DIY - Degreeing Camshafts for Turbo M/S5x Engines

[chikinhed]

It doesn't take much research to discover that the NA cam timing settings may not be the best for a turbo set up. Overlap is not a good thing if your engine has higher exhaust manifold back pressure. I had measured mine to be a 2:1 ratio to boost. When you read "overlap is great on a turbo engine" people are usually talking about a monster size turbo where the exhaust manifold back pressure is never as high as the boost pressure. That is not your average boosted BMW engine that we see on this forum (Yes, there are some exceptions). By trying different cam timing settings I found that as I reduced overlap the spool and transient response improved (based on datalogs). Then vacuum increased from about 15"Hg up to 18-19"Hg and the engine felt more crisp.

To degree your cams you will need:

• Magnetic base 1.000" dial indicator
• Moroso 11" degree wheel (or any brand that tickles your fancy)
• Stainless steel or steel wire to make a pointer out of
• Small piece of plate steel to make a flat mounting surface for the magnetic base to stick to

You will have to modify the degree wheel in some way to fasten it to the crank pulley. I took a piece of tubing and made an attach point to the degree wheel. This was version 1.0 for me. It made it more difficult to turn the crankshaft without access to the crank bolt.









Another BF.com member had an easier, less eliquant method of attachment but actually much more user friendly than mine.




Degree wheel mounted to the AC crank pulley and indicator wire bolted to the timing cover crank position sensor attach bolt location.




Another angle of the degree wheel and pointer installed.




Twisted SS wire bolted to crank position sensor attach bolt hole on front cover.




Steel plate, cut to fit, placed over the spark plug holes and bolted down using valve cover studs. Drill hole in plate over spark plug holes so that air can move in and out of the cylinders as the crank shaft is rotated.





Remove the screw in tip from the 1.000” dial indicator and replace with a 2” long piece of welding rod or equivalent. If you put a slight ‘S’ in the end of the rod it will engage the threads in the dial indicator and it will stay in place.




Magnetic base 1.000” dial indicator sitting on steel plate bolted to cylinder head.




This is how you would check piston to valve clearance during assembly of the engine. Replace the valve springs with weak hardware store springs, install the head on the assembled bottom end using a used head gasket of known thickness and tighten it down. Rotate the crank starting at 30° BTDC and stop at 5° increments through to 30° ATDC. At each position depress the valve until it contacts the top of the piston. Take a measurement with the dial indicator measuring the distance from valve seat to piston contact. Record all measurements.






Once you have the degree wheel and pointer attached, rotate the crank shaft in the forward direction and stop at TDC for #1 cylinder. Never rotate the crank shaft backwards or it will screw the measurements. You can find TDC by using the timing pin, using a dial indicator on the top of the piston or some have used the timing marks on the front cover but I found that mine were off slightly. With the dial indicator installed on the steel plate you will need to position the dial indicator so that the end of the pin (welding rod) is between the cam bearing and the cam lobe and the end of the pin is contacting the lifter perpendicular to the face of the lifter. This is important for obtaining accurate readings. Intake and exhaust valves will be closed at this point. Zero the dial indicator by rotating the bezel (needle pointing to zero). Rotate the crank shaft until the dial indicator reads 0.050” and stop. The indicator is super sensitive so this may take a bit of practice. Don’t turn the crank backwards! Once at 0.050” write down the crankshaft degrees indicated at the pointer. ie. IVO 5° ATDC (intake valve open 0.050” at 5 degrees after top dead center). You can continue to rotate the crank until the needle on the dial indicator stops spinning in that direction. This will indicate peak lift of the camshaft ie. 0.453” or 11.5 mm. You can also record the degrees at which the center of the peak lift occurred. These are nice to know if you have bought some companies “Secret Sauce” camshafts and the company was too lame or scared to give you the actual specs. So, continue turning the crankshaft until you arrive back at 0.050” valve lift (0.050” before valve closes) and record this number ie. IVC 45° ABDC. Now do the same for the exhaust valve and record EVO, EVC and max lift.



Now you have a bunch of data. You can compare the data that you have to the data that I measured and figure out what direction you need to rotate your cams to get the same cam timing. I’d recommend sitting down and doing some reading on why it would make a difference and what you are trying to accomplish with the set up you have. Take your numbers and enter them into the calculators at this site…… http://www.wallaceracing.com/Calculators.htm

Now you have more data to play with, here is my data (Use the 0.050" 'R' numbers. The 'A' numbers are with the Vanos actuated)…..






These recommendations that I have posted where with a GTX3582R open T4 .82 on an S52. If you have an M50 with a GT42R on it these may not be the ideal settings for you. YMMV.

Timing the Schricks using the blocks gave me a LSA of about 113.8° whereas I have set mine to 119.7°. This does a few things. It reduces overlap which reduces the exhaust contaminating the intake charge and reduces combustion chamber temps. The other thing it does is opens the exhaust valve a bit sooner reducing pumping losses, helps spool the turbo as we will have slightly higher pressure passing through it. Closing the intake valve a bit later allows for us to get more intake charge into the cylinder even though the piston is on its way back up the cylinder on compression because of boost.

Now, to actually adjust the cams you need access to the bolts at the exhaust cam sprocket. Loosen the bolts, adjust cams and I strongly recommend you measure the cam timing a couple of times to be sure that you got them both right. When you loosen the bolts for the exhaust cam sprocket either cam can shift slightly do to the valve springs acting against the cams. Check your Vanos travel after adjusting the cam timing as well.

Happy Degreeing!

[M3poseur]

^^^
Thank you for taking the time to do a write up and sharing your knowledge.

[vollosso]

High-five.


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[Gmfwd]

Fantastic!

Thank you for sharing

[hobbit382]

Nice post! Now don't you wish you had dual vanos?

[jakermac]

The ATI damper has some nice degree marks all around the outside that simplifies this process significantly. And speaking of dual Vanos, anyone think it'd be a good idea for a normally aspirated autocross car to boost the bottom end/mid-range torque? Motor is pretty "built" otherwise.

[Bke36Is]

Great info here! Now if I could find a set of shricks for a great price I'd be in business!

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[chikinhed]

I'll keep editing the original post as I remember stuff. I was insanely tired when I write the DIY.

[Matutino]

I highly recommend checking the the cam measurements several times, my exhaust cam was off after doing the intake cam, big difference.
I got smoother idle, better spool, higher vacuum and the fact that I can brag to people I didn't use the blocks to set my cams

[Butters Stoch]

I highly recommend checking the the cam measurements several times, my exhaust cam was off after doing the intake cam, big difference.
I got smoother idle, better spool, higher vacuum and the fact that I can brag to people I didn't use the blocks to set my cams

But I get 19-20in vac by using the blocks. Also, can u put up a log of your spool now ?

[Matutino]

But I get 19-20in vac by using the blocks. Also, can u put up a log of your spool now ?

Will do.

[NOTORIOUS VR]

Awesome thread... You make Canada proud!

[Bke36Is]

But I get 19-20in vac by using the blocks. Also, can u put up a log of your spool now ?

I as gonna say the same, i get 19 in hg now using the blocks and idle is smooth as can be! But I know there's room for improvement still. Good info here none the less!

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[chikinhed]

But I get 19-20in vac by using the blocks. Also, can u put up a log of your spool now ?

The common causes for low vacuum are elevation (1"Hg per 1000 ft) intake manifold leaks, bigger piston ring end gap, idle speed, cam timing or advanced ignition timing. We could easily have any of those set up differently than your car or any one of those variables maybe masking one of the other variables. This is why I would not use engine vacuum to surmise if you have appropriate cam timing for a turbo'd engine and without actually measuring what your cams are set at we can only assume (attention Milky) that you have a lower LSA (lobe separation angle) set up for NA engines.

[milKt]

Here me am.

This post is GOD DAMN delight to our communinty.

My Schrick sticks will be snug (one day)

[3literheater]

Awesome thread!

If you have large enough mag bases you could probably put it on the Steed Turbo manifold and reach over. That way you wouldn't have to make a steel plate.

[philly98540]

Well done on both logic and execution.

[boostd4]

Am I the only one that can't see the pictures? I'm logged in and unblocked content.

[chikinhed]

Am I the only one that can't see the pictures? I'm logged in and unblocked content.

Are you on a phone or a compy?

[chikinhed]

Awesome thread! If you have large enough mag bases you could probably put it on the Steed Turbo manifold and reach over. That way you wouldn't have to make a steel plate.

I have a PDF stencil of the steel plate that I can email to you to make it easier if you'd like.

[E36 HateR]

Am I the only one that can't see the pictures? I'm logged in and unblocked content.

Are you on a phone or a compy?

Pictures work for me on a galaxy phone and on my PC.

Excellent write up!

[3literheater]

I have a PDF stencil of the steel plate that I can email to you to make it easier if you'd like.

I appreciate that, but I am not at the motor build point yet.

Also with my job I have mag bases that reach from 4" to 36" haha so I wouldn't need the stencil.

[mboor]

Awesome thread Chickenhead ?great write up

[Bke36Is]

Ill have to keep this info handy for when I dial in the cams I don't have yet! Lol

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[s13flyboy]

Great thread, great knowledge, awesome!