Hi guys, I have never measured a valve gap before and was wondering how much you should expect to push on the feelers to slip them into the gap.

On the 4.2 engine you can't slip the feelers in directly, the need to bend to get between the cam shaft and the shim so you do need to push on them a bit to get them to bend.

Right now I can fairly easily slip in a 0.3mm feeler onto the exhaust valves, the max spec is 0.27mm.

The specs are:

Inlet valves clearances (mm) 0.18 - 0.22
Exhaust valves clearances (mm) 0.23 - 0.27

Is it easy or difficult to slightly compress the spring and get a false reading?

Video here in a few minutes.

 

You do realize that you can buy ANGLED feeler gauges for situations like this.
They are less common but they can be found.

bob gauff

 

It should take a bit of a push but not require forcing - the 0.25 looks about right.

Far better to err on the wide rather than too small a gap. Too wide just results in a bit of valve clatter sound but too small a gap can prevent the valve closing properly giving blowby and eventually burning the seat.

I've chosen my words very carefully to avoid giving the double entendre spotters too much ammunition!

Graham

 

Thanks, I have never come across these before, just orders a set from ebay for $10.

 

Thanks Graham, looks like all the exhaust valves were about .25mm and all the inlet valves were .2mm.


I'll have another look when I the angled feelers arrive.

 

As it has not been mentioned, the proper way is to use two stacks of feeler gauges.

One stack is bigger than the desired clearance and one stack is smaller.

The bigger one should not pass through the gap while the smaller one does.

 

Anyone know where you can buy the valve hold down tool 303-540 at a reasonable price?

 

I have used that tool and I will tell you now that it is DIFFICULT to adjust the valves with it. My advise is to REMOVE the exhaust cam and replace shims that way.

The tool (or some way of depressing buckets) can be used for the intake cam as it is very time consuming to remove the cam.

I would leave the lash alone if it is close. You are going to be frustrated trying to get the lash perfect if that is your goal.

bob gauff

 

I was able to measure the valve gaps today with the angled feeler gauges.


The specs are:

Inlet valves clearances (mm) 0.18 - 0.22 or 7.09 to 8.66 thous

Exhaust valves clearances (mm) 0.23 - 0.27 or 9.06 to 10.63 thous


The inlet valves, back of engine to front are (well these were the biggest feelers I could get in) in thous.

9 - 9 ==== 10 - 9 ==== 9 - 8 ==== 8 - 7


The exhaust valves, back of engine to front are, in thous.

11- 12 ==== 11 - 12 ==== 11- 11 ==== 10 - 10


So most are out of spec, and one inlet and 2 exhaust, are very out of spec.


Could this cause the warm up noise I'm experiencing and do they need to be fixed?

 

Tiny print is hard to read.

In my opinion, they are not far enough out to be noteworthy.

Check the parts catalog and see what is the smallest increment
that you can change. If it is a thou or more, then you are unlikely
to be able to change anything under a thou difference.

 

I agree.

I've not adjusted the tappets on a Jag but I've done it on Lotus & a thou or two out is acceptable, especially the ones that are too large as they'll wear smaller as the valve head hammers it's self into the seat.

 

FYI...

A Go-No-Go feeler set is the hot ticket for checking things... I didn't find them in angled, but here's a straight set...


example: one blade is 10/12... slips in easy, but won't go past the 12 without extra effort? gap = 11... easy peasy...

 

Hi folks, my first post here. I am still in search of my XK8 so I cannot comment on the ease or difficulty of this service for this engine but I had an 89 Taurus SHO that needed this every 60k miles. It calls for 2 simple tools. One holds the bucket down and the other pops out the shim. I used a magnet so not to lose the shim. A pain of a service on a transverse engine. I couldn't find the service interval for this on the XK8. I was under the delusion it wasn't needed. How often is this done? Thanks