Explain how I fixed it???
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Explain how I fixed it???
I had a problem where at WOT above 3500 RPM the car would ping, then loose power as the timing was kicked back from the knock sensor, at the same time the fuel would go rich and black smoke would come out...until I let off the gas.
It also smoked when I started the engine, but that was valve guide seals and I knew how to fix that.
Well, I decided it was time for the seals...and I took the opurtunity to put in some better valve springs when I did the seals. That was last Friday, I was happy it no longer smoked when started...and the valve adjustment was better...and surprisingly enough...it now pulls cleanly to 5000 RPM+ with NO pinging above 3500 RPM! I thought it was a fluke maybe...so I drove the hell out of it just to see...and it is now confirmed...that problem is now gone for good.
Only one question now...How do valve springs/seals fix high rpm pinging???
It also smoked when I started the engine, but that was valve guide seals and I knew how to fix that.
Well, I decided it was time for the seals...and I took the opurtunity to put in some better valve springs when I did the seals. That was last Friday, I was happy it no longer smoked when started...and the valve adjustment was better...and surprisingly enough...it now pulls cleanly to 5000 RPM+ with NO pinging above 3500 RPM! I thought it was a fluke maybe...so I drove the hell out of it just to see...and it is now confirmed...that problem is now gone for good.
Only one question now...How do valve springs/seals fix high rpm pinging???
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Explain how I fixed it??? (BBA)
My 86 pinged as well when the seals were leaking...but it turned out I had worn valve guides as well.
When the oil was getting into the chamber it would end up fouling the plugs overtime.I think the oil was keeping a complete burn from happening causing excess fuel to be blown out the exhaust and causing a misfire or ping.That would cause fuel and oil smoke as well.Defintely a loss of power there and annoying timing retard by the knock sensor.
Just be glad its all done now and running like its supposed to.
When the oil was getting into the chamber it would end up fouling the plugs overtime.I think the oil was keeping a complete burn from happening causing excess fuel to be blown out the exhaust and causing a misfire or ping.That would cause fuel and oil smoke as well.Defintely a loss of power there and annoying timing retard by the knock sensor.
Just be glad its all done now and running like its supposed to.
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Explain how I fixed it??? (Bill's86Coupe)
Bill..did you replace the springs or seals when you fixed yours, or did you have the heads reconditioned/replaced and that fixed it? See, my guides are slightly worn also...but heck, over 106K miles I exect it :D
I'm just surprised the drastic change in the way the motor runs by simply changing springs/seals. It even runs smoother...I can barely feel it idle now, even in gear.
I'm just surprised the drastic change in the way the motor runs by simply changing springs/seals. It even runs smoother...I can barely feel it idle now, even in gear.
Thread Starter
Safety Car
Joined: Dec 2000
Posts: 3,767
Likes: 5
From: Jacksonville Fl
Re: Explain how I fixed it??? (BBA)
I'm thinking about what you said...worn seals letting oil in causing incomplete burn..etc...
Well, if that was the case, I would have seen discoloration on my plugs...they looked perfect...slight chalk color, no wetness, no buildup of junk.
Also, you would think it would be worse at low rpm/hi vacuum if it was sucking oil past the seals...since at hi rpm/wot the vacuum is too low to suck anything in. Does that make sense to you? I'm thinking maybe more along the lines of the valves were floating at hi rpm's...causing fuel to not ignite completely or even blow back into the intake...which could cause all kinds of weird noises. That could probably set off the knock sensor too, I would think.
The whole thing still confuses me....I probably won't stop thinking about it until it makes sense or someone who knows for sure ca come forward.
Well, if that was the case, I would have seen discoloration on my plugs...they looked perfect...slight chalk color, no wetness, no buildup of junk.
Also, you would think it would be worse at low rpm/hi vacuum if it was sucking oil past the seals...since at hi rpm/wot the vacuum is too low to suck anything in. Does that make sense to you? I'm thinking maybe more along the lines of the valves were floating at hi rpm's...causing fuel to not ignite completely or even blow back into the intake...which could cause all kinds of weird noises. That could probably set off the knock sensor too, I would think.
The whole thing still confuses me....I probably won't stop thinking about it until it makes sense or someone who knows for sure ca come forward.
Race Director
Joined: Aug 2000
Posts: 14,130
Likes: 7
Cruise-In II Veteran
Re: Explain how I fixed it??? (BBA)
When I pulled the heads off the engine, I brought it to the machine shop(had almost 95k miles) and had them measure and check the wear..it was BAD...the alloy heads are notorious for wearing out in the guides.
Thats what Ive found out..its worse on the exhaust valve then the intake for some reason.
I let the "pro" show me what was wrong since Im not a expert internal engine builder or anything.
My plugs were alot worse then what you described about yours..mine were getting black and fouling every 2,000 miles..some bad,some not so bad.
So while I was at it, decided to get the whole engine redone, new pistons, rings, rehone etc etc.
Maybe your plugs were good but the extra oil in the chambers getting burned off by them wasnt giving enough spark to get all the remaining fuel burned...that would prob lead to a dead cylinder over time. Happened in my case.
However in your case you noticed a ping,which just may not be a complete burn in there.Or maybe igniting the oil/gas made it hotter in the chambers.Im sure someone else can chime in here later with better details.
