ls7 head sealing issue
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ls7 head sealing issue
My ls7 blew a head gasket last night (I hope). Stock bottom end 13.3:1 static compression, msd atomic intake, 1 7/8 headers, cometic .036 gaskets, stock head bolts, 250/262 cam, e85. Ran it all last year without issues. I recently switched to e85 and this is my third outing with the car since then. I believe the stock head bolts to be the cause. We had a cold front come through yesterday and the da dropped from 3000+ to 1900. I am obviously going to replace head gaskets and get aftermarket bolts or studs. What is everyone's opinion on bolts vs studs? I cant see my combination requiring studs but I also didn't think I would have issues with the factory bolts. With that said this isn't the first time I have seen an ls engine have cylinder head sealing issues after converting to e85. Anyone have experience with the speed master studs? I'm leaning towards the arp bolts just because of the price point but would value others opinions.
“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
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Re: ls7 head sealing issue
It has a composition sensor. It has been 80-85 percent since I started using a couple week ago.
“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
Re: ls7 head sealing issue
So is the equivalent of saying "My Duramax"? Does "Your LS7" belong to a car, street rod, hover boat?
Is this an attempt at deflecting what sounds like improper torque procedure or prep on the weather?
So you have an all aluminum, titanium outfitted 7 litre engine, and your inquiring on some ching chang chong fasteners? I'd go for it.
Re: ls7 head sealing issue
I'd go with name-brand studs.
Felix, qui potuit rerum cognscere causas.
Happy is he who can discover the cause of things.
Happy is he who can discover the cause of things.
Re: ls7 head sealing issue
Probably too much ignition timing that did it. A common problem with E85.
Try retorquing the heads first.
There's probably at least one bolt loose.
You'll find it by going through one bolt at a time, put a paint mark on it, crack it loose, retorque to spec and take a note of where the paint mark ends up compared to where it started.
That's how you find out.
But it's far easier to just blame the parts.
Try retorquing the heads first.
There's probably at least one bolt loose.
You'll find it by going through one bolt at a time, put a paint mark on it, crack it loose, retorque to spec and take a note of where the paint mark ends up compared to where it started.
That's how you find out.
But it's far easier to just blame the parts.
Re: ls7 head sealing issue
How much spark advance are you running between 5000-6000 rpm with the e85?
Re: ls7 head sealing issue
You should know that "my ls7" is slang used by non other than a jort wearing corvette owner..
It was a reference to this day being likely the highest cylinder pressure the engine has seen since it was put on e85. I'm sure the community speedtalk troll knows this.
I was a question of experience with the fasteners it was clear that i was leaning towards arp bolts with the belief that the studs are overkill on my engine.
“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
Re: ls7 head sealing issue
Retorqueing tty bolts doesn't seem like it would give me any kind of an accurate result. The bolts are designed to stretch and will make them all falsey appear loose using your method when retorqued. The manufacturer makes it clear that they are to be discarded after being torqued.joe 90 wrote: ↑Sat Jul 07, 2018 1:26 am Probably too much ignition timing that did it. A common problem with E85.
Try retorquing the heads first.
There's probably at least one bolt loose.
You'll find it by going through one bolt at a time, put a paint mark on it, crack it loose, retorque to spec and take a note of where the paint mark ends up compared to where it started.
That's how you find out.
But it's far easier to just blame the parts.
“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
Re: ls7 head sealing issue
The ecm adds 4 degrees for true 85% ethanol and interpolates down to 2 at 50% ethanol. It had 83% in it when it happened when it goes into power enrichment. Due to the way cylinder airmass is calculated my engine typically sees over 1.0 at wot. That will give you and idea where it was on the timing table.
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“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
Re: ls7 head sealing issue
So the motor can't see over 30° correct? That doesn't seem excessive to me by any means. But, taking head gaskets out of a NA LS isn't really typical either. Have you considered that it may not be a head gasket? I'm to the point that I'm done with the stock head bolts in anything but stock or slightly warmed over $HIT.
Jorts? I saw a black Z06 the other night blowing white smoke going down the interstate, it had an "anus destroyer" bumper sticker on it and was being driven by a millennial wearing a romper. Was that you? You a St. Louis guy by chance?
Jorts? I saw a black Z06 the other night blowing white smoke going down the interstate, it had an "anus destroyer" bumper sticker on it and was being driven by a millennial wearing a romper. Was that you? You a St. Louis guy by chance?
Re: ls7 head sealing issue
slo-svt wrote: ↑Sat Jul 07, 2018 9:10 am
Retorqueing tty bolts doesn't seem like it would give me any kind of an accurate result. The bolts are designed to stretch and will make them all falsey appear loose using your method when retorqued. The manufacturer makes it clear that they are to be discarded after being torqued.
In which case you'll never learn anything new.
Re: ls7 head sealing issue
There are other tables to consider besides the high octane timing table you posted.
These are not from your calibration, just noting it for things to consider besides the main, high and low octane, spark tables. You might be commanding more timing than you realize.
These are not from your calibration, just noting it for things to consider besides the main, high and low octane, spark tables. You might be commanding more timing than you realize.
Code: Select all
P.E. Spark Advance Correction Vs. Eq. Ratio Vs. RPM
Eq. Ratio RPM
800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200 5600 6000 6400 6800 7200
1.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
1.05 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
1.10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0
1.15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.5 2.0 2.5 2.0 1.5 1.5
1.20 0.0 0.0 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.25 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.30 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.35 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.40 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.45 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
1.50 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
Code: Select all
ECT Spark Advance Correction Vs. Load Vs. Coolant Temp.
gm/cyl. Deg. C
-20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
0.08 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.12 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.16 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
0.20 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.5 -1.0 -3.0 -3.0
0.24 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.5 -1.0 -2.0 -4.0 -4.0
0.28 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.0 -1.5 -3.0 -5.0 -5.0
0.32 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.0 -2.0 -4.0 -6.0 -6.0
0.36 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.5 -3.0 -5.0 -7.0 -7.0
0.40 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -2.0 -5.0 -6.0 -8.0 -8.0
0.44 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -2.0 -5.0 -7.0 -8.0 -8.0
0.48 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.0 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0
0.52 4.0 3.0 2.0 2.0 2.0 1.5 1.5 1.0 0.5 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0
0.56 7.0 5.0 4.0 3.5 3.5 3.0 2.5 2.0 1.0 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0
0.60 9.5 7.0 5.5 5.0 4.5 4.0 3.5 2.5 1.5 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0
0.64 11.5 8.0 6.5 6.0 5.5 5.0 4.0 3.0 2.0 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0
0.68 13.5 9.5 8.0 7.0 6.5 6.0 5.0 3.5 2.5 1.0 0.0 0.0 -3.0 -5.5 -7.0 -9.0 -9.0
0.72 15.0 10.5 9.0 8.0 7.5 6.5 5.5 4.0 2.5 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.76 16.5 12.0 10.0 9.0 8.0 7.0 6.0 4.5 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.80 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.84 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.88 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.92 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
0.96 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.00 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.04 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.08 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.12 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.16 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.20 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.24 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.28 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.32 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
1.36 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl
-Carl
Re: ls7 head sealing issue
I zero ect out above 100f and the pe table completely i also zero out iat table until about 120 which it was below.The only adder that should have been in play was the flex fuel adder and main spark table.In-Tech wrote: ↑Tue Jul 10, 2018 1:57 am There are other tables to consider besides the high octane timing table you posted.
These are not from your calibration, just noting it for things to consider besides the main, high and low octane, spark tables. You might be commanding more timing than you realize.
Code: Select all
P.E. Spark Advance Correction Vs. Eq. Ratio Vs. RPM Eq. Ratio RPM 800 1200 1600 2000 2400 2800 3200 3600 4000 4400 4800 5200 5600 6000 6400 6800 7200 1.00 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.05 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 1.15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.5 2.0 2.5 2.0 1.5 1.5 1.20 0.0 0.0 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.25 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.30 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.35 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.40 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.45 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5 1.50 0.0 0.5 0.0 -1.0 -1.0 -1.0 -1.0 -1.5 -2.0 0.5 3.0 3.5 4.0 5.0 4.5 3.5 3.5
Code: Select all
ECT Spark Advance Correction Vs. Load Vs. Coolant Temp. gm/cyl. Deg. C -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 0.08 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.12 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.16 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.20 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.5 -1.0 -3.0 -3.0 0.24 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.5 -1.0 -2.0 -4.0 -4.0 0.28 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.0 -1.5 -3.0 -5.0 -5.0 0.32 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.0 -2.0 -4.0 -6.0 -6.0 0.36 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -1.5 -3.0 -5.0 -7.0 -7.0 0.40 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -2.0 -5.0 -6.0 -8.0 -8.0 0.44 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -2.0 -5.0 -7.0 -8.0 -8.0 0.48 1.5 1.0 1.0 1.0 0.5 0.5 0.5 0.5 0.5 0.0 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0 0.52 4.0 3.0 2.0 2.0 2.0 1.5 1.5 1.0 0.5 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0 0.56 7.0 5.0 4.0 3.5 3.5 3.0 2.5 2.0 1.0 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0 0.60 9.5 7.0 5.5 5.0 4.5 4.0 3.5 2.5 1.5 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0 0.64 11.5 8.0 6.5 6.0 5.5 5.0 4.0 3.0 2.0 0.5 0.0 0.0 -3.0 -5.0 -7.0 -9.0 -9.0 0.68 13.5 9.5 8.0 7.0 6.5 6.0 5.0 3.5 2.5 1.0 0.0 0.0 -3.0 -5.5 -7.0 -9.0 -9.0 0.72 15.0 10.5 9.0 8.0 7.5 6.5 5.5 4.0 2.5 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.76 16.5 12.0 10.0 9.0 8.0 7.0 6.0 4.5 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.80 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.84 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.88 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.92 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 0.96 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.00 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.04 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.08 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.12 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.16 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.20 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.24 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.28 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.32 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0 1.36 18.0 13.0 11.0 10.0 9.0 8.0 6.5 5.0 3.0 1.0 0.0 0.0 -3.0 -6.0 -7.0 -9.0 -9.0
joe 90 wrote: ↑Sat Jul 07, 2018 7:44 pmslo-svt wrote: ↑Sat Jul 07, 2018 9:10 am
Retorqueing tty bolts doesn't seem like it would give me any kind of an accurate result. The bolts are designed to stretch and will make them all falsey appear loose using your method when retorqued. The manufacturer makes it clear that they are to be discarded after being torqued.
In which case you'll never learn anything new.
So do I just keep retorquing the factory tty fasteners, everytime assuming it loose from the previous time until they finally break? What is the end result with your test? What do I stand to learn from it? I am all for testing but you test is flawed when using tty fasteners...
Update:
The head gasket was not the issue. The piston has a chunk missing (corner of intake valve relief to top ring land) and the sleeve is cracked... I have to look more into it tonight but my initial assumption is it detonated and broke the piston and then hydrauliced and cracked the sleeve. I have to check and see if the rod is bent or damaged when i get the engine out and inspect the rod bearing for detonation marks. I also am feeling like there may have been an issue with ptv the more i look at the pictures which could have just have easily caused both. I will look a little closer tonight after work.
“Pure logical thinking cannot yield us any knowledge of the empirical world; all knowledge of reality starts from experience and ends in it.”
Albert Einstein
Albert Einstein
Re: ls7 head sealing issue
You say you "recently" switched to E85. What was the previous fuel? It's not easy to detonate E85. Is it possible the damage started on the previous fuel?