weep hole in 356 B fuel pump?

[Lars Hvidsteen]

I have been confused about why there was a small ammount of engine olie on the lower half on the fuel pump after each drive, i have checked everything and all is good, so a took my mirror pen and tryied to look up under the pump.

I was told that this will leak gasoline if the diaphram is worn and/or oil if the shaft seal is bad, BUT my pump is an earliere B pump and do not have a shaft seal??

what to do

thanks

Lars

[Dick Weiss]

Yes to both, but more so for a drain if gas gets past the diaphragm.

[Al Zim]

FYI I think that is the 3rd series of domed topped pumps that were manufactured. It has the clips on the pin and a brass insert for one of the valves. If your diaphragm is leaking, most of the gas will go down the pump around the activation (push) rod and fill the crankcase. In normal circumstances the fuel pump is only necessary to move the fuel from the pump to the carburetors. Shut the petcock off when you park the car. al zim

[Wes Bender]

I think you meant to say the GAS will go to the crankcase, Al.

[Lars Hvidsteen]

I think you meant to say the GAS will go to the crankcase, Al.

if my diaphragm ( which only have driven 2000 miles was leaking , wouldent there be coming gas out of the weep hole? there i only comming a small ammount of oil out??

[Wes Bender]

That would be correct, Lars. I was only correcting Al's comment on fuel filling the crankcase.

[Lars Hvidsteen]

Anyone who can explain why oil is getting out of the drain/breather hole in the fuel pump??

Can It be that the ventilation of the crankcase that not work good enough? I have checked the valvecovers and the ball valve is workings perfect. But the ball valve offcause on working when turning right/left and I have paid attention to when after a long run on the high way in a straight line with 120 km/h and slowing down , turning away from the highway, the engine make a single big "puff" in the tailpipe?


thanks.

[Dick Weiss]

Lars,

Did you rebuild the fuel pump and pre-loaded the diaphragm flat to the flange/surface before snugging up the 6-screws?
If not, the diaphragm will 'wrinkle' a little and possibly leak gas from the joint; As far as any oil leaking, it could be from excess wear of the push-rod in either the OEM bakelite/fiber spacer or the aluminum casting since neither one doesn't have a shaft seal lake the later pump. Also, the spacer or casting may be warped and gaskets may not seal properly--after the stroke dimension of 29-34mm is set.
Be sure to pack the rocker-arm pocket w/suitable grease.

Dick

[Al Zim]

Perhaps you have too much crank case pressure due to worn rings, or bad valves and valve guides. The clue being the puff of smoke on deceleration. If the valve comers are wet on the outside of the vent and the underside of the engine is wet this could be a distinct possibility. Borrow a compression tester remove the valve core and set the engine to cylinder 1 check the valves to see which cylinder is on compression probably #3 set the timing to #3 pull the parking brake on and put the car in 2nd gear. Put sir into the engine and listen to where it comes out. out the oil filler bad rings you cannot check the valve guides. You have a 55 year old engine. Be careful! al zim

[Dick Weiss]

As Al mentioned, having worn out valve guides & valve stems will allow oil passing thru during acceleration and decelerations --
especially having the later exhaust rockers w/the "squirt holes" If bronze guides exist, they need the oil per material specs.
I don't use seals on the intakes and a recent rebuild, the heads had seals on all the valves!

The ball-check valve covers were introduced to prevent oil flowing into the rocker chamber(s) during hard cornering due to the "plain-
jane" pushrod tubes; Extending 1-end kinda eliminated this but the cover can still breathe--and leak like the regular vented covers.
Note that ball-check covers won't fit on the later heads (912s) having a casting change for the blind bolt hole holding the intake manifold(s)

Dick

[Jim Alton]

For the record, my first air-cooled car (the VW Microbus) leaked fuel into the crankcase via a bad fuel pump diaphragm when I drove it home to Dayton, OH after buying it near DC (Bolling AFB to Wright-Patterson AFB).

A few days later I found myself shopping for a "good used" VW engine.