Palmer QuickSwitch 4-way valve for the Autococker
© Ravi Chopra, 1999
Ive heard a lot of airsmiths complain about the stock 4-way valve on the Autococker. It appears to be just fine for the stock trigger-pull, but many airsmiths seem to have trouble with it leaking or not being smooth enough when they go all out with a top-end trigger job. In response to this, several companies have come out with aftermarket 4-way valves. Glenn Palmer is just the latest to offer his own idea of the ultimate Autococker switch. The Palmer QuickSwitch is actually identical to the 4-way he builds into his Blazer semi-auto, but encased in brass shell that allows it to be mounted on the standard Autococker front block.
Palmers has gone in a decidedly unique direction in the design of his 4-way valve. Where most aftermarket 4-ways seek to offer a simpler, but smoother design than the stock valve, Glenn Palmer has gone in the complete opposite direction. Where the stock valve has four parts and four O-rings and most aftermarket valves have only two parts and two O-rings, the QuickSwitch has no fewer than six parts and six O-rings! While this does make for a somewhat more complex design, there was a good reason for doing it this way. But before you can understand the design, you need to understand the problems he was trying to overcome.
In the stock 4-way, the piston O-rings seal on either end into end-caps that have a slightly conical shape. When the fit is tight enough to prevent any leaking, the stock valve can be quite a bit stiffer than many airsmiths like. When it is polished out for smoother action, the valve has a greater tendency to leak, and if over polished can actually be made to begin venting before the valve is completely switched. Most aftermarket valves go for smoother action by doing away with the end-caps and having the valve be a simple tube of fixed diameter. The problem here is that the piston O-rings are constantly rubbing back and forth across the outlet holes at the same spot, making for uneven wear and early failure.
Glenn Palmer avoided all these problems by creating the three internal chambers with four cylindrical inserts. Unlike the stock valves end caps which can require a relatively long travel to go from completely sealed to completely open, the design of these inserts and the precision of their manufacture ensures that they open and close over almost imperceptibly small distances. The result of this is a valve that switches extremely quickly without the stock valves sloppy, leaky character. At the same time, the piston O-rings open and close around their entire circumference making for even wear and greater long-term reliability.
Like most aftermarket 4-ways, the QuickSwitch switches in just under 2mm of travel, much less than the stock valve. This allows airsmiths to time Autococker triggers for considerably shorter pulls with less risk of leaking and blowback.
One final nice design feature is that all of the components drop into the valve body through the front and are held in place with a large allen screw. Anyone who has tried to reassemble a stock 4-way knows what a pain it can be trying to get the C-clips back in. The Palmer design is much easier to work with.
Design rating 
The QuickSwitch is constructed entirely of brass. It is precision-manufactured to very close tolerances as its performance readily indicates. The only problem I noticed was that the back of the piston shaft is a little too large and can be difficult to fit the timing rod collar over.
Soon, an aluminum version of the valve will become available in a variety of colors. Only the outer body (not the inserts or shaft) will be aluminum, so the valve should function identically.
Construction rating [3.5]
You are not going to find a whole lot to complain about performance-wise with this valve. It allows softer trigger springing than the stock 4-way and its sub-2mm switch length allows exceptionally short trigger settings without leaks or blowback problems.
As I mentioned before, this valve opens and seals over very short distances. When it seals, it seals tightly. Unlike many other 4-ways, Palmers QuickSwitch can not be easily made to leak when the timing rod is bumped or twisted.
The only area in which this valve falls a bit short of some other aftermarket valves is in smoothness. Though its action is smoother than the stock valve, most other short-throw aftermarket 4-ways allow even softer trigger springing than the QuickSwitch. This is the trade-off for leak-free performance.
Performance/Versatility rating 
ADDENDUM: Palmer has updated the QuickSwitch. Current valves being produced are incredibly smooth. As smooth as, if not smoother than any other valve on the market. They are still as reliable and leak-free as ever before.
NEW Performance/Versatility rating 
At $39, the Palmer QuickSwitch is nearly double the price of virtually all the competing 4-way valves. It makes sense given the greater number of parts and greater precision required in machining required to manufacture this valve. Just because it makes sense doesnt necessarily mean that it is worth it, though.
The QuickSwitch comes with a one year warranty. This covers manufacture and materials, including O-rings as long as they are not damaged by solvents (eg. petrolium-based lubricants). This is a better warranty than youre going to find on any other 4-way.
Price/Warranty rating 
Glenn Palmer has made one very impressive 4-way valve in the QuickSwitch. Clever design has resulted in a short-throw valve that combines impressive reliability, leak-free operation, and faster, cleaner switching than any other 4-way Ive seen. Its only real stumbling point is the exceedingly high price tag.
All material at this site is © Ravi Chopra, 1999