I believe another poll regarding CRD engine timing belts, rocker arms, and ARP stud upgrades would be redundant and might likely muddy the waters even more than they already are.
I think the narrative on these issues is going the wrong way, as a lot of the discussion regarding valve failures, rocker arm failures and head gasket failures so far has been little more than speculation. Comments like "cheaper by the truckload" torque-to-yield head studs and other complaints regarding both the rocker arms and the valves are indicative that the decision regarding the culprit or culprits for the seemingly over-abundance of head gasket failures and valve train component failures has already been made.
That said, some testing of the valves by a forum member or an associate of a forum member was supposed to have been conducted, but I do not think the results of such testing has been posted as of yet. Perhaps there is no adequate test available to determine exactly why engine valves fail, and that is why nothing has been posted.
Perhaps a better way to go about finding answers would be to have a couple of CRD forum members directly communicate with the actual engineers who designed the R428 engine, and ask them the appropriate questions as to why there seems to be so many problems with the cylinder head and the valve train of the R428 engine. Why were torque-to-yield head bolts used, why are the rocker arms and the valves apparently so weak that they fail often?
I do not believe anyone has tried to contact the V.M. Motori engineers regarding these issues. If I am wrong, and indeed a CRD forum member has contacted the engineers who designed the R428 engine, please post a synopsis of those communications for the benefit of all CRD owners.
spoken like a smart cookie,..btw my mod 1 has been in since may and what a great design I've run full power up the steepest grades in mass, &NYS and it is so much better than the in line stat,some people subscribe to,.