Early 107 sport heads - shimming them up.

[John A. Ross]

While shimming Pauls first 107 head with 1.4 valves and so on we had to have work done on the spring tops to be able to shim them but assumed that was due to the valves used.

With no shims there was no clearance. As said head had some serious work done on it and likely had a different cam but if it had had a higher lift it would have been worse (unless it had a billet carrier to match) it is a mystery

Pauls head now needs work (guides mainly) so he has borrowed my "standard" 107 head but after dropping the sport cam/carrier off his 533 head onto my 107 the shim sizes are once again really small, a lot below 62 thou but consistent.

I wish I had kept the original cam/carrier on this head now as it cam off a running engine.

Did rootes make any special carriers, lifters, spring tops or even valves for these original 107 heads not listed in the parts manual? I am used to seeing more along the lines of 85 thou and up on most heads including 180's

In fact we don't have any shims small enough now, plenty larger sizes but nothing this small.

Looks like we will need to have some made

[OliDP72]

I have a spacer plate under the cam carrier for this very reason. I think I got it from Ben Boult - he does several thicknesses.

[moose549]

https://qedmotorsport.co.uk/product/...various-sizes/ much better than the standard flat shims. There are a few reasons why the shims need to be thin.

cam carrier face of head skimmed to ensure flat before skimming gasket face or to correct warping from welding repairs.

valve seats replaced and set too deep in the head (possibly to increase combustion chamber size to adjust compression ratio, head skimmed too much, or intruder pistons used at some point or turbo compression ratio)

Replacement valves not manufactured to the correct length could be adapted from an off the shelf valve that is a actually for another engine and the person who supplies them may actually supply cam carrier shims to compensate due to availability of exact valves and the potential costs involved in making the valves to correct dimensions.

If the valves are 1.4 it must be a performance engine and head so i would carefully check the spring fitted length if the valves are sitting deeper in the head then the springs may not have enough pre-load on them.

[John A. Ross]

Mike, yes it is 1.4s and well ported. Not had the liufe skimmed off it suprisingly enough.

Paul eventually sent it off and had new guides, seats, valves and so on, shimmed up nicely now so likely one of the culprits you mentioned above. The guides were shot so he just had the lot done and a small skim.

Running very well now.