Valve adjustment Part 2

[Marvin Gruber]

After adjusting all the valves on the 68, I crank it up. Sounds pretty good, no loud clacking. Idles smooth. Take it out for a run. No power, will just pull itself to 50 mph. Adjust distr timing, some help but not much. Cranks better than it did. When you rev it up the carbs make a loud moaning sound. I check the plugs. Dark but brownish color. Not bad. Guess I'm going to have to adjust the valve timing? I didn't move anything when I had the cams out. Wired the sprockets to the chain so nothing got moved. My question is with resetting the valve clearances ( from basicly 008 intake & 012 exhaust to 004 & 006) make that much difference in the valve timing setup? I didn't have my valve timing guage today but I did find it a few minutes ago so that will be my next step tomorrow.

Marv

 

[Deleted member 8987]

Well, the .012 basically retarted your valve timing.
You cannot pull the cams without resetting them on the toothed hub.
Even if you adjust the upper chain many, many times, the cams will need to be reset.
Old races used to tell me to what, advance one, higher top end, terrible low end, Retard the other, it'll scream off the line, but no top end.

 

[Marvin Gruber]

Checked my timing. w/#6@ TDC, Exhaust was at 11 and intake was around 1, pulled spockets and set both to 12. Runs great, whew! I'm happy, little clacking but may reset one.

Marv

 

[Deleted member 8987]

Ain't XK engines fun?

 

[Marvin Gruber]

I can see why they get big bucks to do a valve job. I bet I have 20+ hours in that little project.

Marv

 

[Deleted member 8987]

20 hours, Easy.
On mine, to get the inlet rocker cover off, you have to remove both carbs.
But, with a shorter deck height, easier at the aft end.

 

[DrEntropy]

I can see why they get big bucks to do a valve job. I bet I have 20+ hours in that little project.

Marv

And why a lot of them sounded like they were going to rattle themselves to death.

On our 'Wall of Shame' we even had a few 'home-made' shims... half-inch BAR STOCK, apparently ground down to thickness on a <span style="font-style: italic">grinding wheel</span>. Amazing what kinds of sins DIYers will commit to save a buck.
And what passes for safety wire in some of those sprocket pin bolts, too. Paper clips, finishing nails... :shocked:

 

[Marvin Gruber]

I put everything back together and then remembered I didn't safety wire the sprockets bolts. I did have one valve that was making a slight noise so I didn't mind taking it back apart one more time.

BTW- if anyone needs shims I bought a bunch of them from a garage that went out of business in 02. Have multiples in the whole range. This is first time I have used any of them.

Marv

 

[DrEntropy]

You oughta be <span style="font-style: italic">really</span> good at that R&R by now, Marv! :wink:

 

[Marvin Gruber]

Took her for a spin today, runs smoother than it ever has. Even left a 20 ft tire mark to get rid of any old rubber. Plenty of power. I'm happy.

 

[LarryK]

In 78 or 79 I had the head off my 73 XJ6 for a rebuild as it swallowed a cam follower. I rebiult the engine and was ready for the head when I called the dealer fo a quote to adjust the vavles with the head off. I was told 8 hrs. + parts. Even back then that was a load of money as I had dumped $2K in the rebuild and $500 for a head rebuild with bronze guides.
I ordered 3 sets of shims and when they arrived I had them adjusted in an hour and the head back on by the end of the day. Dealers never charge for the shortcut just the flat rate.

 

[DrEntropy]

Yup.

When I'd do a rebuilt twincam head, I had a set of "dummy" shims. All the same (thinnest) size. Then it's just simple math to get to the proper clearance. Usually use a Sharpie marker to note the first clearance on the edge of the head at the gasket surface, wipe it off with thinner after the math. :wink:

Have a set of 'setup' shims for Jag, Lotus and Alfa. Makes the job simple for me.