khahoang91

So far, it seems like the best route is if you have an ap2, you should keep oem drivetrain and put in some cams, which is what I'll probably end up doing

neeman77

If anyone is looking for some billet Inline Pro cams I have some for sale.

Stage 2

Intake

Lift: .500" (12.70mm)

Duration@.050": 265°


Exhaust

Lift: .490" (12.44mm)

Duration@.050": 255

snmalone

One thing that must be considered as well, vale train noise will also be affected. My 04 S2k was much louder with Schrick Cams installed. For me it was way too loud but the cams made power on a stock valvetrain. I removed the cams because of the loud valve ticking.

khahoang91

Despite the noise do you think it was doing harm to the motor or do you think if you let the cams sit in there, everything would be ok?

Szoylent Green

Was this with the Brian Crower or the Skunk2 cams?

Has anyone plastic-gauged the bearing clearances on the aftermarket vs. OEM cams? I wonder if the aftermarket cams journals might be on the large side of tolerance. There's no oiling passages in the cams, so that can't be an issue. Is there any difference in the wear if aftermarket or OEM springs are used?

The only things I can seem to think of is maybe the cam journals are not sized exactly right Or maybe the extra lift puts too much load on the bearings and pushed the cam into the bearings, breaking down the oil film.

I have NEVER seen this kind of wear in the cam bearing on any engine, and I've probably had over a thousand engines apart. I've occasionally seen cam lobes fail, seen lots of rod bearings fail, spun main bearings, but never anything like this.

Can the cam bearings be bored out and bearing shells inserted?

ddess

BC cams.

But i I was running supertech dual valve springs. Can't remember spring seat pressure but it was higher than stock. Chris ran across a thread from several years ago suggesting to run oem or lighter springs if you are going aftermarket cams. Maybe he will link it. I am spitballing here but could higher valve springs attribute to this accelerated wear?

This motor eventually died from breaking a valve cap off of the stem on cyl 4 exhaust. Cams were removed prior to valve failure.

s2000Junky

Im not a valve spring designer, but when you come with the understanding that a valve springs job is to return the valve to the seat with that task based around the operating rpm range and lift/throw of the spring movement, changing the spring pressure to higher would subsequently allow for a higher rpm operating range before valve float becomes an issue, which is what a spring too weak would do. So thinking logically here, if you increase the lobe/lift wile also adding a stiffer spring, its safe to say 2 fold there is more pressure on the connective components. So its my conclusion that if the new cams provide none to little added lift over stock and the rpm range has not increased, then stock springs are probably the wises choice. If the cams in question dont even increase lift but just change the overlap, then is there really a need for stronger springs when the stock springs have been shown to control valves before float set in above 10k rpms?

I just dont see the need for aggressive dual springs but in the most modified of builds, and that doesn't mean longevity will be improved, it just means better control of valve float for the application/performance. Seems to me, using the lightest spring required to control valve float at a particular rpm should be the goal. I understand that some aftermarket retainers/keepers or valves require a dual spring to be compatible, but with enough reports of cracked/chipped ti retainers etc, I question if any of the performance gained is worth sacrificing reliability and longevity over oem. Underlying all this I think matching the components is important, so there probably should be a clear tested chart for proper valve spring weight per the aftermarket cams being used and what retainers/keepers are compatible with that spring weight. Guessing probably isn't the best option here, when you can see what the bad results can be. Im thinking if any doubt or lack of information, that airing on the side of less spring tension/oem is better then too much.

Bullwings

I've had SuperTech dual valve springs and retainers in my car for 4 years, over 40K miles, and around 30+ track days (motor itself has 100k), and I have no unusual traces of wear present in my oil samples. The car was even daily driven for a number of those years. That said, I have no other motor mods other than a HFC.

I did it as a safety net for my sloppy shifting. It should hopefully save me from minor over revs...

Aurex

Could this be from not using an assembly lube when fitting the new cams? When I look at the image the center of all the caps appear to be in pristine condition and the outside edges are rough/abused. The cam bearings are oiled from the center of the journal, so where the cam was for sure seeing oil pressure it is fine. If the spring pressure was too much and the pressure the spring was placing on the cam was enough to break the oil film down would it not make the same damage across the whole bearing? The oil film would have to be squeezed out somewhere.

s2000Junky

The oil channel just hasn't been worn through even with the rest of the surface yet it looks like. I don't see normal discoloration from heat where lack of oil is the culprit. At the same time, I would think two surfaces where a lot of pressure/friction was present would show a similar heat discoloration cutting through oil film. This almost would seem like the surfaces had too much play so the cams were lose? Maybe it was a combination of added spring pressure with not the right trq spec on the cam tree carrier bolts.