Cylinder Head Rebuild Issues - Valves Stuck Open
 

Had both of my cylinder heads rebuilt as part of a complete and total overhaul, the scope of work was valve grind, valve seals, and valve guides. I replaced all the lifters and rockers with Melling brand. Put 1500kms or so on the truck, had a really rough idle I couldn't figure out. Only to find out later all 8 of the exhaust valves were sticking open when I did a leak-down test. Took my truck to 3rd party mechanic who confirmed diagnosis and claimed he's had issues with the one local machinist and I am the 7th person he's known to have had issues with his work.

Pulled the engine, removed the heads, could see daylight through all 8 exhaust valves when looking through manifold ports, even with cam lobes at 12 position to the rocker. Returned to the machine shop, showed him all the valves were stuck open. He backed off the cam bearing caps and all of the valves then closed. I told him I suspect whatever specifications he might be using were wrong, he pulled out his book and told me there was another specification for a "5.4 3v MOD" that was quite different than the one he had used and might explain it, but he didn't understand why it was only the exhaust valve sticking open and that the intakes should likely be stuck open too.

I opted to go to a machine shop to the next town over. Right away the machinist noted the lifters were all fully compressed and something wasn't right. He asked if I was using aftermarket camshafts, which I am not. The machinist from the other town has been in contact with the machinist I went to. The machinist called me today and was now saying that the lifters were stuck fully extended and that's why my valves were sticking open. He was asking me if I squished them down in a vice first prior to installing them- he theorizes they are all stuck extended and maybe that's why my valves are likely stuck open. He is also saying he doesn't like how tight the tolerances seem to be, and it's difficult to redo valves that have been worked on with no point of reference. He did not like the idea of grinding until the clearances were acceptable and said he would have to figure something out and get back to me.

I'm suspecting the one machinist is trying to bail the other machinist out of liability, but I am willing to admit I could have made a mistake if that's what happened. Are new lifters typically stuck in the extended position, and is it proper installation procedure to compress them first? The only lifter install info I had found when throwing everything together was that some people soak their lifters in oil first, and some people don't.