Cam Timing Question

[jonesb930]

Finally got around to timing my cams in my build. When I time the cams they are not the same side to side.
Left cam I can hit 2.26mm and the right is 2.32mm
If I try the next pin hole on the left it goes way off to 2.62mm
Is this acceptable?
Using this cam in a 3.2SS Twin Turbo application
Here is the cam spec from Webcam:
Porsche GT2 "EVO" (Mech Rocker)
Grind# 563/564
(Set @ 2.3mm with .10mm Lash)
Valve Lash Intake: .004 / Exhaust: .004
Valve Lift Intake: .480 / Exhaust: .460
Duration Intake: 264 / Exhaust 250
Duration @ .050 Intake 248 / Exhaust 236
Lobe Center Intake: 111 / Exhaust 111
Intake Opens 13 deg. Before TDC
Exhaust Opens 49 Deg. Before TDC
Intake Closes 55 Deg. After TDC
Exhaust Closes 7 Deg. After TDC

Valve timing is checked with zero valve lash @ .050 inches of valve lift

[Zuffenwerker]

You can get closer than that if you want to keep messing with it. Are these measurements after the sprocket is fully torqued? A lot of times it will change after torquing. Keep at it if you want to get them the same.
Is it acceptable as is? I believe so but I’ve done a lot of these engines and have always been able to get them pretty much spot on. If your pin is fitting loose there is your minor adjustment depending which way you rotate the engine to tighten up that pin before you torque the sprocket. Hope that maybe helps.

[gled49]

If u want to get closer, move the cam sprocket on the chain a tooth or two, it will give u a different number.

[jonesb930]

I did read that later last night in another thread. I'll give that a try tonight. If I can get them the same its worth the effort.

Originally Posted by gled49

If u want to get closer, move the cam sprocket on the chain a tooth or two, it will give u a different number.

[mikedsilva]

Originally Posted by jonesb930

Finally got around to timing my cams in my build. When I time the cams they are not the same side to side.
Left cam I can hit 2.26mm and the right is 2.32mm
If I try the next pin hole on the left it goes way off to 2.62mm
Is this acceptable?
Using this cam in a 3.2SS Twin Turbo application
Here is the cam spec from Webcam:
Porsche GT2 "EVO" (Mech Rocker)
Grind# 563/564
(Set @ 2.3mm with .10mm Lash)
Valve Lash Intake: .004 / Exhaust: .004
Valve Lift Intake: .480 / Exhaust: .460
Duration Intake: 264 / Exhaust 250
Duration @ .050 Intake 248 / Exhaust 236
Lobe Center Intake: 111 / Exhaust 111
Intake Opens 13 deg. Before TDC
Exhaust Opens 49 Deg. Before TDC
Intake Closes 55 Deg. After TDC
Exhaust Closes 7 Deg. After TDC

Valve timing is checked with zero valve lash @ .050 inches of valve lift

Bill
you probably dont need to move the pin. There is a decent amount of leeway in each pinhole. The slop should allow you to easily achieve identical timing each side. It take a bit of fiddling with loosening the bolt, maybe turning the crank the other way, then tightening again .. you'll figure it out.

[john walker's workshop]

The outer sprocket can be rocked back and forth with the pin in the same hole to fine tune. It's not a tight fit.

[jonesb930]

Thank you everyone for your suggestions. I plan on using a small drift though one of the other holes to "move" the cam slightly on the left keeping the pin in place.

To adjust them this close I put a spacer under the bolt (without that big washer) and torqued it to about 30lbs. I placed a breaker bar on that bolt and just dialed the cam in with the crank at TDC just like we used to be able to do on the old cams. It worked really well. The pin slid right in.

[jonesb930]

I got it dialed in. Had to resort to using the spacer and bolt to tweak it eve so slightly. I can see how those adjustable gears would be handy. I can’t imagine doing this in the car.

[Walt Fricke]

I did it in the car (and in an enclosed trailer) once, because I had forgotten to tighten the three 10mm head bolts on the seal - big leak. To my delight, when I put the stuff back on after tightening those bolts, the indicator read just what it had been before. Of course I was careful not to turn the crank or cam and had marked things. Wasn't easy.

[jonesb930]

Has anyone used the adjustable sprockets that JB Racing sells? They would certainly make it easier to dial the timing in.

[Walt Fricke]

No, but when I get to timing my bolt end cams on my 2.8L SS again, it will be with these parts. These guys know what they are doing.

[targa72e]

I have never found a need for the JB parts (they do look nice). My time is functionally free and I enjoy fiddling with things to make them "just right". Never had a issue getting cams really really close to each other with both old and newer cam bolt systems. I also realize that once the engine is run and things start wearing in and/or engine is running at 7K RPM all bets are off as to what the cam timing actually is.

John

[Flat6pac]

I used the same method for decades then watched the Stompski Racing video about setting cam timing and it brought new light to cam timing.
Steve definitely made it simpler
Bruce

[jonesb930]

Originally Posted by Flat6pac

I used the same method for decades then watched the Stompski Racing video about setting cam timing and it brought new light to cam timing.
Steve definitely made it simpler
Bruce

Bruce,

I just spoke to Steve today and said the same thing to him! I emailed him a question about using his SR097 valve lash took on the exhaust and he called me to discuss instead of trying to put it in an email. What a great guy! Super knowledgeable and willing to discuss all aspects of these cars. Having people like Steve Stomski (and so many others) continuing to provide support and make tools to simplify things really keeps these cars going!

I will be ordering a second SR098 tool to do both sides without swopping it back and forth. I know its a luxury, but I love tools and tend to check, re-check, and check again with these things so moving back and forth got old.

oh, and a note: I reached out to JB Racing and they said it would likely be a year before the adjustable cam gears are available again.

Bill