How much gains from 1.8 or 1.85 on my H/C Car???
05-05-2005, 11:36 AM
#23
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so you guys think i could run the 1.8's without p to v clearance problems? ive also heard about the possible harmonic problems. what about the 1.7's? do you think theyd work? how much power from them? i know there would be clearance for the 1.7's. im jsut looking for some extra power...
05-05-2005, 02:33 PM
#26
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Originally Posted by XTrooper
It's not about winning or losing, amigo. I think we all just want to get things right and pass on correct information. 
You are talking about max lift ratio and I'm talking that those rockers have max ratios at low lifts .100> .200, which is why they make more power down low, without affecting PTV at max lifts.
fewwwwww. We are talking about same thing but different angles.
see Post #15 by me.
05-05-2005, 02:39 PM
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Originally Posted by Viper
Yes, stock is 1.7, but it comes off the seat at 1.52 I believe, THEN goes to 1.7.
Unfortunately, the problem with valvetrain harmonics can crop up with almost any combination of components and any rocker arm ratio. Most never have a problem, but some do. The only way to know is to try it and see.
05-05-2005, 02:45 PM
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Originally Posted by PREDATOR-Z
Re-reading through all this i think we are pulling from different directions.
You are talking about max lift ratio and I'm talking that those rockers have max ratios at low lifts .100> .200, which is why they make more power down low, without affecting PTV at max lifts.
fewwwwww. We are talking about same thing but different angles.
see Post #15 by me.
You are talking about max lift ratio and I'm talking that those rockers have max ratios at low lifts .100> .200, which is why they make more power down low, without affecting PTV at max lifts.
fewwwwww. We are talking about same thing but different angles.
see Post #15 by me.
05-05-2005, 02:48 PM
#29
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Yeap that is it.
Here is a quote by VINCI:
and there is a dyno graph comparison in this thread by mrr23:
https://ls1tech.com/forums/generation-iii-internal-engine/315892-crane-rocker-arms.html
Here is a quote by VINCI:
VHP and Crane Cams have been working with each other for many years. Together, we have strived to provide the very best products we can with the latest technology available. We think, we design, we manufacture, we test....then we market the product. It seems that there has been much confusion about Crane/Vinci "Quick-Lift" cam lobes and "Quick-Lift" rocker bodies. We claim that the use of the Quick-Lift lobes with the Quick-Lift rocker bodies results in "effective valve lift" durations @ .200" valve lift equal to most other cam/rocker combinations using cams with 4-8* more duration at .050" cam lift. This is the result of the Quick-Lift Rocker body design. We do not state that our cam lobes (by themselves) give this advantage. The same laws of physics that limit every other cam designer limit our cam lobe designs. We attribute the advantage in valve lift to the "translation" properties of the varying ratio design of our Quick-Lift rocker body design. If you don’t believe us, test any cam lobe (Crane, Comp, Cam Motion, etc.) with stock LS1 rockers. Install a dial indicator on the retainer and a degree wheel on the crank. Plot a lift vs. degrees of rotation curve. Then install the Crane LS1 1.7 rockers (with the pushrods in the Crane kit) and plot the same curve. Measure the duration at .200" net valve lift. The Crane rockers will definitely provide more duration at this checking point. The reason for this is that, contrary to popular belief, the stock LS1 rockers are only 1.7 ratio above .480" valve lift. They actually start the valve off the seat at a 1.54 ratio. What do you think that ratio does to a "super fast" cam lobe? Slows it down quite a bit? The Crane rockers, properly installed, bring the valve off the seat at 1.79. Doesn’t take a math wiz here to see what combination is going to get open quicker and longer!! If you really want to see something interesting, take two lobes that have identical .050" seat-to-seat timing, identical .200" lifter rise timing, but one provides .583" valve lift with 1.7 ratio and the other providing .551 lift with 1.7 ratio. Plot a lift vs. duration curve with any rocker you want (other than Crane) and measure the duration at .200" valve lift. Then do a plot of the .551 cam with 1.8 Crane rockers (this will net out .583 also) and measure the duration difference at .200" valve lift. You will be impressed by how much more this second plot gives over the first. It’s also quicker on the drag strip! We’ve done this. Every person reading these threads can do something like this.
https://ls1tech.com/forums/generation-iii-internal-engine/315892-crane-rocker-arms.html
05-05-2005, 03:59 PM
#30
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To the original poster, you say you have 59 cc chambers, that being the case, your patriot LS6 heads have been milled a minimum of .020 and most likely .030 which will bring the piston valve clearance even closer. Be sure you take this into consideration, whatever decision you make on your dyno queen.
05-05-2005, 04:27 PM
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Originally Posted by Lost
To the original poster, you say you have 59 cc chambers, that being the case, your patriot LS6 heads have been milled a minimum of .020 and most likely .030 which will bring the piston valve clearance even closer. Be sure you take this into consideration, whatever decision you make on your dyno queen.
the 1.8's will work with my cam too, but the lift will be around .600", so i might have p to v clearance issues, but im not sure. the lift is high, i have 2.02 intake valves, but my cam is smaller, so they may not hit. i know the 1.8s will work cause one of the guys at vince is using one of the 041 cams, like 228/236 .600/.600 114lsa with the 1.8s, so his gross lift will be like .643". if that works, then i know i could get away with it too. but i dont want to buy new valve springs too. well have to wait till someone uses these new rockers with patriot heads/valve springs, cause if i get the rocker kit and new springs, i could buy a whole other set of heads. or like 2 more camshafts, or maybe a big cam, and a new set of pistons. too much money involved in modding...
05-05-2005, 07:08 PM
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I have a question then.... If stock rockers are 1.7 and and a set of aftermarket rockers are 1.7(as advertised) is there a difference. Would this difference change the cam size knowing they both max at 1.7. Also would this affect ptv clearance?
05-06-2005, 01:51 AM
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Originally Posted by leeluther252
I have a question then.... If stock rockers are 1.7 and and a set of aftermarket rockers are 1.7(as advertised) is there a difference. Would this difference change the cam size knowing they both max at 1.7. Also would this affect ptv clearance?
05-06-2005, 12:20 PM
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Originally Posted by leeluther252
I have a question then.... If stock rockers are 1.7 and and a set of aftermarket rockers are 1.7(as advertised) is there a difference. Would this difference change the cam size knowing they both max at 1.7. Also would this affect ptv clearance?
https://ls1tech.com/forums/showpost....9&postcount=12
Yes, PTV would be changed albeit minimally.
Last edited by XTrooper; 05-06-2005 at 12:31 PM.
05-06-2005, 12:30 PM
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Either way you must realize that lift doesn't nessesarily mean increased flow. I don't know anything about your heads but if not ported specifically for high lift the numbers may not be what you'd like to see, flow may stagnate or you may even see the numbers decrease with lift on the flowbench.
05-06-2005, 12:33 PM
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Originally Posted by Homeslice (tm)
Either way you must realize that lift doesn't nessesarily mean increased flow. I don't know anything about your heads but if not ported specifically for high lift the numbers may not be what you'd like to see, flow may stagnate or you may even see the numbers decrease with lift on the flowbench.
05-06-2005, 05:01 PM
#37
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Originally Posted by XTrooper
You must realize that if your Gen III heads don't flow well to at least .600" of valve lift you bought the wrong ones.
