Preferred method for valve adjustment on ground cams

[zachmac]

So, assuming I go with a regrind cam I am anticipating ending up on the high end of the shim range (smaller base circle). My reading / research indicates three possible corrections if I don't want to use all really thick shims:
1) extend valve height via either welded material on end and regrind and / or deepen seats
2) insert lash caps under the buckets
3) mill the cam towers

Option 1) is pretty involved and hard to find someone to do these days, plus doesn't that negate part of the spring "preload"
Option 2) or running the thickest shims both add to valve train weight
Option 3) seems like it may be the best solution? I will of course be using adjustable cam wheels and degreeing everything in.

Opinions / experience?

[mscafide]

I had Abarth cams in my car for years and had the same problem. I just removed the cam tower to head gaskets and sealed with Silicone form a gasket. I never had a leak or any problem.

I still had to use the largest shims Fiat had.

Mike

[narfire]

I went with re-grinds but also installed the oversized valves. With the new valves I seem to remember shim thickness in the 3.7 to 4.0 mm thickness. In the past(stock valves) I have used 4.5mm shims and as you mentioned these seemed kind of thick.

[zachmac]

Yeah, I think I just have to build the head, measure where I am and then decide if it is shims, lash caps and shims, or mill the towers. If I go with the big valves properly seated I am told by some they add some height so that might offset the reduced base circle anyway.

[Curly]

Initially had trouble with lash caps breaking, so went with machining the towers (best engineering solution anyway). Also needed to find a slightly larger diameter tensioner bearing to take up the extra slack in the belt. Don't like the idea of thicker shims - too much extra weight in the valve train.

[zachmac]

Initially had trouble with lash caps breaking, so went with machining the towers (best engineering solution anyway). Also needed to find a slightly larger diameter tensioner bearing to take up the extra slack in the belt. Don't like the idea of thicker shims - too much extra weight in the valve train.

How much did you remove from the towers and where did you source the larger tensioner? I will be using adjustable cam wheels to dial those in but I can see where overall the total belt "circumference" is reduced if the tensioner doesn't pick up the slack.

[Curly]

Initially had trouble with lash caps breaking, so went with machining the towers (best engineering solution anyway). Also needed to find a slightly larger diameter tensioner bearing to take up the extra slack in the belt. Don't like the idea of thicker shims - too much extra weight in the valve train.

How much did you remove from the towers and where did you source the larger tensioner? I will be using adjustable cam wheels to dial those in but I can see where overall the total belt "circumference" is reduced if the tensioner doesn't pick up the slack.

It was at least 10 years ago, so the memory recall isn't all that good; but I think 0.025" was taken off the cam towers. The tensioner bearing was sourced at a local bearing retailer, it was about 1/8" bigger in diameter than the standard one. Don't have its details, but I had a backup plan of machining up a thin collar to press over the standard bearing if I was unable to find a larger one.