4BD1 Knocking

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Originally Posted by lokka

Nope i thought he may have responded to my last post with the offer of help but ive had no reply .:D

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Sorry mate, didn't mean to be rude :-D didn't take notice of half the replies till now.

A heavy breathing Isuzu is not unknown!

Do you have the provent hooked up with the vent into the turbo inlet?

Fingers an toes are crossed here.

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Originally Posted by Bush65

A heavy breathing Isuzu is not unknown!

Do you have the provent hooked up with the vent into the turbo inlet?

Fingers an toes are crossed here.

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Yeah, but I was getting definite blowby through the oil and out the filler and dipstick. The vibration and knocking was enough to make me think that serious damage was being done but I can see no wear and tear so far. Prior to the knocking, I heard squealing like a pulley bearing failing but couldn't find the source. Related to the problem, I don't know...

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Originally Posted by Adrian18

So why do we have holes in pistons ie Justins customer

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My guess.
Dribbling injector leading to a hot spot, combined with no piston-squirters (4BD1+T, not factory T) to cool it and a hot tune (high EGT) to heat that spot enough that it softens and eventually blows through.

IIRC Justin said one holed, two cracked.

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Originally Posted by Ancient Mariner

Have posted these pics before but might be relevent here 83000 k out of my Isuzu truck one of the oil holes to close to the combustion chamber:mad:

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Which engine was that? Piston has one more ring groove, longer skirt sides and a different combustion bowl to my 4BD1T.

The engine is a 10 liter 6sd1tc.Posted pics only as an example of pistin failure

Nah wont fit in a Defender:( Unbelivable the amount of blowby from sutch a
small hole. I have 3 pistons from a 3bd1 here if Mike needs a pistin
The 4th was outside the block so did`nt get counted:o

AM

Squeal could be AC pulley, or loose alt? The only critical thing run from rubber that I know of is the water pump.



Was the rough running at idle or through what rev range?

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Originally Posted by flagg

Squeal could be AC pulley, or loose alt? The only critical thing run from rubber that I know of is the water pump.



Was the rough running at idle or through what rev range?

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She was running really rough at idle, would smooth out as the revs were increased. And the vibration and knocking at low rev got progressively worse over a fairly short period of time, hence me parking it up asap.

The reason I mention squealing is that are there any bearings at each end of the crankshaft that could have failed and thrown the engine out of balance?

Hows the harmonic ballancer ?

Well, I just pulled the pistons, and piston #3 did have a slightly stuck compression ring - ie. smaller of the two compression rings was stuck at one point around the circumference of the piston but free everywhere else but other than that it looks good. #3 sleeve also came out a few mm when I was tapping out the pistons but that shouldn't be an issue. I'm honestly a bit baffled right now...