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Nozzle Question by boosted_diesel_84 on 16 Nov, 2009 16:05
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so i have GTD nozzles installed on my TD, but just does not seem right......so i checked the breaking pressure of them and it was a little low at number 1 being 2150, 2-2300 3-2250- 4- 2150 and these are brand new with less than 8k miles on them, none leaked though, what should i do?
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#1 by Smokey Eddy on 17 Nov, 2009 12:52
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The breaking pressure is determined by the width of the shims inside the injector. You could lap the shim inside it to make it smaller. A thinner shim would result in higher pressures necessary to break right? can someone else confirm this?
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#2 by theman53 on 17 Nov, 2009 15:37
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I haven't done it but I would think the other way. Thicker shim higher breaking pressure. I could be wrong, but the spring would be harder to push if it is compressed more than if it was compressed less.
2278 is what you are looking for correct? I don't know how far off you are allowed but I would think 1 and 4 need some attention. -
#3 by burn_your_money on 17 Nov, 2009 19:07
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Ok, so your injectors are 148 158 155 148 BAR. Bosch uses bar so that is what I'm use to.
How's the car running? If it's smooth I wouldn't worry to much about it. Maybe check them again in another 1000kms and see what's up. If it's idling rough then I would definitely shim up #1 and #4 to around 157 bar.
How was the spray pattern?
Increasing the size of the shim increases the opening pressure
Where did you get your nozzles from? -
#4 by boosted_diesel_84 on 17 Nov, 2009 21:08
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Ok, so your injectors are 148 158 155 148 BAR. Bosch uses bar so that is what I'm use to.
How's the car running? If it's smooth I wouldn't worry to much about it. Maybe check them again in another 1000kms and see what's up. If it's idling rough then I would definitely shim up #1 and #4 to around 157 bar.
How was the spray pattern?
Increasing the size of the shim increases the opening pressure
Where did you get your nozzles from?
car runs ok, i think it could be better
spray pattern was good, nozzles were bosch GTD nozzles that i bought new from a seller on ebay
where can i buy shims from and how do i know what thickness i need? -
#5 by Smokey Eddy on 18 Nov, 2009 02:05
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ah so i was backwards
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#6 by Mark(The Miser)UK on 19 Nov, 2009 08:18
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The variation probably comes from injector body and spring variations.Ok, so your injectors are 148 158 155 148 BAR. Bosch uses bar so that is what I'm use to.
How's the car running? If it's smooth I wouldn't worry to much about it. Maybe check them again in another 1000kms and see what's up. If it's idling rough then I would definitely shim up #1 and #4 to around 157 bar.
How was the spray pattern?
Increasing the size of the shim increases the opening pressure
Where did you get your nozzles from?
car runs ok, i think it could be better
spray pattern was good, nozzles were bosch GTD nozzles that i bought new from a seller on ebay
where can i buy shims from and how do i know what thickness i need?
A good nozzle operating @148bar is fine.
Best thing to do is to lap the higher pressure shims down to meet the lower pressures.
Firstly dissasemble those two injectors and check the thicknesses of the shims.
If the thickest shim is on the 155 bar injector then putting the other shim in will bring you down some.... Maybe enough, then you only need to lap one shim only.
This is easier than lapping mating surfaces which may lead to body leaks. -
#7 by boosted_diesel_84 on 19 Nov, 2009 18:22
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well what if i just wanted to send them out to a rebuilder to get a second opinion, and have them fix it, who is good and cheap?
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#8 by Mark(The Miser)UK on 20 Nov, 2009 19:41
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no such thing as 'cheap and good', unless you look in the mirror.
An alternative to shim or spring abrading, is to use little pieces of tape measure spring. These will raise the pressures between 7 and 10 bar. You can make 500 for a few $.
Putting these shims under the existing shims of the 2 148bar injectors, will thus bring everything into spec.
Contrary to the myth created by the normally very astute Mercedes Forum gang, the hole in the shim is totally unneccessary, or at the very least does not restrict leakoff.
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#9 by smutts on 21 Nov, 2009 10:16
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Quote
no such thing as 'cheap and good', unless you look in the mirror. Grin
