Author Topic: DIY rocker arms  (Read 12552 times)

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Offline rebelce

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DIY rocker arms
« on: November 06, 2015, 01:58:44 PM »
I'm building up a Jimmy straight 6 and need to make some rocker arms. Pat Riley was kind enough to show me the set he built for his and of course the Ferguson's always have nice stuff. Mine need to be slightly different than stock, both angle and offset. So do any of you guys have any suggestions? I have a lathe and an old J-head Bridgeport as well as a lot of friends who do machine work but I like to keep things in house. There are a lot of Jesel rockers in the cupboards for ideas and mock-up parts if need be. Would 7075 be a good material to use? There is nothing in a modern engine that is long enough. Help is needed!  
« Last Edit: November 08, 2015, 01:45:48 PM by Seldom Seen Slim »

Offline SPARKY

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Re: DYI rocker arms
« Reply #1 on: November 06, 2015, 02:10:21 PM »
I have seen articles the adjustable ones off of the 305-351-401-478 being used
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Offline rebelce

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Re: DYI rocker arms
« Reply #2 on: November 06, 2015, 03:52:59 PM »
I've never seen a set but it's highly doubtful they would full fill my needs. Roller tip for a start.

Offline Buickguy3

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Re: DYI rocker arms
« Reply #3 on: November 06, 2015, 04:10:28 PM »
   When we needed roller rockers for the straight 8 Buick we went to T&D Rockers and they said that they didn't build any that we could use. We went to their online catalog and looked in the catalog index and found three part numbers that were stock parts. We had to have a shaft made to fit and have it hardened but we've been happy with their arms. They weren't real expensive but the hardened shaft was pricey.
   Doug  :cheers: :cheers: :cheers:
I keep going faster and faster and I don't know why. All I have to do is live and die.
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Offline rebelce

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Re: DYI rocker arms
« Reply #4 on: November 06, 2015, 04:40:34 PM »
Buickguy3, that is a real possibility, I took a quick look at their site and noticed they provide lengths for the valve side but is there a way to find the overall length? That's the problem on Jimmy's. I'll call them and see what they have to say. Still want to explore the idea of building my own in the meantime. Thanks, it's book marked!

Offline johnneilson

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Re: DYI rocker arms
« Reply #5 on: November 06, 2015, 04:47:09 PM »
I have built a few sets from scratch.
It is not hard, just follow good design and engineering practices.

That said, used 7075 and 6061, both work fine.

You can contact me privately and I will attempt to answer your questions.

It can be done reasonably in terms of cost. You just have to shop around.

John
As Carroll Smith wrote; All Failures are Human in Origin.

Offline rebelce

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Re: DYI rocker arms
« Reply #6 on: November 06, 2015, 07:49:16 PM »
Panic, yes, the valves are being moved .090 to towards the exhaust to center them in the chamber and tipped towards the port 5 degrees as well.  I'm only going to do a section of an old head first, Mike Kirby will play with it and see if it's a worthwhile endeavor. I have to think the whole thing through. No need to have it half done and no way to finish it.
« Last Edit: November 07, 2015, 04:37:56 PM by rebelce »

Offline Buickguy3

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Re: DYI rocker arms
« Reply #7 on: November 06, 2015, 09:06:54 PM »
  You may want to check with Blake Machine in Phoenix also. They custom build the Buick rockers and will do the shafts, too.
  Doug  :cheers: :cheers: :cheers:
I keep going faster and faster and I don't know why. All I have to do is live and die.
                   [America]

Offline Jack Gifford

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Re: DYI rocker arms
« Reply #8 on: November 06, 2015, 11:56:34 PM »
For smaller overall size than aluminum, I made cam followers from 4140 steel alloy. It's easy to machine in pre-heat-treat form; had them treated to 49 Rockwell-C afterward. I purchased the rolling elements (wheels, tip rollers, axles) from Ron Iskenderian because I wanted to use the original non-needle wheels. Ron shared with me the factory process of coining the wheel axles (ends aren't hardened) into their EZ-Roll lifters- I built a small jig to coin them into my followers. The Isky roller tip axles use Circlips. I'm presently doing spin-tests of the OHC assembly, with no faults so far (springs are 290# seat, 590# @.686" lift) to about 6,600 [engine] RPM.
« Last Edit: November 07, 2015, 12:22:25 AM by Jack Gifford »
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Offline rebelce

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Re: DYI rocker arms
« Reply #9 on: November 07, 2015, 09:52:42 AM »
After following your windage thread Jack, I've decided you are a much better man than I in the shop! You do beautiful work and if any of my things come out half as nice I'll be a happy man. I will keep Isky in mind for the rollers.

Offline RichFox

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Re: DYI rocker arms
« Reply #10 on: November 07, 2015, 11:13:32 AM »
Around 1990 or before, Bob Dalton and I made roller rockers for my Hourning-Fisher head GMC. Bob set the whole thing up. He cut the rockers out of 6061 on the CNC mill he had at the time. And he had made a jig for me to drill and ream for the roller axles and drill and tap for the adjusters on a manual mill. Took us a Saturday afternoon. Bob had got the rollers and adjusters from Isky. With todays machines I am guessing a few hours.

Offline rebelce

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Re: DYI rocker arms
« Reply #11 on: November 07, 2015, 11:46:34 AM »
Rich, that's about the best news I've heard all day!

Offline jimmy six

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Re: DYI rocker arms
« Reply #12 on: November 07, 2015, 07:22:54 PM »
I made my own, at least designed them and traded some electrical work in a machine shop to make them for me. He made the stands and right/left rockers. Like many above, I used Isky rollers and Titan adjusters. Used 7075 for the material and the stock rocker shaft ground down a bit to fit the Torrington bearings. Stock shaft did break after 20 or so years of running so I had a couple of replacements made. Rifle drilling was pretty easy along with the grinding and heat treating. Since every thing was straight up and down it went fairly easy.
Offsetting the push rod to the roller tip needs to wait until you know what the distance will be but I didn't concern myself with that since I was not moving the valves. I adjusted the rockers to the stands by using washers I bought from McMaster-Carr. I kept the stock springs for tension. Fergie used aluminum spacers as I remember. When I was done with them I was very pleased with the ratio and what the shop said they would have cost. This was just the machining on the rockers and stands. All assembly and the shaft work was done by me.
I now have 3 different sets, 1 for the stock head, 1 for a Skinner/Fontana, and 1 for a Howard/Arias. All 3 are different and would hard to move from head to head. I would not bother with bearings on the shaft if doing it again. Aluminum on the hardened shafts is sufficient. I would change a few other things today in the design but not much as they have proved themselves.

 A friend is using an Arias 12 port set he bought from someone in the Inliners for a stock head and is making a new shaft to make everything line up. I believe he is going to hard chrome the shaft and grind it to the proper diameter. A little leg work but I think he'll have less than $200 in the new shaft. My pair were right at $200 5 years ago with no chrome plating.

I have 2 sets of new Thomas Magnisium hi-lift rockers for a GMC I never used because I wanted the rollers to keep from wearing out valve guides every year. They ride on the stock shaft with no bearings and use the stock adjuster and just shortened the pushrod side for the additional lift. The pushrod hole in the would need to be enlarged for them to work with better springs as the stock push Rod was pretty small....GoodLuck
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Offline wobblywalrus

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Re: DYI rocker arms
« Reply #13 on: November 07, 2015, 11:58:29 PM »
An aluminum part under cyclic loading that is designed for long term fatigue resistance will often be heavier than a steel item designed for the same life.  Steel is a more forgiving material in this respect.  In my case, where I do not have sophisticated design and test facilities, steel is a very attractive material.

Offline rebelce

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Re: DYI rocker arms
« Reply #14 on: November 08, 2015, 10:44:06 AM »
Jimmy6,  How wide are your rockers? Would you mind sending me a picture of their profile?  I saw the ad in the 12PN for the Aries rockers but they were gone pretty quick.  I think the hardest part will be getting the overall profile cut out. I can take it from there as New England is good for indoor projects! steel or aluminum? Oh boy. 7075 or 2024 would be easier for me to work with I think. Man that's a hard one though. Panic, you're right, 10 degrees may be too much, 5 is better, the chamber is too thin and yes, the exhaust is tipped as well.