PopeyeTheSailorMan

Well as i suspected my pistons are shot. The headgasket blew and the edges of the pistons are pretty much fried. So here is the dilemma, do i need to pull the whole engine and have the machine shop re-hatch the cylinder walls? I did the fingernail test and the walls feel smooth still. I know you can use a dingleberry tool to resurface the walls, but i dont know how comfortable i am with doing that. So let me know what you think about the pictures. Also, why would my pistons do this? The car is fully built and was properly tuned at 17psi with the hondata putting out roughly over 4 to the wheels.

avividmemory

what headgasket were you using?? and to rehone the cylinders, you are more than likely going to have to pull the block, unless you want small shards of metal floating around your crank and what not...and again, i could be wrong, but for safety sake id pull it to do the rehone...

rOby

is that an h22 block? if it is , theres ur problem

AlphaKennyWun

I would like to know what head gasket. Also looks like detonation, 17 psi might be a little high for pump gas if thats what you were using. The lower cylinder wall looks worse than the top combustion area wall, can you feel the scratches down there?

rOby

so its a h22 block w/ stock sleeves and aftermarket pistons?
thats your problem right there if it is. FMR lining

rOby

i wasnt tryna say your stupid.
what were the piston to wall clearences?

PopeyeTheSailorMan

I didnt take it that way, but ive seen 100's of morons out there trying to run the aftermarket pistons with the stock FRM lined sleeves. I'm not 100% sure of the piston to wall clearances, the machine shop has all that data. Im also going to speak with JE about this and see what they have to say. The majority of my information is on my home computer and isnt available right now, so what are the suggested clearances? thanks.

earl

Lucky guess Sometimes the problem after doing something like this is not what you can see and feel but what only a bore guage can measure. Are the cylinders .002 out of round? Did they baloon out in the center? Only your machinist can tell you for sure. If you are not perfectly round up and down the cylinder, the same thing can happen again. The new rings will not seal. Let your machinist look at it.
Hard to say why this happens. At first glance it looks to be extremely lean but you say the tune-up was correct. It could just have been not enough octane for the boost. A little detonation started which caused it to suck oil in that area which made it worse. Really hard to say. Maybe you did everything perfect but the gasoline just wouldn't stand up to it. So hard to say for sure. What ever the problem was, it will repeat if everything stays the same.

PopeyeTheSailorMan

Earl, do you think that the ignition system that was added after the dyno could have helped out in the detonation? When a wideband 02 is used, if you need more octane will it show up in the a/f ratio? Only pistons 1 and 4 were damaged, 2 and 3 seem to be just fine. When a headgasket is blown and coolant enters the combustion chamber wont the combustion chambers increase as well as run lean due to fuel and coolant mixing?

earl

I'm not a tuner so it's hard for me to answer your questions. Since the a/f is just a ratio, I would guess that octane value would not be taken into account. You would certainly need a system that would retard the ignition under full boost situations. Also make sure fuel delivery system is adequate to keep a continuous supply of gas under full throttle situations.
You have a question like "what came first, the chicken or the egg?" Headgasket could have caused the problem or the problem could have caused the headgasket to blow. I'm really not sure but my GUESS would be lean condition or incorrect timing caused every thing that happened.

PopeyeTheSailorMan

I'm thinking the ignition box helped to **** things up.

Fuel goes as follows:
walbro 255 intank
aeromotive fuel filter
aeromotive fpr
-8an feed
-6an return
str fuel rail
800cc inj
hondata 4b (takes care of the retard timing, as im sure you know)

ignition- crane

Jared

Even a Hondata 4b cannot detect full throttle detonation which is the worst kind. That looks like too much boost for pump gas period. I'm sure the detonation caused the piston damage and the blown headgasket. Fuel supply isn't your problem, it's the type of fuel.