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techtalk:evo:engmech03a [2019/07/29 17:55] hippysmack [Cylinder / Head Bolt Issues and Repair] |
techtalk:evo:engmech03a [2024/01/03 20:54] hippysmack |
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====== Cylinder / Head Bolt Issues and Repair ====== | ====== Cylinder / Head Bolt Issues and Repair ====== | ||
- | ===== Stud Removal ===== | + | ===== Sub Documents ===== |
+ | See also in the Sportsterpedia: | ||
+ | * [[techtalk:evo:engmech03b|Time-Sert Repair on Engine Case Cylinder / Head Stud Hole]] | ||
+ | * [[techtalk:ref:tools023#warped_or_damaged_thread_repair|Warped or Damaged Thread Repair]] | ||
+ | ===== Loose Head Bolt Studs ===== | ||
+ | A big concern about the studs becoming loose is the threads being stripped in the case. \\ | ||
+ | The two side by side bolt holes on the right side in the pic below are each drilled into the opposing holes and tapped. \\ | ||
+ | So each hole is depending, in part, of the strength of the other. \\ | ||
+ | With the bolts loosening, it is at least suspect that the threads or the hole strength is compromised. ((Hippysmack of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/197474-leaking-head-gasket-loose-head-bolts/page2?t=2074117&page=2)) \\ | ||
- | |{{:techtalk:evo:engmech:bent_socket_ext_while_removing_cylinder_stud_by_hippysmack.jpg?direct&300|}}|{{:techtalk:evo:engmech:broken_stud_extractor_by_hippysmack.jpg?direct&300|}}|{{:techtalk:evo:engmech:damaged_cylinder_stud_while_removing_by_hippysmack.jpg?direct&300|}}| | + | | Weakest head stud holes in the case. ((photo by Hippysmack)) | Head bolt pulled out of the case. ((photo by Blue Scoot of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/198541-repairing-cylinder-studs-cases/page5#post4360678)) | |
+ | |{{:techtalk:evo:engmech:weakest_cylinder_bolt_threads_by_hippysmack.jpg?direct&300|}}|{{:techtalk:evo:engmech:head_bolt_pulled_out_by_blue_scoot.jpg?direct&300|}}| | ||
- | This idea below to soak the threads in oil was in response to the broken tool(s) above. \\ | + | There is a procedure in the manual for tightening the studs before installing the cylinders and heads. \\ |
+ | Basically you put a steel ball on top of the stud, then a head bolt cap on top of that. \\ | ||
+ | The ball allows you to achieve spec'd torque and still remove the nut without unscrewing the stud from the case. \\ | ||
+ | This 'sets' the studs into the case in addition to the torque applied to the head bolts. \\ | ||
+ | Without the initial torque on the studs, they are totally dependent on the torque of the head bolts. \\ | ||
+ | But they shouldn't back out unless either they weren't installed right to begin with or the hole has been stripped / compromised. \\ | ||
+ | |||
+ | If a stud is backing out, it could have simply be from it being installed improperly to begin with. \\ | ||
+ | It is possible that the stud turned when the head cap nuts were removed. \\ | ||
+ | Heat plays a role in what happens to the studs / nuts also and can lock the cap screw tighter than the stud is to the case. \\ | ||
+ | So it is possible that the top nut was just tight to the stud before breaking loose. \\ | ||
+ | First try and remove any studs that back out and check the threads in the case as well as the stud. \\ | ||
+ | It is also possible to burr the stud threads by dropping them on installation and subsequently ruin the case threads when turning the stud in. \\ | ||
+ | |||
+ | Sometimes the studs will stretch upon torque (especially too much torque). \\ | ||
+ | If this happens, the wrench will say you hit torque, but when you release pressure, the stud spins with you back to it's relaxed state. \\ | ||
+ | In that case, you did not get to final torque. Just something to think about when torque'ing the heads. \\ | ||
+ | Be aware that the stud itself could stretch (or twist in the middle). \\ | ||
+ | You can feel when this happens. It takes longer to get to torque due to the stud turning with you in the middle. \\ | ||
+ | Always follow the torque sequence in the FSM and or your engine builder /supplier when installing the head bolts. \\ | ||
+ | This will also cause a leak if not done properly. \\ | ||
+ | \\ | ||
+ | |||
+ | ==== Soaking the threads for easier removal ==== | ||
+ | Soaking the threads is usually advised before attempting to remove them. \\ | ||
Due to the angle of the block, it's not possible to actually leave anything next to the threads since it will simply slide down the block. \\ | Due to the angle of the block, it's not possible to actually leave anything next to the threads since it will simply slide down the block. \\ | ||
So a 'holding chamber' was made to let the oil sit and penetrate the threads. \\ | So a 'holding chamber' was made to let the oil sit and penetrate the threads. \\ | ||
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This made removing the stud with an 18" pipe wrench easier the next day. \\ | This made removing the stud with an 18" pipe wrench easier the next day. \\ | ||
{{:techtalk:evo:engmech:stuck_cylinder_stud_removal_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) | {{:techtalk:evo:engmech:stuck_cylinder_stud_removal_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) | ||
+ | |||
+ | ===== Stud Removal ===== | ||
+ | |||
+ | ==== Using stud removal tools to loosen the stud ==== | ||
+ | |{{:techtalk:evo:engmech:bent_socket_ext_while_removing_cylinder_stud_by_hippysmack.jpg?direct&300|}}|{{:techtalk:evo:engmech:broken_stud_extractor_by_hippysmack.jpg?direct&300|}}|{{:techtalk:evo:engmech:damaged_cylinder_stud_while_removing_by_hippysmack.jpg?direct&300|}}| | ||
+ | |||
+ | ==== Using a pipe wrench to loosen the stud ==== | ||
+ | |||
+ | A propane torch works well to melt or loosen old Loctite (red or blue) on the threads. \\ | ||
+ | |||
+ | Catch the stud down low, but not so low as to run the wrench into the block. \\ | ||
+ | Lay some rags over the bore, find a small piece of plywood even a short 2x4 block, drill a hole in the middle and slide it down the stud. \\ | ||
+ | Then clamp the stud with the pipe wrench on top of the wood. \\ | ||
+ | Set the jaws of the wrench over the stud, adjust then to the stud. \\ | ||
+ | Use one hand to cup over the wrench and stud and the other on the handle. \\ | ||
+ | You'll get more even torque if you can let your body lean into the handle as well. \\ | ||
+ | It may scare you when the stud breaks loose. It'll make a cracking noise which is normal. \\ | ||
+ | The wrench won't turn all the way around due the the other studs in the way. \\ | ||
+ | So you'll have to remove the wrench and get another grip to continue turning until it gets loose enough to turn by hand. \\ | ||
+ | Once you get to where it doesn't take so much torque to turn it, you can use double nuts on the top threads if you prefer. \\ | ||
+ | The pipe wrench is mainly to break torque. It's easier to get out of hand and damage something if it's not needed after that. \\ | ||
+ | |||
+ | If the pipe wrench slips, you may need to adjust the wrench so the stud is closer to the inside teeth. \\ | ||
+ | You may need to loosen the jaws to move the stud back. \\ | ||
+ | The wrench doesn't have to be tight against the stud to grip. \\ | ||
+ | It works by the magic of binding onto the stud. \\ | ||
+ | It's important to hold center on the wrench and stud with one hand. \\ | ||
+ | You can try getting a grip by tilting the handle up with just a little pressure and then back level. \\ | ||
+ | You just have to find a way to make the wrench bind against the stud. \\ | ||
+ | |||
+ | |If the wrench doesn't grip, make it bind on the stud. ((photo by Blue Scoot of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-motor-top-end/197474-leaking-head-gasket-loose-head-bolts/page6?t=2074117&highlight=head+gasket&page=6)) | | ||
+ | |{{:techtalk:evo:engmech:removing_cylinder_stud_with_pipe_wrench_by_blue_scoot.jpg?direct&300|}}| | ||
+ | |||
+ | ==== Using Double Nuts / Jam Nuts ==== | ||
+ | Install 2 nuts on the top threads and torque the two nuts to 35ft pounds or higher. \\ | ||
+ | Be aware the tall studs can stretch if it takes too much torque to break them free. \\ | ||
+ | Be sure to use rags around the bore so as to not get any debris in the engine while removing the stud(s). \\ | ||
+ | |||
+ | | Three jam nuts used here. ((photo by A 4 liter V8 eater of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/frame-mount-evo-sportster-talk-1986-2003-models/148266-building-a-90-inch-sledge-hammer/page11#post3236162))| | ||
+ | |{{:techtalk:evo:engmech:tightening_cylinder_-_head_studs_by_a_4_liter_v8_eater.png?direct&300|}}| | ||
+ | |||
+ | ===== Cleaning the Case Threads ===== | ||
+ | The threads on the head studs as well as in the case need to be clean and free of rust / debris and they need to be straight in order to obtain proper torque on the heads. \\ | ||
+ | |||
+ | The photos below are of before (L) and after (R) chasing the case threads with a 3/8"x16 tap. \\ | ||
+ | The dirty threads will add preload to the torque readings and can easily give false readings on the wrench which could affect head gasket performance. \\ | ||
+ | |||
+ | {{:techtalk:evo:engmech:head_bolt_threads_before_chasing_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:evo:engmech:head_bolt_threads_chased_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) \\ | ||
+ | |||
+ | ===== Stripped Case Threads ===== | ||
+ | These could be repaired with Heli-coils. \\ | ||
+ | But the repair must be straight with no wobble when drilling. \\ | ||
+ | So it's best to split the cases and take them to a reputable machine shop to have that done. \\ | ||
+ | In the pic below, notice the small clearance between the studs and the holes they run in. \\ | ||
+ | The case threads have to be in perfect alignment to the stud holes in the cylinder. \\ | ||
+ | If not, the cap nuts will not fit on the studs to install them. \\ | ||
+ | The stud would have to be wedged to get the nuts on. \\ | ||
+ | This puts the nuts in a bind when using torque. \\ | ||
+ | It will effectually hit torque on the wrench way before the nut is actually that tight. \\ | ||
+ | It can also warp the studs. \\ | ||
+ | {{:techtalk:evo:engmech:cylinder_stud_positioning_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) | ||
+ | |||
+ | |||
\\ | \\ |