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Roller Rockers VS Flat Tappet

Posted By: Sb Valiant

Roller Rockers VS Flat Tappet - 12/09/12 05:16 PM

Is going to roller rockers worth the money for w2 heads? I have a set of flat tappet rockers on the motor now with over a 600 lift flat tappet cam and was told that the finger style rockers aren't meant for that kind of lift, rpm, ect because they were desinged in the 1970's. I was wondering if those rockers are hurting performance by a good amount or don't waste the time and money for rollers? I am looking into a cheaper set for the w2 heads called crane gold roller rockers. I guess they need machined because they don't come right but are meant for the w2 heads. I guess it beats spending an extra over 600 dollars for the next cheapest set of harland sharps..
Posted By: MR_P_BODY

Re: Roller Rockers VS Flat Tappet - 12/09/12 06:03 PM

As a rule of thumb.. go with roller rockers when you
exceed .550 lift... I'm sure if you measure the actual
ratio of the stock VS the HS rockers you will see
that the stock rockers dont even have a true 1.5 ratio
so IF your engine wants more lift it will be a gain...
the big factor also when running roller rockers is
you have a easier sweep across the valve tip which
will cause wear on both the tip and the rocker using
the stock stuff
Posted By: polyspheric

Re: Roller Rockers VS Flat Tappet - 12/09/12 09:21 PM

because they were desinged in the 1970's

Rocker arm design pretty much stalled around WW2. Everything you see today was already known but not cost-effective as a marketable product.

The relationship that determines side thrust (excess wear and lost motion) isn't only lift, it's lift as a function of the long-side rocker length. The ratio doesn't matter.
Percentages below 30% (rocker lever is 1.40", lift is .420") don't need any help, percentages above 40% (lever is 1.40", lift is .560") do. If the ratio were 200%, the rocker would point straight up and down.
This is why for most engines big block rockers need roller tips at higher lifts than small blocks.
Posted By: fourgearsavoy

Re: Roller Rockers VS Flat Tappet - 12/09/12 11:38 PM

I don't know how good they are but Jack Moore has some MP rollers for W-2's for sale in the race section classifieds
Gus

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Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/09/12 11:46 PM

They are deffiently more then 40 percent. Maybe if close to 60. We Were adjusting valves a while back and my buddy happen to mention that the rockers were sitting up on end pretty good and must be a pretty big cam if not to much for the finger type rockers.
Posted By: polyspheric

Re: Roller Rockers VS Flat Tappet - 12/10/12 12:24 AM

When you say "finger type rocker" you lose your audience.

Since your rocker is about 1.515" long (according to Jesel), 60% means you have:
1. .909" lift
2. very, very bad geometry
Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/10/12 01:19 PM

sorry that's just a nick name for them. They are just flat tappet rockers and cam is post to be around 606 lift but we are going to check it for true lift and see what it is. Also geometry still can't be to good regardless.
Posted By: polyspheric

Re: Roller Rockers VS Flat Tappet - 12/10/12 07:16 PM

You can call them late for dinner if you want, but there's no such thing as "flat tappet rockers".
Posted By: Cab_Burge

Re: Roller Rockers VS Flat Tappet - 12/10/12 08:06 PM

Are you referring to the adjustable stock type ductile iron rocker arms as the finger type?
Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/10/12 10:07 PM

Maybe that's what they are... I will try and get acouple pics up for you guys!
Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/10/12 11:02 PM

Here are some pictures!

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Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/10/12 11:04 PM

Here is another shot of the w2 econo rockers we have. What ever they are called.

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Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/10/12 11:24 PM

Does anyone know what these rockers specifically are???
Posted By: SCATPACK 1

Re: Roller Rockers VS Flat Tappet - 12/11/12 12:15 AM

Ductile Iron Adjustable Rockers. Typically they check out around 1.40 ratio (or less in some cases) instead of 1.50. I bet you would see a noticable performance inscrease with roller rockers.

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Posted By: Hot 340

Re: Roller Rockers VS Flat Tappet - 12/11/12 01:42 AM

Quote:

Ductile Iron Adjustable Rockers. Typically they check out around 1.40 ratio (or less in some cases) instead of 1.50. I bet you would see a noticable performance inscrease with roller rockers.

Are you sure about that? Those arent 273 rockers on there..
Posted By: Cab_Burge

Re: Roller Rockers VS Flat Tappet - 12/11/12 03:11 AM

Quote:

Quote:

Ductile Iron Adjustable Rockers. Typically they check out around 1.40 ratio (or less in some cases) instead of 1.50. I bet you would see a noticable performance inscrease with roller rockers.

Are you sure about that? Those arent 273 rockers on there..

Buy some aftermarket Ductile Iron rockers from Crane, Isky, Erson and whoever else sells them and check them at the retainers and let us know what you find I have Why do you think RAS was so busy when they where doing business on a regular bases Not only are the Mopar ductile iron rockers bad the Ford FE and the early Oldsmobile 303 to 394 C.I. and the early hemi where all bad
Posted By: Hot 340

Re: Roller Rockers VS Flat Tappet - 12/11/12 03:29 AM

Quote:

Quote:

Quote:

Ductile Iron Adjustable Rockers. Typically they check out around 1.40 ratio (or less in some cases) instead of 1.50. I bet you would see a noticable performance inscrease with roller rockers.

Are you sure about that? Those arent 273 rockers on there..

Buy some aftermarket Ductile Iron rockers from Crane, Isky, Erson and whoever else sells them and check them at the retainers and let us know what you find I have Why do you think RAS was so busy when they where doing business on a regular bases Not only are the Mopar ductile iron rockers bad the Ford FE and the early Oldsmobile 303 to 394 C.I. and the early hemi where all bad

Ill check these ones out as I get it all set up. Old bushed w2's. You might be right..
Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/11/12 04:32 AM

Thank u for the info ScatPack1 that really cleared things up for me!!!!
Posted By: astjp2

Re: Roller Rockers VS Flat Tappet - 12/11/12 04:41 AM

My factory 426 hemi rockers were in the range of 1.32-1.36, RAS did a geometery correction and got me to 1.42 average. Went with stage V, they were about 1.5-1.52
Posted By: 70AARcuda

Re: Roller Rockers VS Flat Tappet - 12/11/12 05:54 PM

MP made two different w2 ductile rocker arms ...

a bushed and unbushed rocker...

sold off my unbushed rockers a couple years ago...still got a set or two of the bushed ones..

actually MP listed the unbush ones as econo and bushed one as rockers for the race w2
Posted By: Sb Valiant

Re: Roller Rockers VS Flat Tappet - 12/11/12 09:34 PM

We have the econo so they would probaly be unbushed. So what is the difference between bushed and unbushed?
Posted By: LA360

Re: Roller Rockers VS Flat Tappet - 12/11/12 10:02 PM

Quote:

We have the econo so they would probaly be unbushed. So what is the difference between bushed and unbushed?



The bushed ones have a bronze bush in the rocker shaft bore
Posted By: Moparnut426

Re: Roller Rockers VS Flat Tappet - 12/11/12 10:36 PM

Quote:

Quote:

We have the econo so they would probaly be unbushed. So what is the difference between bushed and unbushed?



The bushed ones have a bronze bush in the rocker shaft bore



your rockers dont know if the heads are econo or not, so its a crap shoot as to what you have, bushed or not. I bought a set of heads and there was a box of extra parts and there was no ryme or reason, I had a few bushed and a few not.

They were great in the 70s, but not so great with todays technology, but some NHRA rules require the use of stock rocker gear IIRC, and most guys will send these in to have the geometry corrected and then ya have a knows good set of rockers.

My vte is ya step up to either Harlan Sharp, Jessel, or T&D, or if you happen to find a used set of norris rockers those babys are awesome.

Posted By: Hot 340

Re: Roller Rockers VS Flat Tappet - 12/11/12 11:17 PM

Quote:

[My vte is ya step up to either Harlan Sharp, Jessel, or T&D, or if you happen to find a used set of norris rockers those babys are awesome.



Its so easy to spend other people's money aint it? Cab, how did RAS correct the ratio's? Obviously you can move the threaded adjuster hole...did they use an offset bushing??
Posted By: Cab_Burge

Re: Roller Rockers VS Flat Tappet - 12/12/12 03:09 AM

Quote:

Quote:

[My vte is ya step up to either Harlan Sharp, Jessel, or T&D, or if you happen to find a used set of norris rockers those babys are awesome.



Its so easy to spend other people's money aint it? Cab, how did RAS correct the ratio's? Obviously you can move the threaded adjuster hole...did they use an offset bushing??

I ask them about the way they correct the ratio, the responce was that they change the adjusters from 3/8 to 7/16 inch diameter and move the center of the adjusting hole to correct the geometry from the center of the shaft to the rocker arm tip(they would grind it and heat treat the rocker arm tip when done) and the center of the shaft to the center of the adjsuter hole, Thats what they said in 2001 or so the best I remeber it They did say that they wouldn't try and offset the shaft bushings as that was to hard to control the centers on
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