Re: 1.7 Rockers ... why so rare?
[Re: BradH]
#2218826
12/22/16 06:02 AM
12/22/16 06:02 AM
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Joined: Jun 2005
Posts: 435 New Mexico
Scott440
OP
mopar
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OP
mopar
Joined: Jun 2005
Posts: 435
New Mexico
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Mainly wanting to know the WHY Mopar fans are not standing at the gates with pitchforks and torches, demanding 1.7! I can see 1.6 for people wanting a bit lower spring rates.
Previous owner of my engine bought a nice, brand new 1.5 rocker. At first I wondered why. Then I noticed the whole community is pretty relaxed about the catalogs not having it.
Last edited by Scott440; 12/22/16 06:04 AM.
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2218827
12/22/16 06:05 AM
12/22/16 06:05 AM
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Joined: Jun 2005
Posts: 435 New Mexico
Scott440
OP
mopar
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OP
mopar
Joined: Jun 2005
Posts: 435
New Mexico
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I read Andy's article. It's a real eye opener. But didn't you pick up a lot of hp in the other engine, going from 0.66 to 0.80? I thought that lift level put you over 800 hp and caused the block to crack. It required a custom cam with awesome lobes to do it, but in this build, 0.75" lift level was chosen, resulting in 750 hp. Yeah, his ratio is 1.6 IIRC, but lift is worth noting. http://www.hotrod.com/articles/how-to-get-755hp-from-your-wedge-mopar/Wouldn't a NASCAR team cry foul and exit entirely if they were required to use 1.5 while competitors kept 2.0 ratios? If we tested a bunch of engines, wouldn't higher lift produce outstanding gains in many, if not most, configurations? What are some things that can cause peak hp at 0.67" ? Just speculating: Trick Heads claim to flow on par with ported E. Victor heads, but do they flow more like unported Eddy RPM heads? Were valve springs mislabeled or defective, resulting in float/instability that caps hp? Is duration curtailing effective CR? Is there something about the runners or cam that do not lack cfm on the bench, but do curtail velocity in practice? I don't know what happened in your test. You've given me something to think about. In the meantime, imagine everyone demanding 1.7. Vendors get tired of broken part complaints and devise bulletproof systems. Everyone switches over. Armed with the knowledge that 0.67 is best, you request a lobe of just 0.39". Your 1.7 rockers get you to 0.67. Now you ask the cam grinder to drop the duration down. The rocker ratio adds a small margin of duration, but let's say overall it's a 15 degree drop in duration. Low rpm torque goes up. Driveability goes up. Valves close sooner so more CR is retained. People with dual plane intakes can ditch them in favor of single planes. Peak hp happens at a lower RPM, making dicey high RPM unnecessary. Low duration usually means less overlap, which means fewer hydrocarbons, if you're into that. And when it comes to forced induction, duration must be low. But the article spells it out in black and white. I'll consider myself warned. Thanks
Last edited by Scott440; 12/22/16 08:11 AM.
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Re: 1.7 Rockers ... why so rare?
[Re: Monte_Smith]
#2218856
12/22/16 10:45 AM
12/22/16 10:45 AM
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crabman173
Unregistered
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crabman173
Unregistered
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Personally I would always rather have ratio than lobe, but it's tough with stock type setups BINGO!!
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Re: 1.7 Rockers ... why so rare?
[Re: Scott440]
#2218964
12/22/16 01:48 PM
12/22/16 01:48 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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I've been dyno testing motors since 1990. I have done the rocker swap waaaaayy too many times to remember....... And in the last 10-12 years it's usually at the customers request, in an attempt to unlock some magic. I don't know what people "think" they're going to find, but from what I've seen, particularly when it comes to bb mopars with std architecture heads, as long as the valve is open far enough at peak piston velocity so that there isn't a big pressure drop across the intake valve at that point, then getting the valve open even faster and farther will yield little to no gain. There are some general exceptions to this, but that's usually how it plays out on the running motor. On one occasion..... On a combination that was pretty air flow limited...... Where I was as sure as I could be that going from a 1.5 to 1.6 on the intake rocker was going to show a nice improvement....... I was wrong by 180deg. The motor lost 15hp by adding the 1.6's. Messed around with lash, jetting, timing...... All to no avail. Put the 1.5's back on....... Power came right back.
That's the most extreme example of the rockers really not helping, but I have seen the higher ratio make less power on a number of occasions.
As it is with just about every other aspect of engine building, there are very few things that "always" make more power, on every combination.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2218982
12/22/16 02:23 PM
12/22/16 02:23 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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If the cam is close to being right it makes very little change.. on the exhaust side I havent ever seen a change on a lot of engines.. I tried a rocker change a few times and only on my W-9 405ci did it change the output(intake rockers) but that cam was way off..it needed another .150 lift than what I had but I wimped out thinking I would be changing springs often
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Re: 1.7 Rockers ... why so rare?
[Re: Scott440]
#2219020
12/22/16 02:55 PM
12/22/16 02:55 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
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I Live Here
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So. Burlington, Vt.
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Jeremiah....... Did you ever check the net loaded rocker ratio with the full spring load?
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 1.7 Rockers ... why so rare?
[Re: Jeremiah]
#2219038
12/22/16 03:17 PM
12/22/16 03:17 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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I do the screen in the intake valley also.. all my engines have it.. on my first W-2 the rockers were labeled wrong.. they were B engine rockers so with the geometry all wrong I had lash caps on it.. glad I did.. it spit lash caps off on a regular basis which ended up in the valley.. the screen kept my spare parts up there and didnt hurt anything.. back then I thought these things were made correctly but I sure did learn otherwise.. even when I got the right rockers
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Re: 1.7 Rockers ... why so rare?
[Re: Porter67]
#2219043
12/22/16 03:22 PM
12/22/16 03:22 PM
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Joined: Aug 2003
Posts: 43,748 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,748
Bend,OR USA
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The pushrod that broke in two (can't remember now if it was a intake or exhaust on # 1 cylinder, sorry)had a defect in the metal that you could see real easy with the naked eye, when it broke it got caught up between the block and the pushrod beside it bending it in the middle but not making it fall out As far as HP gain and the increase in the peak RPM gain the motor had quite a bit of testing on it before the pushrod failure, the rings where seated. I had broke that pushrod on the local Studka dyno in Madras(2500 ft.) in the morning wasting the rest of the day ) and decided to take it to a new(two yrs. old )version of the DTS engine dyno in Klamath Falls, OR(4300Ft. altitude) I did several pulls to get a semi accurate base line on the engine on that dyno to make sure it was healthy and not hurt elsewhere before swapping the pushrods. The main reason for me switching to the DTS dyno in Klamath was Dan, rest in peace, insisting that the dyno in Madras was a real happy dyno, he was correct. That motor lost exactly 100 HP from Madras to Klamath Falls I took the motor back to Madras later and we, the new owner and operator of the dyno, calibrated with his motor on the dyno and it lost exactly 100 HP from making pulls before we calibrated it to the next pull thirty minutes later My real irritant was that I had ordered and paid for the 3/8x.120 wall pushrods for this motor knowing it had 300 lbs. on the seats and 780 lbs. opened and I got 3/8x.083 wall I guess(and hope) that there was a foul up in quality control on that set in production, I hope it wasn't intentionally done that way
Last edited by Cab_Burge; 12/22/16 03:29 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 1.7 Rockers ... why so rare?
[Re: Jeremiah]
#2219048
12/22/16 03:26 PM
12/22/16 03:26 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
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I Live Here
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So. Burlington, Vt.
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Dwayne, do you mean checking for lift at the retainer with everything assembled to run? I'm still learning the lingo over here lol. We did check it and it was pretty close IIRC, I'll have to dig in my notes. Yes, lift at the valve with full spring load and zero lash, divided by the actual lobe lift. I realize this is actually checking the "system" net ratio, since there is deflection of other components besides the rockers, but IMO, unless the pushrods are seriously undersized the majority of the deflection will be in the rocker. Just curious how rigid those rockers are, and whether any additional ratio was "built in" so the net loaded ratio was close to what they are supposed to be. Some brands seem to have this, some don't.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 1.7 Rockers ... why so rare?
[Re: Scott440]
#2219051
12/22/16 03:33 PM
12/22/16 03:33 PM
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Joined: Jan 2003
Posts: 14,539 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
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So. Burlington, Vt.
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My real irritant was that I had ordered and paid for the 3/8x.120 wall pushrods for this motor knowing it had 300 lbs. on the seats and 780 lbs. opened and got 3/8x.083 wall I guess(and hope) that there was a foul up in quality control on that set in production, I hope it wasn't intentionally done that way Not trying to stir anything up, but if your invoice showed they sent you .120 wall, and the one that failed was .083 wall....... I can't imagine they wouldn't have taken them back and replaced the full set with what you paid for. Still doesn't help with the failure on the dyno though.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2219085
12/22/16 04:28 PM
12/22/16 04:28 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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...
Just curious how rigid those rockers are, and whether any additional ratio was "built in" so the net loaded ratio was close to what they are supposed to be. Some brands seem to have this, some don't. From what I've measured, Hughes doesn't (and I know HS and Crane do/did). The way my .600"-offset Hughes 1.6s are setup, the actual ratio using CHECKING springs, not the actual springs, was 1.58, and the standard-offset 1.5s came in right at 1.50. One of the things I have on my task list is to check again w/ the 240-closed / 600-open springs installed. So, it would also be interesting to see what their 1.7 (advertised) measured, too.
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2219092
12/22/16 04:39 PM
12/22/16 04:39 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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Dwayne, do you mean checking for lift at the retainer with everything assembled to run? I'm still learning the lingo over here lol. We did check it and it was pretty close IIRC, I'll have to dig in my notes. Yes, lift at the valve with full spring load and zero lash, divided by the actual lobe lift. I realize this is actually checking the "system" net ratio, since there is deflection of other components besides the rockers, but IMO, unless the pushrods are seriously undersized the majority of the deflection will be in the rocker. Just curious how rigid those rockers are, and whether any additional ratio was "built in" so the net loaded ratio was close to what they are supposed to be. Some brands seem to have this, some don't. What brand of rocker did you find that didn't have any additional ratio built into it? I bought some Norris rockers in 1999 and I had a full set of cranes and and MP ductile iron rockers. The Norris were 1.6 the others 1.5. I was checking things out and with checker springs the Norris rockers had a ratio of about 1.68 so lift was above what it should have been. I don't remember the other numbers but they were also all greater than advertised. Couldn't get Norris on the phone so I called Jesel and somehow got Wayne on the phone. From that point on I always check P/V with the springs I'm going to run. The flex is amazing. BTW, all the rockers had the exact correct ratio when loaded with the springs I as running. What was stunning was once you get over about 130-140 on the seat, the flex is done.
Last edited by madscientist; 12/22/16 07:05 PM.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: 1.7 Rockers ... why so rare?
[Re: Scott440]
#2219171
12/22/16 06:30 PM
12/22/16 06:30 PM
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Joined: Jan 2003
Posts: 31,203 Oregon
AndyF
I Win
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I Win
Joined: Jan 2003
Posts: 31,203
Oregon
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I read Andy's article. It's a real eye opener. But didn't you pick up a lot of hp in the other engine, going from 0.66 to 0.80? I thought that lift level put you over 800 hp and caused the block to crack. It required a custom cam with awesome lobes to do it, but in this build, 0.75" lift level was chosen, resulting in 750 hp. Yeah, his ratio is 1.6 IIRC, but lift is worth noting. http://www.hotrod.com/articles/how-to-get-755hp-from-your-wedge-mopar/Wouldn't a NASCAR team cry foul and exit entirely if they were required to use 1.5 while competitors kept 2.0 ratios? If we tested a bunch of engines, wouldn't higher lift produce outstanding gains in many, if not most, configurations? What are some things that can cause peak hp at 0.67" ? Just speculating: Trick Heads claim to flow on par with ported E. Victor heads, but do they flow more like unported Eddy RPM heads? Were valve springs mislabeled or defective, resulting in float/instability that caps hp? Is duration curtailing effective CR? Is there something about the runners or cam that do not lack cfm on the bench, but do curtail velocity in practice? I don't know what happened in your test. You've given me something to think about. In the meantime, imagine everyone demanding 1.7. Vendors get tired of broken part complaints and devise bulletproof systems. Everyone switches over. Armed with the knowledge that 0.67 is best, you request a lobe of just 0.39". Your 1.7 rockers get you to 0.67. Now you ask the cam grinder to drop the duration down. The rocker ratio adds a small margin of duration, but let's say overall it's a 15 degree drop in duration. Low rpm torque goes up. Driveability goes up. Valves close sooner so more CR is retained. People with dual plane intakes can ditch them in favor of single planes. Peak hp happens at a lower RPM, making dicey high RPM unnecessary. Low duration usually means less overlap, which means fewer hydrocarbons, if you're into that. And when it comes to forced induction, duration must be low. But the article spells it out in black and white. I'll consider myself warned. Thanks Yes, on my 514 with MW ports I made more power every time I added lift. I ended up with 1.85 ratio rocker arms on that engine. But as others have pointed out, what works with MW heads doesn't necessarily work with std port heads. In the case of my 470 engine we evidently already had the valve open far enough with the 1.50 ratio rocker arms that the engine didn't care about the extra lift. I'm going to put the 270cc heads on this engine when they come out and then I'll redo the rocker arm test and I expect to see a power difference. I think the MW head will use the extra lift.
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2219270
12/22/16 10:03 PM
12/22/16 10:03 PM
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Joined: Aug 2003
Posts: 43,748 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,748
Bend,OR USA
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I tried to respond and this web site dumped it Pierre at Smith Bros. didn't offer to replace them after I pointed out that I had paid for the .120 wall and he wasn't going to replace the two bad ones until one of the shop supervisors came in and looked at both of them and told Pierre to replace them both for no charge. Needles to say I normally buy Manton now at a better price and get what I order and pay for Smith Bros. was here in Bend back then, they moved to Redmond, OR (23 miles further north now) several years back. I started buying pushrods from the original owner back in the late 1960s when they where in West Covina, CA, that guy was a real jerk His Son was a lot better to deal with His Son moved the business up here to Bend a long time before I moved here in 2005 and I think he sold it to the current owners in that time frame, 2004 to 2006
Last edited by Cab_Burge; 12/22/16 10:04 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 1.7 Rockers ... why so rare?
[Re: fast68plymouth]
#2219329
12/22/16 11:31 PM
12/22/16 11:31 PM
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Joined: Mar 2003
Posts: 9,113 Rogue River, OR
Jeremiah
master
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master
Joined: Mar 2003
Posts: 9,113
Rogue River, OR
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Dwayne, do you mean checking for lift at the retainer with everything assembled to run? I'm still learning the lingo over here lol. We did check it and it was pretty close IIRC, I'll have to dig in my notes. Yes, lift at the valve with full spring load and zero lash, divided by the actual lobe lift. I realize this is actually checking the "system" net ratio, since there is deflection of other components besides the rockers, but IMO, unless the pushrods are seriously undersized the majority of the deflection will be in the rocker. Just curious how rigid those rockers are, and whether any additional ratio was "built in" so the net loaded ratio was close to what they are supposed to be. Some brands seem to have this, some don't. Sounds fun, I'll roll the engine over this weekend once all of the welding is done and chips vac's up. I'll try to get some pics of the valve train and dial indicator so we can check my work.
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Re: 1.7 Rockers ... why so rare?
[Re: Cab_Burge]
#2219333
12/22/16 11:36 PM
12/22/16 11:36 PM
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Joined: Mar 2003
Posts: 9,113 Rogue River, OR
Jeremiah
master
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master
Joined: Mar 2003
Posts: 9,113
Rogue River, OR
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I tried to respond and this web site dumped it Pierre at Smith Bros. didn't offer to replace them after I pointed out that I had paid for the .120 wall and he wasn't going to replace the two bad ones until one of the shop supervisors came in and looked at both of them and told Pierre to replace them both for no charge. Needles to say I normally buy Manton now at a better price and get what I order and pay for Smith Bros. was here in Bend back then, they moved to Redmond, OR (23 miles further north now) several years back. I started buying pushrods from the original owner back in the late 1960s when they where in West Covina, CA, that guy was a real jerk His Son was a lot better to deal with His Son moved the business up here to Bend a long time before I moved here in 2005 and I think he sold it to the current owners in that time frame, 2004 to 2006 One of the many stories that have convinced me that screen in the valley is cool right there.
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