[Spridgets] Oil leak from dip stick?

[David Lieb]

Marc,
Oil from the dipstick always seems to mean that the engine is generating 
more crankcase pressure than it can get rid of. Either there is excessive 
blowby past the tired old rings, or else the venting is inadequate.

As Bill Gilroy indicated, check out the internal health of the engine, 
especially rings and valve guides, by doing a compression test and maybe a 
leakdown test, too.

A 1973 1275 originally had two forms of smogging; the air pump and the 
charcoal cannister. The air pump is no big loss unless you have a strange 
desire to create a concours RWA Midget. The pump itself was worn out in the 
first 10,000 miles or so of use and represented nothing but a power drain 
from day 1 anyway. Just make sure the holes in the side of the head are 
properly plugged. The charcoal cannister system, however, was a useful 
thing. It was a passive system that robbed no power from the engine at all. 
It is also a little more difficult to remove properly.

The objective of this system was to eliminate most of the gasoline vapors 
from the car. Therefore, the vents from the carb float bowls, the valve 
cover, the timing chain cover, and the gas tank were all connected to the 
charcoal cannister, which served as a filter. Since the system has already 
been removed, your options are rather limited, so lets take a look at what 
needs to be accomplished.

1. Gas tank
As your engine burns gasoline, the level in the tank goes down (darn it!) 
and the volume needs to be replaced by air, otherwise you get the 
not-uncommon scenario of driving a mile or two and "running out of gas" 
because of the vacuum in the tank. You can vent it fairly easily by drilling 
a couple of 1/8" holes in the metal disk inside the gas cap. If your state 
still does emissions testing of 1973 Midgets, have a spare cap for the test. 
While you are back at this end of the car, take a look at the smaller hose 
in the boot which goes into the top of the tank next to the filler hose. 
This connects to the vapor separator mounted in the side of the boot, which, 
in turn, connects to the charcoal cannister. I can almost guarantee that the 
rubber hose inside that metal braid has long since perished. I would 
recommend plugging it at the tank (venting your tank inside the boot is not 
really recommended, even in a convertible). If necessary, you can cut the 
crimp on the hose connection and disassemble it. If the rest of the venting 
system has been disabled, it is no longer doing anything. If the hose has 
perished badly enough, this can cause the gas station pump NOT to cut off 
when the tank is full.

2. Carburetor vents
Assuming you still have the original HS2 carbs, the top connection on each 
of the flot bowl lids is a vent. The factory plumbed these to the cannister 
via a metal pipe. If the pipe is still there, leave it in place and route it 
so that any gasoline that comes shooting out of them if your needle valve 
sticks does NOT go onto the exhaust.

3. Engine vents
The factory used the Y-pipe connected between the two carbs to put a small 
vacuum on the crankcase via the timing-chain cover. They then ran a hose 
from the top of the valve cover to the charcoal cannister. The pipe on the 
valve cover originally had a small orifice on it so that there would be a 
little vacuum in the crankcase to minimize oil loss. There is no telling 
what is left of your system now. Many people saw off the end of this pipe to 
eliminate the orifice and vent it to atmosphere by running a hose down to 
the slipstream under the car (sounds like your DPO did this). They also plug 
the Y-pipe on the carbs and vent the timing-chain cover via a hose over the 
top of the engine and down into the slipstream by the other one. This will 
work ok. In some cases, it could be worthwhile to remove the blanking plate 
on the side of the engine where a merchanical fuel pump would mount and 
install a hose fitting to it and add a third hose over the engine into the 
slipstream.

Another option, if the orifice on the valve cover is still intact, is to use 
the intake manifold connection from the air pump to run a hose to a "normal" 
in-line PCV valve from your local autoparts store and thence to the 
timing-chain cover. Install a fuel filter in the hose from the valve cover 
down to clean the small amount of air that should be coming through there 
and you should have a reasonable amount of vacuum in your crankcase.

As Bill implied, however, if your rings are not sealing very well, you don't 
have a whole lot of hope of controlling the crankcase pressure.
David Lieb