metallic 'pinging' in the left cylinder...

[CC_Vic]

Sorry for the diagnosis questions but my Haynes is 120 miles away..

I've had my bike long enough to know what the bike normally sounds like and I'm getting a more metallic sound from the left cylinder (left if I'm sitting on the bike) since starting it up yesterday. This also happened today. It's the same or very similar to the sound I'd get stopped at a light after a long ride on a hot day that was gone next time I started it up.  

I'm also noticing some loss of power and responsiveness at lower rpms...a slight hesitation early in the gear. It's also been taking a couple of tries to start when cold. This after a strong 2.5 hr ride at highway speeds monday.

The facts: I changed the oil for the first time last Wednesday. It had been a couple of years and the old stuff was black.
I also changed the filter, etc and think I got the O-ring issue right.

It's been a couple years plus since anything else has been done to it.

Where to start?

Thanks in advance-

Vic (in NJ for the moment)

[Bob_Roller]

Vic, I would remove the left rocker arm cover, and check for proper valve clearance adjustment and security of adjuster jamnuts, also the needle bearings on the rocker arms are known to fail, ( look for small pieces of metal in the rocker arm cover).

[MrRiden]

vic,
The first thing I'm curious abut is when is the sound most noticeable? I'll assume that you hear it most at idle. A few things come to mind. I'd pull the left side valve cover and get that cylinder on TDC so there is no tension on the rockers. Try to wiggle the rockers laterally on their shaft and see if you have any play, also move them radially on the shafts to be sure they rotate smoothly. You'll have to back off the tappet adjusting screws to accomplish this. Inspect the tappet screws for deforming. I suspect oil starvation and I want to make sure you haven't done any damage to the rockers/shaft. also check the inside of the cover for metal bits. If all seems well check the head bolt torque [25 to 26 foot pounds] and then the rocker shaft mounting blocks. reset the tappet clearance [intake/exhaust .006 and .008]. Next start 'er up with the cover still off [it'll be a mess so use a catch pan/rag] and visually check that you have oil coming out of the rocker/shaft assembly. I'd next proceed to check for a pinched or misaligned O ring at the filter. All this assuming the oil level is proper and you have access to a tool kit.
rich

[Justin B.]

Also check the rocker shaft end-play.  If it has a lot of play then it makes a pretty good rapping sound...

[MrRiden]

I see Bob, Justin and I are of the same mind on this. Lets hope it's not piston slap!

[Bob_Roller]

Yeah Rich, my first rocker arm bearing failed at about 10,000 miles. I didn't notice any problem with the engine, but I was checking the valve clearance, and found a bunch of metal in the rocker cover. This was back in 1985 so there was no inter-net access, so I took the dealers advice and replaced all 8 rocker arm bearings at that time, along with one rocker arm and rocker arm shaft. If you do get a new rocker arm, they have been upgraded and have a 'plastic insert' on one end and are not the same length, and you have to add shims between the rocker arm and the rocker shaft support ' blocks' to make up for the loss of length. Also try to add the shims to get the rocker arm to contact the center valve tip . There also was metal in the oil pan, so I removed it and did a thorough cleaning of it and the oil pump pick-up tube screen.

[Justin B.]

Most of the time piston slap is more pronounced when cold.  Once everything heats up and expands clearances tighten up and often the slap goes away.  It is especially bad with forged and hpereutectic (sp?) pistons.  The LT1 engine in the '94 Impala SS I had (and also in 'Vettes and F-body cars) would sometimes exhibit this when cold...

[CC_Vic]

Thanks for all of your help so far-  

When I started it up yesterday, the left exhaust was definitely vibrating more than usual..almost bouncing.
I didn't really notice the 'pinging' until I can out of the periodonists office (..traffic noise on the way there? abject fear?) a short while later and started it the second time.
It's more noticable at idle but definitely there while riding as well.
Tools upstate but will get a set here as well.

What tools will I need to do this?
metric ratchet set, torque wrench and hex wrenches +...?
And which manual would you recommend?

Thanks Again

[Bob_Roller]

Vic, you'll need a 10 mm open end wrench for the 2 nuts that are attached to studs that come out of the rocker cover, a 13 mm socket to remove the nut at the center of the rocker cover. That will get the cover off. The adjuster jamnuts are 12 mm, and I think the pushrod has a 10 mm hex on it as well. If you have the OEM BMW tool kit, you should be able to perform this check with the provided tools in there. Oh yeah, you will need feeler gauges as well, also this needs to be done on a 'cold' engine, that is not been run for 8-10 hours, as the internal parts can still be quite warm even though the clyinder head is cool to the touch.

[CC_Vic]

I have my oem tool set.
I'll get feeler gauges on Monday and a torque wrench and will have my wife bring my Haynes manual down.

But it was running the best ever the previous 2 days!

Thanks Again-

[MrRiden]

CC_Vic,
so what ya got?

[CC_Vic]

Thanks for following up; haynes manual, tools and wife on their way back from upstate sunday and I'll be getting going on this Monday.

Bike did start up today and the problem is still there..

metallic pinging (doesn't stop, just speeds up as the revs go up), hesitation, loss of power. No loss of oil. Just one drop on the floor in 3 days.

Not the bike I was riding early in the week, sadly. I love my bike.

Will follow up Monday night

cheers

Victor    

[Semper Gumby]

Hey Vic,

How many miles on the bike?  Does the idle speed seem to float higher than normal?

Good luck.

[CC_Vic]

Hi Bill;

My '80 has 58,500 and seems to be idling the same.
it looks as though '80 is a strange year to buy parts for.
I need to find out the month my bike was made..?

Thanks!
Victor

[Bob_Roller]

If you go to RealOEM.com, and put the last 7 characters of your bike's VIN in the search box at the upper left of the screen, it will give you the month and year of manufacture. It will look something like 19800200, which would be February 1980.