Valve clearances 12V diesel HZJ 80

[clivehorridge]

As a precaution and because I'm a member of the "my 80 won't go over 140kph" club, I took my 340k km truck to service to have the injectors and valve clearances checked.

Verdict: injectors OK but a valve on no. 6 has no clearance.

So they've re-shimmed it and I picked up the car yesterday evening. It drives better, I can tell that straight away. Haven't had chance to try it at speed, that will come tonight on the way to the w/e house.

Question is, I have no service history on the car, but my guess is that in all it's 340,000km, valve clearances will not have been checked/ tampered with, ever!

So how would the factory preset reduce over time? Increase yes, with wear, but reduce to zero?

Any offers?

I'm also concerned that the respective valve may have suffered burning, but I suppose only a compression test would indicate that. I'll try to get one done.

Cheers!

 

[Dave]

Because the valve regresses into the head/seat, thereby moving closer to the camshaft.

 

[frank rabbets]

Hi Clive

You can do a relative compression test yourself by cranking the engine over without it firing and listening to the rhythm. There should be even pulses. A weak cylinder will skip over quickly. When I worked a lot on petrol engines you could easily tell the difference with say 5 cylinders at 175psi and one at 160psi. I suspect a diesel could be tested the same way. I suppose you would have to just unwire the fuel solenoid.

Frank

 

[clivehorridge]

Because the valve regresses into the head/seat, thereby moving closer to the camshaft.

Good answer Dave, why didn't I think of that!

Cheers!

 

[clivehorridge]

Hi Clive

You can do a relative compression test yourself by cranking the engine over without it firing and listening to the rhythm. There should be even pulses. A weak cylinder will skip over quickly. When I worked a lot on petrol engines you could easily tell the difference with say 5 cylinders at 175psi and one at 160psi. I suspect a diesel could be tested the same way. I suppose you would have to just unwire the fuel solenoid.

Frank

Thanks Frank.

Many moons ago, I used to have a compression tester for petrol engines, used to screw into the spark plug thread. Looked crude, like a tyre pressure gauge welded to a spark plug! It worked though!

Cheers