Added note on exhaust gaskets. I was constantly replacing my gaskets on
the 403 engine. Had the manifolds machined which helped somewhat. Had one
manifold cracked which was replaced.
The gaskets had to be replaced too frequently so I doubled the gaskets on
each side . This helped temporarily.
After approximately one year of replacing gaskets engine began running
rough at idle and power appeared to be reduced. Compression check revealed
two right cylinders were low.(engine mileage 92K)
Removed the heads, had the valves and seats reground, and two exhaust
valves replaced. To my surprise I noted that the exhaust port surfaces on
the heads were erroded causing my gaskets to blow even though my manifolds
were machined. I completely forgot to check the heads during my gasket
replacing.
So it is important to insure the head surfaces are checked and don't
operate the engine too long with blown gaskets because it will errode the
head-- then your problems will start.
Too bad someone doesn't manufacture a solid copper gasket for the manifold
to insure a good heat sink for the manifolds
The recommended use of anti-seize on the exhuast bolts is a must. I would
stay away from the anti-seize with graphite as the base component. This
may cause cracks expecially on stainless steel.
I use the anti-seize with a copper base on all exhaust components and
sparkplugs. When you apply it to the spark plugs only apply to the first
two (2) threads. When you have to remove the manifolds or any part of the
exhaust including the spark plugs this will be the payoff on the ease of
removal.
Just think if you break off a spark plug or bolt what happens next?
You can usually purchase the ant-seize at any auto parts stores.
Hope this gives you some input
Bob
the 403 engine. Had the manifolds machined which helped somewhat. Had one
manifold cracked which was replaced.
The gaskets had to be replaced too frequently so I doubled the gaskets on
each side . This helped temporarily.
After approximately one year of replacing gaskets engine began running
rough at idle and power appeared to be reduced. Compression check revealed
two right cylinders were low.(engine mileage 92K)
Removed the heads, had the valves and seats reground, and two exhaust
valves replaced. To my surprise I noted that the exhaust port surfaces on
the heads were erroded causing my gaskets to blow even though my manifolds
were machined. I completely forgot to check the heads during my gasket
replacing.
So it is important to insure the head surfaces are checked and don't
operate the engine too long with blown gaskets because it will errode the
head-- then your problems will start.
Too bad someone doesn't manufacture a solid copper gasket for the manifold
to insure a good heat sink for the manifolds
The recommended use of anti-seize on the exhuast bolts is a must. I would
stay away from the anti-seize with graphite as the base component. This
may cause cracks expecially on stainless steel.
I use the anti-seize with a copper base on all exhaust components and
sparkplugs. When you apply it to the spark plugs only apply to the first
two (2) threads. When you have to remove the manifolds or any part of the
exhaust including the spark plugs this will be the payoff on the ease of
removal.
Just think if you break off a spark plug or bolt what happens next?
You can usually purchase the ant-seize at any auto parts stores.
Hope this gives you some input
Bob
