Brett Gazdzinski wrote:-
I thought I would update the list on the head gasket\valve adj.
job.
Does anyone have a good reason why I cant just turn the shim over?
The wear seems to happen where the valve top sits on the shim,
the shim to bucket surface seems to get stuck by the sludge\varnish.
I>s there a valid reason I cant just turn them over, since the
bucket surface is wider, and does not seem to wear much…?
Brett,
The dealers all keep a box of old shims, turn them over and use
them again. Be careful when you put the micrometer on them to
check thickness that you check at the edge and not the centre
otherwise it sits in the worn cup and gives you a false reading.
I learned that the hard way!
I stopped by a place in South Jersey called Eddies Jaguar restorations.
Eddie, a nice older guy, thought I was nutz for taking the engine
apart(along with my wife), said I should replace the valve guides
or have inserts installed(they do this for cars that used to run
leaded gas). He said the seals wont last long.
Valve guides OR have inserts installed? When you do a conversion for
unleaded the valve guides are only replaced if worn. If the guides
and valve stems are worn, the valve can move laterally thus wrecking
the seals. This is a shop job as the head has to be heated before
the inserts can be drifted out. Any suggestions that this can be done
in boiling water are wildly optimistic.
The valve inserts are replaced not because of wear but incompatible
material. Seats suitable for use only with leaded fuel rely on the lead
to preserve their integrity and are quite quickly destroyed running
lead-free. The head also has to be heated to fit new seats and
these then have to be cut to the correct angle before grinding in the
valves.
Did the head lift off easily or was it “frozen” on the studs?
Graham Gardner
1989 XJ40 2.9
Graham Gardner wrote:
Brett Gazdzinski wrote:-
I thought I would update the list on the head gasket\valve adj.
job.
Does anyone have a good reason why I cant just turn the shim over?
Brett,
The dealers all keep a box of old shims, turn them over and use
them again. Be careful when you put the micrometer on them to
check thickness that you check at the edge and not the centre
otherwise it sits in the worn cup and gives you a false reading.
I learned that the hard way!
No dealer I know of would waste his time and customer’s money by
flipping shims. We have two boxes of new ones to choose from to get the
adjustment " spot on ".
Did the head lift off easily or was it “frozen” on the studs?
No studs on AJ 6 or 16 engines, These heads bolt on.
Regards, Vic
Vic wrote:-
No dealer I know of would waste his time and customer’s money by
flipping shims. We have two boxes of new ones to choose from to get the
adjustment " spot on ".
Vic,
Jaguar list 47 different valve adjusting shim thicknesses available between
0.0850 & 0.1080 in steps of 0.0005.
That’s a stock level of 1128 shims to cover for the worst case scenario
where all 24 valves take the same thickness.
That certainly is “spot on” adjustment.
Graham Gardner
Vic Wrote:-
I don’t envy you that job, pulling Series III heads is one of my least
favorite jobs. Even if the head comes off easily, getting the intake to
break loose from the head is a real chore. I hope yours is not
difficult.
Vic,
I avoided the Series 111 after a bad experience with a Series 11 which had
serious rust problems.
It’s a 2.9 XJ40 that’s developing noisy timing chains.
Brett’s experience with his 3.6 suggests that the all aluminium engines are
a lot easier to split than the aluminium head/ cast iron block XK units.
Regards,
Graham
Graham Gardner wrote:
Vic wrote:-
No dealer I know of would waste his time and customer’s money by
flipping shims. We have two boxes of new ones to choose from to get the
adjustment " spot on ".
Vic,
Jaguar list 47 different valve adjusting shim thicknesses available between
0.0850 & 0.1080 in steps of 0.0005.
That’s a stock level of 1128 shims to cover for the worst case scenario
where all 24 valves take the same thickness.
That certainly is “spot on” adjustment.
Graham Gardner
We generally carry about five of each size in stock, and the same for
Series III 4.2 engines, and the same for the AJ 16 which takes a smaller
and lighter shim. You have to be prepared.
Vic