Cam lift limits
05-22-2005, 01:29 AM
#1
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1.8 rockers What is the highest lift cam anyone ever used? Assuming you have the clearance has anyone run .630+ lift? Any issues with the valvetrain? What springs did you use?
Any issues?
Any issues?
Last edited by Spinmonster; 05-22-2005 at 06:06 PM.
05-22-2005, 03:10 AM
#2
Launching!
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well ive seen lifts in the high 700's before, granted you would have to run a soild roler setup.427's run a cam 0n the .620-.650 range but you need to run them on a shaft mount rocker, and some nice doubles or triples valvesprings, and dont expect them to last very long.
your setup should be fine, make sure you properly check p-v clearence.
your setup should be fine, make sure you properly check p-v clearence.
05-22-2005, 06:16 AM
#3
TECH Senior Member
I would not run 1.8 rockers on a setup like that. do a search, this has been touch on many times.
You want a bigger cam, just custom design one for 1.7 ratio rockers.
Otherwise just sell what you have and get the right parts.
You want a bigger cam, just custom design one for 1.7 ratio rockers.
Otherwise just sell what you have and get the right parts.
05-22-2005, 02:17 PM
#4
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Originally Posted by PREDATOR-Z
I would not run 1.8 rockers on a setup like that. do a search, this has been touch on many times.
You want a bigger cam, just custom design one for 1.7 ratio rockers.
Otherwise just sell what you have and get the right parts.
You want a bigger cam, just custom design one for 1.7 ratio rockers.
Otherwise just sell what you have and get the right parts.
WHY?
So is anyone running .630 lift...with or without 1.8 ratio rockers?
Last edited by Spinmonster; 05-22-2005 at 05:54 PM.
05-22-2005, 03:24 PM
#7
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Originally Posted by Spinmonster
WHY?
Yes, I did a search and never read a 'why' from those who are against the different ratio. If I was running 1.7's my question would still be, "Can I run .630 lift on a custom grind cam?"
I haven't selected a cam. Lift is lift. If the lift is too much I can get any custom grind for $350 to get to the accepted limit of lift.
I have the rockers already. I want an adjustable valvetrain and I am running them. I also want the reduced friction benefit of the full roller set-up.
Although this thread wasn't intended as a debate on higher ratio rockers, the question is raised already by PREDATOR-Z so I will run with it. Is there another issue pertaining to running greater ratio rockers please present it. It seems for simplicity people just say run a big cam with 1.7's so there is no need to recalculate lift or valve events.
So is anyone running .630 lift...with or without 1.8 ratio rockers?
Yes, I did a search and never read a 'why' from those who are against the different ratio. If I was running 1.7's my question would still be, "Can I run .630 lift on a custom grind cam?"
I haven't selected a cam. Lift is lift. If the lift is too much I can get any custom grind for $350 to get to the accepted limit of lift.
I have the rockers already. I want an adjustable valvetrain and I am running them. I also want the reduced friction benefit of the full roller set-up.
Although this thread wasn't intended as a debate on higher ratio rockers, the question is raised already by PREDATOR-Z so I will run with it. Is there another issue pertaining to running greater ratio rockers please present it. It seems for simplicity people just say run a big cam with 1.7's so there is no need to recalculate lift or valve events.
So is anyone running .630 lift...with or without 1.8 ratio rockers?
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05-22-2005, 05:48 PM
#8
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Originally Posted by Blue Hawk
The way I understand it, with higher ratio rockers you're not only increasing lift but also the ramp rate aggressiveness. And your cam is already an XE-R design. You will probably run into valve float issues with that combo.
I guess I had it comming to me. This post is all my fault in that the desire to evaluate the use of the 1.8's is just too tempting rather than to just get an answer to who is running >.630 lift.
I will start a new thread....
05-22-2005, 09:34 PM
#9
There have been discussions( I cannot vouch for their validity) that any more than .333 lift at the cam can creat oiling problems with the lifters. I was wondering if that is why the new z06 has 1.8 rockers to get the .591 lift. I think all the talk about 1.8 rockers on aggresive cams is just that, talk. If you have the right springs who cares if the valve opens quicker...it is not like we have flat tappet cams. I am doing a 403 ls2 now with a .619/.630 with 1.7 rockers.
05-23-2005, 01:15 AM
#10
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Originally Posted by ChucksZ06
There have been discussions( I cannot vouch for their validity) that any more than .333 lift at the cam can creat oiling problems with the lifters. I was wondering if that is why the new z06 has 1.8 rockers to get the .591 lift. I think all the talk about 1.8 rockers on aggresive cams is just that, talk. If you have the right springs who cares if the valve opens quicker...it is not like we have flat tappet cams. I am doing a 403 ls2 now with a .619/.630 with 1.7 rockers.
Kind of in the ball park of what I was thinking on the cam. What are the other cam specs you were thinking of running? Do you remember where you read about the lifter limitations (.333)?
05-23-2005, 09:42 PM
#11
I read about it on this forum but I do not remember who was talking about it. I was going to use a solid cam with the 403 and one of the reasons I did not is the machine shop guy I use was told by comp cams that they recommend bushing the lifter bores when using high lift solid rollers or the lifter bores wear out quickly. I have to think this has something to do with the length of travel and the high spring pressures with solids. anyway that is why I bagged it and am going with a large hydraulic. I think I can get 550 rwhp with it anyway. I have a solid roller in my 406 sbc and I like it a lot so that was my reason for wanting to go that route.
