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-   -   How closely matched are your cam timing(l/r)? (http://forums.pelicanparts.com/porsche-911-technical-forum/565595-how-closely-matched-your-cam-timing-l-r.html)

T77911S 09-23-2010 05:00 AM

Quote:

Originally Posted by john walker's workshop (Post 5575371)
SCs break intake valve springs a lot. when each cylinder is at valve adjust position, if you can push in on the rocker with your fingers and compress the spring fairly easily, it's broken.

the 3.0 i bought had a broken spring.


sure the noise is not spark knock??
what octane gas do you use? how about ignition timing?

Peter Seow 09-23-2010 09:32 AM

Quote:

Originally Posted by T77911S (Post 5576853)
the 3.0 i bought had a broken spring.


sure the noise is not spark knock??
what octane gas do you use? how about ignition timing?

I've always used a minium of 98 octane some more. i think it's shell v power a 100 octane gas.

It could be broken spring. I am taking down the engine next week, My timing is just not right i cant find any bits of metal in the oil and oil pressure is running good at all time so a conrod bearing is highly unlikely, valve springs why not?

I might do a top overhaul at the same time.

Trackrash 09-23-2010 10:36 AM

OK, has anyone tried to advance one cam and retard the other to try to broaden the torque curve? Maybe someone has done this and can post dino numbers.

john walker's workshop 09-23-2010 11:31 AM

Quote:

Originally Posted by Trackrash (Post 5577371)
OK, has anyone tried to advance one cam and retard the other to try to broaden the torque curve? Maybe someone has done this and can post dino numbers.

what, so one side of the engine has power at low rpm and the other side at higher rpm? pure genius!

Peter Seow 09-23-2010 07:00 PM

Quote:

Originally Posted by john walker's workshop (Post 5577480)
what, so one side of the engine has power at low rpm and the other side at higher rpm? pure genius!

Never heard of that method i rather advance both!

JW,

What were your customers sc l/r timing i got a bad one 0.85 and 1.12. Both out of specs.

T77911S 09-24-2010 04:54 AM

Quote:

Originally Posted by Trackrash (Post 5577371)
OK, has anyone tried to advance one cam and retard the other to try to broaden the torque curve? Maybe someone has done this and can post dino numbers.

at the least, i would think the engine would run rough, that is why i think the L to R setting is more important.

my cams were advanced a lot (15degrees) by the PO. the car was almost undrivable. i could not floor it, nor run it past around 3500 rpm without spark knock. retarding the ignition timing, a lot (thats what led me to check the cams), did help and gave me maybe another 1000 rpms. but, i did have other problems. mainly one injector was only putting out half the volume of fuel the others were due to a bad injector line. my point, spark knock if not a broken spring or maybe a tensionor or even cam timing?? maybe the guy that did my cams did yours;)
i would try to find the problem brfore you tear it down, or at least eleminate some things. how is the ignition timing? advance working as it should? fuel pressures right, fuel mixture right?

2.70Racer 09-24-2010 07:26 AM

As I said in post number 3, the cams can be timed exactly to each other and smack on the Porsche specification.
You can adjust a cam as little as 1/10th of 1 degree.
This compares to the pin and sprocket holes of 1.4 degees.
Our friends at Porsche knew what they were doing.
Mike at MBE Engineering knows all about it.

T77911S 09-24-2010 08:44 AM

dont try to put the pin in a hole next to the one it came out of. that is a bigger difference in degrees, try one opposite of the one it came out of.

Peter Seow 09-24-2010 09:00 AM

Does anyone here have a left and right reading?

john walker's workshop 09-24-2010 09:10 AM

depends on engine type number. 930/10 is 0.9 to 1.0.
930/16 and 930/17 is 1.4 to 1.7.
engine type number is forward of the oil temperature sensor and to the left of the oil pressure sender, on the flat area.

john walker's workshop 09-24-2010 09:12 AM

Quote:

Originally Posted by Peter Seow (Post 5578266)
Never heard of that method i rather advance both!

.

that was tongue in cheek, by the way.

2.70Racer 09-24-2010 01:31 PM

T77911S,

Quote "dont try to put the pin in a hole next to the one it came out of. that is a bigger difference in degrees, try one opposite of the one it came out of."

I'll file your post #28 along with John Walkers post #24. :).


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