Assembling a motor to a adapter plate, a motor coupler to a manual transmission there is four critical clearance measurements to be maintain.
All these measurements are taken on a motor and transmission mounting test stand where the motor with a motor coupler and transmission (without the flywheel wheel, clutch and pressure plate). The transmission pilot shaft was inserted into the pilot shaft bearing that is install into the motor coupler. You do not want to butt the pilot shaft tight into this bearing. According to my shop manual, this clearance can range from 0.125 to 0.1875 of a inch. If you go to the VW dealer service department, they can give you these measurements from there shop manuals. Using a machinists ruler that has a slider gage, measure the distance from the face of the transmission and the face of the motor in four places 90 degrees apart. This is what the thickness of the motor adapter plate will be. I gave all these dimension to Mike Brown to make me a motor adapter for a GE-11 motor which will also fit a WarP-9 and WarP-11 motor with one motor coupler that fits a 1-1/8 and a 1-3/8 inch motor shaft by using different bushings using the same pattern which he has for a 92 S10 V-6 pickup which will also fit any V-6 and V-8 GM transmissions. The third clearance measurement is the the clutch plate dimension from the flywheel. Standard is about 0.030 to 0.040 of a inch. For racing, it is recommended to go up to 0.050 of a inch. If the 0.050 inch is too much which may cause jerking starting, than back off about 0.001 inch and test again. I had to use a different size throw out bearing, because I was using a S10 flywheel, clutch and a pressure plate that is design for a 6 cylinder that is connected to a transmission for a 8 cylinder engine. The fourth clearance measurement is the driveline U-joint that inserts into the transmission. You do not want the U-Joint butt up tight into the transmission. The up and down action of the axil will slid the U-Joint splines back and forth. Check this amount of travel when the vehicle is on grade and than with the tires off grade. Normally when vehicle is off grade, the axil will drop which will push the U-joint into the transmission. You should have the vehicle on jack stands when assembling the motor, transmission and driveline maintaining this same clearance. If you did not record this clearance dimension, than fine out from a VW service department what this clearance should be. Be sure to use the same transmission cross member height in the same location. The motor and transmission should be level in relation to the differential. The driveline should maintain the same angle which may range from in a certain degrees in different vehicles. Do not have the transmission and differential inline with each other, or the U-Joints needle bearings will not rotate and will wear out. Roland ----- Original Message ----- From: "Adrian DeLeon" <[email protected]> To: "Electric Vehicle Discussion List" <[email protected]> Sent: Tuesday, March 05, 2013 1:07 PM Subject: Re: [EVDL] 82 vw rabbit magic number > No effect. The "magic number" is the distance between the transmission > mating surface of the ICE engine block and its flywheel mounting flange. > Reproducing that distance with a transmission adapter plate and taperlock > coupler will put the flywheel/clutch assembly exactly where it was after > the conversion. > > I've seen recommendations that the distance be kept within 0.005" of the > original number. From my own conversions, there was a LOT of wiggle room > in the bell housing and on the transmission shaft. I think the precision > only needs to be such that the clutch disk properly grabs the transmission > shaft and the clutch mechanism properly engages/disengages the clutch. > YMMV. > > Some details can be seen here: > http://evbimmer325i.blogspot.com/2012/06/measuringthe-magic-number-althoughthere.html > > -Adrian > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
