Part 2:
So the mechanic pulls the engine apart and see's all the holes in the pistons. conversation went like this:
Mech: "first thing i did was check the head to see if the valves were touching the pistons. it didnt look like it. So i rang up my engine builder and explained it to him. he said that his seen it before, kids bring engines back a week later with holes like urs. it was detonation. the tune was shit. u cant go running all that boost without premium fuel"
Me: "i always ran BP98. it has a full tank it in now, 98ron."
Mech: "Well what about ur fuel system. sure u had big injectors in there, but a stock fuel pump cant cope with them. it prolly leaned out on high boost"
Me: "Umm it has a brand new pump. flows 255lph, good enough for the power i was making, its good enough to outflow the stock lines"
Mech: "WHat about the timing? did the 'tuner' check the timing"
Me: "Yeh the first thing we did was time the engine."
Mech: "Well it knocked its head off. nothing else too it. My engine builder has been doing this for years, he hasnt messed anything up. THe piston to wall is fine, nothing is out of spec. not OUR fault. Now how much u gonna give me for pulling the head"
Me: "Ur asking me to pay for repairs to my 1500km old engine? lol, sue me"
Anyways so i took the car home, pull the engine out, orded new pistons and shiped it, and my spare engine and EVERYTHING else off to another reputable builder. I left everything assembled so i could could organise the engine to be professional stripped to find the cause of the problem.
Few hours go by and i get a call. "Hey did u realise u had piston to valve contact? Take a look at the pistons. Did the builder check the valve clearance with vtec locked in? This cam is pretty wild compared to stock and with a shaved head and decked block, u should expect it..." ...... Umm no he didnt, he told me many times 'all i did was get the bottom end rebuilt and slapped the head ontop. I didnt even take off the dizzy. i did nothing wrong..." Right..
Problem #1: Piston to valve clearance. Valves were mashing the pistons during vtec. Maybe the problem was enhanced by his 'tighter valve lashings' he did to quiten the engine down.
So a few days go by and i get another call from the engineer. "Everything else on the bottom end checks out ok. I couldnt really accuratly measure the piston to bore because of the wear."
So the bottom end gets rebuilt. Well actually i trashed most of the bottom end (cylc etc) cause it overheated so many times and the deck has sunk 0.008". So the old bottom end is rebuilt, new bearings and seals all around again.
Few days more go by and i get the low down on the head. Apparently the valve guide clearance was way over spec on 8 valves. 4 valves were not even holding compression properly at all. The engineer was surpirsed it made any power at all. All valves were straight though, and nothing was bent. Head since has been completly rebuilt and all new guides right around.
Problem #2: Valve guide clearance. THis in turn caused the piston to valve clearance to come out of spec and piston to valve contact occour on the vtec cam. Another by product of this was oiling down of the pistons. The guides leaked oil into the chambers. This caused both hot-spots to form at the sharpest and thinnest points (the intake valve releifs), along with overheating the pistons causeing piston to wall contact, which in turn we THINK cause all the overheating issues. It probably also reduced the octane of the fuel down to 86 or lower causeing knock which probably finished off the overheated pistons. Bowzer made a great comment - Yes the new pistons will be modded to reduce hotspots occouring. I have also gone with weicso pistons this time. The reliefs are a little thicker and they come coated for less expansion.
This is how the car sits atm. Just waiting on a few parts from the US.
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