26 replies to this topic

[nzxu1]

Can some one help me out with or point me in the right  direction of  a diagram for the correct sequence of an   L34  distributors  igniton leads please  .

[arrimar]

Cap order is 15734268

[Uncle Chop Chop]

The engine firing order IS cast into the inlet manifold. But because the L34 dissy is a twin point, the plug leads are in a different order on the dissy cap.

[Hell34]

The engine firing order IS cast into the inlet manifold. But because the L34 dissy is a twin point, the plug leads are in a different order on the dissy cap.

http://holdenpaedia....L34_Distributor

[nzxu1]

God this is driving me nuts !  l've tried the  1,5,7,3,4,2,6,8.  sequence and it's backfiring  out the carbie  now    

[arrimar]

Have you got the coil leads around the right way (points beside timing mark conected to the coil that feeds centre of cap)?
Is the rotor arm that is fed by centre cap contact pointing to No1 when TDC on Compression stroke?

Be careful pushing the HT coil leads into the cap. Modern leads have thicker boots than the originals and can crack the cap if forced on.

[IMORAL]

Isn't that the standard firing order ^ ?

[IMORAL]

so the first pic has standard firing order then no7 on the second pic has a different order?

not having a shot. just trying to understand it that's all.

[EunUCh]

The firing order remains the same , one of the rotor arms will line up with #1 when setting up dizzy , the other will line will line up

with #4 , one set of points will be open or just open , the other set should be closed.

 

Presuming that the  HT lead is connected to the center brush on rotor this will be # 1 fire position and it will fire 1 7 4 6.

The other arm will fire 2 8 5 3 ?

post #2 is correct for lead config.

[nzxu1]

Thanks for your help and suggestions guys , have still  had no luck getting it running  so l'm going to pull it out and put new points and condensors in and start again ...........thanks for those pages skap  .

[Dr Terry]

Thanks for your help and suggestions guys , have still  had no luck getting it running  so l'm going to pull it out and put new points and condensors in and start again ...........thanks for those pages skap  .

If you know a workshop which still has a distributorgraph, that would make life much easier.

 

It is critical that both sets of points have the same dwell angle & fire exactly 90 degrees apart (45 degrees in the distributor).

 

I've found trying to set up dual point distributors without distributorgraph makes it very difficult to get it right.

 

As the others have said, 12784563 is the engine's firing order (same as a regular 308) but the lead position order is 15734268.

 

Dr Terry

[EunUCh]

When you pull the dizzy to replace some parts maybe throw up some pictures just for interests sake ?

 

It should not be too hard to work out what goes on , the rotor cap can only go on one way on the shaft , usually on stock dizzies

( and probably the one in question ) the notched out section on the shaft lines up with the rotor arm , or this case one of the rotor arms.

 

The dizzy usually has a mark on the body (a line that has been stamped into the body) near one of the cutouts that locate the cap.

This is the #1 plug firing reference point , one of the rotor arms will need to line up with this mark (both arms can line up ) but we need to

be sure that the set of points switching the coil to the rotor arm that lines up with this mark are open or just open on #1 TDC.

 

As said ,the firing order is 12784563 but because of the extra arm on the rotor that is 180 opposite we need to consider that #1 fires

and next is #2 ,  what you do is treat it as if it were a stock dizzy and work it out .

 DIZY.jpg   31.01K   3 downloads

 

The red dots denote the rotor arm that lines up with #1 on initial set up either on the bench or in the car.

The green dots denote what the other rotor do , hard to explain but follow the firing order starting at 1 , next is 2 which is actually 5

on the single point set up , it might seem a little complicated but all they did was halve the number of ramps and double other things

to gain more dwell time.

 

I could well be wrong but i think what Dr Terry was referring to in some of the other twin point set ups is that they had twin points but only used one coil which did mean that gap was critical ? , where as the dual point dual coil is basically an  independent system where

a slight error in gap would not be so critical given that it is basically two 4 cyl setups in one ?

 

interesting stuff.

 

 

 

 

[76lxhatch]

I've found trying to set up dual point distributors without distributorgraph makes it very difficult to get it right.

A dwell meter is the next option, a lot of digital multi-meters even have them. Set up the points one at a time with other setups where both sets are firing the same coil.

[a9x868]

nobody has pointed out that the standard 308 distributor is an 8 lobe shaft 

and the L34 distributor from redco or repco which ever

is actually a 4 lobe shaft that operates two coils and two firing points 180 degrees apart

on the same unique twin contact rotor with two condensors and no vacuum advance

i know tim slako in w.a is a gun with these particular L34 distributors

 

and i have been told the tacho needs to be set to the 4cyl position to work correctly

please correct me if i,ve been mis informed

Edited by a9x868, 18 November 2016 - 08:02 PM.

[Uncle Chop Chop]

The engine firing order IS cast into the inlet manifold. But because the L34 dissy is a twin point, the plug leads are in a different order on the dissy cap.

 

 

http://holdenpaedia....L34_Distributor

 

Which means I was correct.

[S pack]

God this is driving me nuts !  l've tried the  1,5,7,3,4,2,6,8.  sequence and it's backfiring  out the carbie  now  

Perhaps you have the distributor installed 180 deg out of sequence?

[Dr Terry]

I could well be wrong but i think what Dr Terry was referring to in some of the other twin point set ups is that they had twin points but only used one coil which did mean that gap was critical ? ,

No so !!.

 

The 4-lobe L34 dissy is indeed, effectively two 4-cyl ignition systems which are interleaved. The 'other' dual point set-up like the Mallory 'YL' V8 set-up use the 2 points on 8 lobes.

 

The critical thing with the L34 dissy is that the alternate points open exactly 90 degrees apart (45 dissy degrees). If you just use a dwell-meter & get the 2 sets of points to have equal dwell, it would be close, but how close?

 

The most important thing is that all cylinders fire at the same timing, e.g. 10 degrees BTDC. If the points open slightly out of timing say as little as 5 degrees at the dissy, this alters the timing by 10 engine degrees on every 2nd cylinder.

 

If you just use a dwell-meter, as 76lxhatch has suggested this is a good start, but to check the timing on alternate, the best method would be to mark the balancer for all cylinders & check the timing on both sets of points. I other words treat it as two 4-cyl engines. If adjustment is necessary, then adjust the No. 2 set of points to maintain that exact 90 degree separation.

 

Dr Terry

[76lxhatch]

I always forget that the standard balancers only have one mark, having one with heaps of degree markings is great

[EunUCh]

Just trying to make sense of this ! ?

Using 4 lobe shaft set #1 as per usual with single mark but line up #2 TDC & mark balancer (if or if  not graduated ) as well , check timing on #1 (10) then swap timing light lead to #2 and adjust point gap accordingly to aim for same timing on each ? , it might mean that one gap may be more that the other so long as the timing is 10 on each ?

 

[Dr Terry]

Just trying to make sense of this ! ?

Using 4 lobe shaft set #1 as per usual with single mark but line up #2 TDC & mark balancer (if or if  not graduated ) as well , check timing on #1 (10) then swap timing light lead to #2 and adjust point gap accordingly to aim for same timing on each ? , it might mean that one gap may be more that the other so long as the timing is 10 on each ?

You've got the gist of it. 

 

It's easier to just set both sets of points to exactly the same dwell angle. then use the #2 timing mark to check how close you are. Only adjust the 2nd set of points if #2 cylinder's timing is out compared to #1.

 

In the perfect world, with no wear in the dissy the timing for all cylinders should be correct if both points are set exactly the same.

 

The fact that one set of points has a slightly larger gap doesn't matter if the timing for all cylinders is correct.

 

Dr Terry

[UCSLE]

never tried it , but you should be able to run the motor on one coil and 4 cylinders to eliminate problems ?

 

just like the old variable displacement Cadillacs