85 M20B27 Valve Adjustment

[tomstin]

I'm having trouble adjusting the #5 exhaust valve lash. It is always noisy. It's been trouble for years, before and after I had the head serviced while replacing the head gasket. On my last attempt I replaced the eccentric on the rocker...no help. There are a lot of potential variables between the length of the valve, rocker shaft wear, rocker wear itself and cam shaft. Or a little of all of them.

I could try to "sneak" the cam out the front enough to replace the rocker. A bit tedious and risky on damaging something along the way.

Has anyone had experience with valve lash caps? Seems like an option but I've never used them.

Other ideas?

[digger]

You probably need to explain what trouble adjusting lash mean. if the adjustment is correct then the noise is not caused by the adjustment and something else is worn or the noise is an injector or something else.

you should be able to feel if the adjustment is correct and there is the option of adjustment with feeler between the cam lobe and foot of the rocker (reduced clearance if you check there instead of at the eccentric due to the rocker ratio)

if there is wear, then the chances are there is wear in other places so changing 1 rocker makes no sense unless it has failed

[tomstin]

Digger, I can't seem to get the gap between the top of the valve and the eccentric on the rocker into spec. I forget how tight I could get it, but it was a few thousands too loose and therefore noisy.

It appears the thinest lash caps are .080 and I'm a bit worried with those installed the overall lash maybe too tight??????

[McGyver]

Remove the eccentric and check it for a flat spot. Running it too loose could have damaged it or wore it out. Swapping on a new eccentric should be very simple.

I have never seen an m20 with lash caps, I've never needed one, and I don't think using them is a good idea. Your valves should be able to be adjusted into spec. If you can't get them into spec, figure out why and fix that problem.