1981SC Pinging - Page 2

teenerted1 · 11-05-2008, 04:03 PM

you didnt say how long in storage and you dont say where you are located, but could it be the fuel has seperated, do you have ethanol blended fuel in your area? thats my only guess.

Nicks911 · 12-02-2008, 06:08 AM

Car was stored for two years with brimming tank and stabil. That fuel was drained and it has been driven ~3K since storage so I don't think fuel is the problem as it has many tanks run through the system.

However, I think the person who voted for tired engine at ~133K might be right. I never really monitored my oil consumption that closely but it appears to be about a quart per 500 miles now that I have been logging it.

I know that buring a quart of oil 800-1000 miles is considered normal how high can oil consumption get before you have to rebuild?

If it is blow by causing the consumption problems and band aid fix to get me through the next 6 months / 6K miles? (I go onto my next assignemnt then and the car will sit for another two years)

NIck

T77911S · 12-02-2008, 06:37 AM

Quote:

Originally Posted by Nicks911

Spent some more time with the car and a timing light. If I set the idle to factory spec I get too much advance and pinging at 6K. If I set the timing so the advanve at 6K is correct I'm about 10 degrees more retarded then factory spec. Cra runs OK just hestitates a bit at low RPM. Thoughts?

Nick

my 77 is the same. my vacuum retards timing 15 deg. my mech. advance is 20 deg. for a total of 35 deg adavnce. if i set my timing to spec, 0deg at idle, i have 35 at 5k and spark knock. if i set it to 30 at 5k, then it is 5 deg AFTD but on spark knock. i left it at 30 deg, but removed the vacuum, and lowered the idle. it does not start as quick as it use to, but it seems to run ok. idle does not seem as smooth either.
the dizzy was rebuilt a few years ago.

Superman · 12-02-2008, 08:34 AM

I'd guess you have a broken spark plug insulator. The ceramic part. If not, then a crack in an ignition wire that's grounding to something. The symptoms are classic.

Nicks911 · 12-03-2008, 12:32 PM

Superman

Are the symptons "classic" for my problem or for T77911S?

Nick

Nicks911 · 02-09-2009, 09:57 AM

Replaced Plugs wires cap & rotor and the ping was much more subdued. Set idle advance to 0 degrees and pinging went away completely. Car seems to run fine this way.

Additionally with the new WUR keeping the FI pressures within spec and all the new ignition parts car runs better much better than before. Starts right up and drives away smoothly when stone cold. A few mornings here it was down in the teens.

Just wanted to give an ending to the story as it may help others.

Nick

RoninLB · 10:24 AM

Quote:

Originally Posted by T77911S

my 77 is the same. my vacuum retards timing 15 deg. my mech. advance is 20 deg. for a total of 35 deg adavnce. if i set my timing to spec, 0deg at idle, i have 35 at 5k and spark knock.

try running with vacuum line disconnected and max advance at 35

ps: keep it disconnected

T77911S · 02-09-2009, 11:06 AM

i did not like hte way it idled. sounds better with the retard. also with the retard, i can richen the mixture some more without the surging.

if you still have your 2.7, try a 3.0 throttle body. i just put one on and i am very pleased with the improvement.
the 2.7 will come out soon anyway, i have a 3.0

RoninLB · 02-09-2009, 11:20 AM

with the 1977 Calif smog ignition curve I think you're creating problems with pinging and CHT heat. Other states and Canada had the vac line attached but plugged from the factory.

Idle sounds should be sharp due to no overlap of the CIS cam. Fuel mix to a 3.5 as per J Walker etc.

thanks for the 3.0 info but I've been into carbs for awhile now.

btw... I use 87 gas with extensive engine monitoring, although I suggest 91