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#1
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roller rockers
I put a roller cam in engine gross valve lift .503 intake .496 exhaust .I have stock heads with stock rockers ,I would like to put roller rockers, should I get 1.55 or can i go taller? like 1.60 or 1.65 and will it free up a little more power? or a waste of money. and where can i get the right length push rods? thanks
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#2
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Re: roller rockers
The rollers aren't a bad thing to have, just because of the reduced friction and the ability to adjust preload better than shimming the stockers.
If you go 1.65, you effectively get a slightly "bigger" cam because of the added lift and a little extra duration (plus a bit higher valve acceleration up the cam lobe ramp). If your combo supports that, then it can maximize those things but don't expect a huge difference (I think I picked up about 6HP on the engine dyno when I swapped in 1.65s). Pushrods can be ordered in almost any length from most of the suppliers (Crane, Comp, Lunatti, etc.). You just use a pushrod checker (adjustable) to get the proper geometry and then use that spec to order. Also, check the head to pushrod clearance ... the middle ones like to rub if you go with a slightly larger pushrod or the geometry isn't spot on. If you're running some pretty stout springs you can go up slightly in diameter (and make sure you get top quality material like heat treated chromemoly). See: http://www.cranecams.com/userfiles/file/304-310.pdf for an example of how to spec out a custom pushrod.
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Ken Mosher 1987 GN original owner 650+ HP Black 2015 BMW 328xi XDrive wagon 2012 Volkswagen Tiguan (the Tig!) Night Blue Met (sold) 2006 Trailblazer SS Red Jewel Tint 395 HP AWD (sold) 2014 Silverado LTZ Crew 4WD 2012 Honda VFR 1200F Tahitian Blue (sold) 2015 BMW S1000R Racing Red 2013 Honda CBR500R Red (wife's bike) 2014 Triumph Bonneville T100 2003 Harley Davidson V Rod Anniversary Edition |
#3
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Re: roller rockers
thanks for the info .rollers free up a little more power that is always a good thing in hot air engine .gonna give it a go. thanks again
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#4
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Re: roller rockers
Keep in mind to much lift on untouched heads can lead to clearance issues with the stock guides.
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60lb injectors Gen 2 with Extender Chip Webber 212/206 roller cam Turbonetics BB CPT 61 CAS V4 Stretch Intercooler Alcohol Injection 4 inch MAF pipe with integral sensor 2800 stall lots of fun with a little 6 banger! Best ET 11.43 |
#5
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Re: roller rockers
Good point... you'll want to check spring clearance and such when installed. The lift you spec'd there isn't huge, but the 0.503 + 1.65 ratio will be worth checking to make sure spring coils don't bind and the keepers don't smack into the top of the valve guides (which can be cured by milling a little off the guide).
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Ken Mosher 1987 GN original owner 650+ HP Black 2015 BMW 328xi XDrive wagon 2012 Volkswagen Tiguan (the Tig!) Night Blue Met (sold) 2006 Trailblazer SS Red Jewel Tint 395 HP AWD (sold) 2014 Silverado LTZ Crew 4WD 2012 Honda VFR 1200F Tahitian Blue (sold) 2015 BMW S1000R Racing Red 2013 Honda CBR500R Red (wife's bike) 2014 Triumph Bonneville T100 2003 Harley Davidson V Rod Anniversary Edition |
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