Mid lift rockers

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Steve.k
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Mid lift rockers

Post by Steve.k » Wed Aug 23, 2017 3:07 pm

Anyone ever try the mid lift 1.80 rockers. Have new set in box was going to try.

engineguyBill
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Re: Mid lift rockers

Post by engineguyBill » Wed Aug 23, 2017 11:11 pm

Steve,

If you are talking about the Mid-Lift rocker arm system that Crane Cams developed 12 or 15 years ago, it is an excellent concept. Used them on several BBC engines with very good results. I think they (Crane) dropped that product when they reorganized several years ago, but Chase Knight dis say that they were going to resume manufacture of the line.
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Re: Mid lift rockers

Post by Geoff2 » Thu Aug 24, 2017 5:35 am

Bill,
How did these differ from the standard rockers? I presume the p'rod cup was moved up or down a little relative to the trunnion , probably down.

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Re: Mid lift rockers

Post by Steve.k » Thu Aug 24, 2017 9:04 am

I did a bbf for a guy and he gave me a set for part of the work. Ive had them for quite awhile. Going on Trackboss Cleveland number one. Is Chase the engineer who designed them ? Sounds like he pulled out when crane had trouble or something like that? Can't remember how story goes.

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Re: Mid lift rockers

Post by DaveMcLain » Thu Aug 24, 2017 9:45 am

Steve.k wrote:I did a bbf for a guy and he gave me a set for part of the work. Ive had them for quite awhile. Going on Trackboss Cleveland number one. Is Chase the engineer who designed them ? Sounds like he pulled out when crane had trouble or something like that? Can't remember how story goes.
Are you talking about the Mid Lift Geometry rockers that were made by Jim Miller? The ones that are flat on top? I've used a few sets of those and they have worked well. Setup is easy enough in that the top of the rocker needs to be perpendicular to the stud axis when the cam and valve are both at mid lift. This gives the correct geometry on both sides of the rocker at least as far as Miller's ideas are concerned.

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Re: Mid lift rockers

Post by Steve.k » Thu Aug 24, 2017 10:24 am

Yes Dave those are them. Jim Miller thats the guy yes. Suppose to be way easier on valve train with his setup

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Re: Mid lift rockers

Post by DaveMcLain » Thu Aug 24, 2017 10:43 am

I think they will work just fine. Jim Miller has a book that explains many of his ideas about the mid lift geometry concept but essentially it means that at mid lift the pushrod, pushrod pivot and the trunion centerline produce a 90 degree angle at mid lift and at the same time the valve stem, and a line through the pivot point(not contact point) and trunion are also perpendicular.

I've had good results on engines that I've used them on; Cleveland, Big Ford, Big Chevy and Small Chevy. So far, so good...

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Re: Mid lift rockers

Post by Steve.k » Thu Aug 24, 2017 10:47 am

Dave does he still make them and or does anyone else use his therory?

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Re: Mid lift rockers

Post by DaveMcLain » Thu Aug 24, 2017 12:22 pm

I don't believe he makes them anymore. The guy who would know is Paul Kane at High Flow Dynamics(mostly big Ford specialist). He could tell you all of the details. For what its worth I did buy a copy of Miller's book last winter so that is still available.

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Re: Mid lift rockers

Post by engineguyBill » Thu Aug 24, 2017 1:45 pm

Steve.k wrote:I did a bbf for a guy and he gave me a set for part of the work. Ive had them for quite awhile. Going on Trackboss Cleveland number one. Is Chase the engineer who designed them ? Sounds like he pulled out when crane had trouble or something like that? Can't remember how story goes.
My contact at Crane Cams, regarding the Mid-Lift product was Mark Campbell, Vice President, Reasearch and Development. Mark went to PAC Springs after Crane and I have lost track of him over the last few years. Mark did a Mid-Lift technology seminar at the PRI Show a few years ago, which was very informative. I do have some printed material concerning the Mid-Lift product but it is in a stotage unit in Michigan at this time. The concept is very creditable in my opinion and valve event graphing has proved that there is more area under the valve lift curtain with this system.
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Re: Mid lift rockers

Post by engineguyBill » Thu Aug 24, 2017 1:55 pm

DaveMcLain wrote:I think they will work just fine. Jim Miller has a book that explains many of his ideas about the mid lift geometry concept
Anyone know if Jim Miller's book is still available? I tried Amazon, with no success.
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Re: Mid lift rockers

Post by Steve.k » Thu Aug 24, 2017 2:05 pm


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Re: Mid lift rockers

Post by DaveMcLain » Thu Aug 24, 2017 2:58 pm

Steve.k wrote:http://www.mid-lift.com/INTRO-TECH.htm. Some info here.
That's the book and that's where I ordered it from too. It is somewhat poorly organized but pretty interesting.

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Re: Mid lift rockers

Post by engineguyBill » Thu Aug 24, 2017 6:31 pm

Thanks guys.
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Re: Mid lift rockers

Post by midnightbluS10 » Thu Aug 24, 2017 8:12 pm

Steve.k wrote:Dave does he still make them and or does anyone else use his therory?
He still has a few rockers and has some of them on sale right now. Not sure about 1.80's specifically. This was in the email I received from him on August 9. It looks like he may be clearing out old inventory. Most everything he made is discontinued it looks like.

Miller MID-LIFT SB Chevy/Ford Stud Mount Rockers with 12-Point Hammer Forged Adjusters.
$80.00 DISCOUNT
Limited Time!

This email is the ONLY LINK you will have to the special discount pages for both the PVS PA30 SERIES 3/4" diameter Miller gun-drilled trunnion STUD mounted rockers, in 1.60, or 1.70 Ratio, AND .150" RIGHT OFFSET pushrod cups for "N" Head, or Twisted Wedge.

Don't miss this chance to get the strongest, 7075-T6 Aircraft Grade alloy and most precise geometry stud mount rocker arm money can buy, from the founder of the MID-LIFT Patent, that changed the rocker arm industry.

CLICK ON THE PHOTOS ABOVE OR BELOW TO THE SPECIAL LIMITED TIME DISCOUNT PAGES for BOTH THE PA30 SERIES ROCKERS OR THE ADVANCED ROCKER ARM TECH BOOK.
For more info, go to: MID-LIFT.com

(NOTE: You'll have to return to links or photos in this email for the discount.)

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