2.7 CDI injector issue

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fester

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Guys one of our Jeep drivers over here has a problem with one of his injectors. Apparently it's had 3 goes at seating after addressing some black death issues and he feels now the injector does not pull down through the rocker cover sufficiently to seal on the washer properly. He also has the issue of the injector bolt hole thread stripped but that is a minor hassle.

I've not done my injectors yet so not sure what he can do. Is it possible to use 2 of the copper washers to take up the slack or is there a thick washer available. Or does anyone have another solution. He says there is a lip in the cover that the injector body hits rather than pulling firmly on to the washer. AT least it seems that is the case. To confirm he has recut the seat each time but keeps getting blow by around the injector. Number 3 injector if it makes any difference.
 

Cole@MBS

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Cleaning the bolt holes out fully will cure the problem, two washers won't seal, only by spending the time doing the cleaning will get the injectors seated correctly.......
 
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fester

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He has cleaned it out thoroughly but believes the thread is stuffed. The bolt is not torquing up. He says it feels like it is past retapping. We expect to have to helicoil to reclaim the thread but he said it torqued down properly last time but still leaked. So not confident a fresh thread will cure all. Is it possible the seat has regressed so far that tge injector body does foul on the rocker cover.
 

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Has he cleaned the seats on the head and the injector(ie the parts that seat against the copper washer?
 
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fester

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Has he cleaned the seats on the head and the injector(ie the parts that seat against the copper washer?

Yes he has. He's recut the seat in the head each time which is now what worries him. Injector cleaned as well.
 

RobWheatley

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How much did he take off the seat each time, when I did our Jeep it only needs the lightest touch to get the seat clean and flat.
If he has take so much off that the injector is hitting the head/rocker cover then I would be worried that the seat/head might be too thin now.
Iirc there was quite a bit of clearance between the injector body and head.

Did he change the injector at the same time? if he did maybe the new injector is a fraction shorter than the old one.
 

Uncle Benz

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I have got into the habit lately of checking the depth of the hole with the injector and clamp in place, and then measuring the new bolt to ensure it is not going to bottom out before clamping the injector.
Attempting to stop blowing by turning the bolt further is a recipe for stripped threads if the bolt has already bottomed out. I see nothing wrong with grinding a thread or two off the bolt to shorten it slightly if needed.
 
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fester

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How much did he take off the seat each time, when I did our Jeep it only needs the lightest touch to get the seat clean and flat.
If he has take so much off that the injector is hitting the head/rocker cover then I would be worried that the seat/head might be too thin now.
Iirc there was quite a bit of clearance between the injector body and head.

Did he change the injector at the same time? if he did maybe the new injector is a fraction shorter than the old one.

Yes im worried about the seat cutting too. Same injector just cleaned up.

Where would the injector be hitting the rocker cover. Im wondering if he could open thr hole in the cover. Does it need to seal.

Could extra washer successfully still seal.
 

Uncle Benz

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Slightly thicker washers are available from MB, but i wouldn't advise fitting two.
 

Uncle Benz

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I had one to bits today, so had a close look. A dab of grease on the injector end confirms that it will touch the seat even with the copper washer left out, and by my reckoning he'd have to have cut the seat down by 8mm to run out of room at the top end.
Found this that details the different washers available.
8e79e18c720c0d51862b80ced3273ce5.jpg
 

RobWheatley

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Yes im worried about the seat cutting too. Same injector just cleaned up.

Where would the injector be hitting the rocker cover. Im wondering if he could open thr hole in the cover. Does it need to seal.

Could extra washer successfully still seal.

I think the only part that could touch the rocker cover is the inlet for the fuel unless it is the clamp hitting the head before pulling the injector tight.

When the injector retaining bolt is tight will the injector move at all?

Might be worth measuring the depth of the hole for the injector, removing a second one and measure that to see if there is much difference BUT if there is alot of black death around make sure the engine is hot BEFORE trying to undo the bolt or it WILL shear off.

The one on my Jeep was number 4 and a real pain to get to, ended up cutting the scuttle away to gain access.
 

Carl@MBS

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Check the sealing face on the injector as well this can erode away and will need either cutting or replacing, also as Cole said the bolt hole can be a bitch to clean out fully, if its not then you won't get the full clamping force required.


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Corned

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Sounds to me like it would be easier just to look for a good second-hand cylinder head.
 

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