valve adjustment done...new problem...pinging!

konish · 11-29-2003, 05:18 PM

Well, finally got her buttoned up from the oil change and valve adjustment. Everything checked out, no leaks, sounded about the same. My impression of the oil change and valve adjustment:
1. Oil tank...now I know why a beer bong works! Pretty much the easiest car I've ever changed the oil in...
2. The drain plugs were absolutey clean...I mean not a spec of crud to wipe off...I think it's a good sign!
3. Valves...pain in the rear! From my measurements, they seemed tight. Glad I did it though...I think. Please see my new problem below.

After letting the oil get about 190, I was doing some WOT runs to about 5000. All of the sudden at about 4000 rpm, I get pinging from the left bank...I think it was from the left side. Sounded like marbles being tossed around the inside of a coffee can. I freaked thinking it was one of my locknuts that had come loose. However during 1/2 to 3/4 pedal and relatively slow acceleration up to 5000, I don't get the same pinging. I run 89 octane gas and it did not do this before my valve adjustment. Also, it did not do this during the early part of my shakedown run, but I can't say I was as aggressive with the throttle.
Could my new valve settings be causing this? Not sure where to start...timing I guess, mixture next?

I also have the following question if I may:

1. Valve adjustment lock-nuts. At first I thought my pinging was a backed off locknut rattling around inside the valve cover. However, I figured the valve would come WAY out of spec and the car would loose power(?)....besides on slow acceleration no sound. I snugged them up pretty good, but did not use a torque wrench. If indeed a locknut backed out, what would the indications be? I'm guessing pretty obvious...

Any suggestions?

R/
Dustin

Bobboloo · Bobboloo's Garage

Valve adjustment and pinging are not related.

Pinging is a timing/octane related issue. Check your timing. If it checks out OK then I would suggest higher octane gas.

konish · 11-29-2003, 05:39 PM

when I did my valves I had to remove the cap from the distributor. When I replaced it, I noticed that the cap could be rotated a bit even with the spring clips installed...I thought it was odd. I mean, you could really move it a degree or two! I wonder if during my replacement, I might have moved the cap to a more advanced setting from the original?

R/
Dustin

Superman · 11-29-2003, 07:18 PM

Cap position will not affect timing either. I had an instance of what sounded to me like detonation recently. Twice actually, over several weeks. At the dyno shop, the guy told me I was not hearing detonation, but rather, it was a rattle. That's my guess in your case. I think something might have been left loose. At any rate, valve adjusting won't cause detonation.

konish · 11-29-2003, 09:44 PM

Robbo, Supe,
Thanks. I didn't suspect the valves being the cause of my new pinging problems...I think I was fishing for common mistakes that folks make when doing the valve adjustment that I may have overlooked. Its definetly not a rattle....classic pinging (as heard on my Buell, Moto Guzzi, H-D and an old Toyota P/U I had). Anyway it just seems odd that it would start just after the valve adjustment. True, I have not checked the timing, so that can't be ruled out yet. Also, I've been running the same grade gas for the last 3 weeks, and haven't noticed any noise from the engine. I did check to see if everything was secured back there, but I'm almost certin it isn't something rattling. I'd hate to put premium gas in it just to make the ping go away without knowing the root cause first (again could be the timing). Well, I guess in the mean time I'll just run premium so as not to harm the motor and use part throttle until I can figure this out. Questions:
The advance on the distributor looks like a vacum type, but it has two tubes...a blue one and a orange one. Does the vacum advance only work under full throttle settings?
Does the dist. get it's vacum from the intake plenum (or throttle body?)
Does the DME have a throttle position sensor to change the fuel map when WOT is selected?
I assume pinging can also be caused by a lean condition under load so maybe a mixture problem?

R/
Dustin