John,
As Fred said this hole is for oil return. However the hole also provides a
path to vent the crankcase, the only other path is around the timing chain
in front. The U20 crankcase is only vented through the valve cover, I found
that my head had a near blocked rear hole. This can be opened up with a
Dremel or rat-tail file, you can take quite a lot of material out without
risk of cutting into the water or pressurized oil passages. I made mine
about 1/4" (manifold side) tapering to 1/8" wide (distributor side) by
about 1.5" long. Also make sure all the rubber is in place from the valve
cover to the carb throats, there should be a molded hose from the valve
cover to the air filter assembly (carb-side), and a rubber tee inside the
air filter assembly that connects the vent to the mini stacks at the carb
throats. The latter piece is often missing. One might ask "why did I need
good crank case venting?". Lowering the pressure in the crankcase aids
piston ring sealing, which improves power and mileage, also a poorly vented
crankcase tends to leak even more than normal at the rear main seal. Of
course YMMV...
Todd Osborn
San Jose, CA
2x '68 2L
----- Original Message -----
From: "John McCarthy" <bmccarthy67@hotmail.com>
To: <datsun-roadsters@autox.team.net>
Sent: Saturday, January 26, 2002 9:01 PM
Subject: 2000 Head Hole?
> I started to disassemble the 2000 to move on with the resto. Here comes
the
> stupid question...after removing the valve cover..looking down on the
> cam...on the back right corner (closest to brake master)..the head has a
> hole (not a circular one..sort of a rough broke look..I removed the head
and
> it kind of lines up with the last triangular hole in the block..is it
simply
> a oil return or is there a hole in the head? I can't find anything loose
or
> damaged that could have caused it. Thanks for your time..Buddy
>
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