not much discussed- crank case pressures zero gap rings

sdiesel

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as stated.
what are some experiences with evacuation systems on crank cases

Zero gap rings: have they been tried?
if so what pressures work best in the crank case
with zero gap rings, (with corresponding boost levels of course)
 
BBC, 4.5" pistons, Dykes upper ring, 3 stage oil pump scavenging, supercharger, methanol, 17 lbs of boost.

Crankcase vacuum is being pulled by the oil scavenging pumps and is not regulated like a dedicated vacuum pump.
The pump pulled 7 inches of vacuum before boost.
When we switch to BWE ZGS and Dykes upper rings we saw 9 inches of vacuum.
Once boost comes on the crankcase vacuum goes to pressure but it takes a few seconds.
The cold piston leak down test shows most cylinders below 1%.

The ZGS ring on the Ford 300 six that was not bored and honed with a torque plate showed less than 2% leak down cold before break-in.
Had we used a torque plate I suspect the leakdown would have been less than 1%
Have not checked it since.
 
so rightly deciphering, the scavange pump is not boost regulated, its a three stage pump

zero gaps are do-able and work on a boosted six

the compression was stable with a marked increase.

but wuestion. if there is vacuum in the can , crankcase, then would there not be a chance for ring flutter since there is no counter pressure to the boost pressure from on top. i am missing simething here.
in street speak, if i have a vacuum on one side and pressure on the other, doer it not reason that the pressure will try to eqalize and cause problems with the rings?
 
sdiesel":3d5ril42 said:
so rightly deciphering, the scavange pump is not boost regulated, its a three stage pump
It is an Auto Verdi 3 stage dry sump oil pump.
Why would you boost regulate the engine's oil pump?

sdiesel":3d5ril42 said:
but question. if there is vacuum in the can , crankcase, then would there not be a chance for ring flutter since there is no counter pressure to the boost pressure from on top. i am missing simething here.
in street speak, if i have a vacuum on one side and pressure on the other, doer it not reason that the pressure will try to eqalize and cause problems with the rings?
No,
The rings stay seated better when there is a pressure difference keeping the rings at the bottom of the piston ring groove.
If you can maintain a vacuum in the crankcase it helps
We alway ran a large vaccum pump on our big nitrous engines and kept it regulated around 15 inches of vacuum.

In most cases the dyno shows a power improvement using a crankcase vacuum pump.
 
I am confusing my vac pump with oil pump.
the vac pump boost reg. is what I'm trying to express.

so , this technology ; zgr and vac pump is /is not relevant to a street driven turbocharged six.?
i.e. 6-15 psi boost.
zero gap rings seem sensible,
a vacuum pump an additional complication.
in diesels they are not used, by some for arcane reasons I cannot describe to you.
 
sdiesel":3d4w0bt3 said:
so , this technology ; zgr and vac pump is /is not relevant to a street driven turbocharged six.?
i.e. 6-15 psi boost.
zero gap rings seem sensible,
a vacuum pump an additional complication.
in diesels they are not used, by some for arcane reasons I cannot describe to you.

A vacuum pump is relavent to a street driven turbocharged six and can be useful in any engine in an effort to extend piston ring and engine seal life.

Here is an example of a practical setup.
As mentioned you can add a 1 bar MAP and some additional circuitry to make a fully regulated system
viewtopic.php?f=22&t=79516
 
brain engaged:
can I use a factory mechanical fuel pump plumbed into crank case to provide an RPM regulated vacuum source?
pull vapor from case plumb it to intake,,.., scrub vapor at pump intake through steel wool
 
the 6.9 international diesel uses a nifty belt driven vacuum pump to supply power brake air.
a direct drive 12v motor could power the pump...
 
sdiesel":2k82z58t said:
brain engaged:
can I use a factory mechanical fuel pump plumbed into crank case to provide an RPM regulated vacuum source?
pull vapor from case plumb it to intake,,.., scrub vapor at pump intake through steel wool
It might have enough volume for a N/A engine.
Not sure if it will pull enough volume to keep up with the blow-by under boost.

sdiesel":2k82z58t said:
the 6.9 international diesel uses a nifty belt driven vacuum pump to supply power brake air.
a direct drive 12v motor could power the pump...
This link was about an electric motor drive air pump with a Pulse Width Modulated controller to prolong the pump life.
Then I suggested adding a 1 BAR sensor to the controller with additional circuitry to automatically maintain a preset vacuum level under all conditions such as varying amounts of boost
viewtopic.php?f=22&t=79516
 
a young man up here has developed big numbers with the old internationals.

looking thru his posts , I recall him having to find a means of restricting the pump, as it was scavaging oil.

in one post, he plumb oil seperator to his intake tube. the source of his vacuum..

claimed good vacuum but provided no numbers

used 2 valve cover breather vents to control the vacuum numbers

in a later post he was using the pump, on a heavily boosted engine and found he was pulling oil.
I do not remember the details.

will continue digging, as this topic seems relevant and a source of h.p..

his moniker is racinNdrummin.
over on a ford truck site.
 
Gahhh!! More complications.
If I’m piecing things together right: the point of having constant vacuum on the crank case is to make sure piston rings, as well as seals, don’t have sudden changes of pressure applied to them (i.e. pulsating)? Thereby prolonging life?
Any ideas how much longevity could potentially be achieved?
 
Earliest I'm familiar with vacuum pumps were converted Ford smog pumps. It should be pretty easy to sort the plumbing, and add a valve to keep from sucking all the seals and gaskets in. Maybe in the pushrod cover? Discharge separator tank tied in to the relief valve inlet, to take back any oil drawn by the pump? A passive, set-N-forget package makes sense. Catch cans just seem illogical to me, when the oil can go back in.

Now there are seals made to keep air out as well as oil in.
A vacuum gauge will help with setting drive pulley ratio



https://www.gzmotorsports.com/VCV101A-V ... Valve.html
 
Been doing some digging trying to understand the issues being discussed. Ran across this, here:
https://www.enginelabs.com/tech-stories ... orsepower/

"The concept was first introduced by Bill Million at Hedman Hedders and initially developed on the engine dynos at both Edelbrock and Traco Engineering. Traco-powered Penske Trans Am Camaros were among the first cars to run it in competition.

A Pan-Evac system connects the valve covers on both sides of the engine to the exhaust header collectors with one-way check valves and vent tubes that blend into the exhaust stream at approximately 45 degrees. Exiting exhaust gasses pull a vacuum on the tubes, thus drawing excess crankcase pressure from the sump and discharging it out the collector. This action relieves blow-by pressure under the rings, reducing windage and contamination. Although purely passive, the system proved remarkably efficient, and thousands of racers used them religiously until the emergence of modern external vacuum pumps."

All of what's discussed in that write up appears to relate only to hot street engines and racing engines.
?Why wouldn't you use this sort of set up on a mild to stock engine?
I'm guessing that theoretically there is not enough crank case pressure or cylinder pressure (and potential blow by) to warrant the
"upgrade" to having vacuum on the crank case.
?Even then, why not simply use the one way valve arrangement running from the valve covers to the exhaust collector?
?Could you also plumb the same arrangment to feed into the turbo collector, and thereby have "adjustable" (by way of the accelerator pedal) vacuum on the crank case? (I know it's a simplification of the possible effects and pressure differences, but in theory, would it work?)
 

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motorsickle1130":3505dd0q said:
All of what's discussed in that write up appears to relate only to hot street engines and racing engines.
?Why wouldn't you use this sort of set up on a mild to stock engine?
A mild engine has a PCV valve that is normally sufficient to hold a vacuum on a healthy engine.

A turbo engine creates more blowby during boost than a PCV can handle and would benefit with a pump.
The turbo collector on a log or short tube exhaust manifold doesn't see a low pressure.

I have seen low pressure pulses down to zero gauge presure with a long tube turbo header but that still is not low enough to create a vacuum.
 
A pan-evac passive system would obviously have to be plumbed after the turbo, and only in a short and/or unmuffled setup, both imprudent on the street.
 
67Straightsix":3a9knid2 said:
On a turbo engine would the in inlet pipe to the turbo create enough vacuum ?
If the inlet to the turbo has that much vacuum then there is a problem with the system design.
A turbocharger compressor is a pressure multiplier so you want as little of a pressure drop on the inlet as possible.
Besides I wouldn't want engine waste going through the turbo compressor.
 
67Straightsix":34f4356g said:
On a turbo engine would the in inlet pipe to the turbo create enough vacuum ?
The factory turbo cars that i am familiar with (turbocoupe) are plumbed this way. Pcv on valve cover connected to inlet side of turbo with approx 3/8 steel line. On my 300 i added a jlt oil seperator and used 1/2" line and to my surprise havent had any measurable amount of oil in near 15000 miles checked every oil change. This motor has 230k miles on it. My interpretation is a seated set of quality rings and low expansion pistons shouldnt have much blow by. Forged pistons could be a factor
 
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