I am sincerely hoping that someone can give me a suggestion to
correct this problem. In an XK-150 FHC I am restoring I rebuilt
the 3.4-liter engine and recently replaced it in the car. I have
rebuilt a number of XK engines over the years so I am definitely
not a novice! The engine cranks but will not fire. The battery is
brand new. The fuel pump fills up the float bowls and there is
definitely a spark at the plugs. To verify that I removed the
front plug which is #6, reattached the wire and while grounding the
body of the plug, a spark is clearly seen. My initial thought was
that somehow the thing was 180-degreec out of time, so I removed
the inlet cam cover and cranked the engine so that the front inlet
valve opened and then closed. I then slowly rotated the engine to
6-degrees BTDC as marked on the damper, which is the appropriate
static timing. At that point the offset in the distributor drive
gear is as shown in the factory manual. I then reinstalled the
distributor and rotated it so that a test lamp just illuminated
prior to the rotor reached plug section #6 on the cap. So then,
everything seems OK but the engine will NOT fire! I have never
seen anything like this happen before and I am pretty much out of
ideas, so please guys�help me if you can! All thanks, John–
John Gunselman s.o.c.
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My brother had this problem once on a S1 or S11.
He had work carried out by a machinist and received the head ‘ready to
replace’ .
Got to the stage where he was ready to fire up and nothing, nada, zip.
Turns out the guy had transposed the cams.
Might this be your problem?
Regards Robin O’Connor
'92 XJ40 4.0 Ltr
Auckland NZ
In reply to a message from Robin and Maureen O’Connor sent Sun 15 Aug 2010:
Thank you very much for the suggestion, but I really do not believe
this can be my problem. On this car the rear end of the inlet cam
is ‘‘grooved’’ to drive the tachometer generator and the rear end of
the exhaust cam merely has an oil thrower. I disassembled the head
myself and carefully marked all parts as I always do, so there is
no possibility I transposed the two cams, but just to be absolutely
sure I shall check the cam part numbers against the original parts
manual that I have on a disc. In any case thank you very much for
your kind suggestion, John.–
John Gunselman s.o.c.
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In reply to a message from John Gunselman s.o.c. sent Sun 15 Aug 2010:
Hello John,
You can check if the cams were swapped or the cam timing is
incorrect, by looking through the oil cap. A TDC #6 compression,
timing slots at 90 degrees, the first cam lobes (I&E) should point
away from the center (rabbit ears). It is possible to incorrectly
assemble the distributor drive many ways. If you have compression, #6 at TDC with the timing slots up, and the rotor points at #6
tower, make sure you have the correct firing order. 15 is too
young , 36 too old, 24 just right, counterclockwise. If it is
making sparks, try holding up a carb piston and spraying in some
starting fluid. Don’t worry, we have plenty of ideas…
Paul–
The original message included these comments:
I am sincerely hoping that someone can give me a suggestion to
correct this problem. In an XK-150 FHC I am restoring I rebuilt
the 3.4-liter engine and recently replaced it in the car. I have
rebuilt a number of XK engines over the years so I am definitely
not a novice! The engine cranks but will not fire. The battery is
brand new. The fuel pump fills up the float bowls and there is
definitely a spark at the plugs. To verify that I removed the
front plug which is #6, reattached the wire and while grounding the
body of the plug, a spark is clearly seen. My initial thought was
that somehow the thing was 180-degreec out of time, so I removed
the inlet cam cover and cranked the engine so that the front inlet
Hi John, fair enough.
Next question.
When you say re-built what was carried out?
rebore and new psiton and rings, hone and new rings on old pistons?
I have had instances where there was everything there to make the engine go
but a lack of sufficient compression, have you tried a squirt of oil down
each spark plug to temporarily seal the rings? this has workied for me in
the past on an engine that had been sitting for a while and the rings had
got gummed up.
Regards Robin O’Connor
'92 XJ40 4.0 Ltr
Auckland NZ----- Original Message -----
From: “John Gunselman s.o.c.” jg@johngunselman.com
In reply to a message from norm larsen sent Tue 24 Aug 2010:
Sometimes, a 6 volt starter needs a shot of twelve and a twelve
volt unit needs a shot of 24 to fire a new rebuild or overhaul.
Not for long, though, the starters will spin like crazy and fire
almost anything, but too long and bye bye starter.
Some years ago that’s what it took to fire a ‘‘hot’’ 460 Ford.
Caveat, not for computer managed engines!!!
Unless the start function is separated/isolated.
My hot T’s, A’s and some of the V8’s needed a push for their first
reathes of life. No 12 v’ readily available then.
Carl
Carl–
The original message included these comments:
In reply to a message from John Gunselman s.o.c. sent Sun 15 Aug 2010:
John,
If the car is not running a long weekend could be just the
thing.
If you have fuel in the carbs and you have spark at the
cylinder, I would put a teaspoon of fuel into each cylinder
through the spark plug hole, replace the plug and try it. If
it sputters and tries to run you have narrowed down the
problem to non-delivery of fuel. That should help.
Bernie–
Bernie Daily
Brockport/New York, United States
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