The discussion revolves around the consequences of incorrect valve timings in engines, particularly focusing on the potential damage that can occur when adjustments are made outside factory specifications. Participants explore various scenarios, including mechanical failures and the implications for both amateur mechanics and high-performance racing engines.
Participants express a range of views on the severity of consequences from incorrect valve timings, with some asserting that catastrophic failures are likely while others provide examples of less severe outcomes. The discussion remains unresolved regarding the extent of damage that can occur and the conditions under which it happens.
Participants note that the discussion is influenced by the specific design of engines, such as whether they are interference types, and the varying experiences of mechanics with different engine configurations. There is also mention of anecdotal evidence from racing, which may not apply universally to all engines.
FishmanGeertz said:Can't the valves collide with the piston and basically blow up your engine?
in the case of the mild grocery getter..you bend a valve(s)FishmanGeertz said:Can't the valves collide with the piston and basically blow up your engine?
Yep. There was a Canadian drag-racer that used to frequent US strips in the 80's with his Camaro. He'd leave the line at 10K and pull hellacious wheelies. I talked to his pit crew one day while I was waiting for my friend to make a run so I could take pictures, and the chief mechanic told me that the engines were professionally-built and cost $25K each. Not a lot in NASCAR circles, but pretty steep for drag-tracks dominated by weekenders.Ranger Mike said:oh the death of a high precision engine is a sight to be seen,,as is the sight of owner hysterically sobbing when accessing his check book on line
My friend was on the cusp of the semi-finals in the Winston Cup races at Epping, and when he left the line I knew something was terribly wrong. He managed to slow down and hit the first pit entrance, and the Brut funny-car team rolled into action. They had been rooting for him until he broke, and they tore down the top end of that Duster in minutes. An intake valve had shattered and distributed itself to most of the other cylinders. They buttoned the engine back up and helped us roll the car onto the trailer for the long sad ride home.Ranger Mike said:how right your are Turbo1..drag racing is king of the engine hand grenade contests..as h.p. went up crankshaft main bearing caps would literally walk and shear studs. cam shafts would break due to excessive valve spring loading...engine blocks would get ventilated by broken con rods...oil pans frequently got emptied by stray engine components exiting thur the thin sheet metal...then you add in blowers ,,,,,entire engine blocks separated when the clutch blew and sheared off the flywheel/pplate and mounts ..spectacular and dangerous..
turbo-1 said:Many engines are "interference" designs these days. That means that the valves intrude into the space that is occupied by the pistons when they are near the top of their stokes. Not a good thing, especially if a timing belt breaks because that means you need a new engine when the valves and pistons collide.
Ranger Mike said:entire engine blocks separated when the clutch blew and sheared off the flywheel/pplate and mounts ..spectacular and dangerous..