how did the headgasket look? perhaps its seal isnt the best, considering 3 and 4 are adjacent cyls...not a guarantee on anything, just food for thought

 

i agree, don't trust the piston maker to set end gaps for you, every engine isn't exactly the same.
If you built it and don't know what, for example: ptw or rind end gap is set to, maybe someone else should build it.

haven't seen one measurement in this thread about your engine build.

oh and ditch the log.

 

What are the ring gaps, pics of the cylinder wallas and tops, kinda like to see the dome on the head too, what headgasket is being used?

Im thinking a warped deck and/or head causing a bad gasket seal between cylinders? that would cause an instant dteonation crank ringslands real easy. crap nippons but alot of peopel have success with them. Ring gaps to tight but should show wear on the cylinder walls

 

It's actually the exact opposite. Diesel has a very low octane rating, usually in the single digits to low double digit range. Motor oil is a lot lower than gasoline as far as octane rating goes but it is hard to find exact rating information since octane rating in a motor oil isn't relative to its intended use. Two stroke oil that gets mixed into gasoline or injected into the combustion process with gasoline will drop the octane rating of the fuel by 2 full points (91 becomes 89). There is a very small amount of gasoline that actually gets injected into a cylinder during combustion so it only takes a minute amount of blow-by to cause problems/detonation.

 

This should be stickied at the top of the forum.

 

yes, im actually a diesel mechanic. diesel engines dont use the typical octane rating, they use cetane. since diesels work with much harder fuels to ignite(compression combustion) you can have a much cruder form of fuel, i.e. diesel or oil. a diesel engine will run strickly on oil alone, in these cases you get runaway or the term dieseling.

 

yea one of your problems
ovaling walls
ring end gap
ptw
bad gas
not enuff gas
tuner
maybe its sleeved and ure doin to much boost idk whats the build n specs u or whoever built it to? ptw,ring gap .ect

 

B18C8, Be quiet!!...it doesnt make any sense for you to keep saying the same thing page after page...

To the OP, I'd like to know the oil consumption your engine used, and did your engine ever overheat or have cooling issues? to me, I think you knew your engine had issues and in the meantime trying to diagnose/test it out, you blew it. there are just too many intricate things that go into engine building that if you dont know what your doing, you can cause yourself problems.

not saying you don't but whenever I build/rebuild, I have a machine shop check out all my parts...head, block, rods, pistons...etc to make sure I'm not adding any problems before I get it completely together. just a good rule of thumb when building. on engines your eyes are your worst enemy. a mm meaurement off in some cases can ruin engines.

good luck to you on your rebuild...keep us updated, and thanks Chris for all your years you've been in this community and G2IC helping us.

 

Whatever you have for knock control isn't working or letting you know in time.

 

take this as you will, but i can't remember the last car i tuned that i enabled a knock sensor. ive got over 50 setups under my belt (ok its not much but this is just my hobby) and not one of them ever blew up because of a fuel or timing setting. as chris said, the tuner is last to get the car and first to be blamed. ive been brought some crap over the years and the net result is they dont run very well. ive also been brought some fresh stuff and they rip ***.



this thread is starting to become redundant, posts are either the same few possibilities of failure or people talking in broken internet english... op, rebuild this beast. also just popped into my mind but you can pick up an egt and put that in #3 runner to see if you are preigniting due to high cyl temps which would not necessarily be caused by tune, more of a driving habit