Jx Valve Shim Help Please

[*BISH*]

I`m in process of adjusting the valves on my JX diesel and cant get my head around the shim sizes and what to order. In short I`m having a brain freeze!!


Can anyone help me? I need to get the shims ordered from Brickwerks pronto!! I know that I need to get the exhaust value to 4.5 and the Inlet value to 2.5.



These are the measurements that I have looking down on the engine in order;



1 Exhaust; Gap = 0.5

Shim in = 3.65

Shim needed = ?



2 Inlet; Gap = 0.2

Shim in = 4.00

Shim needed = ?



3 Exhaust; Gap = 0.5

Shim in = 3.85

Shim needed = ?



4 Inlet; Gap = 0.2

Shim in = 4.10

Shim needed = ?



5 Inlet; Gap = 0.2

Shim in = 4.10

Shim needed = ?



6 Exhaust; Gap = 0.5

Shim in = 3.90

Shim needed = ?



7 Inlet; Gap = 0.15

Shim in = 4.10

Shim needed = ?



8 Exhaust; Gap = 0.5

Shim in = 3.95

Shim needed = ?



I look at number 1 gap that I have, and make it that I need a 4.15 shim to close the gap to 4.5. Or then I look again and think that I need a 3.70 shim! Which is correct?



I feel like a dunce asking, but I want to get this right!



Cheers.

[colinthefox]

I can't quite understand your numbers there.

When you say "I know that I need to get the exhaust value to 4.5 and the Inlet value to 2.5" presumably you mean 0.45mm and 0.25mm. I don't have the figures available right now, so can't check them out.

If that's what you're aiming for then I would be quite happy with your existing figures, which are around 0.5mm exhaust and 0.2mm inlet. If you really must change them you will need a 0.05mm thicker shim to reduce the clearance by 0.05mm, and a thinner shim to increase it. Therefore in number 1 exhaust you'd need 3.65mm PLUS 0.05mm = 3.70mm.

0.05mm is around 2 thou in old money, which won't make any appreciable difference to your engine. The figures you have tell me that things haven't moved much since it was previously shimmed up. The main worry would be if one of the gaps had closed right up which would indicate a sinking valve or valve seat, which you obviously haven't got.

[E D I T] Reading again, I'd maybe keep an eye on number 7 in 12 months time, but wouldn't bother changing it now. [/E D I T]

If I've completely misunderstood your query, please ignore all this.

[*BISH*]

Ha, yep looks like I've confused myself with decimal points!
Thank for your reply, sussed it now!

[California Dreamin]

Inlet 0.2 - 0.3mm
Exhaust 0.4 - 0.5mm supposed to be checked/adjusted when warm.
I've got dozens of shims, 4 & 5cylinder push down tools and shim pliers...shame you're not closer.

1 Exhaust; Gap = 0.5

Shim in = 3.65

Shim needed = 3.70mm



2 Inlet; Gap = 0.2

Shim in = 4.00

Shim needed = 3.95mm



3 Exhaust; Gap = 0.5

Shim in = 3.85

Shim needed = 3.90mm



4 Inlet; Gap = 0.2

Shim in = 4.10

Shim needed = 4.05mm



5 Inlet; Gap = 0.2

Shim in = 4.10

Shim needed = 4.05mm



6 Exhaust; Gap = 0.5

Shim in = 3.90mm

Shim needed = 3.95mm


7 Inlet; Gap = 0.15

Shim in = 4.10

Shim needed = 4.00mm



8 Exhaust; Gap = 0.5

Shim in = 3.95

Shim needed = 4.00mm

People take note* should be checked & adjusted at every main service.

Yes...every shim is out by one...No 7 out by two sizes and on the 'small size' if this was being serviced correctly then YES, it needs doing.

Martin

[*BISH*]

Thanks for that Martin.

Once I got the decimal point in the right place, I was ok. What a dullard!

Anyway........ shims are now ordered.

Thanks again.

[California Dreamin]

Swap shim 2 for shim 7 and that will adjust them both to correct spec.

All the others would then be 'on limit' but not dangerously 'closed up' ...which is the main thing you are trying to avoid in order to prevent burning valves.

Martin

[California Dreamin]

JX shims are a bit of a bug bear with me....knowing that people out there are taking your buses for services but very few garages are actually checking tappets, which happens to be one of the most critical parts of the service.
Because there are 'Special tools' involved, this part of the service is often not being done.

Martin