March 2nd 08, 05:16 AM
Odd how things come in batches.
A fellow asked me if I'd ever heard of Gene Berg, which to an engine-
builder is kinda like asking an aerobatic pilot if they've ever heard
of Bob Hoover. (Meaning the REAL Bob Hoover... Robert A. from
Tennessee.)
So I pointed him toward Gene's web site and went back to work. Then
another guy pops up with virtually the same question, except he wants
me to tell him all about Gene's pressure relief oil pump cover.
I pointed him to my blog (bobhooversblog.blogspot.com) and told him to
enter Gene Berg as the search seed in that little white window that
will appear in the upper-left.
I've got a hunch what's going on here and it's always worth a smile
when some instant expert blows up an oil filter. Fortunately, it
happens just after start-up so there's not much danger of them buying
the farm. But it does provide for an Instant Education, always an
interesting process if you're lucky to live through it.
As a point of interest, the best way to adjust the pop-off point for
the typical pressure-relief pump-cover -- in my opinion -- is not to
mess with the spring but to simply REAM the by-pass to a slightly
larger diameter. That increases the area the pressure of the pressure
acting against the ball, causing it to pop-off at a lower pressure.
If you're serious about engines you already know the oil pump is the
virtual heart of a flying Volkswagen and will have developed a few
tools & stuff to ensure optimum fit. One of those tools is a simple
plate -- steel or aluminum -- at least an inch thick, to which you
bolt your new pressure-relief cover... after dismantling, cleaning &
tuning up the thing. The plate is threaded to accept pipe fittings,
allowing it to be plumbed to your source of Hydraulic Power, which in
my shop happens to be an old clutch master cylinder. Bolt things
together, pump it up (you gotta fill the void-space in the new pump-
cover) then lean on the lever... and see exactly when the over-
pressure valve pops-off... and that it always pops-off at the SAME
pressure. (Now heat things up and do it again :-) The same rig, more
or less, is also used to check your oil pressure gauge. Surprisingly
handy, seeing that it's just a hunka metal, suitably threaded &
drilled.
-R.S.Hoover
PS -- You can make your own Full-flow pump cover. ('Way back when,
that was the only way to get one.) And you can make your own pop-off
valve too. Back in the '50's we didn't have any idea in the blue-eyed
world how to calculate the pop-off point so we just started with a
small hole and a test rig as described above, and kept drilling the
sucker out until it was popping-off at the right point. But that
brought to light an interesting point that most of today's instant
experts haven't learned (yet), which is the fact that a ball-type pop-
off valve in aluminum or magnesium tends to cause the orifice to GET
SMALLER over time. That is, the pop-off point gets HIGHER... until
the interesting morning when you blow the filter canister and stand
there with your ignorance hanging out :-)
Which is why Gene never offered an aluminum oil-pump cover... 'an why
we always put a steel bushing in the hole when we converted the stock
piston-type oil-pressure control valve to a ball-type. Just some more
of those 'unimportant' details the Instant Experts tend to ignore :-)
A fellow asked me if I'd ever heard of Gene Berg, which to an engine-
builder is kinda like asking an aerobatic pilot if they've ever heard
of Bob Hoover. (Meaning the REAL Bob Hoover... Robert A. from
Tennessee.)
So I pointed him toward Gene's web site and went back to work. Then
another guy pops up with virtually the same question, except he wants
me to tell him all about Gene's pressure relief oil pump cover.
I pointed him to my blog (bobhooversblog.blogspot.com) and told him to
enter Gene Berg as the search seed in that little white window that
will appear in the upper-left.
I've got a hunch what's going on here and it's always worth a smile
when some instant expert blows up an oil filter. Fortunately, it
happens just after start-up so there's not much danger of them buying
the farm. But it does provide for an Instant Education, always an
interesting process if you're lucky to live through it.
As a point of interest, the best way to adjust the pop-off point for
the typical pressure-relief pump-cover -- in my opinion -- is not to
mess with the spring but to simply REAM the by-pass to a slightly
larger diameter. That increases the area the pressure of the pressure
acting against the ball, causing it to pop-off at a lower pressure.
If you're serious about engines you already know the oil pump is the
virtual heart of a flying Volkswagen and will have developed a few
tools & stuff to ensure optimum fit. One of those tools is a simple
plate -- steel or aluminum -- at least an inch thick, to which you
bolt your new pressure-relief cover... after dismantling, cleaning &
tuning up the thing. The plate is threaded to accept pipe fittings,
allowing it to be plumbed to your source of Hydraulic Power, which in
my shop happens to be an old clutch master cylinder. Bolt things
together, pump it up (you gotta fill the void-space in the new pump-
cover) then lean on the lever... and see exactly when the over-
pressure valve pops-off... and that it always pops-off at the SAME
pressure. (Now heat things up and do it again :-) The same rig, more
or less, is also used to check your oil pressure gauge. Surprisingly
handy, seeing that it's just a hunka metal, suitably threaded &
drilled.
-R.S.Hoover
PS -- You can make your own Full-flow pump cover. ('Way back when,
that was the only way to get one.) And you can make your own pop-off
valve too. Back in the '50's we didn't have any idea in the blue-eyed
world how to calculate the pop-off point so we just started with a
small hole and a test rig as described above, and kept drilling the
sucker out until it was popping-off at the right point. But that
brought to light an interesting point that most of today's instant
experts haven't learned (yet), which is the fact that a ball-type pop-
off valve in aluminum or magnesium tends to cause the orifice to GET
SMALLER over time. That is, the pop-off point gets HIGHER... until
the interesting morning when you blow the filter canister and stand
there with your ignorance hanging out :-)
Which is why Gene never offered an aluminum oil-pump cover... 'an why
we always put a steel bushing in the hole when we converted the stock
piston-type oil-pressure control valve to a ball-type. Just some more
of those 'unimportant' details the Instant Experts tend to ignore :-)