241 Dodge hemi piston height

I'm helping a buddy with a 241. He's putting it in a 64 Valiant wagon. The pistons are the original factory units. With the short block****embled, the tops of the pistons are actually higher than the top of the block, sticking out by about .020". Is that normal? I've had about a dozen old hemis in my time, but this is the first time I've seen one with negative deck height.

 

I don't know about a 241 but I've never had a Hemi, except a low compression blower engine, that did not have the pistons above the deck.

 

I just stuck together a 241 which I know to be an original. The pistons are .035 below the surface of the deck at TDC. If I could find my dial indicator I might have been more accurate but I was forced to use a straight edge and feeler guage.

 

I been thinkin on this (danger). There are not many crank, rod, piston combos for this engine. Could it be that at some point the crank was offset ground? That might explain the deck height.

 

After 58 years of "mechanicing" since it was first****embled almost anything's possible on that 241...perhaps the block has beeen "decked" .020. Check the deck height...spec is 9.29"
http://victorylibrary.com/mopar/deck-height.htm

 

There isn't much crank there to begin with with those teenie journals. Is it the dome that's above the deck or the whole piston top?

 

Original factory pistons are flat tops.

 

Pin height 1.785 Ive run accross them with + deck height but there was a chamfer at the edge. My check was to bolt on the head without the gasket and turn the engine over and look for contact marks, if piston didn't hit the head with a gasket you will fine. With a hemi the combustion chamber goes out to the bore.

 

If the block was decked it would have to be .055. Thats a bunch. The engine that I checked was from a new car warranty take out from 1954.If the pistons extend above the deck .020 check for clearance with modeling clay. If they are too close you could chamfer the OD and end up with more compression (much needed).

 

The engine was stock as far as we know with a stock bore and only about .002"-.003" taper at the most so we went with the original slugs. With an .045" thick gasket I guess we'll be OK. It just hit me funny since I've never seen it before. My 341 is 10-1, but the tops of the domes are only .080" above the deck. The original deck height at 9.25 compression was .012".

 

That area of the outside diameter is of importance. The dome height is little. Think of the hemi combustion chamber. If using flat top pistons the only area of conscern is the outside diameter.

 

I'm rethinkin this as there is no dome height-- right? flat tops.

 

There aint no way that this 241 would have the pistons sticking above the deck from natural causes.

 

Bill I know I've run accross 241s with + deck I looked at some old stock pistons they have a chamfer of about .050 if you compare that to the head chamber there's another .020 to ..030 extra clearence.