What's your rule of thumb on valve adjustment frequency?? Just curious!

 

They are seldom adjusted.

Not sure if this is because the clearances are seldom checked, or because adjustment is seldom needed, or because the actual job of adjusting them is a royal PITA.

*Checking the clearances* is easy, though, so you could do so to satisfy your curiosity if nothing else.

Cheers
DD

 

+ heaps.

Although, as Doug does know, the 6 cylinder is a snap compared to the V12, but since you have a 6, we will leave right there.

 

No experience with the valves on this engine. But, some in other
non hydraulic lifter engines. It is a metal to metal thing. Most, if not all engines in this design live out their useful lives sans valve lash adjustment.


Caveat; That is assuming no abuse.


Very early engines had no means of setting lash other than removing metal. Good for the life of the engine. But, in that era, 100,000 miles was a minor miracle.


The only "weak spot", if indeed it is that I might consider is the "shim" method to set the initial "lash". Are they as long lived as
lifter material, cam lobes, and valve stems??? I don't know.


Carl

 

Interesting, I guess it really varies per vehicle. I recall doing them on my old BMW with some frequency. The specs on the XJ are so clearly indicated on the valve cover that I thought it my be a 30K service or something.

 

Yeah, I've never seen valve adjustment on any of the 'routine service interval' charts.

Interestingly, re-torqueing the head bolts is recommended every 12000 miles....except for North American market cars where that recommendation is absent, along with a few others !

Cheers
DD

 

As to us:


1. Lower compression in USA bound cars? I dunno, if so, keeping the squeeze on not so problematical.


2. they figured that most of us ain't gonna do it anyway...


3. The guys/gals that lease/buy a new Jaguar are not going to keep it over a couple of years...


4. No 100,000 mile warranty to concern Jaguar. I don't know.


Carl

 

Thinking back over the years/decades about the OHC/shim and bucket engines I've had, vs. lifter/pushrod/rocker type, I can't recall seeing an adjustment interval at all for any of the OHC examples.