I'll bet dollars to dimes that the problem is timing. On my '70 TR6
with vacuum advance and retard I had the same symptoms, plus a weird
"burp" a few seconds after turning the engine off. The engine also got
hot when idling, didn't have much power, and had poor engine breaking.
Start by disconnecting your vacuum advance, set your timing statically
(or by timing light with the vacuum retard disconnected), then reset
timing by accelerating hard and listening for pre-ignition. I found
that the vacuum retard is necessary to get the idle down where it should
be, and to provide decent engine breaking. Vacuum retard is active only
with the throttle closed. If you can solve your problems with this
method, then it is just a matter of trial and error in setting the two
vacuum units to achieve maximum power, correct idle speed, and decent
engine breaking.
Lonn Howard
'70 TR6 -mine
'71 TR6 -in my garage
'70 MGB GT -ours
'89 Saab Turbo Convertible -hers
"We are but temporary custodians with an obligation of preservation."
----- Original Message -----
From: <MDDTR6@aol.com>
To: <triumphs@autox.team.net>
Sent: Monday, June 28, 1999 4:40 PM
Subject: Exhaust popping
>
> Hi
>
> I have been enjoying this list for a few months but have not posted
until
> now. I have a 71 TR- 6 and am having a problem with the exhaust
popping
> during deceleration. Last year I had TRF Install the harden seats in
the
> head, shouldn't cause it but included it for background Until this
time I
> had a different head on it and never had the popping. So far I have
replaced
> the intake and exhaust manifold gasket to the head, replace the
by-pass
> valves and then completely blocked them by making a solid gasket,
(this took
> care of my idle slowly increasing) thoroughly check for vacuum leaks,
all new
> tune up components and checked timing, plugging the vacuum retard
seems to
> help but did not take care of the problem, held a rag over the
exhaust, while
> at idle to see if I could detect any exhaust leaks, couldn't find any.
At
> this point I am considering removing the intake and exhaust manifolds
and
> having them milled to insure a true flat surface. I assume you can
mill the
> manifolds, does anyone know for sure? Anyone have any ideas? Any
help sure
> would be appreciated, the popping driving me crazy and taking some of
the
> fun away.
>
> Thanks in advance
>
> Mark Desenberg
> Maine
>
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