darren(SA)
|
| posted on 27/1/03 at 06:00 PM |
|
|
another 40's question
Hi guys,
I took my baby for its first drive today!
things went well (except for the gear lever coming out) ran thru all the gears, mechanically she seems OK. Now, I followed part of Dave Andrews guide
to set webers to the point where the airflow meter was needed. The car seems to go alright, splutters a bit now and then but in general its drivable.
What we want to do, is drive the car until the engine is run in, and then take it for a nice dynotune, jetting it correctly etc. So at the moment we
want the carbs tuned more or less.
quote:
screw all of the idle mixture adjustment screws fully home and then out 2.5 turns.
this is basically all thats been done.
It idles fine, starts up 1st time, splutters occasionally. The timing has been set between 8' & 12' at idle.
Does anybody have a shortcut (ie turn another 1/2 turn) for the mean time?
more importantly, I need to know if it is safe to drive the car with these guessed settings as I've heard you can burn valves if too lean etc.
Ps car is underpowered at higher revs.
engine is modded, includes 290' cam.
thanks
darren
|
|
|
|
|
Stu16v
|
| posted on 27/1/03 at 07:18 PM |
|
|
Hi mate. If the spluttering is at part throttle, it may be a case of They all do that sir! Webers can be a bit finicky on part throttle openings and
may cause hesitation. For road use, some folk prefer Dellortos for this very reason. Also the cam may be adding to the symptoms.
If you have leaded fuel in SA, try whipping the plugs out and see how they are burning. Not dead accurate, but it will tell you if one carb is out
compared to the other, or if things are getting a bit too weak.
There again, it may be the carb balance. In the absence of an airflow meter, try listening to the 'suck' of the carbs with a length of old heater
hose (just like the good ole days....). If a carb is wildly out, you will hear a different pitch in the carb intake. Just adjust the throttle
butterfly balance screw until they sound the same.
HTH Stu.
Dont just build it.....make it!
|
|
|
jollygreengiant
|
| posted on 27/1/03 at 07:27 PM |
|
|
Do what I used to do. It worked fine.
Go to local car shop & buy 4 (yes FOUR) gunson colour tune plugs. With engine hot, remove all spark plugs & fit colour tunes. Now, this bit is best
done inside a garage for best colour obsevation, adjust each mixture screw until you have the colour (blue) as shown on the chart (comes in the box).
Balance carbs (Gunson also do a cheap balancer) and recheck colour on plugs. Switch of engine, refit proper plugs AND
-------------------------------------------------------------.....................ENJOY.
(maybe cheap & cheerful but they do the job, cheaply, for getting a basic setting.)
|
|
|
darren(SA)
|
| posted on 27/1/03 at 08:06 PM |
|
|
thanks guys, I'll try fiddle a bit 2 get them sorted.
quote:
If you have leaded fuel in SA, try whipping the plugs out and see how they are burning. Not dead accurate, but it will tell you if one carb is out
compared to the other, or if things are getting a bit too weak.
we've got both, but I'm running leaded.I would assume a nice grey/white is wot i'm looking for?
quote:
Go to local car shop & buy 4 (yes FOUR) gunson colour tune plugs.
never heard of them, but they sound pretty snazzy, I think I must ask around here and try invest in a set!
thanks
darren
|
|
|
Dave Ashurst
|
| posted on 27/1/03 at 09:19 PM |
|
|
Hi Darren,
Low top end power?
You v.probably know this but do be careful you haven't got too much total ignition advance. If you have then you can damage the engine. Suggest
don't rev over 3000 rpm until you check.
As a rough guide:
Max advance 34 degrees at approx 3300rpm (ref my 1700 crossflow)
Idle advance 14-16 degrees (for a 290 degree cam) ref: Des Hammill's book, "how to build and power tune distributor type ignition systems"
http://www.amazon.co.uk/exec/obidos/ASIN/1874105766/qid=1043699984/sr=1-8/ref=sr_1_0_8/026-4297800-2568419
That might help.
Dave Andrew's site is v.good too.
If it makes you feel better my 40's were a pain to set up - but I think it was worth it in the end.
regards
Dave
|
|
|
jollygreengiant
|
| posted on 27/1/03 at 11:05 PM |
|
|
quote:
Originally posted by darren(SA)
I would assume a nice grey/white is wot i'm looking for?
Nope thats lean. They want to be a sort of pastel gold/light brown in colour.
Enjoy
|
|
|
fastavatar.jpg){kind=avatar}
