

it's been 8 years since i did my sticks, so I'm no help. C'mon diesel-heads, which is right side up?

gmcmhdriver

I have found out from Cummins that the ridge on the retainer goes into the groove in the injector top, just as I thought. However I still cannot find out if the injector retainer is supposed to be flush with the clyinder head or not. Mine wind up being a little over an eigth of an inch above the head. I can see the threads on the screws between the injector retainer and the cylinder head. All my experience tells me this is not a good thing. It is like the injector retainer is standing on a couple of stilts. I will try and seat the injectors once again tomorrow and see what haappens. Might even take some pictures.

98whitelightnin

Yes the retainers sit down inside the injectors. Its been a while since I have done injectors but I dont think they stick up any. Did you remove both retainer bolts or just the passenger side when you removed the injectors? The drivers side is ran all the way down, you should be able to take the injector out without removing the drivers side retainer bolt.

turbomar

Yo! what you are discribing is just fine. there should be a gap between the injector hold down clamp and the head. This ensures that your injector is under constant tension against the copper washer for optimal sealing. Here's a link:
http://www.dodgeram.org/tech/dsl/ISB...or_replace.htm

review step 8 and 9 of the install procedure to properly setup the injectors and their tubes

gmcmhdriver

Hey, Thanks much Turbomar - -this is exactly the information I needed. I really could not see any other way for the injectors to be installed. I realized the injector has to make a high pressure seal at the cylinder head combustion chamber but thought the hold down plate should be a little closer to the head. If you're ever in upper Michigan, let me know and I'll spring for the steaks and beers! Thanks again for your assistance Ken B

AK diesel dog

Yep, that sounds right! I just put new injectors on last weekend and there was a gap between the hold down clamp and the head!

gmcmhdriver

AK diesel dog - - thanks for your response. Then injectors are in, the valves have been adjusted, next is coolant hoses, belts, oil & filter change and then I'll fire it up. Too cold to do any work today - - 40 and snowing a little here in upper Michigan. Thanks again folks for all your help. I'll get back if I have any more problems. Ken B