sticking or stiff rocker arm

[awhnry]

Adjusting the valves in '87 Carrera and found an exhaust rocker that was very stiff and didnt respond to loosening the adjuster. It appears that the valve would not be operating under such a scenario and the spark plug shows a lighter, tan color. The question I have is whether replacement of the rocker will cure the problem and what parts need to be replaced ie rocker arm, bushings, shaft?

Wayne

[Packet82]

Try replacing the shaft and use rsr bushings with it. If you replace the rocker, there's a chance it'll start to wear your camshaft as the parts tend to wear together.

[Steve@Rennsport]

Wayne,

Some clarification is needed here,...

With the rocker arm pad resting on the heel of the cam and the adjuster screwed all the way out, are you saying that the rocker hardly moves or takes a lot of effort to move at all?

How many miles on the engine?

I would remove the rocker arm and shaft to inspect the rocker arm bushing to see if its partially seized. I'd need to see a good, sharp, close-up pic of the rocker pad and bushing bore to tell you anything definitive.


Many factors at work here and the result of rocker removal & inspection will dictate what you do. If the spray bar is plugged and the rocker arm and camshaft haven't received sufficient oil, there are bigger issues to deal with.

[awhnry]

68k on the motor. Car wasnt driven for last 3 yrs before I purchased. Told that valve noise was out of adjustment so I started there. Rocker is difficult to move with adjustment backed totally out. It is number one cylinder. Guess I will remove the rocker tomorrow nite.

[jpnovak]

Has the rocker shaft moved laterally in the cam tower? If so, the rocker bushing could be riding on the outer "expanding" edge causing it to bind.

I agree. Loosen the rocker shaft bolts, slide the rocker shaft out and inspect.

[awhnry]

Now another issue: to give me more room with the rocker removal(and since it was on the remove/replace list), I started to remove the catalytic converter but found that the connecting bolts were a unique star shape that none of my wrenches or sockets would mate up to. Are these something unique to '87's or what are they? What fits on them and how do I find a socket or wrench? I understand that they may be a 16 pt.

[Flat6pac]

12 point, a set of the 12 points are available in the auto stores, NAPA for one. cut them to the size you need.
Bruce

[awhnry]

It is not a 12 pt; maybe an 8 pt but the sockets I am finding are not metric. 7/16 or 5/16 are possible but I dont want to buy otherwise useless sockets to find out. Any ideas?

[KTL]

Is the bolt an internal star (male socket required) or external star (female socket required)?

BMW uses a lot of Torx star-type bolts. So if the car was previously repaired at a German/import repair shop, they could have replaced the cat. conv. bolts with some BMW spares they had lying around (like CV axle bolts for example).

Honestly if the bolts are crappy? Just cut them off. The cat bolts usually get corroded pretty fast and they can break anyway when you remove them. Don't waste your time trying to take them off with a "proper" tool if you don't want them on there anyway. You can get replacement bolts at the local hardware store in stainless 5/16 size. I'll send you some nice 5/16 silicon bronze nuts if you want them. I have a ton of them leftover from when I bought in bulk from McMaster Carr to do my '87 exhaust years ago.

[awhnry]

Finally got time today to work on the removal of the cat. The cat was held together at the muffler by the BMW type bolts/nuts and the six splined socket held by vise grips with either a 12mm or 13mm(I would love to find the tech who worked on the exhaust and mixed sizes during reassembly) wrench on the back side removed the things. However, the bolts holding the cat at the exhaust flange proved to be even more difficult and also odd SAE sizes. I hate to admit it but a sawz-all took care of the problem. After I get the rocker problem fixed, I will have to locate a bypass pipe for reinstallation. The fun continues.....
Kevin, I will take you up on those left-over fasteners.