1.5 vs 1.6 rockers
#1185306
02/24/12 11:17 AM
02/24/12 11:17 AM
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Joined: Sep 2006
Posts: 420
Central Ohio
Ledman_70
OP
mopar
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OP
mopar
Joined: Sep 2006
Posts: 420
Central Ohio
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I'm wondering about going to a 1.6 rocker on my 426 wedge motor. It currently has iron adjustables running on the Voodoo Lunati 513" lift cam, Performer intake, 800 DP Holley, 906 heads with a little cleanup porting. Don't remember the head hasket thickness, just stock size I think. The motor has stock 10.5 to 1 flattop pistons, and I'm wondering how much lift increase I would get with 1.6 rockers. Would clearance become an issue with my current setup? If this is not fesaible, how much more cam lift could I go without getting into clearance problems? Also have Crane springs. I think they were good to 575 lift. Thanks for your opinions guys. Car is a 64 Polara with 833 OD and 3:91 gears.
Jeff Adams
64 426 Polara
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Re: 1.5 vs 1.6 rockers
[Re: Ledman_70]
#1185309
02/24/12 12:34 PM
02/24/12 12:34 PM
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Joined: Jun 2008
Posts: 3,916
usa
lewtot184
master
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master
Joined: Jun 2008
Posts: 3,916
usa
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Quote:
I'm wondering about going to a 1.6 rocker on my 426 wedge motor. It currently has iron adjustables running on the Voodoo Lunati 513" lift cam, Performer intake, 800 DP Holley, 906 heads with a little cleanup porting. Don't remember the head hasket thickness, just stock size I think. The motor has stock 10.5 to 1 flattop pistons, and I'm wondering how much lift increase I would get with 1.6 rockers. Would clearance become an issue with my current setup? If this is not fesaible, how much more cam lift could I go without getting into clearance problems? Also have Crane springs. I think they were good to 575 lift. Thanks for your opinions guys. Car is a 64 Polara with 833 OD and 3:91 gears.
may depend on which iron rocker you have. i've had several sets of crane 1.5 that test to a true 1.6. i've had crane iron 1.6 that tested to a true 1.65. basically what i'm saying is you may blow money for something you already have. i'd put the money someplace else.
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Re: 1.5 vs 1.6 rockers
[Re: Ledman_70]
#1185311
02/24/12 03:17 PM
02/24/12 03:17 PM
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Joined: Dec 2005
Posts: 799
Missouri
bb74swngr
mopar addict
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mopar addict
Joined: Dec 2005
Posts: 799
Missouri
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I have a similar setup with 446, Eddy heads, Speed Pro L2355F30 forged pistons, mopar roller 1.6 rockers, and the same cam you have. These pistons have valve reliefs which helps. I don't remember the piston/valve clearance but it was plenty. Mine was built for 5500 redline but have accidentally spun it to 6500. It was still pulling and no valve train issues.
BigBlock 74 Swinger
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Re: 1.5 vs 1.6 rockers
[Re: Challenger 1]
#1185312
02/24/12 03:22 PM
02/24/12 03:22 PM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
**Photobucket sucks**
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Re: 1.5 vs 1.6 rockers
[Re: 70Cuda383]
#1185313
02/24/12 03:32 PM
02/24/12 03:32 PM
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Joined: Mar 2010
Posts: 632
MD-USA
Dodgeguy101
mopar
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mopar
Joined: Mar 2010
Posts: 632
MD-USA
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
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Re: 1.5 vs 1.6 rockers
[Re: Dodgeguy101]
#1185314
02/24/12 03:42 PM
02/24/12 03:42 PM
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Joined: Jan 2012
Posts: 16
Cincinnati Ohio
challenger11
member
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member
Joined: Jan 2012
Posts: 16
Cincinnati Ohio
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
I don't buy it...put the cam with the lift you want with 1.5 rockers and your valve guides will last longer.imo
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Re: 1.5 vs 1.6 rockers
[Re: Ledman_70]
#1185315
02/24/12 04:04 PM
02/24/12 04:04 PM
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Joined: Aug 2003
Posts: 43,359
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,359
Bend,OR USA
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I have no idea if the cam your running is a solid lifter or hydrualic lifter cam, if solid use a dial indicator on your retainers, both intake and exhaust and check the net lift at the retainer by rotating the motor over through one full cycle(two full crankshaft rotation for each valve) and see what your net lift is, if it is close to or less than .513 then your rockers are 1.5 or less. If it checks higher than .513 then the ratio is more  I like and use higher ratio rockers on a lot of my motors now, they rock  As far as wearing the valve guides out sooner, if the valve opens .500 with 1.5 rockers and you increse the cam lift to .550 then the valve travels more in the guide so wear may occur sooner IF you keep the RPM the same, if you open the valve more and make more power at a lesser RPM and shift it at a lesser RPM the valves will not wear out sooner   More air equals more power Been there, done that  One of the big things on changing rocker ratio is the increase opening and the increased duration at and above the effective duration of the cam Open it(the valves) quicker and sooner and more, especially on mild street type cams,the more power they(Mopar B-RB motors) make
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 1.5 vs 1.6 rockers
[Re: Dodgeguy101]
#1185316
02/24/12 05:08 PM
02/24/12 05:08 PM
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Joined: Jan 2003
Posts: 75,126
A Banana Republic near you.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,126
A Banana Republic near you.
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
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Re: 1.5 vs 1.6 rockers
[Re: JohnRR]
#1185317
02/24/12 07:33 PM
02/24/12 07:33 PM
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Joined: Sep 2006
Posts: 420
Central Ohio
Ledman_70
OP
mopar
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OP
mopar
Joined: Sep 2006
Posts: 420
Central Ohio
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Sorry for the omission guys.... the cam is hydraulic and the rockers are stock iron Mopar. There is a lot of info here, I feel like the guys on the couch with the popcorn. This is the first high output motor I've built, and it's been a pretty good one. I just thought I could get a few more ponies fairly easily/cheaply, but maybe it's not worth the trouble. Now I'm wondering if the Crane springs will hold up to 1.6 rockers. Changing rockers is a lot easier than changing cams.
Jeff Adams
64 426 Polara
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Re: 1.5 vs 1.6 rockers
[Re: challenger11]
#1185319
02/25/12 10:31 AM
02/25/12 10:31 AM
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Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
I don't buy it...put the cam with the lift you want with 1.5 rockers and your valve guides will last longer.imo
what causes the valve to wear out the guide faster with a higher ratio rocker?
if you pay attention to your geometry and keep the rocker centered over the valve, you're not creating more side loads on the valve stem, and moving the valve up and down more from rocker arm ratio is no different than moving it up and down more from a higher cam lobe.
what are the negatives to higher ratio roller rockers, aside from quality control issues from some manufacturers, and the cost associated with them?
**Photobucket sucks**
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Re: 1.5 vs 1.6 rockers
[Re: 70Cuda383]
#1185320
02/25/12 11:29 AM
02/25/12 11:29 AM
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Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
I don't buy it...put the cam with the lift you want with 1.5 rockers and your valve guides will last longer.imo
what causes the valve to wear out the guide faster with a higher ratio rocker?
if you pay attention to your geometry and keep the rocker centered over the valve, you're not creating more side loads on the valve stem, and moving the valve up and down more from rocker arm ratio is no different than moving it up and down more from a higher cam lobe.
what are the negatives to higher ratio roller rockers, aside from quality control issues from some manufacturers, and the cost associated with them?
You will have a more stabil and higher RPM capable valve train with less wear if you design the lift and duration in at the cam and not at the rockers.
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Re: 1.5 vs 1.6 rockers
[Re: Challenger 1]
#1185322
02/25/12 07:13 PM
02/25/12 07:13 PM
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Joined: Jan 2005
Posts: 12,424
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,424
Kalispell Mt.
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I'd put a bigger cam in it before I went with 1.6 rockers. They cause more trouble than there worth IMO.
I used to think the same thing, till someone explained something to me...
using a higher ratio rocker arm, means you're moving the mass of the pushrod and lifter less. by moving them less, you can get more lift and more duration off a cam, without having to deal with accelerating all that mass as much.
and that if you go with a 1.6, or 1.7 ratio rocker from the start, and pick your cam lift/duration knowing that you have higher rocker ratios, then you actually create a more stable valve train because you move the heavy parts, less.
I don't buy it...put the cam with the lift you want with 1.5 rockers and your valve guides will last longer.imo
what causes the valve to wear out the guide faster with a higher ratio rocker?
if you pay attention to your geometry and keep the rocker centered over the valve, you're not creating more side loads on the valve stem, and moving the valve up and down more from rocker arm ratio is no different than moving it up and down more from a higher cam lobe.
what are the negatives to higher ratio roller rockers, aside from quality control issues from some manufacturers, and the cost associated with them?
You will have a more stabil and higher RPM capable valve train with less wear if you design the lift and duration in at the cam and not at the rockers.
Riddle me this than, why not use 1 to 1 ratios? Did you know NASCAR engines keep getting faster and faster ratio rocker arms because they are MORE stable at RPM than a low ratio high lift cam combo. The reasoon is with the higher ratio there is LESS over all motion in the valve train and that means more stability. To keep the same valve motion with a higher ratio you use LESS pushrod and lifter lift, that is just one thing less to have to push backwards. NASCAR engines are some of the highest tech PR engines left and most of them are around 2.2 ratios, even pro-stock... are useing really high (by conventional standards) rocker ratios to help with valve train stability.
If he were talking about a 59 degree SB there would be another benifit to high RPM stability, the PR gets straightened out in relation to the lifter.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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)in the motor and set the lash to zero and then check the lift at the retainers, use the lobe lift on the cam card as your base (unless you want to measure the lobe lift off of the cam or lifter 
