Head Gasket fuel rich?

[f117v6]

Will a leaking HG cause a lean condition? Went to track did three runs powerlogger running everything looked ok o2s afr etc. Car idled a little weird in pits so loaded up took it home and # 3 spark plug ground strap was gone Car had been running strong before , the track passes but if that gasket went would that cause my one cylinder lean condition. I have taken engine apart to short block yes HG was leaking not the worst i have seen and it was #3. The rest of the pistons looked fine {normal}. I had injectors sent to caspers ele. they where good.Trying to diagnose problem so there isnt a repeat . P.S Wanted title to say lean /rich couldnt edit that

 

[Mr.Spool]

Problem is you have no data

Will a leaking HG cause a lean condition? Went to track did three runs powerlogger running everything looked ok o2s afr etc. Car idled a little weird in pits so loaded up took it home and # 3 spark plug ground strap was gone Car had been running strong before , the track passes but if that gasket went would that cause my one cylinder lean condition. I have taken engine apart to short block yes HG was leaking not the worst i have seen and it was #3. The rest of the pistons looked fine {normal}. I had injectors sent to caspers ele. they where good.Trying to diagnose problem so there isnt a repeat . P.S Wanted title to say lean /rich couldnt edit that

things to looks for are fuel pressure rise 1to1 and target a richer Afr with the proper octane and timing.

 

[Chuck Leeper]

Post clear pics of all 6 plugs. Then cut the threads off, and shoot clear pics of the fuel ring...

 

[Nick Micale]

Will a leaking HG cause a lean condition? ..........

My opinion is just the opposite, a lean condition "ate" the ground strap and then trashed the head gasket!

Like Chuck said, the other plugs will help tell the story, as it was lean and hot as hell to evaporate a ground strap.

No data, no decent opinions on the cause, but lean or not enough octane are most likely your issue?

 

[captndave737]

I have a dumb question. What is a #3 spark plug ground strap?

 

[mikestertwo]

I have a dumb question. What is a #3 spark plug ground strap?

It's the ground electrode on the spark plug. The tab you bend to set the gap.

 

[f117v6]

My opinion is just the opposite, a lean condition "ate" the ground strap and then trashed the head gasket!

Like Chuck said, the other plugs will help tell the story, as it was lean and hot as hell to evaporate a ground strap.

No data, no decent opinions on the cause, but lean or not enough octane are most likely your issue?

 

[f117v6]

Hi guys thanks for your replys ,I know I didn't have the a lot of details in my post. I think Hg was questionable before I went to the track.Compression test close ,no milk shake none of the typical type red flags that it was blown I probably should have spent a lot more time on this. My narrow band o2 # at wot 3rd gear top of track where 780 770 afr where 11.00 10.90. I am working on getting the runs off the power logger and on here so I can be interpreted ,,,not great with computers. My opinion was my hg was weak =leaking my tune is very close =to lean side and if the cylinder was leaking would that have leaned it out and caused the spark plug strap . I will see if I can get those plugs and post some pics the rest of the plugs looked OK ,all the Pistons looked OK to but my hot #3 I had the melted Speckles floating around. Thanks for the replys guys I will try to get the pics and power loggers run on, I will be putting the engine back together didn't want to do a repeat ,,and I will be getting more fuel.

 

[captndave737]

It's the ground electrode on the spark plug. The tab you bend to set the gap.

Duh! I had never heard the ground electrode referred to that way.

 

[LANDAU LIMITED]

I never heard of a leaky head gasket burning a strap off a plug. If its leaking that cylinder would be down on power = less heat. Did you check the ring lands on that piston? Was this a new engine or a high mile one? It could have been slowly eating itself due to poor ring seal. Oil is a octane killer. I took a strap off a AC delco plug and it did hurt the ring lands on that piston and had to replace it. If you are running NGK's I heard their straps act like a fuse compared to the others like a stock head gasket compared to a bulletproof ones. When you put it back together it wouldn't be a bad idea to do a leakdown or compression test.

 

[Nick Micale]

I never heard of a leaky head gasket burning a strap off a plug. If its leaking that cylinder would be down on power = less heat..............

I guess you do not have any experience with high HP turbo Buicks, as I have seen this many times over the years on my cars, and lots of other GN's?

The spark plug is the major hot spot in the combustion chamber. A lean mixture, or not enough octane, will get you pre-ignition which first attacks the plug electrode. Usually after a run or 2 at WOT it will finish off the plug and will take out a head gasket if you are lucky there, because it then attacks the head surface, block, piston, or valves.

I have seen a dumb-ass owner destroy the plug electrode on a pass, replace the plug and make another pass which then totaled the engine including the block.

 

[LANDAU LIMITED]

Isn't that what I said? The head gasket didn't take out the spark plug?? I was stressing to check that piston because it may be damaged beyond use and it may be a oil control issue to begin with. Just something to look out for.