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Motor Case Blueprinting

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  • Motor Case Blueprinting

    One of the last projects that I will be starting (eventually) is a 'reproduction' panhead bobber. I have a conglomeration of OEM and aftermarket parts that I will install into an aftermarket frame and re-create the type of bobber that was around when I was growing up in the early 1960's and first developing my Harley addiction. This will be a non-judged bike, built solely for my own nostalgia and enjoyment. I felt it would be nice to be free, just of one build, from the rigidity that we all must follow in restoring our judge-worthy bikes. To that end, I purchased the last set of early panhead reproduction (STD) cases from Ted before he stopped stocking them. I received them about 5 years ago and, knowing that this project was a long time off, I stored them under my workbench.

    Years later, I acquired a correct cam cover and pulled the cases out to hand-screw the cover onto the right case for safekeeping. Wouldn't you know - the locator pins didn't line up correctly..... Apparently, the jig moved when one of the the locator pin holes was drilled. Just to be sure it was the motor case, I checked this error using a spare knucklehead cam cover which yielded the same misalignment. This was a surprise to me, as I had used STD cases from time-to-time over the years and they always prove to be a quality product.

    Now both of these pin locations must be checked against the pinion race center, the other right case locator pins, and the offending pin location(s) corrected in order to assure correct pinion and cam bushing alignment in the installed cam cover. I've seen this before on cases that were repaired and heavily welded and corrected it by pressing a plug into the offending hole and re-shooting the locator pin holes. Unfortunately, I no longer have access to either a blueprint or the correct offset dimensions depicting the distances and interrelations between the pinion race, the bottom motor case locator pins, the center-top case hole and the cam cover locator pin holes. I can probably take this information from another motor case, but in doing so you always introduce the systematic errors associated with working from a production-machined piece rather than from the true design dimensions. I would rather not do that.

    Therefore, if I can find this information I can set up on a Bridgeport and correct this mis-machining. Can anyone provide these distances/dimensions, a sketch or a print? If not, is there a Harley knowledgeable machining company out there that can accurately correct this problem?

    Thank You...
    Last edited by billpedalino; 12-04-2015, 04:21 PM.
    Bill Pedalino
    Huntington, New York
    AMCA 6755

  • #2
    Bill, These are dimensions I came up with by indicating the case as shown and moving along on the Bridgeport indicating a pin in the holes and using a digital readout. I have repaired quite a few cases using these numbers. These are not factory dimensions but have worked for me. If you need it larger I can try to photobucket it. I don't think it is wise to buy the last of anything from Tedd, I bought the last nos non numbered 45" left case this year from them, last on the shelf. It arrived cracked. They made a deal with me, but a welded nos case isn't worth quite as much to someone as a non welded nos case. Kinda makes the nos null & void! Cam Cover Dimensions.jpg Here it is.
    Last edited by BigLakeBob; 12-04-2015, 05:44 PM.
    Bob Rice #6738

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    • #3
      Bill, the bottom lie is. Your just better off buying a new set of cases for Knucleworks or the Germans. If ya can pull it off your self, go for it but if you got to farm it out? No way. STD product were anything but great. I got a set of there repro Panheads back in 88. Fifty miles later the rear head crapped a exhaust valve seat. Totaled the engine. They weren't to kind about dealing with the problem. I will never deal with them again even though they were bought buy another entity. Bob L
      AMCA #3149
      http://www.thegoodoldmotorcyclepartscompany.com

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      • #4
        Was it those damn no lead stellite seats that never stay in? Worse thing ever for a pan head.
        Originally posted by Robert Luland View Post
        Bill, the bottom lie is. Your just better off buying a new set of cases for Knucleworks or the Germans. If ya can pull it off your self, go for it but if you got to farm it out? No way. STD product were anything but great. I got a set of there repro Panheads back in 88. Fifty miles later the rear head crapped a exhaust valve seat. Totaled the engine. They weren't to kind about dealing with the problem. I will never deal with them again even though they were bought buy another entity. Bob L
        Bob Rice #6738

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        • #5
          Bill, I responded in your other post, seems like you posted twice.
          Bob Rice #6738

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          • #6
            Bob, thanks for the drawing. I've been pondering building a jig for just this and you just made it a whole lot easier. Was figuring on making my lock down points on the dowel pin and generator holes. I'm referring to the cover not the case. Thanks again, Bob L
            Last edited by Robert Luland; 12-04-2015, 07:15 PM.
            AMCA #3149
            http://www.thegoodoldmotorcyclepartscompany.com

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            • #7
              Your welcome. I think some of the dimensions would be standard #'s but everything has tolerance (such as the jig built or drill clearance in such). Ex. from my sketch, 3.501 could be 3.500, .939 could be .937, 1.248 could be 1.250, 2.066 could be 2.062. All the could be's are American fractional standards, just a thought when making your jig.
              Originally posted by Robert Luland View Post
              Bob, thanks for the drawing. I've been pondering building a jig for just this and you just made it a whole lot easier. Was figuring on making my lock down points on the dowel pin and generator holes. I'm referring to the cover not the case. Thanks again, Bob L
              Bob Rice #6738

              Comment


              • #8
                Bob,
                Thanks so much for the sketch - it's exactly what I need! From what I can tell, you used the oil pump surface to establish the 'Y' axis and then used the pinion hole as the origin. I'm going to enter this data into AutoCad sometime this week. If anyone wants this as an ACAD LT file, please let me know.

                Bob L - I guess I've been lucky with STD cases. No so with some of the others that were out there when I used to buy them. But given the above, I can fix this one the way Wally Brower (Blitz Mfg.) showed me years ago. I've done several that way and it always worked out fine. I just need to gain access to a Bridgeport. And you are correct; unless yo do it yourself, I guess it would probably be cheaper to buy another set than to have it done....
                Bill Pedalino
                Huntington, New York
                AMCA 6755

                Comment


                • #9
                  Originally posted by Robert Luland View Post
                  Bill, the bottom lie is. Your just better off buying a new set of cases for Knucleworks or the Germans. If ya can pull it off your self, go for it but if you got to farm it out? No way. STD product were anything but great. I got a set of there repro Panheads back in 88. Fifty miles later the rear head crapped a exhaust valve seat. Totaled the engine. They weren't to kind about dealing with the problem. I will never deal with them again even though they were bought buy another entity. Bob L
                  Knuckleworks only has left cases. I have held his prototype right case in my hands but he hasn't produced them yet.
                  Be sure to visit;
                  http://www.vintageamericanmotorcycles.com/main.php
                  Be sure to register at the site so you can see large images.
                  Also be sure to visit http://www.caimag.com/forum/

                  Comment


                  • #10
                    Originally posted by Robert Luland View Post
                    Bob, thanks for the drawing. I've been pondering building a jig for just this and you just made it a whole lot easier. Was figuring on making my lock down points on the dowel pin and generator holes. I'm referring to the cover not the case. Thanks again, Bob L
                    Wouldn't your timing gear cover be a good pattern?
                    Be sure to visit;
                    http://www.vintageamericanmotorcycles.com/main.php
                    Be sure to register at the site so you can see large images.
                    Also be sure to visit http://www.caimag.com/forum/

                    Comment


                    • #11
                      Originally posted by Robert Luland View Post
                      Bob, thanks for the drawing. I've been pondering building a jig for just this and you just made it a whole lot easier. Was figuring on making my lock down points on the dowel pin and generator holes. I'm referring to the cover not the case. Thanks again, Bob L
                      Bob L. - Our jig used the top center case through-bolt hole (the dowel/pin located between the cylinders) and the two lower case dowel/pins as lock-down points. At that time, our Factory connection confirmed that these locations, along with the pinion hole were the primary landmark (locator) points established during the initial machining processes.

                      Our jig was a surface-ground, heavy flat plate with pins pressed into the top surface at the above dowel locations. There was a surface-ground outstanding leg pinned and fixed on the underside surface of the plate that ran parallel to the Bridgeport table and fit into one of the table slots, thus making it easy to set up and check. The plate edges were milled square so they could be indicated as orthogonal after the jig was clamped down. As stated above, the top surface had the three dowels pressed-in at the case through-bolt locations and the case was slid/tapped onto these top-surface dowels and clamped onto the base plate.

                      It was very simple and worked very well. We used it for breather valve work, dowel re-positioning, sleeving pinion race holes, cam bushing/bearing hole machining, repainting the gear studs, etc., etc... I don't know what happened to the jig after Eastern and Blitz moved down South. However, given Big Lake Bob's dimensions, a proper machine shop (hint, hint !!) could make up a duplicate jig quite easily. Unfortunately, we don't have the case through-pin locations, so some time would have to be spent accurately indicating and locating them. Let me know of you have an interest - I would be more than happy to venture into that foreign land called 'Jersey' on a Saturday and sketch/show you what we did.
                      Last edited by billpedalino; 12-06-2015, 07:57 AM.
                      Bill Pedalino
                      Huntington, New York
                      AMCA 6755

                      Comment


                      • #12
                        Originally posted by Chris Haynes View Post
                        Knuckleworks only has left cases. I have held his prototype right case in my hands but he hasn't produced them yet.
                        Chris,
                        Is the Knuckleworks guy from California? If so, I sold him a right knuckle case a couple of years ago at Oley. If so, that prototype was probably cast using my old case.
                        Last edited by billpedalino; 12-06-2015, 08:06 AM.
                        Bill Pedalino
                        Huntington, New York
                        AMCA 6755

                        Comment


                        • #13
                          Bill, not gospel, but might get you started. My own dimensions again.
                          Bob Rice #6738

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                          • #14
                            Originally posted by BigLakeBob View Post
                            Bill, not gospel, but might get you started. My own dimensions again.
                            Again, I'm both thankful and impressed... As with the right side dimensions, I'll set a case onto a Bridgeport and see how close I get to your measurements.
                            Thanks so much for sharing your work and the resulting information Bob!
                            Last edited by billpedalino; 12-06-2015, 07:24 PM.
                            Bill Pedalino
                            Huntington, New York
                            AMCA 6755

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