Diesel knock

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clone123
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Diesel knock

Post by clone123 »

Hi help needed ever since I did my conversion from a 1.6 JX to a 1.9T 1y engine I have always had a diesel knock and I'm just wondering if anyone can tell me which is the best way to get rid of it I have most of the parts of the JX engine including the inlet manifold exhaust manifold turbo the diesel pump the diesel injectors diesel pipes this is the first time I've messed about with diesels any help will be much appreciated do I need to change my setup or is there an alternative to getting rid of it there was no knocks from the engine before the convertion
1985 RHD T25 hightop camper 1.9td 1Y engine
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colinthefox
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Re: Diesel knock

Post by colinthefox »

I think the first question to ask is whether the knock is on one cylinder, or all four cylinders evenly.

If it's on one or two cylinders only, suspect bad injectors first. You can test which cylinder it is by slackening the tube nuts at the injector slightly, one at a time. If the knock disappears and the engine is just firing on the other three, then it's that cylinder at fault. A poor spray pattern from that injector would be the most likely cause. It's unlikely to be injector pump related, because rotary pumps don't usually fail that way. When slackening the nut, be careful of high pressure diesel spray which can penetrate the skin. Put a rag over the injector to prevent that.

If it's on all four cylinders, with horrible lumpy running and loads of black/grey smoke, suspect bad fuel. The solution is obvious. I've had this with tractors left out in the rain with water/sludge in the fuel.

If it's all four cylinders, with just a more "dieselly" sound, rather than a loud knock, suspect timing too far advanced.

If it's on all four cylinders, with white smoke on startup, suspect timing too far retarded (unlikely to be knocking though, I would have thought)

It's very unlikely to be all four injectors gone bad, unless the engine has been run on substandard fuel (ie chip fat)

If it's a bad injector or two, you'll need to take all four to a diesel specialist to have them tested/serviced. I'm not sure which injectors the 1Y has, but I wouldn't use injectors from a different engine. I think the JX injectors are single stage and the 1Y probably two stage injection.

If the engine is running at all then it's unlikely to be the injection pump failed. They are very reliable.

Hope this helps.
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clone123
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Re: Diesel knock

Post by clone123 »

Cheers for all the info colin the van runs fine been running it for the last 12 months just noisy on tickover but sounds fine with a bit of acceleration and pulls like a train .Thanks again that should keep me busy for a while will start testing when the weather permits. :ok
1985 RHD T25 hightop camper 1.9td 1Y engine
It's always easier with a friend

clone123
Posts: 301
Joined: 30 Oct 2015, 22:05
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Location: Manchester

Re: Diesel knock

Post by clone123 »

All injectors seem ok on testing do you no what I should set the pump lift to with using the jx pump and injectors on the 1y engine.

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1985 RHD T25 hightop camper 1.9td 1Y engine
It's always easier with a friend

colinthefox
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Joined: 20 Oct 2009, 18:42
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Location: Somerset
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Re: Diesel knock

Post by colinthefox »

clone123 wrote:All injectors seem ok on testing do you no what I should set the pump lift to with using the jx pump and injectors on the 1y engine.

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Sorry, can't help you there, I have no knowledge of that combination.
1.9D (AEF) pop-top. Aaaaahhhhh........that's better.
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clone123
Posts: 301
Joined: 30 Oct 2015, 22:05
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Location: Manchester

Re: Diesel knock

Post by clone123 »

Thanks for that but just remembered the lad that help me set it up on here told me but I just forgot and I just remembered it's .95 mm to 1.05 mm thanks again

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1985 RHD T25 hightop camper 1.9td 1Y engine
It's always easier with a friend

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