Any damage to stock valvetrain
Evolving Member
Joined: May 2005
Posts: 434
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From: Bayarea, CA
Originally Posted by timzcat
I measured the seal/guide height and it is 24.67mm
Therefore subtract the guide installed height of 19.5 mm and you get 5.18 mm.
This means that 5.18 mm of seal is above the end of the guide.
This means that I am coming up with the same numbers as Revolver.
I am using a digital verneer caliper that I know is not dead accurate but my numbers are almost identical to Revolver's. Thus, the stock springs do not have sufficient clearance, particularly on the 10.8 cam. The 10.2 lift cam is very very close.
David,
I was saying tha the valve stem protrusion in the service manual is differnet as well as the valve lengths. Therefore if you were measuring one valve and Revolver was measuring another then you would get different numbers. Although not the big difference you were seeing.
Edit: I re-read your post and get what you were saying about max lift.
Revolver,
I am going to go back and look at your posted specs on the valves for installed height. The service manual says it is different on the intake and exhaust. Are the spring seats making up the difference so all the valves are the same? Or do the heights need to be shimmed to adjust seat pressure?
On another note, the service manual has the valve diameter as 6.0 mm which freaked me out since the Ferrea valves I have are 6.55 and 6.57. They are also (Ferrea) the same length and stock is different by .02 mm which is only .008 so that can be fixed easily.
Therefore subtract the guide installed height of 19.5 mm and you get 5.18 mm.
This means that 5.18 mm of seal is above the end of the guide.
This means that I am coming up with the same numbers as Revolver.
I am using a digital verneer caliper that I know is not dead accurate but my numbers are almost identical to Revolver's. Thus, the stock springs do not have sufficient clearance, particularly on the 10.8 cam. The 10.2 lift cam is very very close.
David,
I was saying tha the valve stem protrusion in the service manual is differnet as well as the valve lengths. Therefore if you were measuring one valve and Revolver was measuring another then you would get different numbers. Although not the big difference you were seeing.
Edit: I re-read your post and get what you were saying about max lift.
Revolver,
I am going to go back and look at your posted specs on the valves for installed height. The service manual says it is different on the intake and exhaust. Are the spring seats making up the difference so all the valves are the same? Or do the heights need to be shimmed to adjust seat pressure?
On another note, the service manual has the valve diameter as 6.0 mm which freaked me out since the Ferrea valves I have are 6.55 and 6.57. They are also (Ferrea) the same length and stock is different by .02 mm which is only .008 so that can be fixed easily.
whoa.......i just read this entire thread. anyway, so if i got the gist of this. 10.8 lift cams (particular hks 280) will definately have contact. but 10.2 lift (hks 264/272) will be close but not have contact?
Originally Posted by 2hot2handle
whoa.......i just read this entire thread. anyway, so if i got the gist of this. 10.8 lift cams (particular hks 280) will definately have contact. but 10.2 lift (hks 264/272) will be close but not have contact?
I am with Dave. Was thinking the same thing. I have run 272's and 280's for over a year now, last inspection did not show any wear. Infact just pulled a head from a 272/272 car Sat and there was no damage there either. More wives tales rampant on evom.
To add, we have run the 280's to 8800 or so also according to logs. Yes, on stock springs and no, not on purpose. And no, there is no power on stock turbo in that range.
To add, we have run the 280's to 8800 or so also according to logs. Yes, on stock springs and no, not on purpose. And no, there is no power on stock turbo in that range.
Originally Posted by davidbuschur
Holy garbage.
There is not interferance issues with the HKS cams! You may (whoever post this on page 1) that there was interferance with the stock retainer on the flow bench but you would have had to open the valve a TON farther than any cam I have seen does.
No fear guys. For those of you that are worried or want to change don't mess with machining the stock retainers. Even if you do it in the car just drop in a set of better springs and titanium retainers.
I have the 272's in my RS right now, completely stock springs, retainers etc. No problems been running the car on the dyno to 7500.
David Buschur
www.buschurracing.com
There is not interferance issues with the HKS cams! You may (whoever post this on page 1) that there was interferance with the stock retainer on the flow bench but you would have had to open the valve a TON farther than any cam I have seen does.
No fear guys. For those of you that are worried or want to change don't mess with machining the stock retainers. Even if you do it in the car just drop in a set of better springs and titanium retainers.
I have the 272's in my RS right now, completely stock springs, retainers etc. No problems been running the car on the dyno to 7500.
David Buschur
www.buschurracing.com
Last edited by TTP Engineering; Feb 15, 2006 at 10:42 AM.
Originally Posted by Dynofrk666
anyone tested out the GSC cams, i just ordered a set and after reading all this stuff you guys got me worried lol
At the time their explanation and rationale was over my head but after reading this thread I have a better understanding. I will be running an upgraded spring that can handle the GSCs better then stock.
It is very simple. The intake cam at 10.8 lift will cause the retainer bottom to contact the valve seal. It is inevitable, I've done the measurements to back up what Revolver says.
Go back and look and you will see I was originally one of the people that argued that they would not until I had it in front of me and proved myself wrong.
Go back and look and you will see I was originally one of the people that argued that they would not until I had it in front of me and proved myself wrong.
I too had to prove it to myself... I am disinterested in participating in any so of debate on the issue. Saw what I saw first hand, and no one will convince me other wise. Granted, I have seen customers car's with HKS cams and what appeared to be no contact. However, there was on my personal Evo.
Everyone knows I support David's knowledge, and generally take his word as Gospel in this application. I just happened to have a different outcome myself with visible light wear rings.
Everyone knows I support David's knowledge, and generally take his word as Gospel in this application. I just happened to have a different outcome myself with visible light wear rings.
Wow, this thread has come up again
We stock and sell Revolver springs, retainers and cams now. We have been using the springs/retainers on some of our Stage 3 heads (depending on what the car used for we use others too) for about 6 months. Good product.
I still say if you are running 264, 272 or 280 HKS cams you can run them with the stock springs and retainers and never have a single problem from them.
The Revolver cams are freaking amazing by the way. We have installed them in 3 cars now and picked up 40-50 ft lbs in each one of them, over the HKS 280's.
Not for a reflashed car though in my opinion.
David Buschur
www.buschurracing.com
We stock and sell Revolver springs, retainers and cams now. We have been using the springs/retainers on some of our Stage 3 heads (depending on what the car used for we use others too) for about 6 months. Good product.
I still say if you are running 264, 272 or 280 HKS cams you can run them with the stock springs and retainers and never have a single problem from them.
The Revolver cams are freaking amazing by the way. We have installed them in 3 cars now and picked up 40-50 ft lbs in each one of them, over the HKS 280's.
Not for a reflashed car though in my opinion.
David Buschur
www.buschurracing.com
Originally Posted by davidbuschur
Wow, this thread has come up again
The Revolver cams are freaking amazing by the way. We have installed them in 3 cars now and picked up 40-50 ft lbs in each one of them, over the HKS 280's.
The Revolver cams are freaking amazing by the way. We have installed them in 3 cars now and picked up 40-50 ft lbs in each one of them, over the HKS 280's.
A custom tune MIGHT be able to get them to idle but it is going to depend a lot on the rest of the combination. I'd suggest some type of speed density system.
Not sure what other details you'd like. The cams kick some serious ***. My RS made an additional 20 whp and 50 ft lbs of torque. Matt's car this weekend picked up 50 ft lbs of torgue over his best ever and that was with a tune that is not exceeding 2.6 volts of knock on the AEM. Our black car made 761 whp this weekend and 531 ft lbs.
David Buschur
www.buschurracing.com
Not sure what other details you'd like. The cams kick some serious ***. My RS made an additional 20 whp and 50 ft lbs of torque. Matt's car this weekend picked up 50 ft lbs of torgue over his best ever and that was with a tune that is not exceeding 2.6 volts of knock on the AEM. Our black car made 761 whp this weekend and 531 ft lbs.
David Buschur
www.buschurracing.com
