Rear Main Seal

[Buttanic]

Re: Rear Main Seal

Actually the Vortec engine has dished pistons because it has a small 55 cc combustion chamber. Dished pistons and a small combustion chamber creates a lot of squish which helps to reduce detonation and improve combustion. Also with a flat top piston and vortec heads the compression ratio would be too high for regular 87 octane gas.

 

[MGallik]

Re: Rear Main Seal

Buttanic,<br /><br />The low compression quench piston is a semi dished design and a great choice. It's flat above the valve reliefs and dished below. The low compression full dish has no quench at all and was only used in autos and trucks to meet emissions.

 

[16Pilot]

Re: Rear Main Seal

GO TO RAPIDOMARINE.COM, This guy builds pretty nice motors and he is pretty inexpensive.

 

[Fishermark]

Re: Rear Main Seal

I realize that car engines and marine engines have differences, which are important, but for what it is worth, I built the engine in my car (a 1956 Chevy). It is a 1988 350 from a Chevy Suburban. I used flat top pistons and brand new Vortech heads. I used the standard Fel-Pro head gaskets for Vortech heads, (I can't remember the thickness - it does have a bearing on quench). I wasn't sure if I could run regular fuel or not - it turns out I can with no problems at all.

 

[Bondo]

Re: Rear Main Seal

Actually,........<br />In the Standard production Merc.s,... not the Magnums, or HO models,.. Used the Exact Same Pistons as the Standard Production Chevy motors of the time period..........<br />Cast,+ Dished.......<br /><br />It's when you get into the Magnums,+ other Higher Performance motors that you'll find Flat-tops or Forged pistons..........<br /><br />I found this to be True, by taking motors appart,+ it's so noted in Dennis Moore's book...........<br /><br />Marine Engines are Much More like the Standard Production Chevies than everybody wants to Think.............<br /><br />And,.. You're Right about the "D" dished pistons.... It's Just the Ticket for the Votec Heads.......