today i tried to tune the carb as you and the holley book suggested. i
connected a vacum gauge to the manifold and went to work. i discovered the
idle screws 3/4 of a turn out. i do not know where they ended up but it was
more like 1 1/2 out. i pulled 15" of vacum at an idle. it was steady with
very little pulsating. i take this to mean no vacum leaks. you mentioned
getting roasted standing over the engine. mine is like i opened a oven at
450 degrees. so maybe i have a vacum leak. how do i find a vacum leak. i do
not think my secondaries are open. i pressed on the firmly and the did not
move. they look to be shut. i will read the holley book to see what it says
for their setting. i did use a contact pyrometer to measure the delta temp
across the rad and it was 0. i thought it might be the water pump but as i
have said before when i pour water over the rad it does cool down. the air
that is being pulled by the fan is also hot so i know there has to be a
delta temp. i think the rad is just too little for the engine. timing is at
6 at an idle with the vacum line unhooked and plugged. i am running a
mallory unilite. she is running cooler then when i started but not enough.
thanks
for the help
chris in hawaii
-----Original Message-----
From: DJoh797014@aol.com <DJoh797014@aol.com>
To: CVaught@hawaii.rr.com <CVaught@hawaii.rr.com>
Date: Saturday, May 06, 2000 10:53 AM
Subject: Re: timing
>Chris
>
>The object of the game is to achieve the maximum vacuum
>with the mixture just lean enough to obtain it. You screw'
>the mixture screws out (leaning the mixture) after starting
>with them in (Too rich). As you go out the vacuum should
>increase until it no longer changes as you screw out. At
>the point screw back in a little to richen the mixture. Too
>lean a mixture can result in burnt valves.
>
>Where you can attach the vacuum guage is a good
>question. Depends on the manifold and carb. I temporarily
>use the PCV port on the carb base plate. Another source
>could be the brake boost port.
>
>As I said before, make sure the secondary throttle plate
>is 100 per cent closed. A slight opening will make the
>engine run hot. And I mean not on the gauge. I mean
>there is a heat blast given off the engine. Most Tigers
>I've seen running hot is because of timing and too lean
>a mixture. If your secondary is slightly open, bend
>the secondary throttle rod on the driver's side of the
>carb to make it close the plate completely. Operate
>by hand to make sure it snaps shut and is not hanging
>up on some obstruction like a base plate gasket.
>
>Good Luck. Dave Johnson, Aurora, IL
>My operation went fine. New stent in the main pipe
>in my heart. First time in years I have no chest pains
>when leaping tall buildings in a single bound.
|