atr

[h10ndr]

A quote from Frank at "PocketRocketRacing" (H series specialist)

"The type S cams will hit the valve seal/guide in a standard h22 head! Type S cams do not install without issue's in a standard h22 head, and I do not care if someone else has done it "without issue's" Honda DOES NOT do it! the factory type S head has relocated valve guides to make room for the type S cams. The S springs are stiffer as well, the retainers are identical though!"

Is this gospel or truth, as far as i knew the type-s cams are the same as the atr cams, could this be the noise im getting from my engine? @bennyboy @NafemanNathan @judderod @PerformanceAutoworks

I dont want to spread mis-information, just making people aware of what others have experienced. I think there may be some truth to it, but whether it defo will cause issues is where we need Rich to step in. I think you can build around it by using thinner ti retainers for the clearance, but again, its hearsay.

I think many builds have used ATR cams and even Stg1 and 2 skunk cams on stock heads without issue.

I myself ran ATR cams for a while in a std P13 head. Whether this can cause issues further down the line I dont know. But this engine was shockingly assembled by the now bust but infamous (InlineMotors) and didn't last long (oil starvation to no.4). I sourced another H22A7 engine and box and got it fitted by PAW

[judderod]

There is a chance the rockers might hit the valve stem seals because the valve guides aren't set to the same height tolerance between A1/A2/A5 and A7 heads. If that has happened, you'd probably have noticed an increase in oil consumption/black smoke on high rev closed throttle deceleration. You'll also notice excessive wear on your VTEC lobes and rockers. There was a post on a US forum about this. His was pretty bad.

IIRC there's also a chance the underside of the rockers could hit the valve spring retainers. That's pretty serious and could cause that noise I guess but your engine would probably have ate itself by now if that happened.

I checked my A2 before I had new guides put in and both the valve guides and spring retainers were clear of the rockers with JUN cams in VTEC. But it was very, very close.