TheSamba.com :: View topic

Fri Oct 10, 2014 8:19 am

I have resumed work on my rebuild-in-progress. I am working on getting the valve geometry set up. Several of the rocker arms & adjustment screws are not centered over their respective valves, so I intended to shim as needed.

Where, oh where, can a soul find new, correctly-hardened T4 rocker shims in a variety of thicknesses?

I have to assume that since the OEM shims are hardened that it would not be advised to make/source shims out of brass or Delron or what-have-you...jawohl?

Danke.

Fri Oct 10, 2014 10:18 am

Are you doing a stock rebuild or high-performance?

I've never shimmed any rocker arms on any Type 4 rebuild. Everything is supposed to be fine. There's two different rocker arms, so make sure they are on the rocker shafts correctly.

There are aftermarket rockers that you can use and I've seen those....they are awesome.

Fri Oct 10, 2014 12:57 pm

This is a stock rebuild aiming towards reliability. Stock 2.0l, stock FI, stock-spec cam, stock-spec HAM heads...etc.

It is pretty obvious when the two rocker arms are reversed. The problem I see is that on 3 different rockers, the adjusting screw is way off-center from the valve stem. On the worst one the adjusting screw is centered on the edge of the valve stem. I bought new hardened adjusting screws and nuts, and want to make sure everything is aligned correctly. The previous engine builder had used soft adjusting screws, and they were worn and pitted beyond belief.

Fri Oct 10, 2014 3:21 pm

Is it possible that the rockers are bent or the push-rods are of different lengths?

Fri Oct 10, 2014 3:54 pm

HerrMahnenschmidt wrote:
The problem I see is that on 3 different rockers, the adjusting screw is way off-center from the valve stem. On the worst one the adjusting screw is centered on the edge of the valve stem.

Also which edge is it closer towards, top or bottom? I would think this would indicate if the push-rods were too long or too short.

Fri Oct 10, 2014 4:12 pm

talk with Len on that. He built the heads and may have some input if he has seen it before. Normally the rocker screws are very close to centered with just the standard spacers - either kind.

Fri Oct 10, 2014 8:41 pm

Post a picture.

It not imperative that they be dead center.

A stock set up does not include shims under the rocker arm assembly. One generally will need to shim under the rocker arms when switching over to adjusters other than stock adjusters such as Porsche swivel adjusters.

If going that route then you need the 1.7L rocker arm assemblies as well. Then you have to carefully grind them down a bit prior to installation.

Given the money you've invested it would be highly recommended that you go the route of Porsche swivel adjusters. I'll bet Len even tells you that :wink:

Fri Oct 10, 2014 9:12 pm

I'll post pics tomorrow for clarification.

I should clarify that the offset is in line with the axis of the rocker shaft; i.e., the adjusting screws are either slightly left or right of the valve stem, rather than above/below. The spacers I am looking for will go on the rocker shaft itself, to nudge the rockers slightly either left or right to better center the adjusting screws over the valve stems.

The pushrods are all the same length, and are all in good condition except for one that had a chewed up tip from a piece of soft adjusting screw that had broken off, wedged in the oil hole, worked its way through the pushrod, and then began to chew up both the opposite tip and the lifter cup. Yeah, weird. I have replaced that faulty pushrod with a spare I had. Using brand new lifters, of course, to go with the brand new cam & cam gear, which go with the brand new HAM heads, and the brand new everything else that needed replacing.

I have a Sherline lathe being shipped for a completely different project. I may have to simply machine some spacers myself using stressproof or similar (tool steel, perhaps?), and harden/temper them myself. I can competently make such spacers, but I was looking for an easier source for them. Also, I have searched all the various vendors' websites diligently, but no one carries them. The closest I found were for CBPerformance's performance rocker shafts (pn 1145?), but they have an ID of 0.760", and the T4 shaft diameter is 0.78xx something.

All ideas and suggestions much appreciated.

Fri Oct 10, 2014 9:17 pm

Also, on the swivel adjusters, I researched and read nigh every discussion I could find here. The last I read was that there were concerns about adequate lubrication in the swivel adjuster cups, with a legitimate concern expressed about possible and actual failures. I'd have to dig up the link again, but as best I remember, Len had weighed in and somewhat conceded the concern expressed. I may still order a set, and just keep a close watch on them.

Fri Oct 10, 2014 9:18 pm

With stock stuff the adjusting screws are slightly off center so to turn the valve so do not center the adjuster via shims on the valve stem.
For reliability the Porsche swivel feet can't be beat nor do they beat the hell out of SS valve stems.

Fri Oct 10, 2014 9:21 pm

Bleyseng wrote: With stock stuff the adjusting screws are slightly off center so to turn the valve so do not center the adjuster via shims on the valve stem.

Ah. That makes sense. I wonder how far off center their original design was spec'd at.

Fri Oct 10, 2014 9:35 pm

X-2 with Bleyseng as the offset is for turning the valve stem.

I too have been using swivel feet adjusters for well over 40 years as well
as also on the cars I worked on daily REAL Porsche swivel feet adjusters.

Also you would have to swap your 10mm rocker arms for the 8mm style
but, you can also adjust side clearance closer if really needed with the solid
spacer kit #08220 from the type4 store.

I have 4 or 5 sets of 10mm rocker assemblies and of course they have the wavy washers as well as the flat washers (spacers) that I would gladly give
you if you really need those extra spacers. of course YOU would pay postage. :)

Fri Oct 10, 2014 10:14 pm

Bleyseng wrote: With stock stuff the adjusting screws are slightly off center so to turn the valve so do not center the adjuster via shims on the valve stem.
For reliability the Porsche swivel feet can't be beat nor do they beat the hell out of SS valve stems.

Another option that is viable & reliable with respect to adjusters are the Ford swivel foot adjusters. Beyond that it's a gamble.

Sat Oct 11, 2014 9:26 am

Also....if you go to the STF and look in Jake Raby's archive you will find discussions. ..from at least 5 years ago....that many of the type 4 rocker arms are of two slightly different lift ratios. Jake noted at one point that he had to build a jig with a rocker shaft to slide the arms onto to check that they were all the same in a set.

After that discussion I made a quickly jig to check the bucket of 1.7 rocker arms I have (about 10 engines worth).....and found about 8 that had slightly more or less lift ratio. I dont remember what the difference was (I think I have it recorded somewhere)....but I keep them in seperate containers now.

The difference is small but significant enough to make setting really accurate geometry a problem.

The jig was just a plate of aluminum I had laying around. I put two studs into it to hold a rocker shaft and a pair of rocker supports with shims underneath them.
I had a short section of the end of an old pushrod mounted to support the pushrod cup when the rocker arm is on the shaft. I held the rocker arm down on the PR stub with rubber bands. You can measure the difference in both the angle of the rocker arm and in the gap between the rocker arm tip and the plate.

It was just a difference in manufacturing. Ray

Sat Aug 29, 2020 9:02 pm

old thread - now it is my turn. I posted this in performance and got mostly T1 replies. Added it to the swivel foot thread and no replies yet, so this is as good a thread as any.

I haven't checked to see if any of the rocker arms I have fit better. I see two solutions, shim to just off center, or bend the arm .020" +/- without twisting it. Anyone want to throw 10 cents in? My concerns are fast wearing valve guide and a merry-go-round on that exhaust.

The shim was just to get an idea what one washer might correct it by.

Sat Aug 29, 2020 9:41 pm

Your top 2 pics show quite a lot of offset in the left picture. The second picture
Looks good in comparison.
So the shim in your hand will make up that difference possibly.
I was taught to end up with the adjuster off center of the valve stem as it was
Designed to rotate the valve therefore keeping valve and guide wear to a
Minimum.
I also will never sell a newly built engine with elephant feet Installed until
The break-in period if finished.
But, that’s just my position with owners that have no knowledge of the beast.

Sun Aug 30, 2020 9:34 am

old DKP driver wrote: Your top 2 pics show quite a lot of offset in the left picture. The second picture
Looks good in comparison.
So the shim in your hand will make up that difference possibly.
I was taught to end up with the adjuster off center of the valve stem as it was
Designed to rotate the valve therefore keeping valve and guide wear to a
Minimum.
I also will never sell a newly built engine with elephant feet Installed until
The break-in period if finished.
But, that’s just my position with owners that have no knowledge of the beast.

Thanks Chris. Yes valves need to rotate, and the screws did that. It keeps the valve faces and seats from building up carbon. I have other arms with screws I can try. That said, do you shim to put the screws in the proper placement, or do you tweak the arms? Since VW never used shims that I have seen, I am guessing they either lived with the differences between parts runs, or they tweaked the arms when setting them up. Do you know?

Also - are you and the other Bay area folks doing Ok with these fires on the outskirts of the Bay area? Anyone of that group need help because of the fires?

Sun Aug 30, 2020 2:29 pm

SGKent wrote:
Yes valves need to rotate, and the screws did that.

Since VW never used shims that I have seen, I am guessing they either lived with the differences between parts runs, or they tweaked the arms when setting them up. Do you know?

I have the "Heiko" 10mm swivelfoot adjusters now at 80,000 miles and they are doing fine.
They have delivered 20,000 miles of valve opening on my new Len Hoffman heads fresh out of the box.
Although it looks like the big elephant feet would not impart rotation to the valve stems, I see evidence that the valves have been rotating.

The offset of the adjusting screw on the stems on stock engines was supposed to be halfway from dead center to the edge of the stem. I think VW had their machining and dimensions well enough figured out that that normal assembly practices were good enough.

In my 20 year traveling VW consultant career, I have seen some horrific valve stems and some mangled adjusting screws. Sometimes, especially on Type 1 engines, people get the thrust washers confused and you have a dead-on strike betwen the screw and the center of the valve stem. This is bad. You can get a trough in the stem and it stops valve rotation.
Cleanliness counts on valve adjustment day, and there is nothing wrong with hitting each screw/stem with a squirt from your oil can to rinse inadvertent crap out of there ...
(here's 111,000 miles on a factory engine with timely oil changes)

Sun Aug 30, 2020 2:42 pm

Amskeptic wrote: ...
(here's 111,000 miles on a factory engine with timely oil changes)
Colin - did you look at the photo? I think the one on the left is centered too close to the edge. I may have to shim it. Tabira said that the rocker arms are such hard steel it is unlikely they can be tweaked to fix it. Once I have an idea what the worse case fix it then I will see if any other arms have better offset. Yes it is an exhaust arm.

SGKent wrote: old thread - now it is my turn. I posted this in performance and got mostly T1 replies. Added it to the swivel foot thread and no replies yet, so this is as good a thread as any.

I haven't checked to see if any of the rocker arms I have fit better. I see two solutions, shim to just off center, or bend the arm .020" +/- without twisting it. Anyone want to throw 10 cents in? My concerns are fast wearing valve guide and a merry-go-round on that exhaust.

The shim was just to get an idea what one washer might correct it by.

Sun Aug 30, 2020 3:49 pm

Steve, yes you need to re shim the one on the left in your photo from
Yesterday.
Hell you spent a ton of hours on this build so what’s a couple more to make
It right and last a long time.