Throttle position pot

[dickymint]

Plan for tomorrow is sort out the idle problem.
Can anybody confirm these settings on 420SEAC?
1) 0.002" gap top and bottom of butterfly valve.
2) 300mV output on throttle pot.
Is it the green and yellow wires to take this reading?
3) Adjust idle on plenum screw to whatever I like?

Help needed so that I can watch the footie at 12.00!!

Tonights plan is

[2 sheds]

with a hot cam the butterfly might need a tad more than 2 thou clearance, due to low vacuum at idle, i guess you could start with this, .32 V + or- .01
can't remember the wire colours, i haven't touched a flapper type for years, only one combination will give you anywhere near that kind of reading though.

Is there a problem then ?

Tim

[dickymint]

2 sheds said:

with a hot cam the butterfly might need a tad more than 2 thou clearance, due to low vacuum at idle, i guess you could start with this, .32 V + or- .01 can't remember the wire colours, i haven't touched a flapper type for years, only one combination will give you anywhere near that kind of reading though. Is there a problem then ? Tim

Thanks Tim,
Not a big problem (famous last words}its missing a bit with foot off the pedal usually when warmed up.
The tickover is too high at about 1700rpm at the mo.
Steve has told me that he used to adjust tickover by tweaking the throttle cable stop screw so I'm guessing, that air leaks aside, this has upset the throttle pot position.
Hopeing that its not the ignition module breaking down.
Checked back on a few threads and its a toss up between black/red. green/yellow. red/green!
"borrowed" a new Fluke 183 meter with nice pointy probes from work and want to play

[2 sheds]

Definately check the potentiometer, also try blanking the air pipe to the cold start valve at the back of the plenum, if this is working properly blanking will have no effect on a warm engine, you can run without this anyway.
An air leak would cause a slight misfire.

Tim

[dickymint]

Rain stopped play but at least United beat Arsenal!

[dickymint]

The findings were:-

0.012" gap
392.1mV (red & green wires)

Adjusted to 0.003" gap. This bought the reading down to 305mV.

Fired her up and it sounded sweet as a nut, but would not hold idle, no matter what amount the idle screw was turned.

Opened up gap to 0.006" resulting in a reading of
325mV. This gave a nice idle speed of 1300rpm.

Took her out and reallly warmed her up. Bingo no missfire at low revs under load and idle holding at 1300rpm.

[2 sheds]

Nice one, yes i always found an idle of 1300 was good for original SEAC cam (234).
Do you get more pops and bangs on over-run now ?
Tim

[dickymint]

2 sheds said:

Nice one, yes i always found an idle of 1300 was good for original SEAC cam (234). Do you get more pops and bangs on over-run now ? Tim

Didnt really notice as I was concentrating on listening for missing at low revs/high load. Will test for popping and banging through the Brynglas tunnel on the way to work tomorrow
PS will be ringing you tomorrow to order plugs and a air meter to plenum hose.