Performance cam for mechanical heads - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Performance cam for mechanical heads by Dr. Diesel on 08 Jun, 2010 15:56
• Heya guys ('n gals?)
  Ok, so the performance hydraulic cam program is off and running.
  Now I'm looking at adapting it to a mechanical head to see if it'll improve performance there, too.
  
  For everyone who has the willingness and ability to do so, I could certainly use the following measurements from a number of heads to build a database. Once I determine the range that these measurements fall within, I can calculate whether this cam will work or not. On the sample mechanical head I have access to (thanks, BYM) my cam works just fine for the exhaust valves, but will require some trickery for the intakes. I believe I have that trickery sorted out but I need to know if many other mechanical heads have similar measurements, or if this one is somehow unique. (valve and seat grinding history plays a big role here)
  
  Accuracy is very important, as usual.
  
  I need, for each valve:
  
  1. The clearance between the lifter shim and the heel of the lobe (lobe nose pointing straight up)
  
  2: The thickness of the lifter shim (usually printed on the underside, if not, measure with micrometer perferrably, if not, vernier calipers will do.)
  
  3: The base circle dimension of each cam lobe, to eliminate variation due to (abnormal) wear.
  
  
  
  send through PM, please.
  
  Thanks in advance!
  Dr. D.
  
• #1 by Dr. Diesel on 14 Jun, 2010 17:40
• sigh. 
  I have no problem sticking with hydraulic performance cams only. MUCH less time consuming.
  
• #2 by RabbitJockey on 14 Jun, 2010 22:38
• i gotta get time to get to my brothers garage... i'm busy right now, i settle on my house friday woot woot
• #3 by 745 turbogreasel on 18 Jun, 2010 03:25
• Would this trickery work on a D24 cam?  I have a head I can dig up and measure, but I won't bother if there is no chance of it going anywhere.
• #4 by theman53 on 18 Jun, 2010 07:33
• I will try to get this tonight. I don't know how much info I will be able to get as I don't have tools for removing shims to measure
• #5 by Dr. Diesel on 18 Jun, 2010 12:46
• Quote from: 745 turbogreasel on 18 Jun, 2010 03:25

  Would this trickery work on a D24 cam?  I have a head I can dig up and measure, but I won't bother if there is no chance of it going anywhere.
  

  
  I can't think of any reason why it wouldn't... is your d24 solid lifter or hydraulic?
• #6 by Dr. Diesel on 18 Jun, 2010 12:52
• Quote from: theman53 on 18 Jun, 2010 07:33

  I will try to get this tonight. I don't know how much info I will be able to get as I don't have tools for removing shims to measure
  

  
  If you remove the cam, removing the shims is easy with a pair of needle nose, or a quick squirt of compressed air into the little groove. (careful of flying shims!)
  
  You can do it all with a vernier caliper and a set of feeler gauges.
  Here's a good method:
  
  1. measure all valve clearances w/ gauges
  2. remove cam
  3. measure thickness of all shims (keep track of which position)
  4. measure the base circle of each camlobe
  5. reinstall cam (make sure the bearing caps go back on the exact same order and orientation)
  
• #7 by 745 turbogreasel on 19 Jun, 2010 01:34
• I'm pretty sure all North America D24s are mech, all mine have been.
  Only reason I cold think it wouldn't work is if your grinding machine wasn't long enough.
    there might be other differences i am unaware of, but I have more cams than engines, so failure is no big loss.
  
  Another way to remove the shims is to bounce a retrieval magnet off em a few times.
• #8 by Dr. Diesel on 21 Jun, 2010 19:47
• these machines will easily do a straight-eight cam. 
  if you can get me the measurments i've outlined, we'll see what can be done. It would also be helpful to know your valve face depth (vs head gasket surface) piston projection at tdc, and thickness of gasket.
• #9 by clarkrep on 22 Jun, 2010 00:36
• I should be able to have some numbers for you this week. I just got a head back from the machine shop friday. Gotta set the valve lash then I'll know.
  btw thanks alot for all your work getting this cam stuff figured out. We do appreciate it.
• #10 by clarkrep on 05 Jul, 2010 21:05
• You should have my dimensions from a couple heads....
• #11 by punkvideo81 on 05 Jul, 2010 21:40
• my 1.6 td mech head is at the machine shop, might be able to get these figures for you, and would be really excited about a cam for my engine build.
• #12 by patracy on 03 May, 2011 10:53
• Any update on this?  I've got a spare mech cam laying around...