Home grown solid rocker shafts

[oprn]

True!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[oprn]

The time has come to do the same thing to my type 4 engine. A quick search on this site shows nothing for aftermarket fixes but there are rumblings and grumblings about spacers in the engines that have hydraulic lifters. Well both of my type 4 engines are solid lifters...

First observations are that the spring VW put between the rockers is truly very weak! Some guys it seems are doubling up the springs... The next thing that struck me is that the offset between the pushrod and the valve stem on one of the rockers on each cylinder is a lot more than the type 1 engine! The two combined and I think I am beginning to understand why this engine has so much more random click and clatter than I am used to with the old type 1 engines.

Next, The rocker shafts on the type 4 are 20mm diameter and the type 1 is 18mm. So - all those nice shims I got don't work on this engine! Ah well, It just means that I have to hone my machining skills, lots of trim and try to get a lose zero side play. Previously I was using 1" x 5/8" bushings and opening the inside diameter to 18mm. It looks like 1" x 3/4" bushing will be the ticket here as it won't take much to open them up to 18mm.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[madmike]

Kind of Ccchilllllly this morning to be wrenching
_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[oprn]

Ah!! Not so much! It's only a couple degrees below freezing right now and snowing. The forecast is for -21*C by morning but I put in the time last fall and finally hooked up my under floor heating in the garage. The floor in there is a nice balmy 18*C right now so... pretty sweet wrenching! I should have done that years ago!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[madmike]

The under floor electric or hot water?
_________________
'Black Ice'Drag Buggy 'Turbo'
Rail Buggy 1915 turbo
76 Drag/Street bug 2180cc 'Turbo' 11:85 @113 mph"If I go any faster I'll burn up the Hamster" ,gets 28 mpg. also 10/09/22 11.90 @115 mph
"If I'm ever on Life Support,UNPLUG Me, Then Plug me back In see if that Works"

[oprn]

Hot water, trenched it over from the house boiler.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[raygreenwood]

[oprn]

Thanks for the confirmation Ray!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[mark tucker]

if you make a solid spacer for the oe shafts eye wood use good quality C clips to hold the spacer in the oe groove's so it can not float back and forth and use a min of a .040 hard shim agnist the C clip. if desired you can make another aluminum spacer to encapsulate the clip so it cant fall out even if it breaks. there is plenty of room to do that.(that could be done with the spacer if desired, but harder to do right. you could also make a steel spacer and welded it to the shaft witch makes the shaft stiffer.( stiffer shaft is better, but you may not/ probably donut need it.)

[oprn]

Thanks Mark, I will bare that in mind next time I am working on type 1 rocker shafts.

Here is the spacer and the spring it replaces.

Very fiddly process but the first one is done.

_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[raygreenwood]

Well....not sure what all you have done, but the "fiddly" part ma6 not be totally done.

So when I set up solid spacers....we have two measurement items that need to be addressed simultaneously.

This is the stack up:

Keep in mind that everything I am writing is type 4 centric.

Rocker stand | shim | rocker arm | shim | spacer | shim | rocker arm |shim | rocker stand

The two measurement items are:

1. The ~ 0.003" tolerance required in that stack up on the rocker shaft

2. Centerline geometry of the valve adjusting screws to the valve stems.

Notice that I'm my stack up....I have a shim between the rocker shaft stand and the rocker arm at each end.

The reason I do this is because I want to protect the parts that are not deemed to be "consumable" wear parts. Meaning....the rocker stand and rocker arms. We can replace shims.

The problem is that in many cases, putting a shim between rocker stand and arm may not allow you to get the adjusting screw Centerline correct on the valve shim. If you keep the shim thin, you may still have to lap the end of the rocker arm to get a favorable adjusting screw Centerline and still use a shim between stand and rocker arm.

While using a shim in this position is favorable wear wise....it's also great because using a thicker or thinner shim can also allow you to tune the adjusting screw Centerline.

So I set up this way.

1. First, generally install your rockers and pushrods and establish basic valve and pushrod geometry. Meaning....are your pushrods the correct length and any required rocker stand shims correct?.

2. At this point in time, you should have already ground the underside of the rockers for clearance for your swivel feet if you are using them. This is the same process for factory adjusting screws too.

3. Set up and adjust your valve lash and lock the nuts. Remove the rocker shaft and arms.

4. Measure how far under each rocker are either the swivel feet or stock screws protrude.

5. Take an old factory valve adjusting screw and chuck it into a drill and with a file or grinder....grind a shallow point on the end on the Centerline. Deburr it so it's not razor sharp or fragile.

6. Install this screw in each rocker arm in turn....and screw it in so it protrudes the exact same amount your properly adjusted factory screw or swivel foot will from your earlier measurement. Lock the nut.

This Centerline point will now point to exactly where on the tip of the valve stem.....the Centerline of your valve adjusting screw will be.

Now you can adjust the thickness of the shims between the rocker arms and spacer and/or rocker arms and rocker stands....until you have both things.....the 0.003" tolerance in the stack up....and the Centerline of the valve adjusting screws just off center in one direction or the other from the Centerline of the valve stem.

How far off center? I always use anywhere from 0.5mm minimum to about 1mm maximum. Ray

[oprn]

Good stuff!

Would there be any advantage to a wee groove on the side of the rocker next to the block aimed at the valve tip/stem for extra lube between the two and maybe a little splash on the valve stem? A bit like the piston squirters VW recommended on the big end of the rods. Maybe .006" wide and .003" deep...
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[SGKent]

I went back to springs. It is easier to get alignment. Porsche used them with the shims on 914-4 engine and without the shim on 912e engines. Several racing engine manufacturer with pushrod V8s used them in the 70's as well. I don't think there will be a problem. I was able to easily adjust the towers to get the rocker screws in the perfect spot too, unlike the spacer unless you start grinding them down .001" at a time on a magnetic plate, and trying to set up the rocker arms perfectly with a plethora of shims. I'll let you know how it goes but I don't see any problems.

Re rge oiler - the screw threads leak, oil is provided to the screws. Anytime the rocker arms are off the screw should be removes and the passages on each arm well flushed.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[RWK]

The rocker arms should be squared up to the shafts, I have seen close to .006, out of sq. some not much, one shown in pic has been ground .005 and still show witness marks, makes shims, spacers and solid shafts easy and correct. Doesn't hurt to align oils hole with grooves in shafts with your dremel or pencil grinder only some actually intersect, may improve guide oiling also. I offer this service, PM if interested.
T4 shown 10mm rocker

_________________
73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530

[raygreenwood]

[RWK]

Yes, lapping will improve surface finish, problem still is squareness to shaft, lapping won't correct this. once you have full bearing all around things improve when using spacers.
_________________
73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530

[raygreenwood]

[oprn]

All good valuable tips! Thanks for the support that will make this thread useful not just to me but others in the future.

Yes RWK, I do have one rocker arm so far that has witness marks that indicate it is not quite square on the one side. I don't have a surface grinder but I do have a lathe so perhaps I could rig up a jig of sorts that I can use to square it up. Just a bit of bar stock trimmed to a close fit, then slip the rocker on and rig a drive tang with a piece of key stock welded to a bearing collar with a set screw.

I don't see any evidence of oil starvation but it will only take a minute to check that the oil holes line up with the grooves on the shaft. This engine did come out of a Bus and was running terribly hot at one time so I am pleasantly surprised at how little wear is on these rockers! It had oil burnt on to the heads under the tappet cover big time when I tore it down for a rebuild. Even the case had burnt on oil residue on the inside! I have somewhere around 10K miles on this engine now in the Buggy and am very pleased at how clean and new looking the rocker area is.

As for taking off .001" at a time, I am doing that already with the spacers as I size them on my lathe.
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[oprn]

RKW you are correct. The holes in the rockers do not all line up with the groove in the shafts!
_________________
We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age)

[raygreenwood]