Triumph Spitfire idle problem
SD Bateson
Hi everyone -
Over the past few months I've been sorting out various problems with the
latest old clunker that I saved from the scrapyard. The car is a Triumph
Spitfire MKIII, but has been converted to rally spec, then allowed to
degenerate somewhat. I've given the engine a tune-up, and after sorting
out various elusive gremlins, got her running smooth, except for the
idle.
The engine is a 1300, probably running a stock cam etc, but
with HS4 carburettors (From 1500 MKV Spit) and a Triumphtune 4-2-1
manifold leading to a 2" straight through exhaust and silencer.
Although it idles ok at first (at about 850-950 rpm), after about
ten seconds the idle starts to fall, and the engine stalls, unless I
rev it a bit. After another ten seconds of idling, the same happens.
I'd really appreciate any help on this, as it's driving me mad,
and continuosly blipping the throttle at traffic lights is making
me a target for boy racers and their traffic lights grand prix....
Thanks
Simon Bateson
Keele University
England
Dave Williams
-> with HS4 carburettors (From 1500 MKV Spit) and a Triumphtune 4-2-1
...
-> Although it idles ok at first (at about 850-950 rpm), after about
-> ten seconds the idle starts to fall, and the engine stalls, unless I
-> rev it a bit. After another ten seconds of idling, the same happens.
Sounds like you need to clean and adjust the carbs.
Richard O. Lindsay
Installed was a Weber downdraft kit. That is, carb and
manifold combo. The little bugger runs like I've never
seen a Spitfire run before. The kit was from Victoria
in Kansas and cost about $420. It wonderful. Dare I say
it? Yea, I will. It idles like a good ole' Chevy 327...
The problem on the SU's sounds like a vacuum leak at the
inlet manifold gasket or somewhere allied to that system.
Good luck.
Rick
------------------------------------------------------------
Richard O. Lindsay / __ __ __ __
Senior Research Scientist / / /_/ /_ / / /_/ /_/
Amoco Production Research / / / / /_/ /_/ / / / \
/ /_/
/
Irresponsible rantings of the author alone. Any resemblance
to persons living or dead is just luck. May cause drowsiness.
Alcohol may intensify this effect. Pay no attention to the
man behind the curtain. Ricky!!!
------------------------------------------------------------
dpar...@plasma.ps.uci.edu
:
: Hi everyone -
My suggestion to you is to put a 289 in it. After all it's a triumph!
Brian Kiviat
: The engine is a 1300, probably running a stock cam etc, but
: with HS4 carburettors (From 1500 MKV Spit) and a Triumphtune 4-2-1
: ten seconds the idle starts to fall, and the engine stalls, unless I
: rev it a bit. After another ten seconds of idling, the same happens.
You might want to check the slop in the throtle shaft (butterfly shaft)
If it not in good shape, you might be drawing air in through the bearing
assemblies at either end. I don't know the fix, but this might be the
problem. It sounds as though you have a pretty hopped up motor, maybe
some side draft Webers might be cool.
Brian
'67 Sunbeam Alpine
Ed Fair
> -> ten seconds the idle starts to fall, and the engine stalls, unless I
> -> rev it a bit. After another ten seconds of idling, the same happens.
i'd look carefully at the float valve. maybe it's sticking when
the volume of fuel consumption is low? just an uneducated guess.
ed
Vaughan K. Scott
Sounds to me like you got yerself some vacuum leaks. I have a couple
TR-7's, and have had the same problem with the one on the road. I noted
considerable improvement after resealing the intake manifold gasket (still
gotta do the carb mountings). In other words, I recommend you take off the
carbs, intake manifold, and rubber carb mountings, and reseal them with
Ultra-Copper gasket maker by Permatex (though I don't know if you can get
it over there). Good Luck!
Vaughan Scott
sco...@rpi.edu