Blown head gasket

[ORFORD2004]

Today i removed the head on my 2L. the engine have 4.5mm dome piston with big valves and 80-40 cam from international auto sports. I'm running on megasquirt now. There was somme bubbles coming out from the overflow tank and the engine was heathing. My compression was around 215. So i order a 5 layers gasket from Mark and when i pulled the head , look what i found:

[ORFORD2004]

[divace73]

Can't tell yo much about head gaskets, I just fixed up the image link.

[ORFORD2004]

Look like the only cylinder that was ok is the #1
What can cause this??? Detonation???

[So Cal Mark]

I would think detonation. Is the head flat? Were the head bolts torqued properly?

[ORFORD2004]

Th head was suppose to be flat. It will be recheck today. I'M not the one who install the head but the engine was built in a machine shop and the kid had my book.

[majicwrench]

Your compression was 215?? Methinks that is way too much.

[TX82FIAT]

Ageed. compression too high. sounds odd to even say it. the 5 layer gasket will change the compession dramatically and you will need to re-tune the megasquirt. I have megasquirt on my 82 and blew the head gasket. Had to take the timing back. There were two issues. One, the tank of gas used for the tune still had octane booster in it causing problems when that tank of gas was fully used and some bad gas was put in. Detenation at hard accel. I recommend using a good brand of high octane gas consistently. ShelI 93 if you have it. Two, the ports near the fire ring can be opened to much if not careful. The water port is very close to the fire ring on #4. I developed a leak from some corrosion/pressure in that area. looking at your picks it does look like some coolant made its way to the fire rings.

[divace73]

Ageed. compression too high. sounds odd to even say it. the 5 layer gasket will change the compession dramatically and you will need to re-tune the megasquirt. I have megasquirt on my 82 and blew the head gasket. Had to take the timing back. There were two issues. One, the tank of gas used for the tune still had octane booster in it causing problems when that tank of gas was fully used and some bad gas was put in. Detenation at hard accel. I recommend using a good brand of high octane gas consistently. ShelI 93 if you have it. Two, the ports near the fire ring can be opened to much if not careful. The water port is very close to the fire ring on #4. I developed a leak from some corrosion/pressure in that area. looking at your picks it does look like some coolant made its way to the fire rings.

I found it suprising that the octane rating in the fuel wasn't that high in the States, in Oz we can get uo to 98 at the pump (mine seems to like BP Ultimate the best??), speaking of detonation, has anybody out there had sucess with a knock sensor connected to megasquirt, I have thought about this many times. I will be MSing my car very soon and thought it would be a good idea incase of the quality of fuels changed??