I am afraid I have some bad news.
My car overheated while a pipe of the coolant reroute slipped and lost all of my water in a matter of a second.

I didn't realise it because in tunerstudio,which I am monitoring via a carpc all the time, didn't show any overheat. I had 80-90oC when it happened. I the sensor was actually measuring the air in the pipes.

The only sign I had was heavy knocking when I was in boost. So I stopped thinking I was out of methanol/water and the realised that I had a water pipe off the system.

I rejoined the pipe and filled the system with water. The start was quiet hard. It didn't want to start. The engine was flooded. It started when I unflood the engine with 100% tps but it was running rough in idle.
The car in low throttle and boost was running fine. I boosted after this up to 28 psi without any problem. No smoke, no detection that the car has a fault. Just rough idle and couldn't start easily.

The next day I measured the compression. Now are the bad news.
A week before I measured 165 165 170 165. Quiet good number.
Now it was 140-90-90-120. SHIIIIT. I didn't know how deep was the ****...

So I took the car to a friends garage. We took the head out and we found a blown headgasket and the head was not straight underneath( I don't know the word in english) It had to be resurfaced.
The pistons were clean and so does the cylinder walls.The block was straight also. (good news)

So we resurfaced the head on a machine shop and replaced the headgasket.
New compression numbers : dry 140-115-115-130. **** TWICE.
wet: The same numbers

The problems remained the same. Rough idle , couldn't start easily and the engine was flooded all the time.

So we performed a leakdown test. We performed it where the valves were fully closed. We opened the cover to be sure.
The results in all cylinders was that air escaped from the other 3 cylinders. You could feel and hear huge amounts of air passsing through. We also heared good amounts of air through intake side and the exhaust muffler. (valves?)

There was a very tiny leak from the oil dipstick but not something serious.
We will take the head again on Monday and measure it at a machine shop.

Sorry for the long post. I need your opinion on this.

 

Block deck might not be even

 

 

A warped head could cause sticky valves, If you have extremely loud HLA noise, that would be the problem. Head bolts could have stretched. Block or head could be cracked, also there could be damage to the rings.

 

you will resurface the block and the head and put a new HG in

you will never be happy with how it runs again

get a new long block

 

Just as a reference, when we overheated our CBR600RR engine for FSAE, we spun a crank bearing. So I hope for your sake its just a warped deck.