Correct timing for Veronica ?.

[tomorrowcalling]

So Veronica ( one of my rally cars) runs an E30 distributor & ignition system , (Yes I know they turn the opposite way, the object  of the exercise was to change the cam, the 292° cam I had, had gears to suit an anticlockwise distributor)

 

I set up the timing to give around 35° of maximum advance, kind of based on general 2002 settings, however I've just noticed the spec for the ignition system I fitted is around 30° of max advance ( 26° @ 4000 rpm)  and as I'm also chasing an over heating issue I'm wondering if I've been a bit aggressive on the timing.

 

So the question is. Time it as an E30 or a 2002 ?

[Simeon]

If it’s a really a rally car, surely it would spend more time at 4,000 than at idle so I would always time for max advance and let idle take care of itself. 

 

Any noticable issues turning it over with the starter (too much initial advance)? If not, I would leave it alone and look elsewhere for your overheating issues. 

[tomorrowcalling]

1 hour ago, Simeon said:

If it’s a really a rally car, surely it would spend more time at 4,000 than at idle so I would always time for max advance and let idle take care of itself. 

 

Any noticable issues turning it over with the starter (too much initial advance)? If not, I would leave it alone and look elsewhere for your overheating issues. 

 

Yes, it's really a rally car hence I did time it for max advance but it does struggle a bit on the starter so perhaps a bit much initial advance.

 

Cooling wise,  new radiator, new water pump, new thermostat, flushed it a couple of times, I've just added an oil cooler but haven't run it in competition yet.

[Simeon]

You may wel be stretching the distributor in terms of what it will give you. Can I suggest a 123 Tune which will deal with the ‘reverse’ direction. You can dial in whatever you want then. 

[TobyB]

Probably a bit less than you should try using on Betty...

 

You don't say which head you're using, but 36 all in at WOT over 4k is 

usually pretty safe.  And more at partial throttle is usually safe, and gives you more power and better economy.

I run a tii distributor at 36, 11.x:1, dcoe's, and have never seen any evidence of detonation...

whups, that's on 100LL avgas...

 

hth,

t

 

Edited June 29, 2018 by TobyB
octane schmocktane...

[tomorrowcalling]

It's a 121 head and I'm on 98 RON fuel, not sure what the compression ratio is but I don't believe it's particularly high.

 

Agree about the 123 dizzy but this is the "spare" rally car as in it's all my spare parts in one place.  The other car has first dibs on the budget for go faster bits.

[TobyB]

My advice over the internet is to try more advance,

and then watch the plugs for detonation.  In theory, the 121 

is a bit more prone, but I'm not sure how much.

 

t

advance it until it blows up, then back it off 3...

[kota02]

Hello Tomorrowcalling,

Can you share your wisdom of making the engine and distributor from a 318i work in a 2002.

I have installed the engine and from a 1984 318i but went back to the old carburettor and intake manifold setup. I have used an electric fuelpump with a fuel pressure regulator.

I flipped the gear on the 2002 distributor to make it work but at the most, the car would start and idle but as soon as I would try and run it, it would be bogged down, Now it wont even start.

I am hoping that you will share the process 
 

[Son of Marty]

I believe reversing the rotation is forcing the advance mechanism to retard it only works in the direction of original rotation.  

['76mintgrün'02]

The weights still spin out, no matter which way it spins, so it will give advance in either direction.  The center post cams are designed to spin in one direction or the other though, in order to play well with the points' rubbing block. 

 

I just went up to the shop and spun a late style distributor on the Sun machine and made use of the backwards-rotation feature for the first time.

 

I was surprised to see that the dwell remained the same when going in either direction.  However, there was a big difference in when the spark happened, when looking at the degree scale where the light flashes.  If the scale was set to zero for forward rotation, the light flashed 28 degrees later when spun in the opposite direction.  That's assuming I am reading the correct one of the four flashes the second time.  It could be 62 degrees sooner, I suppose.  The closer direction seems more likely though.

 

This is the scale I am referring to.

 

 

This distributor is giving 13 degrees total in forward motion, but only 11 when spinning backwards.  All-in advance happens at 1400 rpm (2800 crank) spinning clockwise, but stops at 1100 rpm when reversed.  The curve is not as smooth in the backwards direction.  It seems a little "choppy".

 

For the most part, I was surprised it worked as well as it did, but I would not try to run one backwards on my engine.

 

I wonder how the older-style advance mechanism would behave.

 

Spinning the opposite direction would make the vacuum pod do the opposite dance.  Meaning an advance pod for clockwise rotation would become a retard pod for ccw rotation.

Tom

[Preyupy]

1 hour ago, '76mintgrün'02 said:

The weights still spin out, no matter which way it spins, so it will give advance in either direction.  The center post cams are designed to spin in one direction or the other though, in order to play well with the points' rubbing block. 

 

I just went up to the shop and spun a late style distributor on the Sun machine and made use of the backwards-rotation feature for the first time.

 

I was surprised to see that the dwell remained the same when going in either direction.  However, there was a big difference in when the spark happened, when looking at the degree scale where the light flashes.  If the scale was set to zero for forward rotation, the light flashed 28 degrees later when spun in the opposite direction.  That's assuming I am reading the correct one of the four flashes the second time.  It could be 62 degrees sooner, I suppose.  The closer direction seems more likely though.

 

This is the scale I am referring to.

 

 

This distributor is giving 13 degrees total in forward motion, but only 11 when spinning backwards.  All-in advance happens at 1400 rpm (2800 crank) spinning clockwise, but stops at 1100 rpm when reversed.  The curve is not as smooth in the backwards direction.  It seems a little "choppy".

You need to go back to your distributor machine and try this again.   With the distributor turning clockwise you are showing 18 degrees of advance.  If the distributor is turning counter-clockwise this shows that you have 18 deg of RETARD.  
 

Distributors that use weights MECHANICALLY change the relationship between the drive gear and the points to alter the timing in 1 direction of rotation it advances and in the other direction it retards.  The 123 distributor will work in both directions (they need a different gear) because there is no MECHANICAL advance it is all done electronically and the system has no idea which way it is turning it just triggers the spark earlier or later based on RPM    

[7502]

This is what my mind went to:

 

 

['76mintgrün'02]

4 hours ago, Preyupy said:

You need to go back to your distributor machine and try this again.   With the distributor turning clockwise you are showing 18 degrees of advance.  If the distributor is turning counter-clockwise this shows that you have 18 deg of RETARD.  

 

I see what you are saying.  Thank you for explaining that so clearly.  The photo I shared was not from this session, but the numbers don't matter.  The DIRECTION matters.  Both directions of rotation are causing the arrow to move counter clockwise on the scale;  which equals retard, if the distributor is also spinning that way.

 

It's funny, I almost typed "unless Byron steps in to correct me," or some such thing.  I appreciate the tutorial. 

 

Tom