O.K. , the short story is : the valve guides on this 1969 C/10's 250 CID L6 are
looser than Madonna's knees plus the intake manifold's PCV fitting is wrong so
most of the PCV venting goes directly into the center intake port , fouling the
# 3 & 4 cylinders with oil even worse than the wobbly valve guides do ~ it has
an irregular miss at the best of time & tune that gets progressively worse with
miles , yesterday Jr. & I got stuck in bumper to bumper cross town traffic for
an hour of mostly sitting still in gear @ idle so now I have a bad miss all the time , under load , @ idle , all the
time ~ I already replaced the brandy new but fouled spark plugs once and I'm
lazy to - day so I grabbed a spray bottle and filled it with tap water , drove
the truck a few miles to ensure it's 100 % warmed up then I held the throttle to
about 3,500 RPM's in neutral and began spraying the water into the carby's air horn .........
As the water gets sucked in the intake and is compressed in the cylinders , it
*instantly* flashes to _steam_ and this blows the accumulated carbon off the
piston crowns and valves ~ it also sometimes helps clean a fouled spark plug ,
this time not so much help on the fouled spark plug but it _did_ blow a bunch of carbon out the exhaust and
runs markedly better now .
The irregular miss is still there , as soon as I can find an undamaged correct
manifold set , I'll yank the cylinder head off and have it properly rebuilt ,
something the Texas Machine Shop couldn't handle apparently .
I'll have silicone bronze valve guides installed along with stainless steel one
piece valves and hardened seats unless they were done before , doubtful
considering the poor work done to the rest of this poor old truck .
Stay tuned .
To - morrow is the periodic Long Beach Veteran's Stadium Auto Swap Meet , I have to go there and get some new Clay Smith Cam decals , I'll keep a lookout for a good used 194/230/250/292 manifold too , maybe I'll get lucky ~ I passed on a Marine one yesterday for $60 as it wasn't drilled for the PCV valve and I feel that's an important thing , not to be left out nor cobbled up by adding an adapter to the power brake port....
BTW : before you go trying this Farm/Junkyard/Backwoods remedy on your oldie ,
be aware that water isn't very compressible so adding too much water in volume ,
to a high compression engine , can *instantly* bend the connecting rods , crack
or shatter the pistons and in some cases , crack / explode the cylinder heads .
looser than Madonna's knees plus the intake manifold's PCV fitting is wrong so
most of the PCV venting goes directly into the center intake port , fouling the
# 3 & 4 cylinders with oil even worse than the wobbly valve guides do ~ it has
an irregular miss at the best of time & tune that gets progressively worse with
miles , yesterday Jr. & I got stuck in bumper to bumper cross town traffic for
an hour of mostly sitting still in gear @ idle so now I have a bad miss all the time , under load , @ idle , all the
time ~ I already replaced the brandy new but fouled spark plugs once and I'm
lazy to - day so I grabbed a spray bottle and filled it with tap water , drove
the truck a few miles to ensure it's 100 % warmed up then I held the throttle to
about 3,500 RPM's in neutral and began spraying the water into the carby's air horn .........
As the water gets sucked in the intake and is compressed in the cylinders , it
*instantly* flashes to _steam_ and this blows the accumulated carbon off the
piston crowns and valves ~ it also sometimes helps clean a fouled spark plug ,
this time not so much help on the fouled spark plug but it _did_ blow a bunch of carbon out the exhaust and
runs markedly better now .
The irregular miss is still there , as soon as I can find an undamaged correct
manifold set , I'll yank the cylinder head off and have it properly rebuilt ,
something the Texas Machine Shop couldn't handle apparently .
I'll have silicone bronze valve guides installed along with stainless steel one
piece valves and hardened seats unless they were done before , doubtful
considering the poor work done to the rest of this poor old truck .
Stay tuned .
To - morrow is the periodic Long Beach Veteran's Stadium Auto Swap Meet , I have to go there and get some new Clay Smith Cam decals , I'll keep a lookout for a good used 194/230/250/292 manifold too , maybe I'll get lucky ~ I passed on a Marine one yesterday for $60 as it wasn't drilled for the PCV valve and I feel that's an important thing , not to be left out nor cobbled up by adding an adapter to the power brake port....
BTW : before you go trying this Farm/Junkyard/Backwoods remedy on your oldie ,
be aware that water isn't very compressible so adding too much water in volume ,
to a high compression engine , can *instantly* bend the connecting rods , crack
or shatter the pistons and in some cases , crack / explode the cylinder heads .
.
.