Lynn E. Hanover

The only mods to a stock pump that I would do/ have done, is to shorten the housing so as to get the end clearance of the internals down to about .002". Just run the open end or the housing on some wet (with Kerosene)

on a dead flat surface. Like a sink cut out or a pane of glass. Wet the back of silicone carbide 400 grit paper

so it sticks to the glass. Run the pump body in a figure 8 motion and assemble the parts and measure end clearance with a straight edge and feeler gage.



The separator plate between the pumping elements have razor sharp corners. Gently break the sharp corners with a deburring tool, and smooth with 400 silicone carbide. Just a bit here or things start going backwards.



On the pickup tube, remove the bug screen and cover. Install (braze or weld) a large diameter washer right at the end of the tube as in the drawing. Grind a large radius into the entrance of the tube. Build yourself a separator plate or baffle with a 3"X5" hole dead center in the plate. Drill out for the oil pickup and mounting bolts. Drill the mounting holes through the oil pan. Install the plate with a gasket above and below, and bolt the oil pan on the whole thing. Shorten the dipstick until it just touches the plate, Run the oil level to just above the plate.



Now you can race or autocross without loosing oil pressure, or foaming the crap out of the oil. Use a straight weight racing oil, and premix for racing.



Do not drop crap into the pan. With no bug screen it will kill the pump.



Lynn E. Hanover

drewrey2004

thanks hanover next motor i do will try to see the difference appreciate the knowledge. i left a thread on the sixport housings in this section if you can give some insight on anything you have done or heard about doing this.

Jay7

Drago, think you can take a pic of the instrument you used to get the accurate timing mark using your degree wheel? Also would this degree wheel work just as good? http://www.jegs.com/webapp/wcs/stores/serv...amp;showValue=1



Jay7..

thebluerx7

so just to confirm i am thinking right here,the intake tdc is at exact 90deg eshaft angle to the left(looking at front of engine with intake on left),also another way of saying it is the clearance volume face of the rotor is at 90deg to the ground/sump surface whatever u want to call it at intake tdc.(straight up and down).



basically ,all the major points eg intake tdc is e/shaft at exactly 90deg to the left,and intake bdc is exactly 270deg around,which is e/shaft pointing straight down.



also intake bdc is where the rotor face is exactly the same volume on each side of the "lump" in the middle of the housing.



am i think all of this is correct? i understand the inake /zorst tdc/bdc just confirming the positioning of the rotor/shaft at intake tdc/bdc etc.



http://www.yawpower.com/dectech.html

Lynn E. Hanover

Well, the Yawpower drawings are dredfull for learning anything. They have enough numbers on them to start a new civilization.



Imagine a box drawn onto the picture of a housing. That box has corner seals as its corners. two corners on a vertical line is a TDC. Two corners on a horizontal line is a BDC.



Easy.



There are two of each. Two TDCs and two BDCs.



A BDC on the bottom is BDC in the exhaust cycle. Largest volume.



A BDC on the top is BDC in the intake cycle. Largest volume.





Likewise, there are two TDCs.



A TDC on the spark plug side is TDC firing. (TDC on the compression stroke). Smallest volume.



A TDC opposite the plugs is TDC in the overlap. (end of exhaust stroke and beginning of the intake stroke). Smallest Volume.



If you need to know where the crank lobe is for anything.



It will be pointing to a small volume and away from a large volume.



The rotary is an Otto cycle 4 stroke engine, that tunes like a 2 cycle dirt bike engine.



Events in the engine like port opening points and closing points are in crankshaft degrees, and called out as being before or after one of the above 4 locations. This keeps the numbers managable, and everyone knows of what you speak. And can replicate on their own engines what you are talking about. Fill in your profile, please.





Lynn E. Hanover



16X rotor on left. 13B on right.

thebluerx7

yep,i understand all that,just wanted to know if intake tdc was exactly vertical beetween the corners.which u have now confirmed.thanks



do u have any mroe pics of ur tdc rig as im having trouble seeing how urs wrks via that one pic u have.i hate pics,if i just could be there with ur rig im sure it would be easy to see how it works.im better hands on if u know what i mean.



i do understand how and what the tdc rig is tryin to achieve ,how to use a degree wheel etc.just hard to see what exactly ur fulcrum setup is etc is doin and how it gets the tdc from the dial indicator.

Lynn E. Hanover

OK.



The aluminum angle pivots on a piece of case bolt. The crank lobe is in the approximate TDC position.



The dial indicator is touching the angle with a bit of preload. So now the crank is sticking through the front stationary gear and main bearing.



Now.



The degree wheel.



Bolted to an old flywheel nut with two 10-32 screws. You need to make the nut hold onto the crank firmly enough that it takes some effort to move it. You don't want it moving relative to the crank unless you want to move it. You can deform the nut a bit in a big vice.



I made a cut through one side of the nut. Milled off a flat land and drilled and tapped the hole. deformed the nut so it would be very stiff when screwed onto the the crank. A 10-32 screw threaded through the hole pushes the slot open more sot the nut turns. Loosening the screw locks the nut on the crank again.



I can draw you a picture of that.



So the big degree wheel will now screw onto the crank.



Now you need a pointer that will align with the edge of the degree wheel. I used a piece of 1" steel strap stock from the hardware store. Majic marker the end black and bend it over so the last 1" is level with the surface of the degree wheel. Scribe a line in the black ink pointing right at the center of the crank.



Bolt the pointer to the front iron with any bolt hole or stud available. It does not matter where.



Now move the crank back and forth and watch the dial indicator. Just try to find TDC in this way by look to find a null in the needle movement. Once you have done the best you can with this method. Turn the shell of the meter to put the zero under the needle.



With no reguard for what number the pointer is pointing at, turn the crank until the indicator has moved .050" in one direction. Make a kark on the degree wheel next to the pointer.



Move the crank back passed TDC until the indicator is again showing .050".



Make a mark on the degree wheel next to the pointer.



True TDC is half way between the two marks. Count off how many degrees there are between the two marks. Divid by 2. That answere when counted off from either of your marks is the correct TDC. Make a mark next to the pointer on the degree wheel. That is true TDC.



Now your wheel is sitting on true TDC. Move the shell of the indicator (don't move the degree wheel)

so that the needle is again pointing at zero. Run the crank back and forth across TDC to that .050" point several times to be sure you have true TDC.



Now with true TDC shoing on the degree wheel and on your indicator. Without moving the crank at all.



Loosen the locking system on the flywheel nut. Gently turn the degree wheel but not the crank until the zero mark on the degree wheel is next to the line on your pointer.



Now lock the degree wheel to the crank again. Recheck TDC using the .050" trick to be sure that the zero on the degree wheel ends up beside the pointer.



So long as the nut and degree wheel do not move relative to the crank you can take this apart and lay on a rotor in the TDC position and start marking up the iron with variuos closing lines. Just ink up the port area with a majic marker and scratch the lines with a brass brad, so as not to hurt the iron.



I am going to do a picture series for doing this, as it is difficult to explain and many want to learn how to do it.



Lynn E. Hanover

thebluerx7

good explanation,nice work.thanks

Lynn E. Hanover

OK, if you got this far fine. If you didn't here is a picture of what you need. For the degree wheel, buy the biggest you can find. If you don't like writing on the new degree wheel, use strips of masking tape.



When you modify the crank nut, drive a screw driver blade into the saw cut, to pry the nut open just a bit. This so you can wind the nut onto the shaft quickly and then sinch it down with the screw. Once you have the TDC mark very close you can tap the steel pointer strap back and forth to make very fine adjustments. The dial indicator and magnetic base are available from Harbor Freight for about $15.00.



If you have a junk rotor available, cut a notch out of one corner, so that about 3/16" of a face is left, then cut away the back of that notch with a 45 degree angle about 2" deep. Now you can look through the back of a corner seal hole and scribe lins to establish the paths of the leading and trailing ends of the side seals. You can scribe a line that shows the actual location and angle of a side seal as it crosses the closing line. Scribe stuff with a brass brad so as to avoid scratching the iron.



Here is the picture.



Lynn E. Hanover

hksthor

does anyone have any good pp port timming spec im want to pp my motor myself but not sure what port timming would net the best results it will be a street/race enging peak rpm around 9g any ideas would be good

steve