high ratio rocker arms

I'm a little confused hear. I would like a set of rockers adjustable and purfer roller. Is anyone one producing a full set saft and pedastools as well. I do have a non adjustable set anyone can have for a core if they wish pm me.
 
64 200 ranchero":3pqfaahy said:
maybe these guys can help rockerarms@rockerarms.com http://www.rockerarms.com/pages/products.html
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This was a great recommendation - I called rockerarms.com and the man I talked to worked with Mike at Classic Inlines. He was extremely helpful - they have adjustable 1.65 ratio rocker arm assemblies for I6 at a good price. And the best part for me is that they're located in Redding, CA which is only an hour from my place. Xctasy's information about high lift rockers is intriguing - but right now my head is finished and I don't want to buy new valves and springs.
 
Odd. I emailed them and was told they only had 1.6 ratio. They quoted a price of $400 with core exchange. $425 if you have non-adjustables to exchange. Now I'm curious as to what is going on there. That's just too much money for rebushed 1.5s.

Who did you talk to and what kind of price did they quote you? I was emailing back and forth with Hector.
 
cr_bobcat":3ljg5pna said:
Odd. I emailed them and was told they only had 1.6 ratio. They quoted a price of $400 with core exchange. $425 if you have non-adjustables to exchange. Now I'm curious as to what is going on there. That's just too much money for rebushed 1.5s.

Who did you talk to and what kind of price did they quote you? I was emailing back and forth with Hector.
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I plan on driving up there some time next week - I'll find out what they have and report back.
 
Here's an old hot rodder technique for modifying shaft mounted rockers.

When you rebush a rocker you can make the pushrod side shorter and the valve stem side longer to get more ratio. But did you know that there's a little more ratio left in a stock Ford shaft rocker without rebushing?

Take a look at the tip where the rocker contacts the valve stem. Usually the wear pattern is toward the inside of the rocker. But if you move the contact area to the furthest point out on the rocker, you have effectively lengthened the valve stem side of the rocker. It simply makes the lever longer on that end. It's not much, but it's something.

Here's how: First, inspect your rockers to see if you have any more room left to move that contact area. If so, measure roughly how much further outboard that contact can go. Let's say you come up with .050". Now, if you open up the mounting holes on the rocker pedestal by elongating them slightly, you can move it away from the valve stems by that much.

The rocker is still the same, but you've changed the effective ratio by moving the contact point a bit. The lever arm on the valve stem side is acting as if it is longer because you're using more of that end.

How much gain in ratio? Like I said, not a lot, and the ratios don't remain constant anyway because of the arc of movement. That's just the simple geometry of it.

Since at the moment I don't have a rocker to measure, let's do this notionally. Lets' say for example, the center of the rocker shaft is 1.100" away from the pushrod ball and the center of the contact point on the valve stem is 1.650" from the shaft centerline, your ratio is 1.500:1. If we shove the rocker shaft away form the valve so that the contact point is hitting the valve stem .050" further out, the long end is now effectively 1.700" and the new ratio is 1.545:1.

But it does add up in two ways. First, the increase in ratio moves the .050" lift measurement on the cam to a little further out on the lifter ramp. That makes the effective duration slightly longer. Secondly, the added ratio translates into a bit of extra lift. if the cam lift is .250" the valve lift would go from .375" to .386". It won't be much, but that extra .011" could be good for a few hp on a stock cam engine.

Four things - it won't net you much extra lift because there's only so far you can go; secondly, you have to make sure the pedestals don't walk after elongating those holes to move the pedestals back; third, you have to make sure the oiling hole is not either blocked or uncovered; and finally, moving the rocker shaft also moves the pushrod angle and you have to make sure they aren't rubbing or hitting the openings in the head. Alternatively, you could bush the rocker shafts, offsetting the bush to move the rocker back.
Good luck!
 
Howdy All:

WOW!!! What a no-brainer! Thanks Jack. I guess it takes an "Old Hot-Rodder" to come up with the simple/easiest/cheapest way. You can bet I'll be using this idea on my next engine. This idea needs to be highlighted with a new post heading.

Have you ever used this idea on an engine, Jack? Did any of the "Look-out-fors" you listed come up at all? That tweak will even work on non-adjustable rockers. Any body that tries this please report your experience and results

.011" increase in lift, by its self will probably not be noticed, but added to other inexpensive valve job upgrades it would.

Thanks again, Jack! Far and away the Ah-ha! of this day.

Adios, David
 
OP, Jack, everyone. Nice work.

I still have nothing to add, but will re-note for re-clarity my earlier information, with some simple amplification. It would be nice if people actually read this stuff. I'm trying to help, but its very stressfull seeing people "not get it". But then, its possible yall do, but I'm missing it.

Anyway

I think this covers in part what Jack is saying, graphically. On the basis of what increases lever arm and valve lift, you have to look at the diagrams, and work it out yourself.


MustangSix":edelmeth said:
....

Since at the moment I don't have a rocker to measure, let's do this notionally. Lets' say for example, the center of the rocker shaft is 1.100" away from the pushrod ball and the center of the contact point on the valve stem is 1.650" from the shaft centerline, your ratio is 1.500:1. If we shove the rocker shaft away form the valve so that the contact point is hitting the valve stem .050" further out, the long end is now effectively 1.700" and the new ratio is 1.545:1.

.....
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images


Examples.

NB// On stock Ford small sixes, the rocker arm shafts are not bushed, but can be.


1. B series Volvo engines, ohv fours and sixes with the "nominal" giant 4.165 bore spacing engine


For all engines in general
When D1 is least,
the lever arm gives D2 the most lift.


165VS145RATIO.jpg


2. The A series 948/998/1275 engines

http://www.ausmini.com/forums/viewtopic ... ht=rockers
drmini in aust

PostPosted: Fri Oct 16, 2009 8:54 pm

Location: near Baulkham Hills, NSW

I tested S rockers, pressed steel rockers, and the late sintered ones.
I found the S ones gave 1.16:1,
pressed steel 1.21:1, and
sintered 1.18:1.
All were measured on the same 12G940 head, with an RE13 cam (0.290" lobe lift) fitted.

I like the pressed steel (round pad) ones, with 0.44" offset bushes in I can get them up to 1.31:1 ratio. And their pads are harder than the S rockers.
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IMGP1558.JPG




Note:If the rocker shaft stays the same diameter, then you'll have to find rocker arms with a bigger inside diameter. FE rocker arms are bigger ID.

You use easily avaliable bronze bushes but have them offset ground. The lift gain is had by having a difference between the shaft diameter and the rocker bush diameter, and then offsetting the difference. So if you have a typical approx 840 thou diameter rocker (Packard, FE Ford) and a small diameter Small Six (144-170-200-250) of about 748 thou approx, then if everything was in order, you would have an ability to reduce the FE rocker ratio from a stock 1.76 to as little as 1.63 to as much as 1.90 by using a 70 thou offset. In practice, the FE rocker on the small six is no longer 1.76, but 1.65 after its centered on the stock 4.76" tall valve, then bushing can take it up to 1.76 or 1.78:1 again. It just depends where you place the offset bush. There are a host of other matters, but if you can just see what happens as per the diagrams, you'll be able to do it yourself without spending 600 bucks plus.

Remember, the art of pushrod rockers is an American institution that it understood fully by all our OHV race engineers, but it seams the English and Swedes fiddle around with it on there 4 cylinder cars A LOT MORE THAN WE DO OUR SIXES. Its hard for me to fathom that the engines that won Le Mans against Ferraris with "better" engines did so with just stock FE and modfied Windsor valve gear engines which were designed by the same people who threw together the small six in 18 months. It would be better that a few tricks from the FE was used in conjunction with normal small six rebuilding work than a few extra bucks go down the gurgler on roller tip rockers that probably don't even de load the valve tip.

100077.jpg


On A and B series BMC engines, (and on Small sixes ) you can re bush

P0003459.jpg


the shaft pedastools (can be rebushed with a single diameter bush, shifted 70 thou in this instance)


or


the rocker arm (shifted 44 thou to create a reduced D1 lever arm so the overal ratio goes up from 1.21:1 to 1.31:1).


offsetting from an FE to a Ford Six bush size (840 thou minus 748 thou ) allows a potential of nearly 92 thou offset to increase lift by reducing the pushrod to rocker shaft pivot distance. In fact, 60 to 70 thou is possible.

See http://www.mgbmga.com/tech/mgb16c.htm
 
It all makes sense to me. I get it. I already have the math done too (at least for the sizw of the offset, not for valve stem length). But lingering things like how to handle oiling are bothering me. If I bush the rockers, do i have drill th oiling home through then go in with a dremel and slot the bush for a new oil channel? Or do you press in a bush from each side, preserving the existing channel?
 
I think rather than all you guys concentrating on this rocker issue some of you need to take on another part of these engines parts so we have good coverage of all parts we need since the death of MR. MILLER. AND HIS FAMILY NOT GOING TO PERSUE the business. jmo
 
BCOWANWHEELS":qeo6qn0p said:
I think rather than all you guys concentrating on this rocker issue some of you need to take on another part of these engines parts so we have good coverage of all parts we need since the death of MR. MILLER. AND HIS FAMILY NOT GOING TO PERSUE the business. jmo
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Oh we've known that here for a long time.
And with Classic Inlines gone now too we are discussing options.
 
I'm actually doing something similar for a B-series engine for my MGB GT by making new pedestals.

Here I go again, trying to squeeze something out of another obsolete engine...... :roll:

One more thing. If you look at the pics of the Volvo rockers that Deano posted, note the adjuster length. The D1 length is the distance from the ball, not the outside of the rocker. A longer pushrod moves the ball higher and shortens D1. You gotta measure from that point to get an accurate assessment.
 
xctasy said:
You use easily avaliable bronze bushes but have them offset ground. The lift gain is had by having a difference between the shaft diameter and the rocker bush diameter, and then offsetting the difference. So if you have a typical approx 840 thou diameter rocker (Packard, FE Ford) and a small diameter Small Six (144-170-200-250) of about 748 thou approx, then if everything was in order, you would have an ability to reduce the FE rocker ratio from a stock 1.76 to as little as 1.63 to as much as 1.90 by using a 70 thou offset. In practice, the FE rocker on the small six is no longer 1.76, but 1.65 after its centered on the stock 4.76" tall valve, then bushing can take it up to 1.76 or 1.78:1 again. It just depends where you place the offset bush. There are a host of other matters, but if you can just see what happens as per the diagrams, you'll be able to do it yourself without spending 600 bucks plus.

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.
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Well, you really need watch out for the alignment of the rocker at half-lift. At this stage, you want the rocker-arm to valve geometry to be close to 90* in order to have proper valve train geometry, otherwise you lose lift. I've found this article to be rather useful in understanding the problem.

http://www.hotrod.com/how-to/engine/ctr ... -geometry/

I ordered a stock 1.76 non-adjustable rocker to play with to see if I can't get the geometry right. Once I've gotten some measurements I'll have a better understanding of what I'm up against.

In the meantime, I've sent emails to both Yella Terra and RAS with some questions but neither seem to be responding at all. It's been a couple of days and I haven't heard a peep out of them. This doesn't necessarily hold up my build at all as I've got enough components around to move forward with my stock adjustable 1.5s and mock up a high ratio setup on one of my other 2 heads that I have sitting around.
 
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