Author Topic: Rockerblock I.C.--Something a little different-  (Read 45226 times)

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #165 on: May 24, 2017, 10:28:16 PM »
Thanks for the suggestions guys. I've looked at all the ways of saving my current rocker arms, but it's going to look "kludged up" if I do anything other than make new ones.----Brian

Offline cfellows

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Re: Rockerblock I.C.--Something a little different-
« Reply #166 on: May 25, 2017, 06:13:52 PM »
It seems to me that minimizing the horizontal (scrub) movement of the rocker arm at the tip of the valve stem requires you to lower the axis of rotation in the rocker tower.  Center of rotation of the rocker arm should be 1/2 the distance of valve stem travel below the tip of the valve stem.  Does that sound right?  That should eliminate the need to make new rocker arms.

Chuck
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Offline gbritnell

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Re: Rockerblock I.C.--Something a little different-
« Reply #167 on: May 25, 2017, 11:52:40 PM »
Brian,
Any engine with plain rocker arms (not roller tipped) create a rubbing action on the end of the valve stem.
To alleviate irregular contact as the rocker arm rocks or rotates the contact surface is made with a radiused end face. I would suggest rather than remaking the arms to just radius the contact surface and then adjust the pushrod length so the rocker arm travels an equal angle above and below mid contact.
gbritnell
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Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #168 on: May 26, 2017, 12:05:39 AM »
Thanks guys. I know the truth of what you are saying. The nasty part is that I knew it before I designed that first set of rockers. It was just a matter of knowing it but not thinking of it.  I have a new set mostly made now, and will post more tomorrow when I get them finished. Based on the geometry of the rocker arms and a total valve lift of 0.100", the total "sideways slide" between the adjusting screw and the tip of the valve stem will only be 0.0015" if I set things up right. The way I had first built things the amount of sideway slide was about 0.040".  I will round the tip of the adjusting screw. I have something a bit different in mind for the pushrods which I want to try, which precludes putting the adjusting screw over the pushrod.
« Last Edit: May 26, 2017, 12:12:40 AM by Brian Rupnow »

Offline Art K

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Re: Rockerblock I.C.--Something a little different-
« Reply #169 on: May 26, 2017, 03:58:54 AM »
Brian,
Your solution for this problem should be interesting.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #170 on: May 26, 2017, 06:54:21 PM »
So---I'm back to where I was a week ago. The new rocker arms are made, and although they look an awful lot like the old rocker arms, there is a big difference in the geometry of the area where the adjuster screw sets. I shortened up the height of the rocker arm support tower by about 1/4", as that played into the overall geometry as well. Now I have to quit playing machinist and go help goodwife get ready for a yard sale tomorrow.

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #171 on: May 26, 2017, 10:17:21 PM »
Here's a little trick I have found. The adjusting bolt in the end of my rocker arms is a #5-40 thread, but a #5-40 hex nut is huge when it's up against something 1/4" wide, like my rocker arms. The trick is to get a #4-40 hex nut which has a considerably smaller outer profile, and drill/tap it out for a #5-40 thread. It looks  much better, proportion wise.

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #172 on: May 28, 2017, 01:19:03 PM »
No machining to report today. Goodwife has been collecting donations for about 6 weeks to have a "Parkinsons Charity Yardsale" in support of the Parkinsons foundation. Our 41 year old son developed Parkinsons Disease a year ago. My garage was stacked right to the ceiling with other peoples junk, so yesterday involved setting it out along both sides of my 100 foot driveway and doing the yardsale thing. After a furious two hours of setting everything out, with help from our son and two of his children, I spent most of the day setting in a big old (donated) chair and helping wife oversee the yard sale. The sale went very well. We made over $600 for the charity. About noon my son and his two young children were getting pretty worn out, so we sent them home. We had a couple of small passing rain showers, but not enough to wreck anything. At the end of the day, even though we had sold a ton of stuff, there were still 2 tons of "stuff" left in the driveway, which Kathy and I had to then pick up and cram back into my garage. The next 2 weeks will see her donating everything that was left to various organizations around Barrie. It was a fun day, and the first day in months that I haven't been designing for a customer or working in my own machine shop on the Rockerblock engine. I'm sore today from using a lot of muscles that don't get used very often. ----Brian

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #173 on: May 28, 2017, 04:35:38 PM »
It's kind of hard to believe, but I only have 6 parts left to make on this engine. I need two cams, two lifters, and two pushrods. Since I am used to operating these small engines on Naptha and oil mix, I will probably set it up to run on Naptha and oil initially. Once I get it to run with a fuel I am familiar with, then I will build the gas-demand valve and see if I can get it to run on propane. I thought I might have things completed by the end of May, but life gets in your way sometimes, so now it will probably spill over into June. I have "bits and bobs" of minor tweaking to do, but other than the 6 components mentioned, all the major parts are finished. I will use the same method for making the cams as I did for the Rupnow Vertical engine and the Overhead cam engine, using the rotary table and milling machine. That method isn't as accurate as the method outlined by Malcolm Stride, but it doesn't seem to matter that much. The engines run well no matter which method is used.----Brian

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #174 on: May 30, 2017, 02:12:46 AM »
Tonight we have finished valves. After the killer yard sale on the weekend, and working "away" today, I hadn't planned on doing anything tonight.--But you know how it is---Just had to do some little thing to keep the flame burning. My valves always look a little "ratty" on the ends after the parting off operation, but I don't try too hard to clean them up perfect. I grind away any "tit" left on the center on my belt sander, but I don't try to polish out all the concentric circles. The heads of the valves don't show after the engine is assembled, and I did actually ruin a perfectly good valve once, getting too enthusiastic about taking out any marks left after the parting off operation.


Offline MJM460

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Re: Rockerblock I.C.--Something a little different-
« Reply #175 on: May 30, 2017, 10:50:49 AM »
Really enjoying following your build, Brian.  Well done also on the yard sale, it is a great cause.  My wife is living with PD though not so early onset as your son, so we keep up with the research through our membership in the local support organisation.

MJM460
The more I learn, the more I find that I still have to learn!

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #176 on: May 31, 2017, 03:20:00 PM »
This morning I cut the first cam. It turned out well although I find that every time I cut a cam using the "end mill plunge" system, the results are always marginally different from the input math I used to set it up. The engine won't mind, as long as both cams are identical. I still have to file a slight radius on both sides of the tip. I won't change any settings when I put my next cam blank in to machine it. That should guarantee that both cams are the same.

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #177 on: May 31, 2017, 08:52:23 PM »
Here we have two little cam birds setting in their nest. They are not hardened yet. I have just finished turning the lifters, and am working on the link between the lifters and the rear side of the rocker arms. Both cams and lifters are made from 01 drill rod, which I will flame harden.  If all goes well and I have no disasters, I will finish the valve train on Friday.

Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #178 on: June 01, 2017, 12:22:59 AM »
We have an operational valve train!!! The cams go round, the lifters lift, the rockers rock, and the valves open and close. I still have a bit of fettling and fondling to do, but it works. I haven't cut my valve springs to length yet, as everything has to be disassembled, the cams and lifters hardened, and intake/exhaust ports drilled into the cylinder head. I was supposed to work (real work) today, but at the last minute it got deferred to tomorrow, so I had all day to play in my machine shop.  I'm quite excited about this as the valve train is the last major sub assembly on the engine. The solid model shows what I did for a pushrod.


Offline Brian Rupnow

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Re: Rockerblock I.C.--Something a little different-
« Reply #179 on: June 02, 2017, 02:06:04 AM »
And a beautiful thing it is!! After a days work "away" I came home tonight and after some very careful set-up, drilled, tapped, and spot-faced the cylinder head for the intake and exhaust elbow fittings. The holes ended up where they were supposed to be, and the elbows fit the way I had hoped.

 

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