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Engine Specific Info and Questions => IDI Engine => Topic started by: Dr. Diesel on June 08, 2010, 03:56:27 pm
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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.
(http://img.photobucket.com/albums/v225/vwpics/CamLobeAnatomy.jpg)
send through PM, please.
Thanks in advance!
Dr. D.
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sigh. ::)
I have no problem sticking with hydraulic performance cams only. MUCH less time consuming.
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i gotta get time to get to my brothers garage... i'm busy right now, i settle on my house friday woot woot
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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.
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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 :(
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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?
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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)
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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.
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these machines will easily do a straight-eight cam. ;D
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.
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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.
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You should have my dimensions from a couple heads.... :)
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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.
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Any update on this? I've got a spare mech cam laying around...