Chainsaw Crakcase pressure testing gauge...

[J1MS]

I found this http://cgi.ebay.com/Chainsaw-Crankcase- ... dZViewItem" onclick="window.open(this.href);return false; while searching for some more two stroke crankcase info.
I guess it works by positioning the piston to cover inlet and transfers then pumping pressure into the crankcase through a pre fitted inlet, the drop down period for the gauge would be measured in time to check seals, rings, & crank cases for leaks.
I'm not sure how it would be used to check the carb other than the float and float valve operation.

[dirtyhandslopez]

Couldn't see the picture, but it's a leakdown testing kit, right? You need to blank off inlet and exhaust ports to get it to perform the way you want other wise it is hard to distinguish between seals and rings. I have the Snap-on one with two guages. Never gets used though, to much set up time factor. Compression tester and old school ways for checking for seal leak is much quicker...

[J1MS]

Couldn't see the picture, but it's a leakdown testing kit, right? You need to blank off inlet and exhaust ports to get it to perform the way you want other wise it is hard to distinguish between seals and rings. I have the Snap-on one with two guages. Never gets used though, to much set up time factor. Compression tester and old school ways for checking for seal leak is much quicker...

Think its working now...

[dirtyhandslopez]

That looks like a homemade jobbie to me. Don't see why it wouldn't work though.
Are you thinking of using it to detect differnt pressures at diffent crank throws, as per your other thread? You would have a hell of a job reading the needle at 6k rpms . Need a didgital set up for that, if they make one.
I still reckon it's easier to check for seals and rings the old fashion ways. Not as many nut's and bolts to undo

[J1MS]

That looks like a homemade jobbie to me. Don't see why it wouldn't work though.
Are you thinking of using it to detect differnt pressures at diffent crank throws, as per your other thread? You would have a hell of a job reading the needle at 6k rpms . Need a didgital set up for that, if they make one.
I still reckon it's easier to check for seals and rings the old fashion ways. Not as many nut's and bolts to undo

There is some more info out there, and info on how to get a reading on a running engine with a gauge short pipe and believe it or not, basicly a a pilot jet, this should give peak crank case pressures, and in theory also allowing enough bleedback time to give a fairly accurate reading...

Otherwise its computers USB ports and expensive stuff, I was just thinking of taking a look at it, nothing serious or complicated...

[dirtyhandslopez]

Using the pilot jet as a nipple to attach a guage?

[J1MS]

Using the pilot jet as a nipple to attach a guage?

The delayed bleed back through the pilot jet allows a reading to be taken, but too big a jet and pressure releases too fast, too small a jet and air will be restricted reading a lower pressure than the true peak... 20-40 thou pilot (that's pre decimal in old money) is the guesstimate from the little reading I have done!!

[Rich_T]

I think you might find this is for checking the carb "pop off" pressures to check the fuel delivery chamber needle valve seats correctly, spring tension and correct building of carb etc.

I used these on the Tillotson carbs I used to mess around with on karts and the odd scooter. These carbs need this sort of testing to make sure they can run inverted and respond quickly to throttle position etc. It is basically used to measure the "pop off pressure" then the "decay rate" followed by the "holding pressure" (for want of a better word). A couple of links to this type of tester http://www.aerocorsair.com/id28.htm" onclick="window.open(this.href);return false; or http://www.eccarburetors.com/pdf/PopOff-Testing.pdf" onclick="window.open(this.href);return false; and instructions here http://www.eccarburetors.com/pdf/Tuning-Info.pdf" onclick="window.open(this.href);return false;

It does not measure cylinder pumping efficency and in any case that would all be relative to your particular engine and I can't see how the assembly they are offering could achieve this with such a small hand pump.

[J1MS]

I think you might find this is for checking the carb "pop off" pressures to check the fuel delivery chamber needle valve seats correctly, spring tension and correct building of carb etc.

I used these on the Tillotson carbs I used to mess around with on karts and the odd scooter. These carbs need this sort of testing to make sure they can run inverted and respond quickly to throttle position etc. It is basically used to measure the "pop off pressure" then the "decay rate" followed by the "holding pressure" (for want of a better word). A couple of links to this type of tester http://www.aerocorsair.com/id28.htm" onclick="window.open(this.href);return false; or http://www.eccarburetors.com/pdf/PopOff-Testing.pdf" onclick="window.open(this.href);return false; and instructions here http://www.eccarburetors.com/pdf/Tuning-Info.pdf" onclick="window.open(this.href);return false;
It does not measure cylinder pumping efficency and in any case that would all be relative to your particular engine and I can't see how the assembly they are offering could achieve this with such a small hand pump.

Yes, I guessed that it would check the carb, but only the valve operation and seating, which would check for correct fuel delivery,
I assumed the gauge to test the crankcase for leaks, that it might have a valve fitted somewhere, and then with the pump connected and squeezed gently a couple of times just to increase the primary chambers pressure to a point probably marked on the gauge, then watch the gauge drop, too fast its got a fault, or hold pressure long enough & its OK.... but I'm just guessing... I never wanted the gauge and pipe for that purpose...
I only put this item up on here cus I had only ever seen this type of gauge used on carbs.
The gauge I would require needs to read in the range of around 2 bar going by the forum info that I had read, this is just to do a basic maximum primary pressure test with part of this equipment. I don't really want to find the efficiency of my engine as such, just really to compare a piston ported and reed valve lammy with high and low primary cranks fitted, to see where the pressure starts to build & then peak for all four combinations, this type of gauge I think could be suitable, but the hand pump is not needed for this as the running engine will generate the pressure while the gauge is attached.
But I had never before this ebay advert, seen a gauge like this for testing primary chambers, only ever carbs. And this one does look a bit home made...

[156 D]

...i have done so much reading that i may have the wrong end of the stick J1MS , but is it just a normal vacuum guage with -20 to + 20 inches of mercury as the scale that it would measure be what you need it doubles as a pressure guage on the + side as you are probably aware...if this were fitted by way of a small spigot threaded and of course 3mm piping, to the inlet manifold, as near to the carb. as possible would this not give what you are looking for???.......it has to record plus or minus vacuum depending how far the throttle is open!!.....i have always believed in higher primary crankcase pressure with tapered transfer ports, wider at the crank end than the head end......