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Old 12-04-2009, 08:33 PM
Yak Yak is offline
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Join Date: Aug 2009
Location: San Antonio, TX
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prechamber leak test and fix?

How do you diagnose whether you've got a leaking prechamber and how bad does it need to be to require fixing?

I reamed the glow plugs and after bleeding the fuel lines I noticed a few tiny bubbles coming from what appeared to be both the outer ring (prechamber-head) and the inner ring (injector-precamber). The pic in this thread is about right: How big a problem is a prechamber leak?

Do I put soapy water in the area and look for bubbles to form? If there are bubbles but no significant air-leak noise and the engine idles okay, should I not worry about it?

I'm planning on doing a compression test, but figured if the injector or pre-chamber is leaking I may as well fix the leak when the injector is out and want to buy the parts ahead of time.

If I want to replace the prechamber sealing ring, is the standard 2 mm size the first choice? I've read you would only need the oversize 2.3 or 2.6 mm if the head has been milled, is this correct or is there some other rationale for an oversize sealing ring?

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Old 12-04-2009, 09:42 PM
DeliveryValve's Avatar
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Join Date: Jun 2006
Location: Central California
Posts: 4,132
You can use soap and water to see if bubbles are forming. But that is pretty much done on a cold engine. On a warm engine, you might want to try a light oil. But put a little first to make sure it doesn't flash fire.

The sealing ring is 2mm. It will take 150 lbs ft of torque to lock down the pre-chamber retaining ring. If you see a problem. You might want to try tighten this ring down and save you from pulling the pre-chamber.

Another source of the the problem could be the heat shield on the injector could be defective. You might want to try to replace that first if you don't have the tools to deal with the pre-chamber.

If you do remove the pre-chamber, make sure you inspect it thoroughly for any cracks or any damage to it's shape.

1983 123.133 California
- GreaseCar Veg System

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Old 12-05-2009, 01:32 AM
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Join Date: Sep 2007
Location: Long Beach,CA
Posts: 29,900
If you remove the Prechamber remember to remove the Glow Plug first.

84 300D, 82 Volvo 244Gl Diesel
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