Valve train issue

[erad]

I think you're looking at the wrong valve. The valve causing problems has come up into the rocker cover area, it's valve spring is no longer under tension, i can spin it by hand while that's impossible to do on the other 7 valve springs.

I have never seen a tappet adjustment like that before. It looks as if someone has installed a whole set of valves which are too short in the valve stems for the application and the dud #4 exhaust valve is the only one which is "normal'. The head of the valve stem is in the normal position, so I don't think it is the collet letting go, but if you can spin the valve by hand, there is no tension left in the valve spring. Head has to come off.

[tomwithannl]

You will probably find it is loose valve seats in the head allowing them to hammer and rotate and then receding into the softer head. I also agree with erad's comment that the valves (the ones with the adjusting screws on the underside) have probably been replaced with incorrect length ones, too short.

Tom

[Roshan C]

You will probably find it is loose valve seats in the head allowing them to hammer and rotate and then receding into the softer head. I also agree with erad's comment that the valves (the ones with the adjusting screws on the underside) have probably been replaced with incorrect length ones, too short.

Tom

So basically i shouldn't bother repairing this cylinder head?
I am also considering dropping in the spare L300 engine i have sitting on my front porch
it looks to be in good shape, got it from a super rusty L300 non runner couple years ago.

I can just swap over the oilpan, fuel pump and turbo stuff right?.
The last option sounds daunting as i've never undertaken something of this scale.

To be honest i got this pajero really cheap, fixed most small issues. There were lots of questionable stuff done to it! but whenever neccesary it got me to school and back without issues.

[Roshan C]

Update: Removed the cylinder head with some help from dad and this is what we found. #4 exh. Valve seat is still there, but the valve has burned away and sealed against the exhaust port. Cyl 1 Exhaust valve has a very sharp edge left, only a matter of time until it would do the same.

[Roshan C]

Some more Pictures: https://drive.google.com/folderview?...JC92tZbtKtZbPA

[tomwithannl]

In over 50 years as a mechanic I have never seen a valve pulled into its seat as bad as the one in your pic WA0001. It is usually the seat that has the problem. I would hazard a guess and say they are poor quality non genuine parts. I would be looking for another head and start afresh.

Tom

[Roshan C]

After cleaning up all soot it turned out the valve edges burned up and left the valve seat intact. This is the first time i took a cylinder head appart, you're the third person who tells me he's never seen valves this bad

I went ahead and cleaned up 'edge' the valve had left behind from sealing the port, in a few days when i'm finished sanding all leftover sooth and rough casting marks it's going to a machine shop.
Afterwards i can say i did that damage in 1km of driving after turning up the fueling, this valve must've had very little life left.

[Roshan C]

Update: got a call from the machine shop, all valve seats are okay just the valves need to be replaced

[4ePikanini]

don't skimp. Do the seats and the valves and the guides and the stem seals now with new keepers.

Set the lash on the bench before you drop the head on.

[Roshan C]

I've now put everything back together, engine sounds much better. But it's still hesitant and does not rev freely, stutters and shakes at certain rpms when revving up