Subject: [TR] Distributor question

From: Mark Hooper <[email-masked]>
Date: Sat, 16 Mar 2013 20:00:00 -0400

A long time back I fitted my 1972 TR6 with a Crane Cams XR700 opto-electronic
ignition. It made starting much easier and being a gadget-guy I liked the
principle of the thing. No complaints.

My car has had a rather irregular idle forever. It's got a slightly warmed
cam, triple Strombergs and a Falcon SS exhaust fed by a 6:1 header. I replaced
the distributor's vacuum retard and that brought down the idle speed a great
deal, but it is still lopey/rough. I recall that the reason I put in the CC
ignition was to help with the idle, but it didn't.

Despite all sorts of valve adjustment, professional carb rebuilding etc, the
uneven idle persists. It was this way before the carbs and roller rockers were
put in. Nothing seems to affect it. The car drives very well and has very good
power through the rev range.

The question: I had thought that removing the points would have made any
looseness in the distributor shaft irrelevant. Was I wrong? Would having the
distributor re-bushed affect things, even if there are no longer any points
pushing on the shaft? I tire of hearing other's smoothly idling machines while
I have to rev the engine before jumping out to rapidly close the garage door
and then diving back in to goose the gas lest she quit.

Mark Hooper
1972 TR6 (should be called Old Lumpy, to my everlasting shame)

** [email-masked] **

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From: "Randall" <[email-masked]>
Date: Sat, 16 Mar 2013 19:25:40 -0700

As a friend of mine says, one test is worth a thousand theories.  Hook up a
timing light and watch what the timing does when the idle is rough.  If it
puts on a light show, you've got distributor problems.  If not, you need to
look elsewhere.

Next place to look would be carb synchronization.  The rubber hose trick is
good enough, just use a chunk of hose to listen to the hiss at each carb
intake.  If they all sound the same, the carbs are synchronized.

Adrian's suggestion of a vacuum leak is good, too.

When you've exhausted all other possibilities, I'd start being suspicious of
that "warmed over" cam.  It's not unheard-of for aftermarket parts to be
defective, and one lobe slightly out of place (or a bent camshaft) can
certainly affect idle quality.  Get a dial indicator and a degree wheel,
check that all the valves open and close when they should.

Although the Crane will compensate to a large extent for slop in the shaft,
it can't do anything for wear/damage to the centrifugal advance mechanism.

-- Randall

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From: "Randall" <[email-masked]>
Date: Sun, 17 Mar 2013 10:51:29 -0700

>  Any aerosol oil will be flammable.

One of those "separated by a common language" things.  I'm sure Adrian meant
it will burn (hence the warning to be careful).

Personally I prefer to use "carb cleaner" as it leaves less of a mess.  It
will also burn easily, though.  But just keep your face away, generally if
it does catch fire the fire will go out quickly with a minimum of damage.

-- Randall

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From: Dave Massey <[email-masked]>
Date: Sun, 17 Mar 2013 18:13:21 -0400 (EDT)

An unlit propane torch leaves even less residue and since there is no liquid
any flames will extinguish as soon as you pull away.  The torch may still be
lit but that's what it's designed to do.

Dave

-----Original Message-----
From: Randall <[email-masked]>

>  Any aerosol oil will be flammable.One of those "separated by a common
language" things.  I'm sure Adrian meantit will burn (hence the warning to be
careful).Personally I prefer to use "carb cleaner" as it leaves less of a
mess.  Itwill also burn easily, though.  But just keep your face away,
generally ifit does catch fire the fire will go out quickly with a minimum of
damage.-- Randall **