Results 1 to 24 of 24

Thread: Modifying cam gears

  1. #1
    Registered User
    Join Date
    Nov 2012
    Location
    VIC
    Posts
    1,303

    Modifying cam gears

    Gents,

    Any PFers capable of doing some [from my understanding] pretty basic machining work or have access to someone that can do it? Basically, i have two cam gears i need modified to be adjustable. My understanding is it would be fairly simple for someone with access to a lathe - cut centre out of standard gear, drill PCD, machine new centre with slots, bolt together.

    Any takers? Ive no idea what grade alloy would be required so i would be relying on you [or whoever it is you know] to provide as part of process. If this is you, please PM me with $$$ in mind.

    Probably shouldve put this in jobs for the boys but whatevz

  2. #2
    BLING BLING PLAYA's Avatar
    Join Date
    Mar 2002
    Location
    adelaide
    Posts
    6,387
    6061 t6 for the new centre is prob fine and common as.
    3D scanning
    3D modelling
    Structural certification
    3 and 5 axis milling

  3. #3
    Opens
    Join Date
    Sep 2004
    Location
    Sydney
    Posts
    1,302
    What engine? If it's Isuzu no luck, but mate has a few different Jap cam wheels from the last century and this, drilled and tapped and a few blank centres. No chance of him taking on the job as recovering from surgery.

    Have found with one morse chain driven wheel at least, they're were as hard as hades, so not as straightforward as just running a boring bar through them with standard inserts. I'd expect you'd need to send the cams to whoever does the job if you're doweling too.

  4. #4
    Registered User
    Join Date
    Nov 2012
    Location
    VIC
    Posts
    1,303
    Quote Originally Posted by PLAYA View Post
    6061 t6 for the new centre is prob fine and common as.
    Ta mate, handy to know. Anything else you reckon is relevant/i need to know?

    Quote Originally Posted by gxxr View Post
    What engine? If it's Isuzu no luck, but mate has a few different Jap cam wheels from the last century and this, drilled and tapped and a few blank centres. No chance of him taking on the job as recovering from surgery.

    Have found with one morse chain driven wheel at least, they're were as hard as hades, so not as straightforward as just running a boring bar through them with standard inserts. I'd expect you'd need to send the cams to whoever does the job if you're doweling too.
    Yep, Isuzu DOHC which is why itll need to be a custom job as i doubt anything out there would come remotely close to being suitable without machining work. Thing is, never had anything like this made up so ive got NFI where to start

  5. #5
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    16,642
    Got a photo?
    I wonder how far off Alfa cam wheels would be (Which are vernier adjustable in the true sense of the word, not slotted "pinch and pray")
    Last edited by Gammaboy; 05-06-19 at 10:25 AM.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

  6. #6
    Registered User
    Join Date
    Nov 2012
    Location
    VIC
    Posts
    1,303
    Ill go one better.



    Standard gear on right, gear with centre cut out on left



    Adjustable insert



    Completed assembly

    To me it looks like the pre-existing half-depth holes on the cam gear have been drilled and tapped

  7. #7
    BOOSTFARKIN Morcs's Avatar
    Join Date
    May 2012
    Location
    Australia
    Posts
    701
    Reacon I could pull this off with my shit in my shed.
    Ie lathe, mill, rotary table etc
    Have never done anything like that so nfi on $$ as dunno how much time.

    I don't have any alloy suitable but do have a lump of 4 inch round steel that would certainly do the job.

    On the other side of the country though.

  8. #8
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    16,642
    Yeah, it's a lathe + Mill job, suspect that it's going to be as hard as fuck for part of that facing operation (says the guy who lightened a bunch of gearbox gears with no coolant and totalled ~3 tungsten carbide tip tools).
    Are there other G180W/G200W wierdos that would want a set?
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

  9. #9
    BOOSTFARKIN Morcs's Avatar
    Join Date
    May 2012
    Location
    Australia
    Posts
    701
    I don't reckon it will be way hard not like it's been case hardened like gearbag stuff.

    My guess would be a high carbon steel that is heat treated on the teeth of the sprocket and not in the centre shown in the pics of the machining marks don't look like hardened steel.

  10. #10
    Registered User
    Join Date
    Nov 2012
    Location
    VIC
    Posts
    1,303
    Metallurgy isnt my strong point but i reckon Morcs is right in that the heat treating is on the outer edge looking at the picture; possibly on the nose that slips over the cam as well to stop it beating itself to death?

    Negative on any other G180Weirdos/G200Weirdos - all of them are serial procrastinators that hoard shit and talk about what they are going to do but dont actually do it hence i suspect it may be a one-off job for someone using a manual lathe/mill [i take it you were asking from a CNC perspective; quick batch run?]

    Morcs, where abouts is the other side of the country? Happy to provide the correct material/cash for the correct material....just need you to be confident because i dont have a spare set of OEM gears to fall back on lol

  11. #11
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    16,642
    Quote Originally Posted by Morcs View Post
    I don't reckon it will be way hard not like it's been case hardened like gearbag stuff.

    My guess would be a high carbon steel that is heat treated on the teeth of the sprocket and not in the centre shown in the pics of the machining marks don't look like hardened steel.
    I was just going on the heat treat "tide mark" that's been partially machined into. I'm actually surprised that it's only the teeth that have been hardened - pretty much every other sprocket I've seen has been Case hardened everywhere or through hardened and is as hard as fuck - sparks coming off the end mill type hard.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

  12. #12
    BOOSTFARKIN Morcs's Avatar
    Join Date
    May 2012
    Location
    Australia
    Posts
    701
    Hit it with a file if it skates off it's hard as
    If it actually takes a bite it will machine easy.

    The gear bit is the easy bit fairly straight forward if it is soft enough.
    It's the lining of everything up that I'm worried about ie setting the degree marks in correct position and the timing in correct position.
    As I can't see from pics how sprocket is located to time sprocket to cam.
    The rest is pretty straight forward.


    Sprockets i if played with have machined with out drama but all are from low powered agricultural equipment or motorcycle stuff.

    Remote WA pm

  13. #13
    Opens
    Join Date
    Sep 2004
    Location
    Sydney
    Posts
    1,302
    Looks like just the teeth have been induction hardened, reckon the rest might be ok. The hard ones here were some sort of sintered shit, needing a trip to SEI carbide, those bastards were hard all the way through, thankfully didn't have to try to tap them, as I used buttons in the lightening holes to hold it together - horrible noise in the cut even so.

    Bit surprised that centre doesn't appear to have any positive location, other than the fastener, unless there's blind holes not shown? Some of the modern stuff uses diamond impregnated washers to accomplish the same...leery of that method in modded cars with high seat pressures!

  14. #14
    BOOSTFARKIN Morcs's Avatar
    Join Date
    May 2012
    Location
    Australia
    Posts
    701
    Actually looking at the pic on pc there is a dowl alinging cam to sprocket fairly simple.

  15. #15
    Registered User
    Join Date
    Mar 2008
    Location
    VIC
    Posts
    84
    Not quite what you’re asking for, but I vaguely recall Rollmaster made a timing chain set for these. If they did, most of their models feature adjustable sprockets. But, from very limited memory here, I think they were pulled from the market.
    Might be worth searching to see if anything is available, or even if anything secondhand is available.

    Edit, also search JP brand.

  16. #16
    Registered User
    Join Date
    Jun 2007
    Location
    Melbourne
    Posts
    771
    When I had mine there were a couple of ways we did the cam timing
    1) Use the offset dowel locating kit for an L series datsun - Just bore out the hole in the cam gear and use offset dowel inserts on the standard dowel. This works but is fiddly and the access is terrible, I did drop an insert down into the sump once which was a real pain. You can just slot the gears with a mill and rotary table, they are just case hardened and it's not thick.
    2) In the end I just modified the gears to have 4 holes which were slotted, no dowels and 4 8x1.5 cap screws into the end of the camshaft.

    Unless you have a high comp motor I wouldn't bother with aftermarket cams as these have shit dynamic comp and you just end up making the problem worse with larger cams. Also when changing cam timing you need to be very careful about valve to valve contact, the high valve angle means it doesn't take much for them to kiss and then they are fucked.

  17. #17
    Registered User
    Join Date
    Nov 2012
    Location
    VIC
    Posts
    1,303
    Quote Originally Posted by Morcs View Post
    Actually looking at the pic on pc there is a dowl alinging cam to sprocket fairly simple.
    Yep, however just realized that in standard form the cam only uses the centre hole of the gear to locate it - its held in position by 1 dowel and 2 bolts, meaning the centre hole would also need to be tapped.

    Quote Originally Posted by private9 View Post
    Not quite what you’re asking for, but I vaguely recall Rollmaster made a timing chain set for these. If they did, most of their models feature adjustable sprockets. But, from very limited memory here, I think they were pulled from the market.
    Might be worth searching to see if anything is available, or even if anything secondhand is available.

    Edit, also search JP brand.
    Rollmaster set with the offset dowel holes/fixed degrees of adjustment was for the Z series SOHC motors; wont work this is a completely different kettle of fish

    Quote Originally Posted by Komdotkom View Post
    When I had mine there were a couple of ways we did the cam timing
    1) Use the offset dowel locating kit for an L series datsun - Just bore out the hole in the cam gear and use offset dowel inserts on the standard dowel. This works but is fiddly and the access is terrible, I did drop an insert down into the sump once which was a real pain. You can just slot the gears with a mill and rotary table, they are just case hardened and it's not thick.
    2) In the end I just modified the gears to have 4 holes which were slotted, no dowels and 4 8x1.5 cap screws into the end of the camshaft.

    Unless you have a high comp motor I wouldn't bother with aftermarket cams as these have shit dynamic comp and you just end up making the problem worse with larger cams. Also when changing cam timing you need to be very careful about valve to valve contact, the high valve angle means it doesn't take much for them to kiss and then they are fucked.
    Engine is forged bottom end/12:1 comp, E85, big cams etc etc. Accessibility and or ease of adjustment isnt really a concern as once the timing is set im hoping to not have to adjust it ever again [yeah i know wishful thinking]. Valve to valve can be engine builders responsibility; he seems to think it will be ok but last time we spoke he wanted gears regardless to retard/advance as required. Cams are A-symetrical profile and on different lobe centres so hoping it doesnt cause issues because the lift is quite large. Kanaris can sort that out, i just need to get him the right bits.

    I remember you mentioned 4 hole/no dowel thing a while back; was the effective PCD of the bolts holding the cam down being small not a concern? Probably showing a lack of understanding but wouldnt the distance from cam centre to where the chain is effectively cause leverage on the bolts?

  18. #18
    Chopped BigMuz's Avatar
    Join Date
    Nov 2001
    Location
    Eastern Australia
    Posts
    12,720
    We did geminis in the olden days by drilling a hole in every gap with about three or four degrees difference in each. It's only maximum effort engines that need single degree variability. Easy to do, even with a pistol drill as long as you can get through the surface.
    Retard Honour Wall.
    Quote Originally Posted by Sloth View Post
    Rob Sloth Young did i ask for your opinion? no. i only want it for a paddock bomb. go play with traffic.
    Quote Originally Posted by Fondles View Post
    you stupid fucken imbicle.
    Quote Originally Posted by Fondles
    your are a fucken idiot of the highest level.

  19. #19
    Registered User
    Join Date
    Jun 2007
    Location
    Melbourne
    Posts
    771
    Quote Originally Posted by F3ARED View Post
    Yep, however just realized that in standard form the cam only uses the centre hole of the gear to locate it - its held in position by 1 dowel and 2 bolts, meaning the centre hole would also need to be tapped.



    Rollmaster set with the offset dowel holes/fixed degrees of adjustment was for the Z series SOHC motors; wont work this is a completely different kettle of fish



    Engine is forged bottom end/12:1 comp, E85, big cams etc etc. Accessibility and or ease of adjustment isnt really a concern as once the timing is set im hoping to not have to adjust it ever again [yeah i know wishful thinking]. Valve to valve can be engine builders responsibility; he seems to think it will be ok but last time we spoke he wanted gears regardless to retard/advance as required. Cams are A-symetrical profile and on different lobe centres so hoping it doesnt cause issues because the lift is quite large. Kanaris can sort that out, i just need to get him the right bits.

    I remember you mentioned 4 hole/no dowel thing a while back; was the effective PCD of the bolts holding the cam down being small not a concern? Probably showing a lack of understanding but wouldnt the distance from cam centre to where the chain is effectively cause leverage on the bolts?
    You still need to be able to adjust the gears once the engine has been built, I've never had an engine yet that makes the best power/curve on the recommended timing. There's too many other factors at play, you need to fuck around with it on the dyno to get it perfect.
    The 4 bolts are just generating the compression of the gear against the nose of the cam, they don't drive it. It's the friction caused by the two mating faces being forced together. They need to be lock wired and become part of the maintenance schedule.

  20. #20
    Hungry Hungry Hippo Tripper's Avatar
    Join Date
    Aug 2002
    Location
    gong
    Posts
    15,137
    I recall a post from TK i think it was, about building a marlin engine for some guy for tractor drags or something like that, any way if memory serves me correct that guy was a gear builder, riverina screamer was/is the name of the tractor from memory, guess it depends on the budget if its worth chasing up with them
    you cant spell advertisements without semen between the tits

  21. #21
    Opens
    Join Date
    Sep 2004
    Location
    Sydney
    Posts
    1,302
    Quote Originally Posted by Morcs View Post
    Actually looking at the pic on pc there is a dowl alinging cam to sprocket fairly simple.
    Ah, light and dark shadow.

    Maybe telling you how to suck eggs, picked this fairly simple trick up on holding the wheel and avoiding tooth damage. https://imgur.com/3O347sn

  22. #22
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    16,642
    Quote Originally Posted by Tripper View Post
    I recall a post from TK i think it was, about building a marlin engine for some guy for tractor drags or something like that, any way if memory serves me correct that guy was a gear builder, riverina screamer was/is the name of the tractor from memory, guess it depends on the budget if its worth chasing up with them
    Riverina Screamer has been sold to Gonz from Gonzlab, the Merlin is going in a ZC Fairlane.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

  23. #23
    BOOSTFARKIN Morcs's Avatar
    Join Date
    May 2012
    Location
    Australia
    Posts
    701
    Quote Originally Posted by gxxr View Post
    Ah, light and dark shadow.

    Maybe telling you how to suck eggs, picked this fairly simple trick up on holding the wheel and avoiding tooth damage. https://imgur.com/3O347sn
    Cheers thanks for that, was just planning on using copper pads in the 4 jaw...that way looks a lot more of a positive engagement.

    TK's Merlin thread
    http://www.performanceforums.com/for...rged-insanity!
    Last edited by Morcs; 12-06-19 at 08:41 PM.

  24. #24
    Non Compos Mentos Gammaboy's Avatar
    Join Date
    Jun 2008
    Location
    Brisbane
    Posts
    16,642
    Quote Originally Posted by Morcs View Post
    Cheers thanks for that, was just planning on using copper pads in the 4 jaw...that way looks a lot more of a positive engagement.

    TK's Merlin thread
    http://www.performanceforums.com/for...rged-insanity!
    Small chunks of aluminium rod dropped into the valleys of the teeth is another good way to clamp.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •