High rpm guys: anybody playing with cam timing?

[caddy]

this is my special puley to fit gti came shft.

[Patrick]

Well, the "right" way to do it would be to put a degree wheel on the crank and measure valve opening with a dial indicator. If someone did this they could make some locking plates to make it fast an easy the next time. I personally don't see the need on an everyday driver, but if someone is going all out...............

[fspGTD]

To set cam advance or retard precisely to desired specs, you could use the following method without any additional tools or parts required.

1. measure the diameter of the flywheel reference surface (the surface where the TDC mark is found.)  I would guesstimate this is about 220-230mm or so (since the largest clutch disc OD is 210mm and it's got to be a little bit larger than that), but measure it on a flywheel to be sure and precise.

2. calculate how much distance at that circumference correlates to 1 degree of cam angle.  3.14159 x flywheel_reference_surface_diameter x 2 / 360 would give you the distance on the flywheel reference surface for 1 degree of cam movement.

3. set the cam to it's upright (TDC) position, lock it with the special tool that goes into the slotted edge of the camshaft with the feeler gauges, and loosen the bolt holding the pulley so that crank can be moved freely.

4. measure a deviation from the TDC mark equivalent to your desired advance (or retard) of the cam, in the desired direction (advance or retard.)  If you wanted to make this step easy, you might be able to apply some "timing tape" or make marks on the flywheel, like they use on gasser engines to set spark timing with the strobe light.

5. tighten the cam pulley to specs (I believe 33 ft-lbs.)

Voila!  Precise setting of cam advance or retard is achieved, without any special parts or tools.  Problem - as has been stated on this thread already, these engines are very tight at TDC, as the piston gets very close to the valves at that point with normal cam timing.  Varying the timing may be running the risk of piston-valve interference (which is no fun and will really ruin your day, believe me.)

[Mark(The Miser)UK]

As a follow on to Jakes i/p; one could move the crank to the point where hand rotation of engine just catches valves. A nice big blood red splodge of paint at this point would show you how far you had left before engine death.... :twisted:
Mark(The Miser)UK

[caddy]

To set cam advance or retard precisely to desired specs, you could use the following method without any additional tools or parts required.

1. measure the diameter of the flywheel reference surface (the surface where the TDC mark is found.)  I would guesstimate this is about 220-230mm or so (since the largest clutch disc OD is 210mm and it's got to be a little bit larger than that), but measure it on a flywheel to be sure and precise.

2. calculate how much distance at that circumference correlates to 1 degree of cam angle.  3.14159 x flywheel_reference_surface_diameter x 2 / 360 would give you the distance on the flywheel reference surface for 1 degree of cam movement.

3. set the cam to it's upright (TDC) position, lock it with the special tool that goes into the slotted edge of the camshaft with the feeler gauges, and loosen the bolt holding the pulley so that crank can be moved freely.

4. measure a deviation from the TDC mark equivalent to your desired advance (or retard) of the cam, in the desired direction (advance or retard.)  If you wanted to make this step easy, you might be able to apply some "timing tape" or make marks on the flywheel, like they use on gasser engines to set spark timing with the strobe light.

5. tighten the cam pulley to specs (I believe 33 ft-lbs.)

Voila!  Precise setting of cam advance or retard is achieved, without any special parts or tools.  Problem - as has been stated on this thread already, these engines are very tight at TDC, as the piston gets very close to the valves at that point with normal cam timing.  Varying the timing may be running the risk of piston-valve interference (which is no fun and will really ruin your day, believe me.)

good , but on stock engine be careful ! valve and piston are verry ....
i've make a special puley because i use a gti cameshaft.
bigger lift and longest inlet and exhaust time, for very high boost.
the piston are modified for the valve secure space.

[Patrick]

I wondered if anyone was running gasser cams in the diesels. Opens up all kinds of options! Guess I have to pull the Chilton's manual out tomorrow to read up on cam specs. Let me see, 1.9, 1.6NA, 1.6TD, 1.7 gas, 1.8 gas, 2.0 gas, GTI's, etc., etc., etc.,...................

[lord_verminaard]

Cool pulley, Caddy.  Do you sell those?  

Also, with your piston modifications, how much deeper of a cut do you make to the piston for the gti cam to work?  This is of much interest to me, since I happen to have a complete 1.8 solid lifter engine sitting in my Rocco, complete with stock "W" camshaft.  

If I do have to use a 1.6, it will have as much 'hot' parts in it that I can scavenge.  

Thanks-

Brendan
84 Scirocco 8v
00 Camaro L36 M49

[16V-Sauger]

this is my special puley to fit gti came shft.

what parts did you use? the inside from the gti pulley and the outside from a diesel?

[935racer]

I played with advancing cams and stuff, never found much gain, fitting a gti cam is a lot of work. Your best bet would be my custom cams :twisted:

[Dr. Diesel]

I played with advancing cams and stuff, never found much gain, fitting a gti cam is a lot of work. Your best bet would be my custom cams
_________________

plug!!  hehe. or my hid conversion kit!   :lol:  :wink:

[935racer]

Yeah sorry about that haha. I hear your HID kits add like 20WHP and increase turbo spool up and decrease EGTS

Sorry I just wanted to point out that you can have a custom ground cam shaft so you don;t have to modify you pully or pistons and still get a performance increase.

[steve]

As a followup to Jake's post.  Count the teeth on a spare flywheel and divide by 360 to find teeth/degree.

Andrew

I did this a few years ago.  I advanced the cam 4 degrees and it really woke up my engine.  It was just shortly after that that I discovered that my valve clearance was total junk (some valves had zero clearance with the thinnest shim) and so I got a new head.  It's been at stock timing ever since because I now have plenty of power and don't feel any need to mess with it.

[SMOKEYDUB]

935 racer when is a stage 3 camshaft or a full blown race cam coming out?

[935racer]

stage 3 is out and done, I'm not going any further with cam developement for  the IDI engines until I start selling more. I just sent andy2 a stage 3 for his twin setup :twisted:

[RabbitGTDguy]

i'd be interested possibly in custom grinds... for the mTDI project, but as far as sharing info goes it'd be nice to see "how" these are performing on the cars themselves. Custom grinds for diesels have been done before, a few even for the TDI in Europe and the gains vs. the trade off of losing low end torque turned out to really not be worth it.  Any info on the performance of your cams specifically 935racer... think I asked that before when I was telling you about the 4bt pump and it never got answered. Even have an extra couple cams sitting here too 1 TDI spare and a couple IDI units...

Joe