Hot cam? or vacuum leak?

[Tom Jennings <tomj@xxxxxxx>]

A: Vacuum leak.

Well this rounds off my engine story. I bought this 258 from a
local friend for $500, recent rebuild, forged pistons and rods,
"some cam", etc.  It definitely was recently rebuilt, but as I've
mentioned here it's had a lot of problems, plus no forged pistons,
stock cast (no reason to believe the head is anything but stock),
stock valves... and the cam is utterly normal.

Not exactly a vacuum leak, but two things: too big a PCV (I just
grabbed one from my box "that fit the hole" and the Weber is
A.F.U.


By pinching off the PCV it idles at 17" Hg, no serious overlap or
early-open cam here. It idles (weakly but reliably) at 450 rpm,
just fine at 500 - 550 rpm (though I set it around 650 - 700).

The strong-pull at 2500+ is simply a 258 vs. 232, and a
correct-sized carb (though the low-speed circuits are setup
badly).

The Weber I disassembled and cleaned and inspected. It is old, but
in decent shape, and the previous owner did not bugger screws or
hammer on it. I'm really not hot to go all through it again, and I
think I'm going to persue a GM throttle body and Megasquirt
controller, so I think I'll toss on a newly-rebuilt Carter YF
(ugh!) I happen to have here and simply drive that. Power will
clearly suck but reliability wins out.

I found the fast-idle and got that working, but there is no
ported-vacuum port. (I verified that it's not because the throttle
plate is open too far due to bad idle setting.)

There's an oil drip, almost certainly from the rear seal, only
when the engine is running, so whoever assembled this motor was an
idiot. THe drip is so far not serious, except that an oil drip on
a recently-rebuilt motor is nothing but bad news.

Clearly, now that I have more facts, I'll be bringing all this
stuff up with the guy I bought it from...