The shop that worked on my cylinder head found a bent valve and replaced it. I can not find any marks on the piston so I am really stumped as to how the valve got bent. He did say that some of the hydraulic lifter/tappets were very stiff but loosened up after he compressed them a couple of times. My question is are they going to do this again and can they cause a valve to bend? Should I just buy new ones and install them myself as I already have a spring compressor for overhead cam heads?

Thanks in advance for any advice. I do NOT want to have to take this head off ever again!

 

If you don't want to do it again just rebuild them. Yes if valve stem gets stuck it can happen but what a miracle it didn't get stuck down some and piston hit it but hey gotta get lucky once .

 

I never thought of it as being lucky but I guess you are right. I thought taking the head off was a nightmare but a hole in the piston would be way worse. I think I'll go buy new ones and drop them in before I put the head back on.

 

Did you get to see the valve yourself? I would be curious if the top was mushroomed vs. bent. I have run into that problem on a high mileage project I was rebuilding in the first motor I messed with that had hydraulic lifters - 83 Porsche 944. Valve won't come out just like when its bent, except technically its still straight. In my case it all 4 exhaust valves had it to some extent but one wouldn't travel the full amount and one wouldn't pass out of the head. The machine shop took a little material off of them to get them back in spec for me rather than having to replace all 4. The mushrooming and material removed was not really noticeale to me with the naked eye, only way I could tell is the valves travelled 100% again.

Not sure if that is ever an issue with Ford's valves but something to consider. It could be an entirely ghetto way of fixing the problem as well but I didn't run into any problems and I drove that car like I stole it while I had it up on Craigslist.

 

I did see the valve but I couldn't tell that it was bent. After they cleaned it up I could tell that it wasn't seating in the head evenly. One side had definitely been closing in the valve seat better than the other. You could see the wear marks on it.