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techtalk:ih:engmech02c [2020/08/25 01:51] hippysmack [Pining Bushings with Solid Pins] |
techtalk:ih:engmech02c [2023/12/20 16:03] hippysmack [Selecting Bushings] |
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| ====== Selecting Bushings ====== | ====== Selecting Bushings ====== | ||
| - | The factory machine work on 70< cam covers is stellar. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717904)) \\ | + | The factory machine work on 70< cam covers is stellar. ((Dr Dick of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/160109-changing-out-cam-bushings-help-on-a-couple-of-questions-appreciated?t=1717904)) \\ |
| Reproducing it at home is nearly impossible. Even in a full machine shop its very time consuming. \\ | Reproducing it at home is nearly impossible. Even in a full machine shop its very time consuming. \\ | ||
| A good (at home) job is possible if you know what your doing. \\ | A good (at home) job is possible if you know what your doing. \\ | ||
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| * Just make sure there are no sharp edges on the bushing or cover bore. \\ You don't need to heat the case or freeze the bushing (unless you choose to). \\ The interference fit isn't great. One or both of the materials will flex under the interference. That adds up to the driving force never getting too great. \\ A note about heating aluminum; as temps rise, so does it's affinity for galling. | * Just make sure there are no sharp edges on the bushing or cover bore. \\ You don't need to heat the case or freeze the bushing (unless you choose to). \\ The interference fit isn't great. One or both of the materials will flex under the interference. That adds up to the driving force never getting too great. \\ A note about heating aluminum; as temps rise, so does it's affinity for galling. | ||
| * Bushing groove placement: | * Bushing groove placement: | ||
| - | * Compare the placement of the grooves in the bushings in the 68 and 78 cam covers below. It's the same. \\ Every factory cover is like this. So is the pin placement. | + | * Compare the placement of the grooves in the bushings in the 68 and 78 cam covers below. It's the same. \\ Every factory cover is like this. So is the pin placement. |
| + | * You have to look at the oiling. ((ryder rick of the XLFORUM http://xlforum.net/forums/showthread.php?t=556788&highlight=cam+bushings+slot)) | ||
| + | * You don't want a slotted bushing on the pinion shaft, because that is what feeds oil to the crank. \\ The slot would allow oil to run from the cover into the gearcase, bypassing the pinion shaft hole and starve the crank. | ||
| + | * The intake with the big bushing gets an oil feed hole drilled in it. No need for the slot. | ||
| + | * The slots go at 9 or 3 O'clock on the other 4 (respectively). | ||
| * Grind the flanges from the bushings as required. | * Grind the flanges from the bushings as required. | ||
| * With a die grinder, relieve the #1 & #3 flanges for gear tooth clearance. Grind until you match up with the cutouts in the cover. | * With a die grinder, relieve the #1 & #3 flanges for gear tooth clearance. Grind until you match up with the cutouts in the cover. | ||
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| Click on a pic to enlarge. \\ | Click on a pic to enlarge. \\ | ||
| + | |||
| + | | Bushings 1,3 and 4 ((photo by billeuze of the XLFORUM http://xlforum.net/forums/showthread.php?t=556788&highlight=cam+bushings+slot)) | Pinion bushing ((photo by billeuze of the XLFORUM http://xlforum.net/forums/showthread.php?t=556788&highlight=cam+bushings+slot)) | | ||
| + | |{{:techtalk:ih:engmech:cam_cover_bushing-1-3-4_by_billeuze.jpeg?direct&300|}}|{{:techtalk:ih:engmech:cam_cover_bushing-pinion_by_billeuze.jpeg?direct&300|}}| | ||
| + | |||
| + | | Rear intake bushing ((photo by billeuze of the XLFORUM http://xlforum.net/forums/showthread.php?t=556788&highlight=cam+bushings+slot)) | Idler gear bushing ((photo by billeuze of the XLFORUM http://xlforum.net/forums/showthread.php?t=556788&highlight=cam+bushings+slot)) | | ||
| + | |{{:techtalk:ih:engmech:cam_cover_bushing-rear_intake_by_billeuze.jpeg?direct&300|}}|{{:techtalk:ih:engmech:cam_cover_bushing-idler_by_billeuze.jpeg?direct&300|}}| | ||
| + | |||
| | 1968 Cam Cover Bushings ((photo by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717904)) | 1978 Cam Cover Bushings ((photo by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717904)) | | | 1968 Cam Cover Bushings ((photo by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717904)) | 1978 Cam Cover Bushings ((photo by Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717904)) | | ||
| |{{:techtalk:ih:engmech:68_cam_cover_by_dr_dick.jpg?direct&350|}}|{{:techtalk:ih:engmech:78_cam_cover_by_dr_dick.jpg?direct&450|}}| | |{{:techtalk:ih:engmech:68_cam_cover_by_dr_dick.jpg?direct&350|}}|{{:techtalk:ih:engmech:78_cam_cover_by_dr_dick.jpg?direct&450|}}| | ||
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| ====== Pining Bushings with a Set Screw ====== | ====== Pining Bushings with a Set Screw ====== | ||
| + | * Instead of using only 1 set screw per bushing, 2 set screws in same hole works better. \\ (one on top of the other, top one locked down on the bottom one). | ||
| + | * You can use 2 set screws (#6-32 x 3/16" long) in each hole. \\ #6 is .138" O.D. (slightly bigger than the pins) \\ #8 is .164" (a bit on the large side for the die cast cover, cool on the pre-AMF cover though). | ||
| * Now, what if your solid pins are too tight for any reason? \\ Your pre-reamed bushing hole is now egg-shaped due to press fit distortions. \\ This also moves the beginning reamer cut position around, off concentric if you will. \\ So the results of the pin job effects the final position of the bushing bore. | * Now, what if your solid pins are too tight for any reason? \\ Your pre-reamed bushing hole is now egg-shaped due to press fit distortions. \\ This also moves the beginning reamer cut position around, off concentric if you will. \\ So the results of the pin job effects the final position of the bushing bore. | ||
| * Whats a guy to do at home? Forget the pins, drill and tap for 1/4" long #6-32 set screws instead. \\ This is way more user friendly. But it still needs special consideration due to the hole being half alum & half bronze. | * Whats a guy to do at home? Forget the pins, drill and tap for 1/4" long #6-32 set screws instead. \\ This is way more user friendly. But it still needs special consideration due to the hole being half alum & half bronze. | ||
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| * Use a good professional quality high speed steel (HSS), __plug chamfer__, hand tap. See [[techtalk:ref:tools120?s[]=bottoming&s[]=chamfer&s[]=tap#types_of_taps|Types of Taps]] in the Sportsterpedia. \\ (no hardware store junk - go to your local industrial supply house). It needs to be a good tap if you expect it to deal with the bi-metal hole. \\ Don't get the 'spiral point' taps. Difference being the angled gash behind the 1st cutting threads. \\ Hand taps lack that gash angle. Suffice to say that the hand tap wont 'tap crooked' as easily as a spiral point will. \\ Now if the guy at the counter asks "what H limit you want", tell him "the smallest he has but nothing bigger than H3". \\ This tap will be marked with HS to denote its made from high speed steel and it will also have the H limit on it. \\ All good taps will have those two markings. | * Use a good professional quality high speed steel (HSS), __plug chamfer__, hand tap. See [[techtalk:ref:tools120?s[]=bottoming&s[]=chamfer&s[]=tap#types_of_taps|Types of Taps]] in the Sportsterpedia. \\ (no hardware store junk - go to your local industrial supply house). It needs to be a good tap if you expect it to deal with the bi-metal hole. \\ Don't get the 'spiral point' taps. Difference being the angled gash behind the 1st cutting threads. \\ Hand taps lack that gash angle. Suffice to say that the hand tap wont 'tap crooked' as easily as a spiral point will. \\ Now if the guy at the counter asks "what H limit you want", tell him "the smallest he has but nothing bigger than H3". \\ This tap will be marked with HS to denote its made from high speed steel and it will also have the H limit on it. \\ All good taps will have those two markings. | ||
| * Also get a tee handle tap wrench. The centered tee makes for much less tap flexure when tapping. \\ It's flexing taps that break. Be it from misaligned wrench forces or too much twisting flex from high cutting forces. \\ HSS taps are much harder than their hardware store cousins. So they are less tolerant of flex. | * Also get a tee handle tap wrench. The centered tee makes for much less tap flexure when tapping. \\ It's flexing taps that break. Be it from misaligned wrench forces or too much twisting flex from high cutting forces. \\ HSS taps are much harder than their hardware store cousins. So they are less tolerant of flex. | ||
| - | * In order to avoid broken taps: | + | * Doing the work. |
| - | * Drills and taps from the supply house aren't very expensive. \\ If you double up and practice the whole operation on some scrap, you will have a much more secure feeling on what your doing when you get to your cam cover. | + | * In order to avoid broken taps: |
| + | * Drills and taps from the supply house aren't very expensive. \\ If you double up and practice the whole operation on some scrap, you will have a much more secure feeling on what your doing when you get to your cam cover. | ||
| + | * Locate the holes to be tapped in the beefiest cover material area. ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1347648&page=8)) | ||
| + | * Your cutting tools need to be very sharp or you will have problems. Even slightly dull drills and taps will tend to bite into the aluminum and skid off the bronze. | ||
| + | * Drill and tap dry (oil makes this phenomenon of 'walking' worse) making your holes crooked and crappy. | ||
| + | * Drill .015" / .030" smaller 1st as a pilot hole. Then chase to size with a finish drill. A drill press makes drilling less artsy fartsy. | ||
| * Once the hole is drilled and tapped install set screws. If need be, you shorten the leading end of screw. \\ Then GENTLY peen the top of hole so they can't unscrew into the rotating cams. You may need to remove the screws in the future. | * Once the hole is drilled and tapped install set screws. If need be, you shorten the leading end of screw. \\ Then GENTLY peen the top of hole so they can't unscrew into the rotating cams. You may need to remove the screws in the future. | ||
