'72 Camper Bus - Loss of engine power

[the north wind]

Hey all - My friend Alex told me about this board today. I'll try and shorten this down as much as possible...

First off, the bus is a 1972 with the Riviera camper. Engine is a 2.0L from I think 78 that we put in, with a weber dual throated carb.

We went on a trip a few weekends ago, was running fine for about 45 minutes, and then we started to lose power. Popped open the back, and the plug wire to cylinder #1 was off. It was all chewed up and wasn't staying on the plug. No shops had it where we were at (near Hood River, OR). I tied it down to keep it in place, and headed back to Portland the next day (hooray for it being a camper bus). Local shop had the wires, so those all got replaced. The engine was still running crappy, so we made a quick jaunt to the local shop, where they said a cylinder was not firing, and to check the valves.

Alex helped me checking those today. We pulled the valve cover, and we see that the nut came off the stud on the right side of the rocker shaft. We pulled the rocker shaft out, and found the nut down by one of the push rod tubes. BUT, the stud on the left pulled right out of the head, and the one on the right was loose as well. It would appear that the thread on the head is stripped, as we can't get the stud to tighten in there. The thread on the stud is medium, but not gone all together.

The head has also been ground down to fit some spacers, I guess... Which seems weird.

Any suggestions on what to do with the stud? The local shop said to call a machine shop, and the machine shop said I'd have to bring the head in for him to re-tap that.

The hole on the left is the stripped thread, as far as I can tell at this point. The thread on the stud looks ok-ish, but not great.


Weird spacer on the left that some PO had to grind out space for... odd?

[Amskeptic]

stud pulled right out of the head, and one on the right was loose as well.

The head has also been ground down to fit some spacers, I guess... Which seems weird.

Any suggestions on what to do with the stud?

Looks like this head has been monkeyed with. The spacers under the rocker stands are generally used to improve valve geometry. Stripping these studs out of the heads is pretty hard to do. The original 11mm nuts that hold the rocker stands down are designed to strip out long before the studs get yanked out of the head. A decent field repair is going to require that you find some step studs like (I don't know for sure but maybe) 10x8X whatever length, where you drill and tap the head to restore a decent threaded bore. Insert the new step studs until the rocker stand supports can sit properly on the spacers with no interference with the stud diameters. Taking the heads off is overkill. Removing the pushrod tubes and plugging the lifter bores will allow you to drill a mess of aluminum shards that go nowhere important and clean up will be easy. Do not underestimate the punishment these rocker assemblies take, do a nice clean job.
Colin

[the north wind]

Thanks Colin. That is good information. Glad to hear we won't have to pull the engine and take the head out. I'll be out of town this weekend, but hope to get this taken care of next week.

Thanks!