I had a 355 afr 190 heads xfi280 cam .576/.570 .015 head gasket stock length pushrods 5.7 rods flat top pistons 6cc and on 1st start up it was making a weird noise like it was coming from the lifter area so I tried adjust them but same noise and after I rev it a little a loud pop noise happen and the engine cut off I tried to restart but was locked up I pulled off both heads and #1 piston was shattered and the rod was bent anybody have any clue what went wrong or what was the noise I was hearing
How much is "rev it a little"? To bend the rod, something pretty much had to stop the piston from moving up, are both valves still in the head? If it was just turning over with the starter with liquid in the cylinder, it could have bent the rod, water doesn't compress. Perhaps the piston was cracked, came apart and a piece of it wedged in the cylinder bending the rod?
I had a 355 afr 190 heads xfi280 cam .576/.570 .015 head gasket stock length pushrods 5.7 rods flat top pistons 6cc and on 1st start up it was making a weird noise like it was coming from the lifter area so I tried adjust them but same noise and after I rev it a little a loud pop noise happen and the engine cut off I tried to restart but was locked up I pulled off both heads and #1 piston was shattered and the rod was bent anybody have any clue what went wrong or what was the noise I was hearing
Sounds to me like you had the valves to tight and was hitting the top of the piston JMO and when you re-adjusted them you went to tight and the valve hit and then the rest was history IMHO.
Be willing to bet you have a bent valve also. :sweat: ain:
But for you sake i hope not i have been wrong before. :thumbup:
Cole
imp:
so, only 280 degree cam with .575 lift and a thin head gasket (0.015). Which creates a similar situation like a cam with .600 lift with valves open a good amount very close to tdc.
Did you check piston to valve clearance before running a setup like this?
Sounds to me like you had the valves to tight and was hitting the top of the piston JMO and when you re-adjusted them you went to tight and the valve hit and then the rest was history IMHO.
Be willing to bet you have a bent valve also. :sweat: ain:
But for you sake i hope not i have been wrong before. :thumbup:
Cole
imp:
If you happen to have only a two valve relief piston, and you installed the piston upnside down in the block, there is a good chance the valves hit the piston.. just an idea.. unfortunaltly ive seen guys do this not paying attention when they install the rod and pistons
It takes a lot to bend a rod. Hydraulically locked is a reasonable explanation if there are no witness marks from the valves getting into the piston, and if there is no scuffing to the cylinder walls from rings end butting. Trying to get a handle on this w/o a picture and w/o all the info is hard- can you take a few shots of the rod, piston, cylinder, etc.? Try to give us ALL your info- everything that you can think of that might help.
Was there water in the oil or oil in the water? Did the engine flood w/fuel, does it have an electric fuel pump? What was the ring end gap and piston to wall clearance? Any chance the pistons were KB?
Did the rod bend a little or a lot, did the big end let go or was it still attached normally to the crank? Wrist pins tight? What do the rod bearings look like- was there any detonation?
I think it was just the "Hyperutectic" pistons used. That's what they do with detonation. They are higher in silicon content; think of it this way, glass also contains silicon, and glass "shatters", it's "brittle". Since all the auto manufacturers went with hyperutectic pistons, the aftermarket has followed. But, new vehichles all have EFI and sophisticated ignition systems designed to avoid detonation. Hyperutectic are less forgiving than "straight cast", and even moreso as compared with forged. Piston shattered, rod got wrapped around the crank, and locked everything up; pretty straight-forward occurance. What brand pistons? "One" particular brand has a history of problems, unless stringent ring gaps bare followed. It could have also been a defective piston; two major brands are now made offshore.
My guess is that something made its way into the cylinder and made a funny noise for a moment until it caused the piston to fracture and the bent rod is just collateral damage.
What exactly does this mean? To my use of the term "deck clearance" this is the amount of space from the crown (not including valve reliefs, dishes, or domes) of the piston to the block surface that the cylinder head bolts to.
If this is the case .028 is extremely tight.
The other important measure is the distance between an open valve and the approaching piston. For a street engine a good rule is the intake misses the piston crown by at least .080 inch and the exhaust by .1 inch. This is because street engines don't get torn down very often and wear in the cam drive can allow the piston and valve to meet.
For a competition engine you can run this tighter say .050 and .080 with the understanding that over a season the critical wear items will be checked if not replaced.
This is an effort on top of squish/quench clearance which pretty much requires the engine be assembled with clay on the piston and rotated to get an impression of the valve then opened up, measured, adjusted if necessary, then reassembled. Here's a link to the process http://www.carcraft.com/howto/116_0701_valve_to_piston_clearance/viewall.html
Let me add that when you do this it must be with a solid lifter, a non running hydraulic cannot be trusted to maintain position of the plunger against the retainer (even a pumped up lifter may sink against valve spring pressure) so either use a solid for testing or take apart a hydraulic and fill it with washers just as you would for determining push rod length.
I'm surprised at the bent rod, not so much at the hyper piston gone to pieces. The valve and valve train usually gets the worst of this type collision but hypers are quite strong but brittle, they don't like to be hit. The bent rod is more like something you see with a hydraulic lock. While this is usually coolant getting into the bore it can also be the result of too much oil or fuel or other liquid being poured into the intake system prior to start up. It's possible this started with liquid in the bore and the valves got bent as the piston came apart. But your dimensions and the bent valve really point me at the clearance between pistons and valves.
Bogie
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