View Single Post
Old 01-03-2013, 10:46 AM   #1360
Patrick Olsen
NASIOC Supporter
 
Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
Vehicle:
1997 Legacy 2.5GT
QuickSilver Metallic

Default

Quote:
Originally Posted by dragoontwo View Post
Patrick, are you doing an N/A build or turbo? It sucks to hear about your experience with Delta Cams.
For the most part I've been planning to just do a N/A build, but I occasionally waver and think about doing a low pressure turbo setup of some sort.

Interestingly enough, I spoke with John (I think) @ Outfront Motorsports a couple weeks back. They use the stock EZ30R cams, even with their big power turbo builds.

Quote:
Originally Posted by dragoontwo View Post
Quote:
Originally Posted by Marnix View Post
EG cams do not fit EZ cams.
If this was directed at me, I know this. I'm an SVX owner with an EZ30R torn apart in my garage.
I think Marnix may have missed that you were commenting on two different discussions running through this thread in recent days - Baldturbofreak's comments about EG33 cams and my comments about EZ30R cams. Maybe we should mix in some ER27 discussion, too, just to really confuse this thread!

Quote:
Originally Posted by Marnix View Post
The lifters are exactly the same as what Porsche uses on the 997 engines, it even has a Porsche partnumber on it:






According to Wikipedia, these Porsche engines use the Variocam Plus system:

2006-2008 3.596 litre 325 hp water-cooled flat-6 (VarioCam Plus) (911 997 pre-facelift Carrera series / Targa 4)
2006-2008 3.824 litre 355 hp water-cooled flat-6 (VarioCam Plus) (911 997 pre-facelift Carrera S series / Targa 4S)
Carrera S powerkit: 3.824 litre 385 hp water-cooled flat-6 (VarioCam Plus)
2007-2009 3.600 litre 480 hp water-cooled flat-6 (bi-turbocharged) (VarioCam Plus) (911 997 pre-facelift Turbo)
2008-2010 3.600 litre 530 hp water-cooled flat-6 (VarioCam Plus) (911 997 pre-facelift GT2)
2008-present 3.614 litre 345 hp water-cooled flat-6 (VarioCam Plus and DFI) (911 997 facelift Carrera series / Targa 4)
2008-present 3.800 litre 385 hp water-cooled flat-6 (VarioCam Plus and DFI) (911 997 facelift Carrera S series / Targa 4S)
2010-present 3.800 litre 530 hp water-cooled flat-6 (bi-turbocharged) (VarioCam Plus) (911 997 facelift Turbo S)
2010-present 3.600 litre 620 hp water-cooled flat-6 (bi-turbocharged) (VarioCam Plus) (911 997 facelift GT2 RS)

So if you can find the valve lift or cam lobe height of those engines you know what the lifters can handle. For sure you should upgrade the valvesprings when running more lift.
Thanks very much for the info and the pics, Marnix, particularly the ones showing the lifter actually in operation. Part of my problem in figuring this out is that I never really played with the heads at all myself - once I had them off the engine, they got boxed up and sent out to Delta. I've never even pulled one of the lifters out to look at how it works.

When it comes to using different cams with a smaller base circle and higher lift, in my mind there are two issues:

– First, the lifter has to be able to span the difference in lobe heights between the low and high lift lobes. So, hypothetically (not having the FSM in front of me here at work), if the stock lobes were 4mm lift and 10mm lift, and the new lobes were 5mm and 13mm, that center portion of the lifter would have to “reach” 2mm farther to maintain contact with the low lift lobe. While I don’t know what Ken @ Delta would plan on for lobe heights, looking at the first and second pictures I’ve quoted, I’d say there’s no issue there – looks like the lifter can cover a pretty big spread in lobe heights, much bigger than I would ever expect to actually run.

– Second, when the valve is shut, with a reduced base circle, the lifter will need to rise up out of the lifter bore higher to maintain contact with the camshaft. There’s a danger that the lifter could become unstable if it is pushed too far out of the bore. I don’t know at what point that would become a concern.

Does that make sense to others? I’m just trying to think this through a bit, and again without having the heads here to play with it’s hard for me to visualize.
* Registered users of the site do not see these ads.
Patrick Olsen is offline   Reply With Quote