Timing Issues

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mpdm3

mpdm3

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I purchased a Duster that was pretty much done, has a stroked 360 (408) with MSD Atomic fuel injection that was controlling the timing. I could never get the car to run and idle right at lower RPM's despite multiple changes in initial and total timing and some support from tech forum on MSD. So I have disconnected timing control from the MSD, unlocked the distributor, installed a 28* button on the mechanical advance and put springs on that will get me to full mechanical advance just north of 2500 RPM. My question is where should I set the initial timing? The engine was dyno'd with 36* total advance, that is where peak HP and torque were achieved. I am assuming I should set initial at 8* BTDC?
 
mpdm3 said:
I purchased a Duster that was pretty much done, has a stroked 360 (408) with MSD Atomic fuel injection that was controlling the timing. I could never get the car to run and idle right at lower RPM's despite multiple changes in initial and total timing and some support from tech forum on MSD. So I have disconnected timing control from the MSD, unlocked the distributor, installed a 28* button on the mechanical advance and put springs on that will get me to full mechanical advance just north of 2500 RPM. My question is where should I set the initial timing? The engine was dyno'd with 36* total advance, that is where peak HP and torque were achieved. I am assuming I should set initial at 8* BTDC?
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Get as much initial as you can. You control that with the advance unit in the dizzy. Then set the total.
 
yellow rose said:
Get as much initial as you can. You control that with the advance unit in the dizzy. Then set the total.
Click to expand...

I am assuming MSD is fairly accurate on the degree of advance with their buttons, so red button = 28*, this would mean 8* BTDC correct?
 
Isn't a musclecar era car that should have a 28* bushing in that distributor.

See yellow rose's comment and do it.

It may have been dyno'd with 36* of timng for max power, that's only part of the timing profile. Initial timing is even more important to idle and low speed driving manners.

I sell 10 and 14* advance bushing for MSD distributors and they make a world of difference!
 
crackedback said:
Isn't a musclecar era car that should have a 28* bushing in that distributor.

See yellow rose's comment and do it.

It may have been dyno'd with 36* of timng for max power, that's only part of the timing profile. Initial timing is even more important to idle and low speed driving manners.

I sell 10 and 14* advance bushing for MSD distributors and they make a world of difference!
Click to expand...

When the Atomic was controlling the timing, it had 36* total timing and that came in at 2500 RPM's, car ran great. It was the initial timing during idle and low speed driving that was the issue. Assuming I want to get to 36*, what button do you recommend for the MSD? That will determine my initial timing. Does initial timing need to be set BTDC or can it be set ATDC?
 
mpdm3 said:
I am assuming MSD is fairly accurate on the degree of advance with their buttons, so red button = 28*, this would mean 8* BTDC correct?
Click to expand...


Your math is correct. But just set the total, the initial is in the dizzy.

IMVHO, 8* initial isn't enough. So you need to take a bunch out of the dizzy. When I started doing this I used to weld up the advance mechanism and set it at 10*. With the total set at 35*, I would have 15 initial. You can get more than that now if you are careful with the rest of the tune up.
 
yellow rose said:
Your math is correct. But just set the total, the initial is in the dizzy.

IMVHO, 8* initial isn't enough. So you need to take a bunch out of the dizzy. When I started doing this I used to weld up the advance mechanism and set it at 10*. With the total set at 35*, I would have 15 initial. You can get more than that now if you are careful with the rest of the tune up.
Click to expand...

So I will have a lot of initial advance. Assuming I go 10* in distributor, I will have to run 16* initial. Think my timing marks only go to 10* before and after.
 
mpdm3 said:
So I will have a lot of initial advance. Assuming I go 10* in distributor, I will have to run 16* initial. Think my timing marks only go to 10* before and after.
Click to expand...

Oops, 26* initial. Seems like a lot.
 
Take a timing light. Get the car warmed up, advance the idle timing to 15*. Shut the car off, see if it starts easy. If it does, bump it to 20*. Find the point that the starter is unhappy... you'll find it. Dial it back to a point just shy of the hot start kickback, do the math, new point that you observed subtracted from 36. That's the bushing you need.

Not even stock 318's like 8* of timing. Stock 340's like 14-16. Depending on the cam in your stroker, it may want anywhere from 14 to 26 degrees at idle.
 
crackedback said:
Take a timing light. Get the car warmed up, advance the idle timing to 15*. Shut the car off, see if it starts easy. If it does, bump it to 20*. Find the point that the starter is unhappy... you'll find it. Dial it back to a point just shy of the hot start kickback, do the math, new point that you observed subtracted from 36. That's the bushing you need.

Not even stock 318's like 8* of timing. Stock 340's like 14-16. Depending on the cam in your stroker, it may want anywhere from 14 to 26 degrees at idle.
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Thanks, I like the approach. Thinking I may need to get a timing tape, I have the stock balancer and only 10* on the factory marks.
 
Some guys found they needed a bushing for LESS advance than MSD offers. Somebody on this board was making them
 
Search hillbilly timing tape. That will slve your timing tape issues.

This is like kids and ice cream... If your kid likes vanilla ice cream and you hand them chocolate, it won't act right! You may think that 8 or 10* is what the engine may like (handing the kid chocolate) when 15 or 20 initial is what the engine lkes (Vanilla).

Let the engine TELL you what it likes and don't force what you think it may like. :)
 
crackedback said:
Search hillbilly timing tape. That will slve your timing tape issues.

This is like kids and ice cream... If your kid likes vanilla ice cream and you hand them chocolate, it won't act right! You may think that 8 or 10* is what the engine may like (handing the kid chocolate) when 15 or 20 initial is what the engine lkes (Vanilla).

Let the engine TELL you what it likes and don't force what you think it may like. :)
Click to expand...

It sounds like you were not programming nearly enough initial into it. If it was me, I'd hook the computer back up and let 'er rip. Almost nothing likes 8*. If it's a stick car, and open-chamber heads, I would change the rate of advance to bring in something like 28* to 32* at around 2800,and then bring the rest in a little later.Since we are not in the race forum, I'm assuming this is a streeter. So By slowing an reducing the initial hit, and delaying the power-timing a bit, it is often possible to run a lessor grade of fuel.But above all, increase the idle timing to what others have suggested.
Put the curve in, then work the fuel tables.Keep tabs on where the AIS is (if you have one), cuz you may have to reset the minimum throttle opening.
 
AJ/FormS said:
It sounds like you were not programming nearly enough initial into it. If it was me, I'd hook the computer back up and let 'er rip. Almost nothing likes 8*. If it's a stick car, and open-chamber heads, I would change the rate of advance to bring in something like 28* to 32* at around 2800,and then bring the rest in a little later.Since we are not in the race forum, I'm assuming this is a streeter. So By slowing an reducing the initial hit, and delaying the power-timing a bit, it is often possible to run a lessor grade of fuel.But above all, increase the idle timing to what others have suggested.
Put the curve in, then work the fuel tables.Keep tabs on where the AIS is (if you have one), cuz you may have to reset the minimum throttle opening.
Click to expand...

It is a street car. Using the computer and bringing timing in sooner I got a lot of detonation, never could get initial and total timing to work properly. Got to a frustration point and MSD was no help. Figured it was best to disconnect the computer and time it the old fashioned way, but still use the EFI.
 
mpdm3 said:
It is a street car. Using the computer and bringing timing in sooner I got a lot of detonation, never could get initial and total timing to work properly. Got to a frustration point and MSD was no help. Figured it was best to disconnect the computer and time it the old fashioned way, but still use the EFI.
Click to expand...

That's my point:
The engine will be wanting 16 to 20 degrees of idle timing. But may not want any more than 28*to 32* by 2800 to 3200. But it wants 36* for power timing.So sometimes you have to delay the power timing to 3600 or possibly,later. I know nothing about your combo, so I'm just throwing numbers at you. A mechanical dizzy can almost never hit all the bases, so it's always a compromise.You just have to let the engine tell you what she wants and when she wants it, and try to give it to her,as best as you can.
 
My 360 loves 20 initial, then I go 15 mechanical to give me 35 total no pinging all in around 2600.
 
crackedback said:
Search hillbilly timing tape. That will slve your timing tape issues.

This is like kids and ice cream... If your kid likes vanilla ice cream and you hand them chocolate, it won't act right! You may think that 8 or 10* is what the engine may like (handing the kid chocolate) when 15 or 20 initial is what the engine lkes (Vanilla).

Let the engine TELL you what it likes and don't force what you think it may like. :)
Click to expand...

Not sure I understand the hillbilly timing tape, can't wrap my head around marking those advanced marks ant then setting timing to them. Seems the marks would be retarded and not advanced.
 
You lost me.
In post #1,you say"and put springs on that will get me to full mechanical advance just north of 2500." Full advance, in your case, is 36*.This is early timing. Earlier I assume than your ECU timing; that was already detonating, and which you had to "delay the majority of the timing until 2500 hundred but paid for it at idle and low speed". If you had been running 8* all the way to say 2000 and then started bring in the timing to say 30* at 2500(delaying the majority) and then pulled in the remaining 6* by 3600;That would very definitely be unsatisfactory at idle and low speed.
So; the way I read this,is that with the Atomic ECU, you delayed the majority of the timing to 2500 and had knock. And now you wish to bring it all in just north of 2500, and are expecting it to not knock? Either I'm missing something, or..................This is messed up.
FWIW; Too-early timing is not the only thing that causes detonation. Detonation is an indicator of too much heat in the combustion chamber.
So, I guess,Time will tell...........
 
Think about the direction of rotation and which marks will get to the timing marks first... cause first is advanced more than the later ones.

Don't get confused because you are marking at the 5* ATDC mark. If you roll that new mark to zero, is the original balancer 0 mark closer or further away from the timing cover 0 mark?

All it takes is a little math to figure out where the marks go for any timing you desire up to 40* BTDC.
 
AJ/FormS said:
You lost me.
In post #1,you say"and put springs on that will get me to full mechanical advance just north of 2500." Full advance, in your case, is 36*.This is early timing. Earlier I assume than your ECU timing; that was already detonating, and which you had to "delay the majority of the timing until 2500 hundred but paid for it at idle and low speed". If you had been running 8* all the way to say 2000 and then started bring in the timing to say 30* at 2500(delaying the majority) and then pulled in the remaining 6* by 3600;That would very definitely be unsatisfactory at idle and low speed.
So; the way I read this,is that with the Atomic ECU, you delayed the majority of the timing to 2500 and had knock. And now you wish to bring it all in just north of 2500, and are expecting it to not knock? Either I'm missing something, or..................This is messed up.
FWIW; Too-early timing is not the only thing that causes detonation. Detonation is an indicator of too much heat in the combustion chamber.
So, I guess,Time will tell...........
Click to expand...

Now you lost me. The initial timing in the Atomic ECU was around 14* with full timing of 36* at 2500. The spring tension installed in the distributor will get me to full mechanical advance at 2500, full advance at that point would be the difference in initial and the button installed in the distributor. What I am trying to determine is what should be the correct initial advance, knowing I am going to get to 36* somewhere around 2500 RPM. To my knowledge MSD does not offer a spring that will bring in mechanical advance any later than that.
 
crackedback said:
Think about the direction of rotation and which marks will get to the timing marks first... cause first is advanced more than the later ones.

Don't get confused because you are marking at the 5* ATDC mark. If you roll that new mark to zero, is the original balancer 0 mark closer or further away from the timing cover 0 mark?

All it takes is a little math to figure out where the marks go for any timing you desire up to 40* BTDC.
Click to expand...

This kept me up last night. If the crank turns clockwise and you are putting advance marks based on the damper being at 10* BTDC, is that going to give me 15* advance if I set that mark at TDC? I am probably over thinking this whole thing and may not have enough understanding to pull it off.
 
mpdm3 said:
This kept me up last night. If the crank turns clockwise and you are putting advance marks based on the damper being at 10* BTDC, is that going to give me 15* advance if I set that mark at TDC? I am probably over thinking this whole thing and may not have enough understanding to pull it off.
Click to expand...


I don't know what hillbilly timing tape is either, unless it's home made. In that case, you take the diameter of the dampener and multiply that by 3.14159. Divide that number by 360 (the number of degrees in a circle). Then take that number and multiply it by the number of degrees that you want to set the timing at, or you can find BDC, 90 and 270 degree marks for setting the valves. I hate math. So just for giggles, let's say you want to find 35* BEFORE TDC. It would look like this:

7.25 x 3.14159 = 22.776257. That is the distance around a small block dampener. Now 22.776\360 gives you .0632681 which is how far apart each degree is. Take that and multiply it by 35 and you get 2.214835. That is the total distance in inches you measure form the mark on your dampener where you make another mark. You line up the new mark with ZERO on the timing cover at full advance to set total timing.

All this is for not if you have a degreed dampener. Or you buy a timing tape.

Hope I didn't muddy everything up for anyone.
 
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