Big Valve Twin Cam Tappet Clearance Problems between Cam Lobe and Cam Follower

[Bainford]

You will need a Degauss machine to demagnetize your shims.

If you have one of those old Weller soldering guns, you can demagnatise the shims by passing them through the loop of the soldering tip a few times with the trigger depressed. I have done this a few times with small screw drivers or the tweezers I use in model building, where I work with metal parts small enough they are hard to see, and any magnatism is a real pain.

[4129R]

This will magnetize the shim which will then attract metal debris from the oil.

For some reason, the shims seem to have zero magnetic attraction after I have smoothed them with emery paper.

The surface area of the shim actually exposed after installation is minimal, and they are in a very sheltered position.

[GavinT]

Are the shims hardened? . . and if so, how thick is the hardening?
Not ground away?

[BDA]

The shims are hardened. It's common for people to sand them down several thousandths. As thin as they are, I would expect them to be hardened completely through.

[GavinT]

Oh, OK.
A mate of mine used to make his TC shims from some sort of silver steel - part 'em off on in the lathe.
Heat with a gas axe and drop them in oil which seemed to work.

He machined up a piece of round stock with a recess in the end to snugly hold the shim so he had at least a fighting chance of grinding/lapping them true and flat.

[BDA]

Lotus updated the toe adjustment on the Esprit. You can replicate that on the Europa but it involves some fabrication. Basically, rather than put washers between the radius arm and the bushing, you shim under the bushing flanges. In this picture (https://s3-us-west-1.amazonaws.com/groupsioattachments/45658/77758251/164779/0?AWSAccessKeyId=AKIAJECNKOVMCCU3ATNQ&Expires=1652210879&Signature=NMGVYt4vVGfPr9oYFWfqhirwECI%3D&response-content-disposition=inline%3B+filename%3D%22Esprit%2520-%2520%2520Susp%2527n%2520Rear%2520-%2520Shims%252C%2520Toe%2520Adjustment%2520-%2520PNs.jpg%22), the parts numbered 39 and 40 are the shims I'm talking about. They will have to be made.

You can also use alignment shims that come in several thicknesses and are sort of horseshoe shaped so you don't have to take the radius arm off it's pivot bolt. This is a US store but there ought to be something similar in your area (https://www.harborfreight.com/144-piece-body-shim-assortment-67585.html?_br_psugg_q=shims).

Lastly, you can use real washers. If you can get them, air craft washers generally come in two thicknesses and their quality control is better than hardware store washers but hardware washers work just as well.