Rocker arm assembly mounting stud problem

[Art Tiller]

I am bought new cylinder heads for my AeroVee 2.0 engine. I am wanting to use the rocker valve assembly's from my old heads. The mounting studs that came with the new heads are different than the studs from my old heads. The assembly will not mount flush with the spacers on the head. In the picture the stud on the left is installed on my old head. A stud from the new head is held next to it on the right. I have highlighted in yellow the smooth area between the threads of each stud. You can see that the original stud's non thread area is much longer than the new one on the right. Can anyone tell me why there is such a difference in geometry. Also, where can I get a mounting stud like the one on the left. Got a part number?

[Bryan Cotton]

Art,
I'd check with Sonex. But a couple questions come to mind:
1) Can you remove your old studs and will they fit in your new heads?
2) Is it just the shims that won't fit on the studs? Do the rocker shaft mounts fit on the new studs?

[Art Tiller]

Thanks Brian,
I thought of that, but I think lock tight was used and I would damage the studs getting them out. I am still going to keep the old heads as spares. I am going to ask Sonex about this. I will let you know the outcome.

[Art Tiller]

I am going to heat up the studs on the old head, double nut the threads and see if I can get them out. I am pretty sure the old studs will work for me. I sent Sonex a message from their web page asking for new studs. I am not sure how they will react when they find out that I bought the heads from another supplier. At the time I bought the heads Sonex seemed to have a long lead time in getting things out to the field. I have a friend that decided to buy a Jab instead of waiting on parts for his AeroVee.

[Art Tiller]

By the way, I am on a Facebook page of VW bug enthusiasts. These people are nuts about VW Bugs and Buses. I found out that there are multipole stud sizes for these rocker arms.

[Bryan Cotton]

I am going to heat up the studs on the old head, double nut the threads and see if I can get them out.

Art,
Don't heat the studs. Heat the aluminum boss they screw into. You want the aluminum to expand and not the stud - makes the fit looser. They will probably come right out using the double nut.

[Art Tiller]

I was successful in removing the old rocker assembly mounting studs from the original heads and moving them to the new heads. I used the double nut method and it worked beautifully without heating. Rocker arm geometry solved. I am able to use the original push rods.

I then began to inspect the rocker arm assembly. The shaft and shims did not fair so well during my initial attempts at mounting the assembly to the new head. So I ordered a rebuild kit from Jbugs. That went together very well. Complete with new shims.

But, the kit did not come with a serrated flange bolt and end cap. The flange bolt I can reuse, but I think it would be wise to get a new end cap.

I have a feeling that Sonex does not like it that I am using someone else's cylinder heads. They have not responded to my attempts to contact them via the web page. I wish they could either sell me a new end cap or direct me to a new source.

[Area 51%]

CB Performance part number 1643. It's the whole shaft with caps and bolts.

[Art Tiller]

Those CB performance rocker arms look like they have the proper caps and bolts. I will check with them to see if I can get the caps and bolts seperate.
Thanks,
Art