Hi,

Collecting information about JLR newest generation of V8 engine called "AJ133 GEN III" shows me that the supercharged version of it doesn't have any automatic valve gap compensation devices either on intake nor at the exhaust side.

Instead of automatic adjustment the valve train is built with graded tappets which for sure is the best solution concerning stiffness and low mass. On the other hand the system is sensitive to all events reducing the nominal valve gap clearance which will cause burned valve seats in the end.

So a periodic check of the valve clearance would be good but I think the complexity of the job especially when you have to readjust is extremely high. Due to the use of graded tappets the camshafts have to be removed in case of any adjustment. To do this timing chains, camshaft phasing devices ... have to be removed. Jaguar told me this job will take approximatly 22h with the motor in the car (jag f-type) ! Being familiar with jaguars service fees. Wow

Because most Jags ( f-type , XKR ) will not have high mileage in short time , especially during the warranty periode, it is no big risk for jaguar not to recommend any period check to the valve train . But how is the situation on other cars like Range Rover S/C or Jag XF ?

Who has experience with (high mileage) Aj133 SC engines and can give me some advise to the following questions:

What mileage a first check of the valve gap clearance should be done ?
Whats your experience during clearance checks . Any readjustments necessary ?
What about accuracy of factory setup ?
Are there any other engine components like S/C , timing chains , tensioners ... which are more likely to break down ?
Does LR give any maintenance recommendations about this issue ?
Is it true that any valve gap adjustment can be seriously done with the engine in the car ?

Would be happy to get serious information from all who really have their hands on this engines everyday.

Best regards
Uli

 

IIRC there's no need to remove the cams to adjust the lash. There's a special tool to blow the old tappets out with compressed air.
I haven't tried to adjust the lash on a F-type yet, but this adjustment is possible in X150 and X351 Jags. Anyway, it doesn't take a long time to drop down a front subframe with an engine on it.
The accuracy of the lash seems to last forever. I've saw a lot of Jags with pretty high milage and there was no need to reset a valve lash.
Also, the factory settings are pretty accurate, i don't even remember a single claim for a whole Russian market.

The known problems are:
-VVT units
-Timing chains
There's no recomendations, except regular oil services (and as for me, the oil service interval MUST be shorter, than JLR claims).