Degree Wheel for Cam Timing?

jamesjedi · 12-19-2017, 08:56 AM

Hi,

Anyone use/recommend a degree wheel for cam timing? The engine is a 964 and on an engine stand.

Thanks for any help.

Spenny_b · Spenny_b's Garage

Not that I've seen for these engines (have used them before on other engines I've built)....the only method I've seen and used is to set the cams once "x" mm of valve lift is achieved, with 0.1mm valve lash and the crank is at absolute TDC, "x" being specified by the cam profile you're using. In the case of 964 Carrera cams, it's 1.26mm if you want full advance.

Trackrash · Trackrash's Garage

Google degree wheel and click on images. Choose one and print it out. Glue on.

jamesjedi · 12-19-2017, 03:30 PM

Thanks for the replies. I have never used one. Interesting idea to just print one from the Internet.

Would they not help in determining TDC when used with a TDC tool?
Thanks again.

Trackrash · Trackrash's Garage

Quote:

Originally Posted by jamesjedi

Thanks for the replies. I have never used one. Interesting idea to just print one from the Internet.

Would they not help in determining TDC when used with a TDC tool?
Thanks again.

Yes, you would have to calibrate it. I used a dial indicator before I put the heads on to get it correct to TDC.

jamesjedi · 12-19-2017, 04:29 PM

I am probably going to get one if it makes it easier.

jamesjedi · 12-21-2017, 08:21 AM

Pelican does not have one. Still reading about them. Grady Clay recommended it for determining TDC for an engine that may have had the pulley move. I am replacing my pulley with an OEM - it should line up with the pin.

Moroso 62191: 18" Degree Wheel Professional | JEGS

Trackrash · Trackrash's Garage

I should also mention that my paper wheel was only used during my assemble. I notched my OE pulley for use when running on the motor. I thought Patrick Motorsport used to sell degree wheels?

ChrisBennet · ChrisBennet's Garage

A friend of mine made me a piston stop that threads into the spark plug hole to verify TDC.
I clop a digital angle finder on the flywheel (its magnetic) and turn the crank slowly until the piston hits the stop. Note the angle. Then turn the crank the other direction until piston hits the stop. Note this angle. TDC is halfway between the 2 angles.

For example: If the first angle was 40 degrees and the second angle was 60 degrees, TDC would be at 50 degrees. Remove the piston stop and rotate the crank until the angle finder reads 50 degrees and you’ll be at TDC.

Sorry I don’t have pictures.

VFR750 · 12-22-2017, 04:05 AM

I made one
Paper glued to a plywood ring. Pressed onto the pully

bpu699 · 12-22-2017, 04:21 AM

I found it tough on other cars to do cam timing with a tiny degree wheel. Much easier and more accurate with a BIG wheel. Buy one from any auto parts store, about $15. Then, go get some magnets from home depot to attach to the pulley. Works great...

Bo

Catorce · 12-22-2017, 08:02 AM

People get all wrapped around the axle with degree wheels and accurate reading of where the pulley is at when they should be more concerned about where Piston #1 is at in its stroke.

There is enough lash in the system to where even a degree wheel can be inaccurate.

All you care about is piston #1 TDC. Therefore, all you need is a digital dial indicator with a long enough probe to contact the piston crown, and a way to hold this in place.

That's what I do. It's as accurate as possible and you don't even need to look at the pulley.

Tippy · 12-22-2017, 02:02 PM

I'm trying to understand what the importance is? This isn't a single-cammed V8. The procedure to time the cams doesn't require a degree wheel, unless the 3.6's do?? I'm lost.

Spenny_b · Spenny_b's Garage

Quote:

Originally Posted by Catorce

People get all wrapped around the axle with degree wheels and accurate reading of where the pulley is at when they should be more concerned about where Piston #1 is at in its stroke.

There is enough lash in the system to where even a degree wheel can be inaccurate.

All you care about is piston #1 TDC. Therefore, all you need is a digital dial indicator with a long enough probe to contact the piston crown, and a way to hold this in place.

That's what I do. It's as accurate as possible and you don't even need to look at the pulley.

Quote:

Originally Posted by Tippy

I'm trying to understand what the importance is? This isn't a single-cammed V8. The procedure to time the cams doesn't require a degree wheel, unless the 3.6's do?? I'm lost.

I'm sitting here nodding my head in agreement with you both, have been quietly wondering this for the last week....can't help feeling that this is overthinking the challenge (but hey, I'm a relative rookie and happy to be educated otherwise). The thing I shouldve done before fitting the heads, was to mark-off the ATDC and dwell periods on my flywheel....stupidly I didn't and had to do it through the spark plug holes...but enough repetitions and you get some very consistent results to cam time from. [grabspopcorn]

Trackrash · Trackrash's Garage

Quote:

Originally Posted by Tippy

I'm trying to understand what the importance is? This isn't a single-cammed V8. The procedure to time the cams doesn't require a degree wheel, unless the 3.6's do?? I'm lost.

You are right, on a stock motor with a stock cam. He11, you would probably be OK just lining up the punch marks. The dial indicator is just a double check IMO.

Now, if you have a cam with steep ramps and timing that gets the valves close the pistons, it's a different story. On my motor one change in the sprocket pin made like 4 degrees difference on the crank. That is why I used a degree wheel.

VFR750 · 12-22-2017, 04:53 PM

I’m using the wheel to map piston to valve clearance too.

Plus I mapped my old cam’s profile and I will map the new one.

If your not doing either these two things, I don’t think you need one.

Catorce · 12-22-2017, 04:56 PM

Quote:

Originally Posted by Tippy

I'm trying to understand what the importance is? This isn't a single-cammed V8. The procedure to time the cams doesn't require a degree wheel, unless the 3.6's do?? I'm lost.

You're 100% right, it doesn't technically require any tools. Z1 mark on the pulley and case parting line are TECHNICALLY all you need.

But when you are building a really nice motor, with big cams, you look at the z1 mark and it looks a half inch thick. Then, there is a parallax error trying to line up the mark with the case parting line which is a really crappy seam.

All I am trying to say is that when you are striving for precision, the Z1 / case parting line thingy that represents TDC seems awful vague. So instead, I ignore that piece altogether and focus on the TDC of piston 1. No degree wheel, no nothing. I can tell with a highly sensitive dial gauge where I need to be.

The single cam v8 analogy is lining up everything "dot to dot" which is also vague at best. Which is why a degree wheel is used on a built small block.

Tippy · 12-22-2017, 06:03 PM

Quote:

Originally Posted by Spenny_b

.......but hey, I'm a relative rookie...........

That's the silliest thing I've read here!

Kudos to your work!!

Tippy · 12-22-2017, 06:05 PM

Track/VF4/14, ah, ok. I understand better the goal now.

Tracking valve opening, thats pretty cool. I'm used to just looking at graphs. 😂

Spenny_b · Spenny_b's Garage

Quote:

Originally Posted by Tippy

That's the silliest thing I've read here!

Kudos to your work!!

Ah mate, very kind of you to say, and also to imply I'm not a rookie...but I really am....versus some of the pro's and wisened folk here, I'm barely off first base!