• Login:
Page 1 of 5 1 2 3 ... LastLast
Results 1 to 10 of 50
  1. #1
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts

    Bigger cams for ZC32s track car

    I'm planning on putting some bigger cams in the yellow track car, with the ultimate intention of turning it into a race car for my 21 yo son to get his racing licence.

    So I thought you guys might enjoy following this journey.

    Firstly, changing cams in a Swift seems to me to be an "engine out" exercise for amateurs like me, and as we want to keep running the car during the cooler months, I decided to get a spare engine:


  2. #2
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts
    Information on modifying these engines is hard to come by, in particular the ZC32S variant of the M16A engine, which is different from the ZC31S engine of the same designation. My plan is to fit the biggest cam I can without changing the bottom end. So it is important to understand the stock cam timing, and piston to valve clearance.

    Measuring cam timing is relatively straightforward, you just need a cam degreeing wheel (mine is home made) and a dial indicator guage.



    According to my measurements of the stock cams, the "advertised duration", which is the duration based on 0.1mm of valve lift, is 253 degrees on the inlet, and 237 degrees on the exhaust. The maximum lift I measured is 8.9mm for the intake, and 8.05mm for the exhaust. So now I know what I need to compare prospective cams to in terms of lift and duration.
    Last edited by Sprinkles; 16-09-17 at 10:11.

  3. The Following 2 Users Say Thank You to Sprinkles For This Useful Post:

    lunar tick (16-09-17), Philfr (16-09-17)

  4. #3
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts
    The next measurement I need to get is the piston to valve clearance, which is a bit more involved. I don't want to fit a cam that results in the valves hitting the pistons. The best method for measuring piston to valve clearance is the so called "clay method".

    This involves pulling the engine down to a short block, and putting clay on top of the pistons, then measuring the indentation the valves make in the clay.

    So I turned my son and his mate loose on this task. I wasn't too pleased to see a hammer being used early on:




    But the boys made quick work of disassembling the engine:











  5. The Following User Says Thank You to Sprinkles For This Useful Post:

    Veefource (20-09-17)

  6. #4
    SSOC Addict lunar tick's Avatar
    Join Date
    Aug 2015
    Posts
    341
    Thanks
    56
    Thanked 106 Times in 79 Posts
    Fantastic work Sprinkles! Keep us updated with your findings. I am thinking of a slightly more aggressive set of cams in my ZC32. Another 15 brake and some more top end power would make the car IMO. I'm currently considering these - http://www.monster-shop.jp/index.php...48&language=en - which seem to be striaght drop in cams that will work with OEM valve springs. But it's hard to know just how much more aggressive than OEM cams they really are.

  7. #5
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts
    That Monster cam is one of the candidates, it's intake is the same duration as stock, and slightly more lift, the exhaust has more lift and duration. I'm hoping a bigger cam than that will fit, from R's or Kelford, I'm not sure that Monster one is different enough from stock to be worth the trouble.

  8. #6
    SSOC Addict lunar tick's Avatar
    Join Date
    Aug 2015
    Posts
    341
    Thanks
    56
    Thanked 106 Times in 79 Posts
    Yes, that's my concern too. I contacted Kelford about their cams for ZC32S but they replied that their cam designs would not physically fit without some minor modifications (can't remember exactly what these were). I'm guessing a significantly bigger cam will mean a change of valve springs too?

  9. #7
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts
    Quote Originally Posted by lunar tick View Post
    Yes, that's my concern too. I contacted Kelford about their cams for ZC32S but they replied that their cam designs would not physically fit without some minor modifications (can't remember exactly what these were). I'm guessing a significantly bigger cam will mean a change of valve springs too?
    Have a look on Kelford's web site, they have got about four different cams for the M16A. I think the minor mod they might be referring to re the physical fit could be clearance around the valve buckets, but I would think this would only be for a cam with a LOT more lift, you could imagine the lobe being taller and hitting casting adjacent to the bucket. They have a cam that's a similar spec to the R's cam. The other thing to be mindful of is their cams are for the ZC31S derivation, and it has a different cam angle trigger to the 32. The 31 is 2-2-1-1, and the 32's trigger is 2-1-1. I assume they are removable, Kelfords sent me a photo of just the trigger in a plastic bag.

  10. #8
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts
    Quote Originally Posted by lunar tick View Post
    Yes, that's my concern too. I contacted Kelford about their cams for ZC32S but they replied that their cam designs would not physically fit without some minor modifications (can't remember exactly what these were). I'm guessing a significantly bigger cam will mean a change of valve springs too?
    Have a look on Kelford's web site, they have got about four different cams for the M16A. I think the minor mod they might be referring to re the physical fit could be clearance around the valve buckets, but I would think this would only be for a cam with a LOT more lift, you could imagine the lobe being taller and hitting casting adjacent to the bucket. They have a cam that's a similar spec to the R's cam. The other thing to be mindful of is their cams are for the ZC31S derivation, and it has a different cam angle trigger to the 32. The 31 is 2-2-1-1, and the 32's trigger is 2-1-1. I assume they are removable, Kelfords sent me a photo of just the trigger in a plastic bag.

  11. #9
    SSOC Addict Sprinkles's Avatar
    Join Date
    Oct 2016
    Location
    Australia
    Posts
    389
    Thanks
    24
    Thanked 97 Times in 74 Posts

    Piston to valve clearance measured

    Tonight I've measured the piston to valve clearance with the intake cam in the fully advanced position, which was a bit of a journey of discovery. The VVT cam phaser has a locking pin in it that locks it in the fully retarded position when it has no oil pressure, which isn't much help as this gives the most piston to valve clearance. I want to know the minimum PTV clearance so I know how big a cam I can fit without the valves hitting the pistons.

    I ignored the "DO NOT DISMANTLE" embossed on the phaser, and pulled it apart. It was then a simple matter of using compressed air to unlock the locking pin, advance the phaser and put a spacer in it to hold it in the fully advanced position.

    Anyway, then onto the measuring. Firstly, here's how the clay (actually Plasticine) is set up on top of the piston. Blue is intake, pink is exhaust.




    An hour and a half later, after the head and cams have been reinstalled, then engine turned over by hand, and the cams and head removed, here's the result. I oiled the valves to stop them sticking to the Plasticine.



    Then slice through the Plasticine, and we can see how much clearance is between the valve and the piston.



    4.4 mm on the intake side, and 4.9 on the exhaust side, which is more than I was expecting. So the R's cam should fit fine, and I might even have enough clearance to shave the head to increase the compression ratio if I'm lucky.

  12. The Following 2 Users Say Thank You to Sprinkles For This Useful Post:

    el.crichon (17-09-17), Highco (22-09-17)

  13. #10
    SSOC Addict lunar tick's Avatar
    Join Date
    Aug 2015
    Posts
    341
    Thanks
    56
    Thanked 106 Times in 79 Posts
    That's a great bit of research there. Thanks again mate. Do you have a link for the Rs cams you're considering? Will they run with OEM springs?

Posting Permissions

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