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1.7 crane roller rockers [Archive] - StangBangerz Forums
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Steves LX
09-01-2008, 09:17 PM
I have a friend that wants my 1.6 motorsport RR's. He has a brand new set of 1.7 Crane Energizers that he wants to trade me. My GT40 Y heads stop flowing at .500 lift. The cam I have is a trick flow stage 1 which is .499 IN and .510 Ex. So will puttings these 1.7's on here make my car lose power or gain power or stay the same?
k062693w
09-01-2008, 09:31 PM
Here is what your lift will change to!!!
.510" lift is valve lift (w/ 1.6:1 rocker arm ratio)

.510 / 1.6 = .318

.318" is lobe lift (regardless of rocker arm ratio)

.318 x 1.7 = .546

.546" is valve lift (w/ 1.7:1 rocker arm ratio)

If that helps!!!!
Timido
09-01-2008, 11:03 PM
Make sure to check your piston to valve clearance. Best way to tell what they do is dyno the car swap the rockers and make a pull.
Steves LX
09-01-2008, 11:27 PM
Make sure to check your piston to valve clearance. Best way to tell what they do is dyno the car swap the rockers and make a pull.

O.K. I will do that. I talked to DSS about the pistons in their block I have and they said the valve reliefs in the pistons I have are cut for up to .650 lift. I would think with the TFS stage 1 cam I should still have plenty of clearance.
NXcoupe
09-07-2008, 04:04 PM
Come on up Steve and bring a copy of Pinks Allouttakes for me too!
ibstrokin
09-07-2008, 04:19 PM
According to Bullet Cams, 1.7 RR's will drop your peak rpm by a couple hundred rpm. If your heads don't increase in flow above .500", then I don't see the point. But Tim said it right, it's all theory until you have factual #'s.
85_SS_302_Coupe
09-07-2008, 06:22 PM
Personally i don't know as much about valve train as the rest of you guys, but i never liked the idea of 1.7 rockers. My mentality is get a cam with more lift if you want more lift, but i can understand where finances and such come into play.
NXcoupe
09-12-2008, 01:14 PM
Actually using 1.7's will accelerate the valve more than a 1.6 will. That means it will open farther at any given duration point as well as open the valve farther in the same given duration span overall. This means it opens it at a faster rate and closes at a faster rate. This can help and sometimes hurt a camshaft's performance.