djl@fisher.UUCP (Dan Levin N6BZA ) (04/27/85)
Background...
1966 Ford Mustang Coupe - 200 cid Six - Ford 2.77 3 Speed Manual
For those of you unfamiliar with the Ford straight six, the
exaust manifold bolts (with gasket) to the block, and about four
inches below that joint, the manifold to muffler pipe bolts onto
the manifold. The pipe looks like this...
| |
| |
/ \
-- 1 --| |-- 1 --
-- | | --
| |
| | <==== 2
Well, sort of :-). Any way, the points marked by 1 are where a
semi-metallic gasket (donut shaped) sits, and this mounts to the
beveled bottom surface of the manifold.
Problem...
I have had two problems, which I believe are related. First,
the donut gasket burns out. Second, the pipe (I am on my third now)
burns through at point 2, and breaks off from the manifold.
I have had two different groups of people tell me two things.
The muffler types say that it must be the timing, that if it was
the muffler being clogged up, the car would not run. The mechanics
(and my intuition) say that if the timing was off by that much,
the car would not run, and the poor exaust valves would be so much
carbon by now.
The only problem that anyone (including myself can find) with the
car is that the vacuum advance is broken. The muffler seems fine,
and the timing/engine seems otherwise ok.
Plea...
So, does anyone have any ideas? I am at wits end. It would seem
that the problem cannot exist, for if it did, the car would not
run. Yet, every 800-1k miles, the pipe breaks off again! I am
willing to listen to any suggestions, however far fetched.
Thanks in advance, as they say,
--
***dan
{allegra,astrovax,princeton,twg}!fisher!djl
The misplaced (You call *that* a ski slope??) Californianrs55611@ihuxk.UUCP (Robert E. Schleicher) (05/03/85)
> Background... > 1966 Ford Mustang Coupe - 200 cid Six - Ford 2.77 3 Speed Manual > > For those of you unfamiliar with the Ford straight six, the > exaust manifold bolts (with gasket) to the block, and about four > inches below that joint, the manifold to muffler pipe bolts onto > the manifold. The pipe looks like this... > > | | > | | > / \ > -- 1 --| |-- 1 -- > -- | | -- > | | > | | <==== 2 > > Well, sort of :-). Any way, the points marked by 1 are where a > semi-metallic gasket (donut shaped) sits, and this mounts to the > beveled bottom surface of the manifold. > > Problem... > I have had two problems, which I believe are related. First, > the donut gasket burns out. Second, the pipe (I am on my third now) > burns through at point 2, and breaks off from the manifold. > > I have had two different groups of people tell me two things. > The muffler types say that it must be the timing, that if it was > the muffler being clogged up, the car would not run. The mechanics > (and my intuition) say that if the timing was off by that much, > the car would not run, and the poor exaust valves would be so much > carbon by now. > > The only problem that anyone (including myself can find) with the > car is that the vacuum advance is broken. The muffler seems fine, > and the timing/engine seems otherwise ok. > > Plea... > So, does anyone have any ideas? I am at wits end. It would seem > that the problem cannot exist, for if it did, the car would not > run. Yet, every 800-1k miles, the pipe breaks off again! I am > willing to listen to any suggestions, however far fetched. > > Thanks in advance, as they say, > -- > ***dan > > {allegra,astrovax,princeton,twg}!fisher!djl > The misplaced (You call *that* a ski slope??) Californian *** REPLACE THIS LINE WITH YOUR MESSAGE *** One possibility: Does your six have two exhuast outlets into head pipes (ie, 3 cylinders on each?), or just one? If two, does one of the exhuast manifold outlets have a heat riser valve? This is typically done on V-8s, but would only apply to straight sixes if there were multiple exhuast manifold outlets (and maybe not even then). The heat riser is placed on one outlet, and closes off the outlet when the exhaust gas is cold. The exhaust gas on this side is then routed through a channel "through" the metal of the intake manifold, causing the intake air/fuel mixture to warm up quicker. As the exhaust heats up, the heat riser valve opens. I imagine that if it doesn't open up, there is excess heat build-up at this point. Bob Schleicher ihuxk!rs55611