Valve compressor for 3.8 XK engine - availability

[bob3913powell]

Where can I obtain (to buy or hire) a valve compressor suitable for my 1967/68 3.8 XK engine cylinder head?
bob3913powell

[PPV]

Have you tried the club spares department? They seem to have most items for hire.
Regards,

[oldtimer]

Hi Bob,

The correct tool for all XK Jaguar engines is a valve spring compressor made for Jaguar and supplied by Churchill tools No JD 6118.
A picture of this shows that it would be fairly simple to make. It comprises of a block that attaches to a chosen cam shaft bearing with the cap removed . A two foot length of inch diameter water is pipe attached to the block by way of a hinge. A link which slides along the tube has a drop down similar to a socket with scallops cut in each side and engages with the edge of the valve spring retainer. Not a very good description but hope it makes sense. When the lever is pressed down the spring is compressed. To prevent the valve from opening six half round wood blocks need to be attached to a six inch wide length of five ply. The cylinder head is then placed onto this and it's own weight keeps it in place. Each valve spring can be compressed and the collets hooked out through the scallops referred to earlier. And of course it makes re assembly so much easier and quicker

Companies like Halfords, Jack Sealy and Machine Mart amongst other probably supply the more commonly used G clamp. These are suitable for smaller engines . Should you chose this route it is essential to ensure the G is large enough to accommodate the Jaguar head.

I have struggled with the G cramp style spring compressor and found it most unsatisfactory

I have the dimensions for the wooden supports should you require them.

Oldtimer

[piman]

Hello Oldtimer,

I have a video by Ron Beaty of Forward Engineering (As was) on rebuilding the XK engine. The fitter in the video used a tool which I've never seen before and have been unable to source. It was simply a circular tool about 6" to 8" in length. He used the board you describe and sipmly pushed this tool directly onto each valve which released the collets. The clever bit is the same tool is used to replace them and I'm wondering how it works?

Alec

[oldtimer]

Hi Alec,
That description makes absolute sense . If you can imagine a round ring (a bit like a thick washer with the hole in the middle large enough to extract the collets) that would fit over the top of the spring/collet retainer with two short vertical stays welded onto the ring And then the other ends of the stays welded on to a piece of say 1 1/2 inch diameter tube And then obtain an old shovel and chop the shaft off 6 inches below the handle and insert the short shaft into the 1 1/2 diameter tube , there you have it.

If the above makes sense to you ,How does that sound ?

That sounds fine but I think you would need to resemble a Gorilla to have the strength to press it down and compress the double valve spring with one hand and remove or insert the collets with the other. The item I tried to describe above has much the same spring compression devise but is attached to a long handle to give the necessary leverage.

Just as a matter of interest, the first valve spring compressor I mentioned is identical in design to that used on the Rolls Royce Merlin as fitted in the Spitfire - there not everybody knows that --- really showing my age now!

Let me have your comments

Oldtimer

[piman]

Hello Oldtimer,

both removal and replacement was a one handed operation, which is why I think there is a bit more to this than a simple shaped piece of round steel. Yes the head would need to be quite low to get your body weight behind it but it was a very quick and effective tool.
The one trick I learned a long time ago on any engine is to give the valve collar a good rap so as to unseat it from the collets before trying to compress the springs, makes it much easier.

Alec

[oldtimer]

You are right, give the retaining ring a whack to break the sticksion. Give it two whacks and very often the collets jump out anyway.

Oldtimer

PS Don't give all the secrets away