kango
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| posted on 30/11/06 at 04:37 AM |
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Timing setting
What do I need to do to my distributor (1600 Kens STD) if I am running no vacume advance and what should I set the timing at.
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kango
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| posted on 30/11/06 at 10:08 AM |
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Sorry that is a Kent standard motor with 40mm Webers.
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kango
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| posted on 4/12/06 at 10:04 AM |
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Is there nobody that can help me?
Timing setting and dizzy modification.
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mcerd1
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| posted on 4/12/06 at 11:09 AM |
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Have you seen/ read either of these books?
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rusty nuts
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| posted on 4/12/06 at 07:15 PM |
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Set the timing to around 8 degrees BTDC should be near enough to get it running then get it set up on a rolling road
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kango
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| posted on 6/12/06 at 04:14 AM |
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1) Have not red any of those books. What is the bottom line that they suggest.
2) Have set the timing 8 DEG BTDC right up to 12 deg BTDC and the revs still pick up very slowly.
Somewhere I red something about locking something in the dizzy and/or removing one of the springs inside (not shore), but can not find this info
again.
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caber
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| posted on 6/12/06 at 08:40 AM |
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Ok some of this is from memory so people may provide corrections. First thing to do is set a timimg to get engine running then use a good strobe to
" map " the distributer. If you have checked or made a new TDC mark on the crank pulley and you have a strobe that allows you to set
different delays then note down the advance at every 1000 RPM from idle which should be set at the slowest even running speed.
Then start at the top end. you should find a figure and rev point for this from an owner's manual the max advance should not exceed 38° and will
probably come in at about 5000 revs but may be lower.
As you have taken off the vac feed you may have to set the idle advance off standard, the trick is to set it initially by ear finding the point where
the engine idles smoothly at lowest revs without hunting.
Do the mapping exercise again and see where things have changed, hopefully the curve is the same and has just moved up though it may have lifted at
the bottom and remain more or less the same at the top depending a bit on the construction of the distributor.
Now go for a drive and find a long steepish hill. Try running up here in as high a gear as possible note the revs and listen for pinking, a metallic
sound from the engine that comes from pre-detonation, the fuel charge being burned before the piston has reached TDC, it is a quite distinctive sound
and if you go at it too long engine temperature will rise significantly.
Do the run again at differing engine speeds and note where pinking occurs, the engine should be working hard so throttle open and get in the right
gear for each run.
When you get back you will be able to mark the points on your curve where you are getting pinking, the curve has to be flattened at these points by
reducing the advance.
Now dismantle the dizzy having carefully marked where it is set in relation t the engine, it is also wise to mark where the rotor arm is pointing it
is often quite possible to put it bacl 180° out!
Remove top plate with the contact points below this you should see a pair of pivoted weights restrained by springs, these are the bits that control
the rate of advance as the engine speeds up. Firstthing to do is to determine if you have too much advance at the topof your rev range. If there is
pinking or if you are getting more than 38° then you need to move the stops thatrestrain the weights when they are fully extended, this can be done by
bending pins or putting tubes over them. Changing the rest of the rev range requires playing with the springs. It can be helpful to raid a few other
distributors for sprngsas they all vary a bit! Most have one weak and one strong spring if you have pinking over most of the rev range then put in two
strong springs, if you didn't have any pinking put in two weak springs, then put it all back together, repeat the timimng curve measurements and
plot these to seeif you have moved the curve in the right direction. If you have and you are still topping out the advanceat the same revs as your
original curve then repeat the driving and see if you have got rid of the pinking.
This can be a long process requiring several tries. you can weaken the strong springs by extending them with pliers but be careful not to extend them
too much, it may be possible to adjust weaker springs by squashing them.
Once you are happy with your curve try adjusting the idling timing upwards and go for a drive again once you have some traces of pinking at all revs
back off the idling timing until this just goes away. You should now have best possible timing settings so repeat your mapping for the record.
If you have a rough idle try adjusting the fueling to get it even if this cannot be made to work you will need to adjust the inside stops on the
balance weights. If you can't get a good curve with the springs for example the advance reaches maximu at to low revs then you can file material
off the balance weights or add weight with blobs of solder to give finer adjustment.
You have now done the equivalent of mapping an electronic ignition with a PC!
Best of luck with this
Caber
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