My Brown, unnamed Federal 1980 Spitfire is one step closer to breathing easy
thanks to everyone's advice. Yesterday I removed the manifolds without too
much pain, using a slightly modified procedure. I decided to pull the
manifolds as I could hear what seemed to be a manifold leak which could not
be found through inspection. For quite some time, I suspected it might be a
cracked exhaust manifold, but I could not be sure. This project would turn
up with a couple of challenges, and suggestions are greatly appreciated.
My first challenge was removing the nuts from the exhaust manifold/catalytic
converter joint. One stud was shorter than the others and may have been
broken by a previous owner. Two of the nuts came off after soaking them in
penetrating oil. The nut closest to the front of the engine was frozen. I
used a Dremel tool to cut the nut off of the stud, but perhaps should have
used a grinding stone versus a cutting disk. I ended up putting a couple of
gouges in the stud (slightly deeper than the original thread). I may be
able to chase the threads with a die and then use a nut/jam nut combination
to ensure that the nuts hold on the stud after reassembly. Has anyone
removed and replaced the studs on a late-model catalytic converter, or
replaced them with cap bolts? Suggestions?
Enlisting the aid of a good friend, we set out on the journey to liberate
the manifolds. I had my Alden wratcheting open-end 9/16" wrench handy in
case it would be of help. To ease removal of one end stud nut and take care
of a leaky water pump, I pulled the water pump, pump housing and carb
coolant lines.
I attacked the end stud on the front of the engine with the Alden wrench,
figuring the wratcheting action would speed things up a little. The wrench
broke on its very first use. The wrench design includes some very narrow
pieces of metal, and I would be surprised if anyone could use this wrench
for long. I switched to a standard Craftsman open-end wrench and removed
the nut with very little effort, verifying that I did not overly torque the
wrench.
All of the other outer stud nuts came off the engine with little effort,
with the exception of the end stud near the firewall. My friend and I
proceeded to work on the inner studs, and I verified that initial attempts
to remove the long nuts with a Craftsman 9/16" open end were fruitless. I
could not put enough torque on the nuts to free them. I did soak the nuts
daily with penetrating oil for a week in preparation for the removal.
We decided to try an new approach and use a long drift to pound on the end
of the manifold clamp. We wondered if popping the manifold clamp pressure
point off of the manifold edge might reduce the pressure enough on the stud
to allow for turning the nut.
One of the clamps popped off with about 15 minutes of banging away. The
other one moved but did not swing free of the manifold after a good 90
minutes of effort. It dawned on me that I should try the open-end wrench
again on the nuts. BINGO! They both started turning, and ironically, while
the nuts were frozen, the studs had loosened from the head. I unscrewed the
nut/stud assembly and off came both manifolds.
It appears that the manifold to catalytic converter joint had a mild leak,
but the gasket does not show signs of burning. I also discovered that the
guts of the catalytic converter are missing. I'll reassemble the joint with
a new exhaust flange gasket, rather than chance leakage without the gasket.
I plan on removing the exhaust pipe transmission hanger to reduce pressure
on the exhaust flange gasket. The manifold gasket is clearly burned through
between exhaust ports 2 and 3 (almost an inch of gasket missing). The EGR
valve was missing when I bought the car, and the irony is that this car
passed Washington-State smog testing in this condition, with only the air
pump in operation. It failed on the first test attempt, when I had the air
pump disconnected.
My friend suggested using a cold chisel to loosen the last end nut, or to
cut off the nut. We considered using the Dremel tool, but decided to try
the chisel. Bad choice. The nut seemed to start turning after about 10
blows, then we discovered that the stud sheared off at the head surface. It
looks like we will be using an EZ-Out to pull the stud carefully from the
head. No fun, but we will do everything to avoid having to pull the whole
head. In the meantime, I have all new studs and nuts for reassembly. The
studs that hold the water pump to its housing will also be replaced, as they
are a bit eaten.
The next chapter posting will cover reassembly of the manifolds. I am still
debating putting the dual HS4 carbs at this point that have been sitting
here for a year plus. Does anyone have a good source of HS4 gaskets
(carb-manifold joint)?
Cheers,
Ron Deaver
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