blownsmoke2

I had a thread going last week called I think I've got a blown head gasket. Well we took the head off Saturday and much to my suprise 4 out of 6 pistons were melted on outside edge along cylinder wall. I'm trying to figure out why this happened. My pyro hardly ever hits 1200 degrees and thats in manifold. Also why does #3 and #4 look brand new? Most of the melting is were the exhaust valves are but that makes since because the exhaust valves suck the heat out so its the hottest point. I think what ticks me off the most is I really thought I was doing it right this time. 5,6XXmi ago I dropped a valve seat in last motor so I took this one to Scheid and had them due the head,cam,injectors,firerings,and studs and here I am again pulling motor. By no means is it there fault,but what due I due now? Due I pull it out and put Aries or Ross pistons in it or stock ones,or turn the whole thing back to stock and give up? Maybe its the injectors spraying wrong or to much timing, to many programs. I don't know. Any insight would be appreciated because at this time I'm to frustrated to think about it.

PourinDiesel

Check the injectors. Maybe your just running too much fuel for what you are doing. You might not have enough air.
Could be many things.

53 willys

bummer I am sorry for your trouble....like you said I thought you had done it right by the mods you listed...I wounder what happened?????

Luvnacumns

Man don't give up now....

Rob C

Back when I use to run a blower on my small block Chevy race motor, I use to melt pistons from to much boost, not enough fuel, and it would eat them up around the exhaust valves. You didn't say if you did a turbo upgrade with all the other stuff you did, but figured I would throw it on the table as a possible reason.

PourinDiesel

Just a thought: I seem to remember other engines melting when stacking a Hot Juice with a programmer. You might have way too much timing.

bulabula

Ouch, sorry to hear about that.

Due to its placement, your single pyro reads the "average" temperature of all 6 cylinders; some cylinders can be hotter than 1200, some will be cooler. Its due to things like production tolerances and most likely differences in fuel injectors (some passing more fuel than others). If you had a pyro installed for each cylinder, you would have much better knowledge on whats going on in there on a cylinder by cylinder basis. Don't be naive and think that all cylinders are pumping the same energy - especially at the ragged edge.

Another issue that might be working against you is that there are differences in pyro's - some can read hotter and some read colder. Whats a hundred'ish degree's amongst friends? Probably nothing at 900F, but can amount to something when playing around 1300F on a routine basis.

Back in the day, we used to spend considerable effort in monitoring individual cylinder temps and calibrating equipment to ensure we had an accurate picture on whats going in those big diesels.

Don't know why the inner cylinders are running cooler than the outside, so I'll leave that to someone else.

hth

abc4yew

Your pyro lead could be toast....like PourinDiesel said....too much fuel before combustion....poor spray pattern....What kind of injectors....any fuel in the crankcase. Lots of reasons for burned pistons....The more advanced the timing the cooler the EGT's but the cylinder temps are still very hot and if you heat sink the pistons and cylinders (little or no drop in temp between combustion events).....then the pistons will melt.... Never heard of anyone melting pistons with too much air .... always too much fuel at the wrong time. ks

jeremy judge

Maybe the injectors on #3 and #4 are bad this would bring down the pyro temps if they were running 500 degrees and the rest were 1500 degrees,like the one guy stated it is an average of the cylinders.

blownsmoke2

I think its either a timing issue or the way the injectors were honed and they spray wrong I don't know. I'm leaning toward timing. I think if the injectors were spraying when the piston is at full destroke the fuel may just be ponding on them than spraying in the cone. Now i'm trying to figure out should I put aries or ross pistons in or just put stock ones back in. Any suggestions? Also when I drive this truck 99% of time only run Juice on 2 and EZ and BD off. But it must not take much to melt pistons. Also I never had timing rattle, I thought that was one of the symptoms of too much timing. Also the morning I sled pulled truck I mixed actual methanol with water instead of just water which adds more timing yet. Either way I think i'm done with SL and stacking boxes. I beleive I'm may just do a TST,stage2 cp3,injectors, and my sledpuller 66 turbo. Maybe even bigger injectors.Huh?

blownsmoke2

I think when this thing goes back together I will put a pyro in along with at least one more on other end of manifold.

PourinDiesel

Dude you must be made of money to put that thing back together again!

blownsmoke2

I'm running a HTT Sled Puller 66 turbo.

TheBigNasty

I.E. running lean. This is not the case with a diesel because they run lean in normal situations because there is no throttle regulating air.

53 willys

get the good pistons....do it right....again