thinkin about switchin to the GSC cams also

 

Some guys have been having real problems getting the GSC's to idle properly.

Supposed to be 100deg Saturday so no track, hope to get the cams in instead.

 

People should contact Greg about how to install camshafts and break-in.

Idle issues are mainly caused from initial timing at stock rpms levels under 1000rpms. It has to be adjusted in order to get them to stay idle for the most part. I'll probably experience that myself.

 

You suggest folks contact GSC before installing cams? I'm interested to hear how these are any different than another?

I made the timing adjustment to Muckman(sp?) but he had no luck, also someone left him under them impression that the cams needed to idle at 12:1 afr. Typically the only cars you see idling that rich are either poorly tuned or have old peak and hold injectors without an injector driver.

 

Not sure where the information came up about what AFR it should be for idle. I've never used AFR to determine an idle speed or other adjustment.

GSC has some rules that most may or may not use when installing their camshafts. I don't think they are necessarily different from any other camshaft install. Its just that we're so used to not using the usual precautions because it seems so flawless. But for whatever reason, people don't look on the back of the cam card to see their instructions.. I'm saying to make sure you do so before calling Greg about specifics like how to get them to idle..

Don't worry, I'll be in that dilemma soon enough myself.

 

Are you still hitting the dyno tomorrow sir?

 

We shall see... Depends what kind of oil my local speed shop carries. I typically run RP HPS which has high levels of zinc and phosphorous and was not prepared soon enough to place an order through summit where I typically get my oil. I do have a bottle od redline break in additive for adding to conventional oil to bring up the zinc an phosphorus levels.

Works dead so I think I'm going to bail out and look around.

 

Please keep us updated.

 

Found RP break-in locally.

 

Does this mean that you will definitely be hitting the dyno tomorrow?

 

No.... Depends on how break-in goes, need time to sort out tune as well.

And 100deg Weather tomorrow.

 

Advise to anyone thinking about these cams.... If you do not have tuning software and some experience do not attempt to install them yourself.

I have the cams in and through the first part of the break in sequence, now waiting for the engine to cool down to continue. I took a few pics along the way.

 

How well have you got them to idle ? Do they require a rich AFR mixture?

 

Idle is tough, more so than skunk2 pro series.

With the tuner 1's the engine would idle at -21", with the GSC's it's closer to -11". Anything below 3k is rough and requires a richer tune to remain stable.

I used all the normal tricks 21deg timing in the idle area and adjusting the throttle plate stop. Currently the idle is set at 1300, I feel that it could be managed a bit lower but I've only begun ironing out the tune.

 

Were the cams actually degreed? Every set of Skunk2 Pro Series cams I have tuned like to idle around 900 RPMs and mid to low 14's AFR and around standard timing - all with 15+" of vacuum. I can't speak for these GSC camshafts, but it all seems out of sorts. Sounds more like the tune needs a LOT of work.

 

The cams were not degreed, they were said to be a direct drop in with springs.

Going from -21" to -11" you lose a lot of resolution, hence the trouble below 3k.

I have also never seen such problems with pro series cams, one difference being skunk uses staggered primaries and the GSC do not. Until I installed the cams and experienced them myself I was under the impression others had done something incorrectly. Makes me wonder if the cams were ground properly, skunk had a similar issue with the original pro1 cams.

 

Great work on your build! I'm really interested to see what your dyno graph looks like, but I'm deployed and the gov't computer blocks your picture. Would it be possible for you to email it to me or host it on facebook as I can see pics from there?

 

Turns out the Supertech 1002D's are not the way to go with GSC's.

Valve spring surge at 7k regardless of boost drops 15 ft/lb, looking to pick up a set of DR's and try again.

 

Supertech 100DR's in order through IPG, fast response and best price!

 

Good luck sir!

 

Sorry to hear about the valvesprings, but I hope the new ones work out for you. Greg at GSC has done some amazing work with camshafts as I've seen his work first hand. I was stationed at Charleston AFB, SC which is literally a few miles up the road from his shop.

 

You need to degree the motor. Just because it says they are a drop in cam doesn't mean anything. I'm sure the head/block has been decked. That changes things ya know....

 

Yup, Tuner1's were straight up too... caused no problems there. I'll move the gears on the dyno, trying to degree a motor in the car isn't something I'm looking forward to trying. I'm trying to do an as accurate comparison as I can given small changes that have become needed as I go. If they turn out to not be drop in cams as suggested that is important information to provide

I spoke with Greg he recommends stiffer springs, I'm going to give that a shot.

eCtune LOG

 

Valve surge?

 

Sorry:

http://www.youtube.com/watch?v=AtTuk7pix5s

http://wiki.answers.com/Q/What_is_surge_in_springs

"The factor which causes unpredictable valve spring behavior at high reciprocating frequencies. It's caused by the inertia effect of the individual coils of the valve spring. At certain critical engine speeds, the vibrations caused by the cam movement excite the natural frequency characteristics of the valve spring and this surge effect substantially reduces the available static spring load. In other words, these inertia forces oppose the valve spring tension at critical speeds." Not my quote