97 replies to this topic

[24gerrard]

You have completely missed the point, the stamped rockers totally eliminated the need for rocker shafts along with support towers and all the drillings for oil feed and accurate boring for rockers. It also lowered engine heights (and widths in the case of a 'V').




I have only ever seen single stamped pieces that very typically look like this ..

A sorry, now I know what was described.
This is a pressed rocker for a pillar ball mounting.
I think you will find it still needs oil feed or at least splash.

[Magoo]

Above is a saddle rocker, which a variation on the theme, sort of.

Below is what Clayton Leach invented: the stamped ball-stud rocker arm. The ball is the trick. Hardening and finish are critical. If they are right you can get away with murder. If they are not it won't work at all.



Leach was a brilliant guy responsible for dozens of GM patents and innovations. For an afternoon of fun, do a patent search on his name. Perhaps surprisingly because the stamped rocker is such a marvel of applied engineering, he was not originally trained as an engineer but as a mathematician. I suspect he didn't rise through the ranks of management in part because he was so valuable where he was, doing his thing.

At one time GM was full of technical people of this caliber. In these years it was, in my opinion, the greatest engineering company in the world.

[cheapracer]

This is a pressed rocker for a pillar ball mounting.
I think you will find it still needs oil feed or at least splash.

The oil comes up through a bleed hole in the top of the hydraulic lifter in the block which pushes it up the pushrod and comes through a small hole in the ball dent in the rocker and simply partially fills the rocker up and then gets splashed over the valve from the rockers action. This avoids the need for any oil galleries up to and through the head or passing through the head gasket - brilliance found in simplicity.

[cheapracer]

At one time GM was full of technical people of this caliber. In these years it was, in my opinion, the greatest engineering company in the world.

Not just GM and not just engineers ie; designers.

[bigleagueslider]

Above is a saddle rocker, which a variation on the theme, sort of.

Below is what Clayton Leach invented: the stamped ball-stud rocker arm. The ball is the trick. Hardening and finish are critical. If they are right you can get away with murder. If they are not it won't work at all.

Leach was a brilliant guy responsible for dozens of GM patents and innovations. For an afternoon of fun, do a patent search on his name. Perhaps surprisingly because the stamped rocker is such a marvel of applied engineering, he was not originally trained as an engineer but as a mathematician. I suspect he didn't rise through the ranks of management in part because he was so valuable where he was, doing his thing.

At one time GM was full of technical people of this caliber. In these years it was, in my opinion, the greatest engineering company in the world.

magoo,

I agree that Clayton Leach was brilliant engineer. However, I would propose that the most difficult aspect of that stamped rocker design was not the spherical pivot, but the metallurgy at the valve end tip. The local contact stresses at the tip were much more severe than those at the pivot interface.

I would also agree with the other posters that there are many other examples of innovation in piston engines. I brought up the example of Clayton Leach because he did much of the stamped steel rocker development on his own. But as for other innovations, I would definitely include cast iron crankshafts, powdered metal conrods, plastic intake manifolds, or solenoid fuel injectors.

slider

[cheapracer]

But as for other innovations, I would definitely include cast iron crankshafts, powdered metal conrods, plastic intake manifolds, or solenoid fuel injectors.

slider

But they are all material improvements that didn't change an engine's design, the stamped rocker was a whole new method that changed many areas of the engine's design - or rather eliminated areas.

[24gerrard]

But they are all material improvements that didn't change an engine's design, the stamped rocker was a whole new method that changed many areas of the engine's design - or rather eliminated areas.

I dont know if I would completely agree Cheapy.
Some of the vintage engines we work on have external piped oil feeds and few oilway drillings.
The pillar mounted rocker is not that far removed from a shaft mounted one.
It was a huge improvement in mass production techniques at the time.
GM also produced a fully sealed (welded together) engine, was that from the same designer?

[cheapracer]

Some of the vintage engines we work on have external piped oil feeds and few oilway drillings.

Oilways, thread tappings, oil unions and onions, pipes and inevitable oil leaks ... thats better than nothing at all? On what planet?

The pillar mounted rocker is not that far removed from a shaft mounted one.

A stud, a half ball and a stamped bit of steel with very minor machining process, a pushrod with drilled ends and a lifter with a drilling.

Vs

Mutiple pillars requiring machined bore and oilway drilling, shaft/s, circlips, thrust springs, thrust washers, bronze bush and/or machine bored rocker, the rocker itself and a cylinder head with multiple drillings/plugs and casting considerations for those as well as the extra drillings in the block to supply.

Recently in this forum arguing simple reality is becoming a real humourless drag.

Edited by cheapracer, 26 November 2011 - 10:29.

[Magoo]

magoo,

I agree that Clayton Leach was brilliant engineer. However, I would propose that the most difficult aspect of that stamped rocker design was not the spherical pivot, but the metallurgy at the valve end tip. The local contact stresses at the tip were much more severe than those at the pivot interface.

Not really. The valve pad is much of a muchness with most any non-rollerized rocker arm. See the Chevy and Pontiac V8's OHV predecessors at GM: Chevy stovebolt I6, Buick straight 8, OHV Cadillac and Olds.

Another key innovation of the SBC was the block casting, which was performed upside down and required only four sand cores, where the Cadillac OHV V8 used 24 and the Ford flathead V8 over a dozen. Arguably the first true thinwall block casting. The process was worked out by John Dolza, who was also the DRE (as we would call it today) for the Rochester mechanical fuel injection system. Dolza was an Italian immigrant who came to the USA in the '20 with two graduate technical degrees. One of his early assignments at GM was the original Buick straight 8, to take this ramble full circle. Another absurdly brilliant person whose name one can spend an afternoon enjoyably patent searching.

[MatsNorway]

Recently in this forum arguing simple reality is becoming a real humourless drag.

Its the chance of the seasons. Its a phenomenon occuring in many of my other forums. Most noticeable on the ones that got dark vinter nights (and days if you happen to live in shitty northic areas)

[Tony Matthews]

... dark vinter nights (and days if you happen to live in shitty northic areas)

Hey Mats! I feel really sorry for you - I don't like the short days and early nights, but it must be much worse for you...

Edited to add - Only 3½ weeks to the shortest day!

Edited by Tony Matthews, 26 November 2011 - 21:39.

[Lee Nicolle]

Hey Mats! I feel really sorry for you - I don't like the short days and early nights, but it must be much worse for you...

Edited to add - Only 3½ weeks to the shortest day!

Come to Oz Tony, 3 1/2 weeks to the longest day, lovely 27 deg C here at the moment.

[Kelpiecross]

Come to Oz Tony, 3 1/2 weeks to the longest day, lovely 27 deg C here at the moment.

Yes, but - after it has just rained for a week with no sign of the sun at all.

[Tony Matthews]

Come to Oz Tony, 3 1/2 weeks to the longest day, lovely 27 deg C here at the moment.

A very nice thought, Lee, I could do with some sun! Haven't been to Oz since 1990, I would like to see more... I don't beleive what Kelpiecross says, he's just trying to put me off!

[Vanishing Point]

I dont know if I would completely agree Cheapy.

The pillar mounted rocker is not that far removed from a shaft mounted one.

It is when it's used on egines with solid cam followers and the valve clearances need setting properly within a few thou's using a feeler gauge like on the old Vauxhall Viva.In which case it would be interesting to see how Cheapracer's oil feed idea works and I'll leave him to adjust the tappets while I find something with a 'proper' rocker shaft/rockers and proper adjustment screw and locknut set up to adjust instead like on the Triumph 2.5 engine (or even better a big block MOPAR ).I'm obviously not the only one who disagrees with Cheapracer's ideas.

http://www.ehow.com/...-big-block.html

Edited by Vanishing Point, 27 November 2011 - 18:34.

[Tony Matthews]

the Triumph 2.5 engine.

Ah yes, the engine that conquered the World...

[Vanishing Point]

Ah yes, the engine that conquered the World...

See above.No surprises that MOPAR used rocker shafts to conquer GM.

[cheapracer]

Ah yes, the engine that conquered the World...

I weakened for a moment, I couldn't help myself but to look at his post to see how he could possibly bring a Triumph 2.5 engine into this conversation - 2 minutes more of my life wasted which i won't make the mistake again but here we go ...

In which case it would be interesting to see how Cheapracer's oil feed idea works and I'll leave him to adjust the tappets

Nothing changes about the oil feed, why would it, and you screw the locknut on the stud up or down to suit the clearance just the same as for the hydraulic lifter - nothing changes.

Hundreds of thousands of Oz and American 6 and V8 street machines for 50+ years have been changed over to "solid cam" with nothing more than the fitment of the cam and solid lifters with no other changes required (some option better rockers, roller rockers, roller rockers on individual posts etc.).

Next time why don't you actually Google or Wiki for some facts first before you offer another post of completely uninvestigated nonsense.

Edited by cheapracer, 28 November 2011 - 04:34.

[Vanishing Point]

I weakened for a moment, I couldn't help myself but to look at his post to see how he could possibly bring a Triumph 2.5 engine into this conversation - 2 minutes more of my life wasted which i won't make the mistake again but here we go ...




Nothing about the oil feed changes, why would it and you screw the locknut on the stud up or down to suit the clearance just the same as for the hydraulic lifter. Hundreds of thousands of Oz and American 6 and V8 street machines for 50+ years have been changed over to "solid cam" with nothing more than the fitment of the cam and solid lifters with no other changes required (some option better rockers, roller rockers, roller rockers on individual posts etc.).

Next time why don't you actually Google or Wiki for some facts first before you offer another post of completely uninvestigated nonsense.

I didn't need to google anything because in those examples I was just going by experience long before the internet existed.I decided as a teenager then that the GM idea,on the Viva,was just a cheap rate,badly thought out answer,to the right way to locate the rockers properly,on a pushrod engine,compared to the Triumph.Which seems to be confirmed by the up to date internet method of investigation in which someone has made some similar positive comments about the shaft mounted rockers on my obviously 'preferred option' of Mopar engineering (like the Triumph) when compared to the idea of pedestal mounted rockers.

I know you just (have to) tighten the rocker securing nut on the pedestal type as a compromised way of setting the valve clearances.That's because the idea doesn't locate the rocker in the centre in the same way that using a shaft does and therefore can't be adjusted in the correct place at the pushrod,using the correct type of fine adjustment provided by the adjustment screw of the typical shaft type rocker.

The idea of pedestal mounting,instead of using a rocker shaft,also doesn't locate the rocker as good as the shaft arrangement does,which might explain some of the comments about the suitability of pedestal mounted rockers for use at higher engine speeds,compared to shaft mounted ones,in the article concerning shaft mounted rockers on MOPAR engines.

Going by the same experience I don't remember the Viva having any oil supply bled from it's solid cam followers to the pedestal mounted rockers.But having had enough of just trying to set the tappet clearances it's not surprising that I probably couldn't be bothered with looking any further into the workings of the motor.So on that issue I'm happy to accept the correction if I'm wrong.

Edited by Vanishing Point, 27 November 2011 - 21:51.

[Lee Nicolle]

See above.No surprises that MOPAR used rocker shafts to conquer GM.

Lets get real. Mopar used tin rockers on a shaft from about 1968. Only 273s had a proper shaft rocker system after that they were all tin rockers on a shaft and hydraulic lifters

And I like a lot of people have run race engines over 6500rpm with solid lifter cams and standard rocker posts and tin rockers. Doing this mushrooms the valves somewhat, as does using a sliding rocker with big cams.
I use roller rockers on all high performance engines I build these days as they are near bulletproof. And they are these days readily advailable for conservative dollars.
Mild street engines are fine with standard rockers, though I generally replace them all as I go as they are generally worn out due to age.

[bigleagueslider]

I didn't need to google anything because in those examples I was just going by experience long before the internet existed.I decided as a teenager then that the GM idea,on the Viva,was just a cheap rate,badly thought out answer,to the right way to locate the rockers properly,on a pushrod engine,compared to the Triumph.Which seems to be confirmed by the up to date internet method of investigation in which someone has made some similar positive comments about the shaft mounted rockers on my obviously 'preferred option' of Mopar engineering (like the Triumph) when compared to the idea of pedestal mounted rockers.

I know you just (have to) tighten the rocker securing nut on the pedestal type as a compromised way of setting the valve clearances.That's because the idea doesn't locate the rocker in the centre in the same way that using a shaft does and therefore can't be adjusted in the correct place at the pushrod,using the correct type of fine adjustment provided by the adjustment screw of the typical shaft type rocker.

The idea of pedestal mounting,instead of using a rocker shaft,also doesn't locate the rocker as good as the shaft arrangement does,which might explain some of the comments about the suitability of pedestal mounted rockers for use at higher engine speeds,compared to shaft mounted ones,in the article concerning shaft mounted rockers on MOPAR engines.

Going by the same experience I don't remember the Viva having any oil supply bled from it's solid cam followers to the pedestal mounted rockers.But having had enough of just trying to set the tappet clearances it's not surprising that I probably couldn't be bothered with looking any further into the workings of the motor.So on that issue I'm happy to accept the correction if I'm wrong.

Vanishing Point,

The cost reduction innovations in the GM production cast iron small block V8 heads was truly impressive. Besides the "tin" rockers, there was the press fit rocker studs, the elimination of separate valve guides, the "umbrella" oil seals, the elimination of valve seats using local induction hardening of the cast iron head, the ability to set the valve clearances easily in a mass production process, and designing the valvetrain geometry such that all of the machined features in the head and block were parallel and coplanar (rocker studs, valve guides, lifter bores, etc.). Balancing these cost compromises with performance is a very difficult task.

slider

[Grumbles]

Recently in this forum arguing simple reality is becoming a real humourless drag.

There are only two things we need to do to make "Dumb and Dumber" virtually disappear. The first is to use the "ignore" function and I'd guess that most of us have already done that.
The second one is a bit harder, all of us (and I mean ALL) have to resist the temptation to reply to their half-arsed drivel. If we can all do that then both the writers and the drivel will become invisible and hopefully the threads will return to normal.

Be strong.

[Greg Locock]

OK, and on that note can people resist quoting them in their replies? Serial offenders will get hit over the head with the same baseball bat. I've had enough.


Here's how to do it. Go to My controls, look down on the left hand side to Manage Ignored Users. type their names in the box. easy

[cheapracer]

Here's how to do it. Go to My controls, look down on the left hand side to Manage Ignored Users. type their names in the box. easy

Or click on their name, "view member profile", "options > options", "ignore user", "Update Ignored Users".

[packapoo]

I seem to rememeber they ran one in a Targa Tasmania but i didn't hear much more or can't remember much more (damn you Johnny Walker).

I got a headache trying to work out the patent, try again tomorrow ...

http://www.google.co...A...mp;q&f=true

Loss of memory - must've been bootleg.
(There're some pretty good Black Label clones wandering around I seem to recall.)

[Tony Matthews]

The second one is a bit harder, all of us (and I mean ALL) have to resist the temptation to reply to their half-arsed drivel. If we can all do that then both the writers and the drivel will become invisible and hopefully the threads will return to normal.

Be strong.

And if you are driven to reply, don't quote a section of their rants. If you do, those of us who have them on 'ignore' get a teasing glimpse of their posts, sometimes enough to think "I'll just have a quick look..." and be drawn into the madness. Yes, be strong!

[Catalina Park]

And if you are driven to reply, don't quote a section of their rants. If you do, those of us who have them on 'ignore' get a teasing glimpse of their posts, sometimes enough to think "I'll just have a quick look..." and be drawn into the madness. Yes, be strong!

Says the man that quoted the bit about the Triumph 2.5 motor.

[Tony Matthews]

Says the man that quoted the bit about the Triumph 2.5 motor.

My post carries so much weight because I too have sinned...

[Catalina Park]

My post carries so much weight because I too have sinned...

You are forgiven. I have done the same thing too.

But to change the topic to experimental things (instead of just mental)

[Magoo]

Because the standard 4 cyl Mini was overpowered in many situations. The British motoring public was unprepared for 0-60 times in the 22-second range.

[Tony Matthews]

The British motoring public was unprepared for 0-60 times in the 22-second range.

Anything under 30 seconds can lead to nose-bleeds and impotence.

[Bloggsworth]

Ah yes, the engine that conquered the World...

Specially with fuel injection....

[JtP1]

Ah yes, the engine that conquered the World...

Probably from the noise of the tappets. Show me a Triumph push rod engine from that period and I will show you an engine with noisy tappets and most likely worn thrust bearings, unless it was built last week.

[Magoo]

Anything under 30 seconds can lead to nose-bleeds and impotence.

[Vanishing Point]

Specially with fuel injection....

Just throw the injection system in the skip and put a set of webers on it with all the time you've saved setting the tappets compared to a Viva.

Edited by Vanishing Point, 28 November 2011 - 18:33.

[Vanishing Point]

Probably from the noise of the tappets. Show me a Triumph push rod engine from that period and I will show you an engine with noisy tappets and most likely worn thrust bearings, unless it was built last week.

I can only remember one and that was caused by someone who'd forgotten to put the oil sealing plugs in the ends of the new rocker shaft when the engine was rebuilt so it not only had noisy tappets but a completely scrap rocker shaft too .

But you're right about the bottom end knocking out in no time probably because of somone who'd convinced his bosses that 4 mains were enough for a straight six motor.But that still doesn't make those post mounted rockers any better compared to a 'proper' rocker shaft set up.

[Magoo]

The oil comes up through a bleed hole in the top of the hydraulic lifter in the block which pushes it up the pushrod and comes through a small hole in the ball dent in the rocker and simply partially fills the rocker up and then gets splashed over the valve from the rockers action. This avoids the need for any oil galleries up to and through the head or passing through the head gasket - brilliance found in simplicity.

You may find this interesting/amusing... of course, the ball-stud rocker was originally devised by Clayton Leach, an engineer with Pontiac. And as the story also goes, Chevrolet also obtained permission to use the setup so it first appeared simultaneously on the 1955 Pontiac and Chevrolet V8s -- two distinct engines with philosophical similarities but significant detail differences.

Leach originally designed his ball rocker to lubricate through the rocker stud, and this was the system used on the Pontiac, via a longitudinal oil gallery in the head casting and drilled studs that pressed into the galllery. Meanwhile, the Chevy oiled the rocker arm up through the lifter via tubular pushrod. Pontiac, whose chief engineer when the V8 was introduced, Ed Delaney, was a belt-and-suspenders kinda guy (and button shoes, it is said) didn't abandon the separate oil galley until 1964. The Pontiac also employed reverse cooling in its original form.

[Catalina Park]

Because the standard 4 cyl Mini was overpowered in many situations. The British motoring public was unprepared for 0-60 times in the 22-second range.

Thanks!

[cheapracer]

The Pontiac also employed reverse cooling in its original form.

Radiator in the trunk/boot?

[Tony Matthews]

A following wind was essential.

[Fat Boy]

Anything under 30 seconds can lead to nose-bleeds and impotence.

Maybe that's my problem....

[cheapracer]

Maybe that's my problem....

Tissues and hold your head back for a minute will stop nose bleeds.

[GrpB]

Not sure about the great benefits of a one piece piston/rod, but if you had to make something like that work, instead of rocking the piston/rod you could make the 'rod' big end a slot perpendicular to the bore axis with a width equal to the stroke. Use an assembled crankshaft with roller bearings instead of journals and as long as rpm/inertial loads don't get too high it could work with the big end roller bearing translating in the slot. A direct acting cranktrain, as it were.

[Grumbles]

Not sure about the great benefits of a one piece piston/rod, but if you had to make something like that work, instead of rocking the piston/rod you could make the 'rod' big end a slot perpendicular to the bore axis with a width equal to the stroke. Use an assembled crankshaft with roller bearings instead of journals and as long as rpm/inertial loads don't get too high it could work with the big end roller bearing translating in the slot. A direct acting cranktrain, as it were.

That mechanism is known as a Scotch Yoke, and is notable that in that it produces pure harmonic motion. One engine that I know of that has used it is the two-stroke horizontally opposed Bourke Engine. Like lots of other alternative designs it has failed to live up to expectations.

[Greg Locock]

It is interesting that the Bourke fanbois have latched onto the scotch yoke as being so important, with various odd claims made for it. In reality it allows crankcase supercharging, with an opposed piston engine, but that seems to be the only real advantage.

[gruntguru]

I have only ever seen single stamped pieces that very typically look like this ..

Search your memory cheapy. I'm sure youve seen one of these.

[gruntguru]

I seem to rememeber they ran one in a Targa Tasmania but i didn't hear much more or can't remember much more (damn you Johnny Walker).

I got a headache trying to work out the patent, try again tomorrow ...

http://www.google.co...A...mp;q&f=true

I doubt they ever got as far as powering a car with one.

Some friends of mine were thinking of investing and asked me to accompany them on a guided tour with the "inventor". I advised them to run a mile.

The little spider things pushing the pistons up, actually roll past each piston in turn.

[gruntguru]

It is interesting that the Bourke fanbois have latched onto the scotch yoke as being so important, with various odd claims made for it. In reality it allows crankcase supercharging, with an opposed piston engine, but that seems to be the only real advantage.

For me the main advantage was the lightweight, short, rigid assembly that replaces two pistons and two conrods. Piston-bore alignment, short skirts, zero side thrust are other key benefits.

Drawbacks not often mentioned are the minimum 4 cyls required for an even-firing 4 stroke and the imbalance of such an arrangement.

Edited by gruntguru, 05 December 2011 - 01:33.