Valve Spring/Rocker Arm question
Valve Spring/Rocker Arm question I have a Futral Motorsports F14 high lift can (232/234 .646/.612 lift) and I am replacing my rocker arms with the quick lift Crane 1.7's. I am running manley springs(221426) on dart 225 heads that are good for .650 lift. The thing I am concerned with is that the lift will be too much for the springs. I read how the 1.6 rocker arms are like a 1.72 and if the 1.7's are the same way, it would be more than my spring rating. What do you suggest?
Thanks,
Bobby
Thanks,
Bobby
Final ration on the Crane's is 1.72. Overall lift should be OK. There is more to valve springs than lift, what is your installed seat load and open load. Those are the things you need to examine.
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I would not use those rockers with such an agressive lobe. They were certainly not designed for that. Look at Crane lobes and you'll understand why.
Either get your stock ones rebuilt by Harland Sharp or go with a standard 1.7 aftermarket not that variable lift tech.
Either get your stock ones rebuilt by Harland Sharp or go with a standard 1.7 aftermarket not that variable lift tech.
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Verdad Gallardo TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Good luck, I doubt he would release this info (proprietary lobes).
Look around for a Cam Dr sheet, I know Patrick G has some with the regular FM14
On these the rate is about 50 intake and 51 exhaust (XE=53 and XE-R= 49)
so the high lift must be more than that at some lifts.
I had one but the site hosting died and it is lost.
Look around for a Cam Dr sheet, I know Patrick G has some with the regular FM14
On these the rate is about 50 intake and 51 exhaust (XE=53 and XE-R= 49)
so the high lift must be more than that at some lifts.
I had one but the site hosting died and it is lost.
Just curious, have you run this setup yet? Do you know your installed height? It appears that unless you are exactly at 1.800 you could be running those springs really tight since you only have 0.700" to coil bind if installed at exactly 1.800 and your lift is 0.649. I would also check the retainer to valve seal clearance as well if you haven't done so.
I am currently running with this setup. Sorry for my ignorance, but I don't know my installed height. Futral recommended these springs when I bought the cam. Are there better springs out there than can handle more than .650 lift? I emailed futral to get the specs and see if the cam would be ok with crane rocker arms but haven't received a response yet. Also, how exactly would I check retainer to valve seal clearance?
Thanks,
Bobby
Thanks,
Bobby
You need to remove the spring and measure between the bottom of the retainer and the top of the seal. If you are already running this cam/spring combination then you would know by now if it was an issue. PAC just introduces some dynamite dual springs, that I think are good to 0.700" lift. Yeahdoug is a member of LS1tech so you can shoot him a PM.
150# at 1.800"
440# at 1.100"
Coil Bind at: 1.030"
Max Lift: .700"
Spring Rate: 402#/in
Spring Weight: 95 grams
OD 1.300"
150# at 1.800"
440# at 1.100"
Coil Bind at: 1.030"
Max Lift: .700"
Spring Rate: 402#/in
Spring Weight: 95 grams
OD 1.300"
