Head Issues - thougths?

#1

I had a local BMW performance shop overhaul a motor for me and swap it back in the car. It sounded a little rough from the start, but nothing bad. I took the car to Sebring Oct 2nd and headed out for some laps. It felt down on power during the two warm up laps I took, but seemed to be running OK. I figured it was breaking in and decided to step it up for a lap but kept the RPM’s under 6K. Car started missing and dropping cylinders. After passing the S/F line it went, no power and missing a lot. After limping it around to the pits we looked into it.

After checking all the easy stuff, I popped the valve cover off. Found the issue.

ALL of the exhaust side retaining clips had come off and also broke both rocker arms on cylinder 1. Where you see the clips is exactly where they were when I opened the cover. I am pretty sure the broken arms on 1 had to do with the clips coming off and allowing the arms to catch both lobes on the cam.

I was thinking the shaft spun, but the retainer indents on the shaft were exactly where they needed to be. I doubt it spun and ended up exactly back in the original spot. Since the cover holds the retainers down, I am confused as to how they came free and ended up where they did.

The only thing we can come up with is it was not put back together right at the shop.

Has anyone seen this before? Any thoughts as to the cause? The RPM never went over 6K, downshifting or other wise.

#2

I believe one of Ranger’s many motors had this issue where the shop did not install the retaining clips properly.

#3

The clip that holds the rocker arm shafts in place seems to be missing (front of the head)? If so, rocker arm shafts moved and rotated.

#4

Good call. The bar is missing in the pictures. I looked at the other pictures I took and sure enough, it was missing. That would allow the rocker arm shaft to rotate and throw the clips. Once the clips were off, the arms could float around and ultimately break.

I’m amazed the shaft spun then ended up back in the original spot.

Thanks!

#5

Hmm, seems to be a bit of that going around. (no pun intended)

It looks like the intake is spun some too.

Matt

#6

I would say the shop owes you a new head.

#7

The shop has already re-done the head, replaced 4 valves and gave me a new head gasket set and bolts…they owe me for my time though, or a lot of beer.