high ratio rocker arms

67Straightsix":pzyrhpjl said:
I pretty much understand what you're saying, but I don't quite understand how you get the 70 thou offset without enlarging the bore on the rocker. I have made bushings and have been experimenting with FE rockers - my problem is the bushing thickness is only .031 so you'd have to enlarge the bore on the rocker to make an offset bushing (I don't think there's enough material on an aluminum rocker to do that and be strong enough)- also, the geometry of the rocker is off. I'm thinking if you lower the rocker pedestal approx a .25" that would correct the rocker geometry.

Take a look at this old B-series MG rocker I have on hand and you can see where the rocker was rubbing the valve stem. The distance from the pushrod ball to the rocker shaft center is almost exactly 1.00". From rocker center to the outermost edge of the rubbed area is 1.45". The published spec for this MG rocker is 1.46:1, so that's probably pretty close to right.

From the edge of the wear area to the very end of the pad I still have about .080" of unused space. If I simply move the rocker pedestal back by .070" it allows the rocker to use that space. My ratio goes from 1.46:1 to 1.53:1 just by doing that.

My cam lift is .265" so the my valve lift jumps from .3869 to .4055 inches, a gain of .018 in lift and a corresponding slight rise in effective duration. It isn't much, but on this tiny engine it could be worth a couple of horses.

Alternatively, you could offset bush the rocker itself. A .030 offset rocker bushing would mathematically give me similar results, BUT - the distance between the valve stem and the rocker shaft center is fixed. That end of the lever remains 1.46" no matter what the rocker bushing does. You would have to offset the rocker shaft a similar amount to get the gain of a longer lever arm.

Right now I'm leaning toward just making new pedestals because the height also needs to be adjusted a bit to correct some geometry that I think is off. But the bushings would be a very easy thing to do as well.
 

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Ok so I just spent a little while doing some math and using what you guys have posted in here this is what I have came up with.

If your stock rocker is 1.43:1 you need to move the arm toward the valve .095 to get a 1.62:1 rocker ratio.
This is using a rough measurement i did with a phone ruler ( my ol lady has mine in her car. idk why).
That is saying the PR side is 1.3125 center to tip and valve side is 1.8733 center to tip.
so taking that .070 bushed rocker shaft and a .025 bushed stock rockers.
Now for the questions.

How much do you have to shim the pedestals to fix the geom?
does that affect the ratio? or effective lift?
I am sure it does, but how do you apply that math to the ratio?
Also, buy moving the arm toward the valve, is there any mods to the wear pad needed to be done?

And by the way guys, looking at how much it cost for certain new shafts and rocker arms, I can see how 1.6 rocker assemblies cost $400 for a company to make money.
 
My sample 1.76 FE rocker showed up today. Holy smokes is it close to the rockers on our little engine. Now I wanna go take some measurements of the 223 rocker shaft I have out in the garage to see if that guy has the same dimensions as the 200 shaft or if it matches that of the FE valve train. Maybe there's some horse trading I can do on this thing. The geometry of the pushrod side of this 1.76 rocker is definitely different than that of the 200 rocker. It looks like I've got to angle this bad boy a few degrees higher on the valve side. This will mean I need to carefully figure out what the installed height needs to be or start looking at taller valves. I've got a fully assembled head sitting on my work bench so I'll have to try to gauge the relative geometry. The shaft diameter size "might" be close enough that I can install this 1.76 on with the 1.5 side by side and do some comparisons.

Dare I say that this is starting to look feasible. I have a couple routes I can go, I think: longer valve stem or shorten the pedestals. I may try to fab this up with some pieces of plywood roughly cut to the size of what these new pedestals would be. There's gotta be someone here in town that can cut up some ingot for me once I get it all figured out.

If I can use stock FE rockers with a set of custom pedestals and maybe sweet talk someone into making me a custom length shaft, I might be in business....

:beer:
 
Can you post some pics of them side by side?
I am gonna hit the pick n pull around here soon and see if I can't find an old set of fe rockers to play around with.
If the ratio works out better than 1.6 I may build some for my engine. If not I'm just gonna go with the RAU high ratio rocker assembly. Like I said earlier, it doesn't look like those guys make a lot off the ones they sell for our engines.
 
So here is a question for ya. What engine is your rocker assembly from? Looks like yours mounts different than mine does. On mine the bolt goes through the center of the pedestals and the shaft. Yours looks like it is off set. Also, there is more meat on those FE rockers to of set bush them if you can get the pedestal height correct they may work just fine.
 
Oh, that other set of rockers is from a separate failed experiment. That is the full rocker setup for a 223 inline. Those rockers are way too long and are something like a 1.43 ratio. I have 3 other setups: 2 non-adjustable, 1 adjustable. They are all the 1.5 ratio for the 200/250. It's also the same rocker shaft O.D. as that of the Falcon 6. Was hopin to get lucky but alas, no.

I haven't looked into what those 223 pedestals will do for me with the FE rockers. I will probably just have someone fab me some new pedestals offset by the appropriate amount to use a customized 840 thou shaft. The shaft for a 200/250 is something like 750 thou. I'll probably contact RAU to build an undrilled 840 that is the proper length. That way I don't have to bush anything and potentially weaken parts.

I'm trying to work a pedestal loose from one of my other shafts to see how much meat I have to play with. If I have enough to just re-center drill the holes for the shaft then that might work too. Still too early for me to have that figured out though.
 
cr_bobcat":hgp6l6d9 said:
Sorry it took so long. Photobucket hadn't been cooperating for me the last few days.


I've put the Equal sign in here three times, but HTTP DOESN'T SHOW IT.

But I'm sure you get the idea.


http://i1361.photobucket.com/albums...Arms/20160122_054241_th_zpsqiieiy44.jpg[/IMG]









Rocker to pushrod alignment in the side elevation improves as you raise the valve from its nominal 4.79" to 5.16". The taller valves are aftermarket 283/307/327/350 Chevy first generation, used by early 289/302/351 non Cleveland head modifications 'back in the day'.

SI can get you anything you want. Holden Australia used them in the factory 1974-1978 L34/L31 308 Homologation special , and Yellla Terra used them as an upgrade to the Bathurst L6 202 12 port cylinder head.

All small six stuff is a bit of a disaster for valve height, which is why in 1976, Ford went to Clevleand valve heights and port geometery on its cross flow engines. 1.73:1 rocker ratio longer valves about that lenght and more.


Getting the picture, Ford Australia did this 40 years ago, and FE designers did it 60 years ago.

High riser FE engines have 5.45" tall valves, and a differerent Valve angle of 13°, but raising the valve and pedastol to suit helps.



All the advice from Faron (FordSedan Delivery) was that he uses lash caps to correct geometery with his adjustable FE roller rockers. Pictured is the non adjustable.

You can drill for adjusters, or jest get the aftermarket roller rockerts.


Bill Ambler asked for some cross sectional views on the iron and aluminum headed small six, from those, you can see the pushrod angles between FE and small six exist simply becasue the camshaft is in a different position.

some cross sectional views of the FE Edlebrock Performer head give you the ideas on what changed between the small six and the FE.






Its not rocket science...its rocker science, and its easy...
 
amazing all you engineers ! have done all this for what ? this has already been solved and the cost alone throws all you engineers to the rear........................ put your brains to work on a double roller timing chain for the 250
 
Oh, I know I'm so close to cracking this nut. I didn't know Faron went this route too. I was contemplating getting a few other samples to play with. I figure that geometry ain't so bad when you know exactly what it is you're looking for. I have most the numbers figured out (Matlab is an awesome tool). I can plug and play different specs but I need real samples to look at/measure. I'm always looking for the path of least resistance!

Sorry Bob....gears are a bit foreign to me. I'm an electrical engineer by trade and even then I'm about as far away from a tech as can be. But if you want me to spec an industry standard over this, i'm your man.... Well, that and even though I technically "own" a 250, I don't know exactly where it is. I pulled the head and C4 but the block I couldn't transport. I assume it's still at the dude's house but I don't have the room for it and I reckon I already got my $200 worth of parts out of it... that being said, eventually I'll mosey over again to see if its still there...
 
We luv ya Bob!


Just a note, Faron (FordSedan Delivery)didn't go this route on his 220 hp 250 12:1 engine, he used an old cam grind with not much lift, not much duration, he didn't need 1.73 or 1.76:1 rockers to get his 12 :1 compression, 14 second 66 Mustang to do high 95 mph passes.

He just followed the 1971 Ak Miller based articles and built the engine they way he saw fit. Gene I think has that engine now. Faron mearly said to us all that he liked to use lash caps to fix up any clearnace issues on his race and road FE engines, and that he was quite happy having a solid lifter rocker gear. Faron says quite a lot of very revolutionary things about everything, we just didn't get it the first time around.


(y) I'm breaking my comttment responding to this post, but it it helps, then its all good.

Why would I go buy an Aussie twin roller chain and broach it for a US US 250, when there is so little market for it?.Mike1157 found the A series Mini 1275 double roller chain and similar 18r Toyota and 308/304 Holden twin roller chain was able to be matched with a 5.0 aftermarket sprocket on a US 250. So if you want one, get your enginer dude to have a go, and set up your own service.

Its basically just a machining operation that will cost you the time to rework the existing parts. JP make it from common white box supplies, but even Diecrest don't have any customers for a 250 gear drive, and there were about 4 million 250 engines made between 1971 and 1992. Al using US technolgy. And we make 350 to 400 hp naturally aspirated 4.1's down here from taxi cap engines, with blister pack rings and bearings and often locally made knock offs of US pistons.


IMHO, its not engineers. Engineers do for 10 dollars what costs you 100. They are like lawyers at the bottom of a lift shaft, a good start culling off the bad ones, but a nessesary evil. I think back in the day, Mao Tse-tung asked his subjects to eliminate all the sparrows out of Shaghai back in the 70's, but it created an insect problem....

There is no way to collapse the quality price trade off in your favour excpet by informing you.

You just have to bite the bullet, and do it. If you've gotten a good price on the rockers, then props to you brother...its becasue an Engineer has gotten off his butt and done the work for you.


I've done the rocker swap here using borrowed FE rockers myself, cost an armload for stuff s relative to a Chevy 350, cheaper here in New Zealand than it is in the USA. Its all supply and demand. The Aussies down here, form import and locally made sources, sold only about 2500 new Small block Chevy 350 engined cars a year from 1971 to 2016, but over 60000 per year in line sixes per year between that time. So its 24 times more expensive to do a Small Block Chevy than it is to do a any in line six down here. That's why the solutions are now Australian and why your getting tcked off. The cost of doing a 5.0 SBF or SBChevy of any kind will keep dropping, and its unlikley anyone here will help collpase the service price equation.

Back in the day, we made for 700 milion dollars a 240 plus hp 15 second streat pounding Ford in line six sedan that would whip the hiney of any Ford car made anywhere, but no one wanted it. They buy Camry's instead. So its just the way things is heading. LOL!


I do my information for free, but not my product. I'm broke as any New Testment apposle except Judas Isacariot on a Thirty pieces of silver performance bonus, spending a percentage of my time helping you guys. Becasue you'll have saved me thousands over the 15 years I've been here. Thanks everyone, and a large amount of info is from engineers here.


Its a take it of leave it deal. If it don't help you none, just don't read my posts. It's nothin I take personally. Some people just like milk, others want to meat.

You've gotten what you need on the rockers, job done for me.

You've now gotten a free rundown of what you need to do to do a SBF 5.0 timing gear conversion with a cheap Indian twin roller chain that British Motor Coprporation designed to win the Montecarlo in 1963, then Toyota used a similar version as did General Motors Australia as they copied it on the updated 1969 Holden 253/308 HQ Monaro engines chain. That chain won the Australian Touring car championhip's 163, 621 mile race in

1966 Morris Cooper S 1275 (130 lap, 500 mile race)
1975 Holden LH Torana L34 308 (163 lap 621 mile race here on)
1976 Holden LH Torana L34 308
1978 Holden LX Torana A9X SS 308
1979 Holden LX Torana A9X SS 308
1980 Holden VC Commodore 308
1982 Holden VH Commodore SS 308
1983 Holden VH Commodore SS 308
1984 Holden VK Commodore SS 308


When the timing chain was down graded to single roller, it still won, but failed at Monza.
1986 Holden VK Commodore SS Group A 304

They then homologated the 1971 HQ Holden 308 timing chain again, and kept winning.
1987 Holden VL Commodore SS Group A 304
1990 Holden VL Commodore SS Group A SV 304
1993 Holden VP Commodore 304


Then the 5.0 Ford twin roller timing chain set, won Bathurst seven (7) times, but the 1967 win in a 289 hp 225 HP V8 also used a similar chain on the 1967 Ford XR Falcon GT 289, so it could be 8 wins

1994 Ford EB Falcon Boss 302
1998 Ford EL Falcon Boss 302
2006 Ford BA Falcon Boss 302
2007 Ford BF Falcon Boss 302
2008 Ford BF Falcon Boss 302
2013 Ford FG Falcon Boss 302
2014 Ford FG Falcon Boss 302


So if you use a timing gear like Mike1157's and an Indian made twin roller timing chain, then you have 7331 miles of race proven reliablity in the chain, and about, oh, 4347 wins on the timing gear set.


Thus end the words of xctasy...
 
I don't like foreign made parts regardless where there made. U.S. FOR ME 100% no offence. and as useual juust basics from you nothing exactly specific.
 
Well the timing chain set has been done and we know how to do it due to the endeavors of mike and will.
If you would like one, I have a feeling you will have to buy a kit and mod it yourself or find someone to help. I'm not a huge fan of the stock timing chain set, but I do feel that it's still pretty beefy for the amount of power most people will be making with their engines. One other option, although I am not sure how hard this would be with the 250 gears, you could get the chain and grove the gears to match. However I am sure those gears are hardened and may not be that easy to machine. idk. But on the rocker arms, I enjoy learning and have no experience with them at all and it has kept my attention and made the wheels up stairs continue to turn. Most that have been chimming in I am sure are the same way. It's not to step on your toes or ride your coat tail. If that is how you feel I do appalogize.

In all honesty, I would absolutely love to take over the business that mike had, but I am in no situation to do so. I will say that down the road I Amy get into it at some point though.
 
Spoke with Hector at rocker arms unlimited Friday. .....he says he will have 1.6 and 1.7 ratio roller rockers ready in 6 to 8 weeks......no prices yet......
 
Allllriiight! I emailed him again yesterday about getting 840 shafts, undrilled, and the proper length for our six. Maybe we've all made enough noise for this option to be at least worth the R&D. They do this and I'll send all my buddies their way. :beer:
 
Cr_bobcat

Man, I have a few questions for what you are doing.
What ratio are you going for?
If going with the .840 shaft, are you gonna drill out the pedestals?
Does going with that size shaft work with the VT Geom?
Have you figured out what the ratio would be by going with those rockers?
Do you need to trim some width off of the rocker? They are a little wider at the fulcrum point than the inline 6 rockers.

64 falconsix

Keep us up to date on those rockers. I think I would be all about getting some 1.7 rockers.
 
I was going to just build my own pedestals. I would also grind the sides of the rockers to narrow them up. My goal is to not bush anything. Was going to just use square stock, drill the correct size holes for mounting screws and the shaft. Once I had one mounted i could doublecheck the geometry before drilling the correct through hole for the pedestal mount screw and again for the oiling holes for the rocker arms as it will all be different than the stock set up.

Edit: Ratio I want is 1.7. If it goes a little higher, so be it. My goal is 500 thou lift, based on the intake flow numbers quoted on the CI website for a modified large log. My cam has 0.294" lift at 264* duration. I don't want to jack the SCR up enough to deal with more duration, mostly because I'm not rebuilding the bottom end right now.
 
Ok I got ya. Was just curious. Once I get out of California I will have my garage back and be able to mess with this stuff more than what I can now.
 
Here is an idea.
Has anyone just thought about making a mounting plate, installing studs, and running high ratio rockers on that?
I know it will be a little costly, but may open the door for rocker options.
 
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