Re: Lubrication Notes
Posted: Fri Mar 06, 2015 9:07 am
For years a oil pressure kit has been sold for type 4's with a longer piston to increase low oil pressure. Couldn't this also be used in a type 1?
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For years, people have been selling hocus pocus. That was the point of my article.Bleyseng wrote:For years a oil pressure kit has been sold for type 4's with a longer piston to increase low oil pressure. Couldn't this also be used in a type 1?
Nope. Not giving you ^ that explanation here.Bleyseng wrote:Ding ding ding...
"D" is the reason 914 guys installed the longer oil control piston. Stock 914's oil runs hot 220-240F on the California freeways so this was the work around
So you're saying it was designed to dump the "waste cooled" oil right near the pickup so the coolest oil would be fed to the bearings?Amskeptic wrote:Are you aware that the Type 4 developed its own relief-dump-to-oil intake to help the pump get oil? That is the weird chamber deal near the cam gear wall.
Did you look at the pictures I drew? The red sleeve? Is it not there in the two bottom pictures? I somehow keep missing, even with text and drawn pictures (colored highlights, too!) what I am trying to say with enough clarity.asiab3 wrote: What we do not see in most photos, (or notice, in Ian's vertical shot up the bore,) is the second part of the ball mechanism, which is a cylinder sleeve machined into the top of the bore. The ball is a perfect fit to the sleeve hole.
Yes please. Is your photograph the sleeve that Adrian installs along with the ball, or is it just a comparison of the factory piston to the ball?asiab3 wrote: This does two things:
1) When a hot engine is shut off, the spring seals the ball to the sleeve, so NO oil is allowed to leak out. He says this keeps the oil system primed between startups and extends engine life. He also said a side effect of this, was a nearly 100% reduction in hydraulic lifter bleed-down over non-seasonal periods of inactivity, since the oil has no where to go when one lifter is stuck compressed on a cam lobe.
2) When the crank case relief bore is worn out, the spring seals the ball against the sleeve so no oil pressure is lost due to wear under hot oil/low pressure situations like a hot idle after a freeway flog.
To me, this makes sense. Should I continue peppering him with questions?
Robbie
I do not remember seeing the sleeve in the original article, and I may have been too focused on the pictures of just the ball and modified spring.Amskeptic wrote: The red sleeve? Is it not there in the two bottom pictures?
My photograph is of an actual sleeve he uses; unfortunately I did not get a great angle of the inner bore. Apologies.Amskeptic wrote: Is your photograph the sleeve that Adrian installs along with the ball, or is it just a comparison of the factory piston to the ball?
…and be able to communicate to Adrian my question.
I can see the new images, and the details in the past images.Amskeptic wrote: A) …give him an opportunity to explain how oil bypasses the cooler when cold, and get back to us)
aa) I believe the ball can't serve as a pressure-actuated "oil temperature thermostat." I believe it is serving only as a total oil pressure control valve, just an on-off switch.
When you explain it this way I now understand how the factory vs. ball seal at the top of the bore. Because of the way Adrian explained the bore wall wear issue, I had a hard time separating the piston tops' abilities to seal off at low pressure from the pistons' leakage past the bore walls.Amskeptic wrote: B) This is important! You wrote,
"When the crank case relief bore is worn out, the spring seals the ball against the sleeve so no oil pressure is lost due to wear under hot oil/low pressure situations like a hot idle after a freeway flog."
If you read my article, I claim that the factory piston is seated during any and all low pressure moments, it does not matter if the sides of the piston are sloppy in the bore, the crown of the piston is being forced against the seat with 17 pounds of spring force. These relief/control valves are closed at operating temperature! Do you, Robbie, think there is pressure loss due to oil leakage through the closed relief valves, if they are sealing at the top of the pistons? If the bearings flow three gallons a minute when they are worn and the viscosity is thin, how much do you think leaks past the relief and control valve piston tops?
If the sleeve did not block the main gallery, then the oil cooler would never get dedicated oil flow when the engine was hot.asiab3 wrote: My photograph is of an actual sleeve he uses; unfortunately I did not get a great angle of the inner bore.
I wonder if the sleeve takes up the exact space that is shown in your drawing. I no longer have an empty case nearby to scrutinize, but if the sleeve is machined into the case between the cooler gallery and the main gallery and DIDN'T block and passages, would it then be able to serve as VW designed?Amskeptic wrote: A) …give him an opportunity to explain how oil bypasses the cooler when cold, and get back to us)
aa) I believe the ball can't serve as a pressure-actuated "oil temperature thermostat."
I believe it is serving only as an on-off switch.
I seriously think that this is all marketing nonsense, like the cascades of marketing nonsense that have plagued these cars from the beginning. Look at the phrase "having too low oil pressure could quickly lead to disaster" and go ahead and apply it to their stupid "easy fix" that they can SELL in a "kit", without ever dealing with the only true reason for low oil pressure - opened up bearing clearances.Bleyseng wrote:Yes, the "kit" is two valves.
"Low oil pressure got you stressed? 914 engines are known for having low oil pressure. On an air cooled motor, having too low oil pressure could quickly lead to disaster. There are two pistons in the 914 engine case that regulate oil pressure. Replacing these pistons with these special ones results in higher oil pressure throughout the engine. Ideal for racing motors, or just heavy street use."
They are just longer versions I guess to increase spring pressure.
I read on the internet, so it must be true, that Jake Raby only uses solid lifters in his T4 builds. Does anyone know his thoughts on the cases which lack control valves? Has anyone seen if his engines have the valves or not?Amskeptic wrote: [we interrupt this program for the following Type 4 Control Valve bulletin . . .
Type 4 control valves were NOT used in hydraulic lifter engines for the simple reason that the lifters happily utilized cold oil pressure to pump themselves up if and as necessary. Hydraulic lifters are continually bleeding themselves in operation at every down ramp off the cam lobes. I speculate that if you revert to solid lifters in a hydraulic non-control valve crankcase, the relief valve might spend too much time towards the bottom of its bore, playing "high rpm control valve", diverting oil that should be making a dedicated loop through the oil cooler]
The control valve with a relatively fresh engine will dump excess pressure and allow the cooler to cool a greater quantity of oil than the engine is consuming. I do not have the information or experience to dictate what the hydraulic lifters consume, but if you have solid lifters in a hydraulic case, you are losing the control valve function. The implications here would be that the cooler is only cooling the oil that goes through the bearings, no extra cooling.lilpig88 wrote:This is a very good question and I'd love to hear more thoughts on it.
It seems everything I've found searching forums and the web trends towards speculation instead of evidence. I have a hydraulic lifter case (GE - no control valve) with solid lifters and cannot help but wonder if there are any real implications here. I might attempt some testing this summer...maybe.
(My 1974 and 1979 Bentley manual's make no mention of the single-relief plunger differences, only spring length and tension differences.)From August 1969 an oil pressure control valve is located behind the main bearings. [diagram above] This valve assures that the oil supply to the crankshaft bearings is kept at a constant pressure. At the same time, the annular groove in the oil pressure relief valve has been discontinued.