Just stumbled across this page in pursuit of slant six stuff.
Weird cid they have here...
I´ve never heard of a 173 or a 181.
Check out this site:
http://www.rosspistons.com/items.php?Cu ... mTypeID=45

Can someone explane this to me perhaps?

CHRYSLER: 173, 181, 198, 225

PART # 28-11, FLAT TOP, RACER NET $534.06
PART # 28-21, DOME TOP, RACER NET $601.14
PART # 28-32, REVERSE DOME, RACER NET $601.14

_________________
Mopar or no car.

Bye the way, who the F**K is Tu Ning?

173 and 181 are V6's. The standard bores are a bit different. ..... .........

CJ

Ok, thanks that explains it...
Btw. does anyone know about the domed pistons?
How good are they, and how much do they bump up the CR?
How much can you shave of the heads before the valves interfear with the domed pistons?
Torque and horsepower increase guestimation?
And are these pistons expensive at $600?
I live in Finland and don't know for sure what the normal cost of ordinary or these are.

_________________
Mopar or no car.

Bye the way, who the F**K is Tu Ning?

You don't need (or want) domed pistons with a RG SL6 (RG = a tall block SL6 = 198 & 225 blocks) These engines have so much negitive deck height that you can get to a higher compression with a flat top piston and the piston will still not get to the top of the cylinder bore.

A 170 (low block) is a different story, this combo needs the domed piston and valve notches to get higher compression ratios without head milling.

Todays 'new' engines use carefully designed dished tops to get the best flame travel and a complete mixture burn. Domes tend to block flame travel and that makes 'cold spots' and a less effective mixture burn.
DD

What kind on engine are you building? Laakkosen hinta noille on ~780 eeroa...

I seem to have understood something horribly wrong.Please explain me. Due to the lack of inadequate english vocabulary I didn't understand what you tried to teach me.
First I have to understand the true meaning of the words dome and dish.
I've thought "dome" means "up" from a straight surfice, and dish means "down" from a straight surfice. (I always confuse with the words convex and concave)
If I've understood the words correctly then do you mean that a domed piston is even further down in the cylinder than a normal one?
And the dished one more upwards?

You say -"Todays 'new' engines use carefully designed dished tops"
Do you mean the pistontop or the cylinderhead top?
I'm sooo confused now......

_________________
Mopar or no car.

Bye the way, who the F**K is Tu Ning?

Rebel....domed=convex, and dished=concave. What Doc Dodge was trying to tell you is that the dome gets in the way of how the flame travels across the top of the piston as it spreads out away from the spark plug. With a dished, (or concave) surface, there are no protrusions to interfere with that same flame travel, therefore the conbustion is more complete, thus giving a higher efficiency to what the engine does.

With a 225 c.i. slant six, the top of the piston is already below the deck surface, and with a domed piston, you would increase the compression ratio, but the side affects would not be welcome. One could more easily and less costly increase the compression ratio by cutting material from the deck surface, the head, or a combination of both, and still use a stock piston.

Roger

These are custom pistons. You can have them made flat or dish (forget the domed).
Race motors will want flat to get the most compression.
Street motors, where lower compression is needed, will want a dish. This helps force the fuel/air mixture to a smaller area near the spark plug. This is known as quench which helps in burning efficiency. It's impossible to have quench with low compression and a flat piston in a slant six.

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Slant Cecil