305 cylinder head ports/vents?

rdsrus · Post by **rdsrus** » Tue Feb 03, 2015 2:18 pm

Anybody able to tell me what the 2 ports/vents that go to the intake area are for? Wouldn't think it was for crankcase ventilation. Thanks in advance, Bill

G-Man · Post by **G-Man** » Tue Feb 03, 2015 2:21 pm

It was a feature intended by honda to reduce oil seepage down the inlet valve guides by venting them to atmosphere.

Deleted on later models.

G

rdsrus · Post by **rdsrus** » Tue Feb 03, 2015 3:01 pm

Thank you again for the info G-man. Bill

LOUD MOUSE · Post by **LOUD MOUSE** » Tue Feb 03, 2015 3:41 pm

I think the vacuum/suction through the intake area of the head when the valve opened would suck AIR FROM THE FILTER AREA through the vent tubes into the combustion area (from the special engineered/designed valve guide) and had something to do with possible moisture at the valve stem. HONDA discontinued this about the 1967 issued engines.
May be wrong but that is how I know it?????..................lm

G-Man wrote:It was a feature intended by honda to reduce oil seepage down the inlet valve guides by venting them to atmosphere.

Deleted on later models.

G

G-Man · Post by **G-Man** » Tue Feb 03, 2015 4:10 pm

LM

I think we are talking the same language. By venting to atmospheric pressure (the air filter) the pressure at the valve guide is increased and the tendency to pull air / oil from the head into the combustion chamber via the valve guide is reduced.

G

LOUD MOUSE wrote:I think the vacuum/suction through the intake area of the head when the valve opened would suck AIR FROM THE FILTER AREA through the vent tubes into the combustion area (from the special engineered/designed valve guide) and had something to do with possible moisture at the valve stem. HONDA discontinued this about the 1967 issued engines.
May be wrong but that is how I know it?????..................lm

G-Man wrote:It was a feature intended by honda to reduce oil seepage down the inlet valve guides by venting them to atmosphere.

Deleted on later models.

G

LOUD MOUSE · Post by **LOUD MOUSE** » Tue Feb 03, 2015 4:17 pm

Nope I don't think so. ........lm

G-Man wrote:LM

I think we are talking the same language. By venting to atmospheric pressure (the air filter) the pressure at the valve guide is increased and the tendency to pull air / oil from the head into the combustion chamber via the valve guide is reduced.

G

LOUD MOUSE wrote:I think the vacuum/suction through the intake area of the head when the valve opened would suck AIR FROM THE FILTER AREA through the vent tubes into the combustion area (from the special engineered/designed valve guide) and had something to do with possible moisture at the valve stem. HONDA discontinued this about the 1967 issued engines.
May be wrong but that is how I know it?????..................lm

G-Man wrote:It was a feature intended by honda to reduce oil seepage down the inlet valve guides by venting them to atmosphere.

Deleted on later models.

G