Thread: 4BD1 Knocking

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.

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.

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...

Originally Posted by Adrian18

So why do we have holes in pistons ie Justins customer

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.

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

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

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?

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?

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 ?