Subject: A rocker gear oiling idea. Anyone ever tried this?
2443TT
A.k.a.: Ian
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posted on November 4th, 2006 at 08:57 PM
A rocker gear oiling idea. Anyone ever tried this?
I had this idea about how to reduce valve train weight, and increase revability at the same time for our pushrod flat 4's. You see I have a lathe now
so i'm dreaming up all kinds of crazy things ...
There would be 2 parts to the setup. 1st is converting the rocker shafts in the heads to have oil supplied to the shafts and rockers by means of an
external oil line, which isn't a problem for any of us that run full flow systems, and turbo's.
The second part is making some custom solid core titanium pushrods. The benefits being that its solid so its stronger than a normal pushrod. As a
result it can also be thinner than a normal pushrod, which is good for improving clearances. Its also way lighter and stronger than aluminium, but has
simular thermal properties so it means 6+7thou cleanrances cold and nice close gaps when hot.
Oil mods:
Starting with a solid shaft valve train, drill from center position of where the pushrods run all the way through the shaft with about a 1mm drill
bit.
Then from each end drill all the way through the shaft with a 4mm drill bit. This will become the new oil gallery which links to the 1mm holes. Both
ends will be plugged with a shortened bolt (so it doesn't block the 1mm oil gallery to the rocker). The other end will be fitted with a -4
From back of the shafts (as most aftermarket shafts are not drilled for mounting studs in the center), counter sync to the 4mm oil gallery. This will
allow oil flow around the mounting stud to the outer rockers.
Last of all, the center of the rocker needs to be drilled and tapped for a oil supply fitting. I'd probably run a steel hardline simular to brake
lines to the edge of the head, and then fit a bulkhead fitting with a -4 jic fitting for oil supply.
Oil supply to lubricating the ends of the pushrods is supplied by the lifter at one end as normal, and by the rocker (but backwards oil flow) at the
other end. Thats provided your rockers have forced oiling that is.
Anyone have any thoughts on this?
dangerous
A.k.a.: Dave Butler Muffin Man
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posted on November 5th, 2006 at 07:03 PM
I am all for, improving valve train control, and reducing lash, and valve train weight is the good place to start.
I like the idea of the oil feed in the rocker shaft, but you might have to dream up a way of getting the oil past the rocker studs.
On the Pauter Type 1 shafts you may have some trouble also, because the shafts are a three piece item, to clear the .375" studs that replace the 8mm
ones.
The Autocraft Pro Series heads used a "spray bar" to lube the springs, valves and pushrod balls. These typiclly have only a 30 to 40 thou hole for
all the lube required,
but in a bush type arm (as opposed to needle rollers), you will need oil pressure.
We used to plug all the pushrods to save weight that the oil adds,
but have since learned that pushrod stiffness is more important than weight,
when it is on the pushrod side of the rocker arm.
Lighter valves , springs and retainers are money well spent.
I like the conical valve springs and small retainers that are aroung now on so called "modern" pushrod(and other for that matter) engines.
Titanium is a good material for these Items, but for a pushrod it would have to be as heavy as the steel ones,
to combat inherent(sp?) flex.
Titanium is a litte more dense than aluminium, but has a fatigue life that is superb compared to aluminium.
The latest V8 supercars use 5/8" diameter pushrods to prevent flex and the resultant harmonics.
If you wanted to use a light pushrod, my preference would be a taper aluminium, but I personally would only use this with light springs.
I like chromoly myself.
Some times a hollow item with some heat treatment can be stiffer,
due to the increased effective surface area that reduces flex.
Lots of Ideas there that are worth the extra discussion.
Quote:
Originally
posted by westi
That's mad Alan.
whatnow
A.k.a.: Henry
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posted on November 20th, 2006 at 09:15 PM
i like the idea and have thought about this one myself.
in my thoughts i would only run the oil gallery from the centre gallery to the rockers on the head side/inside of the rocker as this is where the
friction is. to get the oil past the studs i had thought of running a larger main gallery and waisted studs. if you could get it to seal properly i
think your method would be better. i had thought of piping the oil to one end of the shaft not the centre, again i like your method better.
as far as pushrods i liked the idea of tapered ribbed pushrods, but had no idea as to how to make them without the use of a CNC tools.
dangerous, any idea of where to look for more info in tapered springs etc. i'd never heard of them and like the idea.
henry.
[ Edited on 20-11-2006 by whatnow ]
dangerous
A.k.a.: Dave Butler Muffin Man
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posted on November 20th, 2006 at 10:18 PM
The latest Gen 3 GM V8s use a conical spring, as domany other newer vehicles.
so I would start the search for aftermarket springs and retainers for these engines first.
Upgrades to my current system would be spray bars to cool the springs,
conical springs with small diameter retainers,
and you can now get titanium locks for just about any stem size.
Mine are cyrrently 11/32",
but Mike from North Carolina has donated some 5/16 stem Titanium valves to my racing program,
so those are in my future also.
