I’m pleased to advise that the head went into place tonight.
Finally!
I am a little paranoid about bending the valves, so please check me out on
this.
I installed the head with the camshafts loose and therefore valves closed.
I should to set one camshaft (with the bearings still loose) to the position
dictated by the alignment tool (#6 cylinder with lob pointing out), tighten
the bearings and they do the same with the other camshaft. (AND THEN NOT
TURN THE VALVES INDEPENDENTLY OF ONE ANOTHER) Correct?
There is one essential thing to do before you touch the camshafts. And then
check and doublecheck that you have it right. And that is that #6 cylinder
MUST be at (you look up the position. I don’t want to tell you wrong.).
It seems to be important to tighten the cam bearing cap nuts a little at a
time. The real reason probably is to avoid undesirable stresses. I find
that tightening them gradually makes it easier to hold the camshaft in its
aligned position.
Stuff some rags in beside the timing chain so you won’t drop anything
inside.
Let’s hope that the 4 holes in the sprokets line up with the holes in the
camshafts. Install and tighten 3 bolts on both camshafts, then you can
rotate the engine enough to allow installing the 4th bolt. Then again,
maybe you didn’t remove the bolts.
Gene McGough
XJ6C II 1976
XK-150 FHC S834515DN
. . .
I installed the head with the camshafts loose and therefore valves closed.
I should to set one camshaft (with the bearings still loose) to the
position
dictated by the alignment tool (#6 cylinder with lob pointing out),
tighten----- Original Message -----
From: “Lou Danzico” loudanzico@verizon.net
Sent: Wednesday, June 04, 2008 8:12 PM
the bearings and they do the same with the other camshaft. (AND THEN NOT
TURN THE VALVES INDEPENDENTLY OF ONE ANOTHER) Correct?
In reply to a message from Lou Danzico sent Thu 5 Jun 2008:
Lou
Although not essential, make sure that the distributor is pointing
to the cylinder on compression stroke. Obviously both 1 and 6
cylinders will be at TDC but the dizzy may be pointing at either,
if you are unlucky, you can time the cams to perfection only to
find that the distributor is 180 degrees out! It’s simple enough
to pull the leads and replace them but then you have a non standard
engine…–
The original message included these comments:
I installed the head with the camshafts loose and therefore valves closed.
I should to set one camshaft (with the bearings still loose) to the position
dictated by the alignment tool (#6 cylinder with lob pointing out), tighten
I’m pleased to advise that the head went into place tonight.
Finally!
I am a little paranoid about bending the valves, so please check me
out on this.
I installed the head with the camshafts loose and therefore valves
closed. I should to set one camshaft (with the bearings still loose)
to the position dictated by the alignment tool (#6 cylinder with lob
pointing out), tighten the bearings and they do the same with the
other camshaft. (AND THEN NOT TURN THE VALVES INDEPENDENTLY OF ONE
ANOTHER) Correct?
So far, Lou, but as Gene implies; it’s absolutely(!) essential that the
engine is set to the TDC mark on the crankshaft damper…
In principle it ‘better’ to set and tighten down the camshafts on the
bench with the cams correctly positioned. Then you can observe if there
is any intervalve snagging while tightening down. But it’s no great
shakes - the important thing is really the position of the crankshaft…
To add; with the cams aligned with the setting tool the valve timing now
sets #6 as the firing cylinder. If the dist rotor now also points to
this cylinder you sitting pretty…
In reply to a message from Lou Danzico sent Thu 5 Jun 2008:
Lou
I'm new to the forum, and so far love it. I am not
however new to series one XJ’s having owned several and
worked on them for ten years. Putting on a XJ head can be
scary, I know, especially the first time. It sounds like
your doing everything right and the forum suggestions are
very good. Just remember that even though bending valves on
XJ heads is very common and easy(if you don’t know what your
doing), if you take your time and ask question like your
doing you’ll be fine. Anyone who bends valves on a new XJ
head is either ill informed or is just a bad mechanic and
never thinks it will happen to them.
It’s all a mechanical puzzle that fits together one
way, you just have to remember to take all of the pieces
into account. You put the head on right with the cams loose,
but before you tighten step back and take everything in,
rotor position, crankshaft position, timing chain position,
cam position, piston position, and cam sprocket position. If
all of these are in place, then you tighten the cams.
The BIGGEST MISTAKE that is made is that the cams are
tightened to quickly and people try to match everything to
their position. WRONG! The cams must be tightened to fit the
position of the engine, if it’s correct. Even if you have to
tighten and loosen the cams a hundred times to get it right,
that’s what you must do. If you try and MAKE the cam and cam
gear fit together you’ll bend valves.
Just as longs as you wait until everything is lined up
to tighten the cams you can’t bend valves, otherwise the
engine would never run.
Also on carbureted engines you can advance the cam a
few notches and not only will it run better(in my opinion)
but the likelyhood of bending valves is decreased. But don’t
do that unless you absolutely know how.
You sound very capable and I’m sure you’ll have a
beautiful runner.–
The original message included these comments:
