Hi all, I know these issues are very hard to diagnose
without personally examining tge car, but I’d like to
solicit some opinions anyway.
The car is a '72 XJ6 4.2 automatic, with the vacuum
retard dizzy. I’ve been playing with the timing some
lately, and have it set about tge best I can get it -
advanced till it started to ping then backed off a few
degrees.
So the car runs great now all the time except for tge
first couple seconds when I floor it from a dead stop.
That will cause some clunking and knocking sounds from the
footwell area. After a second or two the knocking noise
vanishes, and I can’t get it to happen under any
circumstances except full throttle from a dead stop.
I know its difficult, but any ideas where to start
looking? There is a clunk in the front when going over
speedbumps, so maybe in the suspension? Exhaust hitting
the floor? Please don’t say engine rebuild!
In reply to a message from redtail sent Mon 22 Nov 2010:
Hi the thought of flooring the throttle from a standstill would not
be something I would ever attempt The strain on all parts of the
transmission must be enormous and not something I would ever do
good luck Dennis–
The original message included these comments:
So the car runs great now all the time except for tge
first couple seconds when I floor it from a dead stop.
That will cause some clunking and knocking sounds from the
footwell area. After a second or two the knocking noise
vanishes, and I can’t get it to happen under any
circumstances except full throttle from a dead stop.
In reply to a message from redtail sent Mon 22 Nov 2010:
Hi the thought of flooring the throttle from a standstill would not
be something I would ever attempt The strain on all parts of the
transmission must be enormous and not something I would ever do
Sometimes getting away from the scene warrants it, Dennis…?
But as you say - and such tearaway will also put strain on engine/box
mounts. And causing displacement of anything connected to engine, like
drivetrain and exhaust, into physical contact with the body - making
noises. This aspect is sort of ‘innocent’ - but he could check
clearances and clampings, and should maybe check the engine and gear box
mounts…
Frank
xj6 85 Sov Europe (UK/NZ)>The original message included these comments:
So the car runs great now all the time except for tge
first couple seconds when I floor it from a dead stop.
That will cause some clunking and knocking sounds from the
footwell area. After a second or two the knocking noise
vanishes, and I can’t get it to happen under any
circumstances except full throttle from a dead stop.
In reply to a message from redtail sent Mon 22 Nov 2010:
I’d check trans mount bush if you get knocking over speed humps–
The original message included these comments:
That will cause some clunking and knocking sounds from the
footwell area. After a second or two the knocking noise
looking? There is a clunk in the front when going over
speedbumps, so maybe in the suspension? Exhaust hitting
In reply to a message from Norman LUTZ sent Wed 24 Nov 2010:
Thanks for all the info guys. For what its worth, full
throttle from stop is not my normal driving habit, I’m
just trying to diagnose some funny noises.
Zack–
redtail
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