Recommended total engine timing

[Newbomb Turk]

Compression ratio and cylinder head efficiency and material is what determines how much total timing is needed more than camshaft, intake, carburetor than all the other things listed.

Uhhhhh, not really.

Compression certainly affects the AMOUNT of timing you need.

If by cylinder head efficiency you mean combustion chamber efficiency then yes, it has an effect on timing. Spark plug location is far more critical than chamber shape.

Cylinder head materiel has ZERO affect on timing. None.

Camshaft has as much to do with timing and especially the curve as the other things mentioned.

Where the engine makes peak torque and power has a major effect on what the timing curve looks like.

An engine with peak torque at 3500 and peak power at 5000 won’t have the same CURVE as an engine that makes peak torque at 5200 and peak power at 6800. They won’t even be close.

This is what guys are missing. Peak torque and power want totally different timing. That’s the physics of it.

Of course, if we go down the rabbit hole of slew rate, I can definitively say that 99% of the guys running locked out or all in by 2500 have no clue what their timing is at peak torque and power.

That’s giving up power. All this is easily provable.

 

[Newbomb Turk]

Damn that's impressive. What was the combo of you don't mind me asking?

It’s been on several different combos. They have been 500-500 hp street/strip pump gas engines.

One was on @MOPARMAGA’s 451 big block. I forget his numbers but I’m sure he knows them.

I know last time it was on the pump it made 680 hp. That was on Av gas with a trace of some additive I can’t think of right now. It is about 13:1 compression.

And yes, we tested the Av gas against Sunoco 110 leaded and it lost power.

 

[RustyRatRod]

I farted. How's that for timing?

 

[Hysteric]

And yes, we tested the Av gas against Sunoco 110 leaded and it lost power.

Why do you think that was the case? How it the plugs look?

 

[70SwingerGuy]

Just because everyone did something a certain way 50 years ago and got good results doesn't mean there isn't a better way to do it now.

THIS^^ applies to so many threads on this site

 

[9secRR]

Of course, if we go down the rabbit hole of slew rate, I can definitively say that 99% of the guys running locked out or all in by 2500 have no clue what their timing is at peak torque and power.

That’s giving up power. All this is easily provable.

When I’m making a pass balls to the wall (timing locked out at 37*) what is the timing actually at? Is there a way or method to see what the timing is at?

 

[-Boosted-]

No pun intended. I’m still waiting for the explanation.

You needed to expand the quote to see what I was referring to with my attempt at a joke.... lol


Newbomb Turk said:


So the physics were different back then?

I don’t think so.

There is a reason the factory put a curve in the distributor. And used vacuum advance.

Since you are the head cheerleader for locked out timing, maybe you could explain, with exceptional detail how an engine’s timing requirements are the same when VE changes with load and rpm.

Try using your own words. Pictures of texts from books won’t work. Use your own words.

I can’t wait to be educated.

Thank You in advance.

 

[Garrett Ellison]

One of the older devices sometimes misused with locked out timing…

 

[Newbomb Turk]

Why do you think that was the case? How it the plugs look?

I’m not exactly sure. The plugs looked normal.

That engine is going back on the pump one of these days. Maybe we can talk him into doing the test again to see if the results are the same.

 

[Newbomb Turk]

When I’m making a pass balls to the wall (timing locked out at 37*) what is the timing actually at? Is there a way or method to see what the timing is at?

Yes. Take the ignition out of the car and put the distributor on a test bench.

Hook up the ignition exactly like it is in the car and spin it up.

You’re already locked out to any variation in timing shows up easily.

Then you’ll know exactly when the box retards and how much and you can account for that when you set your timing.

You can do it in the car but it’s a PITA. It’s very difficult to hold the throttle steady, see the marks and then increase the rpm and do it again until max rpm. You can just hold the throttle at max rpm so you know how much total retardant there is. I can tell you I’ve done that and it is a bit unnerving to wing the engine all the way up, bend over the fender and taking a look.

BTW, what ignition and distributor are you using?

 

[Newbomb Turk]

One of the older devices sometimes misused with locked out timing…

View attachment 1716396405

I’ve never seen one of those. What era is that?

 

[Icetech]

lock at 26.... motor starts nice... and is VERY safe..... always go for safety!

 

[RustyRatRod]

THIS^^ applies to so many threads on this site

I absolutely 100% agree. However, the flip side is, there are some things that still work just as well as 50 years ago. The original Purple cams come to mind. Sure, there are "better, more modern" grinds, but the Purple cams still do exactly what they advertised so long ago. If you can find them. lol

 

[Garrett Ellison]

I’ve never seen one of those. What era is that?

Mid eighties to early nineties if I’m not too far off base. Made my Allison electronics. There’s a High-8 Magnetic Resonance Converter system with the top tier DEC controller on eBay I’ve been keeping an eye cocked towards.
Crane PRO DEC 9500 & 8000-7800 HI-8 Digital CD Ignition Box & Engine Control | 80007800

 

[9secRR]

Yes. Take the ignition out of the car and put the distributor on a test bench.

Hook up the ignition exactly like it is in the car and spin it up.

You’re already locked out to any variation in timing shows up easily.

Then you’ll know exactly when the box retards and how much and you can account for that when you set your timing.

You can do it in the car but it’s a PITA. It’s very difficult to hold the throttle steady, see the marks and then increase the rpm and do it again until max rpm. You can just hold the throttle at max rpm so you know how much total retardant there is. I can tell you I’ve done that and it is a bit unnerving to wing the engine all the way up, bend over the fender and taking a look.

BTW, what ignition and distributor are you using?

MSD 6 AL ignition box, MSD 8534 distributor.

 

[Newbomb Turk]

MSD 6 AL ignition box, MSD 8534 distributor.

I’m 100% positive it will retard with rpm.

What I can’t say is when it starts and how much it will retard.

I have some videos of different boxes retarding on my YouTube page.

Baldwin Carbs has (at least he used to but I haven’t looked lately) some videos of the same thing.

That’s where I first learned of slew rate and such. That’s why I bought my own test bench. It can be so bad it’s no wonder guys can “upgrade” ignition systems and lose power. The retard certainly affects power.

@92b is going to do some testing when he gets a minute to do it. I’m waiting on his results. It should be interesting.

If you are down for the cause, you can send me your box, coil and distributor and I’ll test it for free as long as you pay the freight and I can make a video and post it to my channel.

Let me know.

 

[Newbomb Turk]

Mid eighties to early nineties if I’m not too far off base. Made my Allison electronics. There’s a High-8 Magnetic Resonance Converter system with the top tier DEC controller on eBay I’ve been keeping an eye cocked towards.
Crane PRO DEC 9500 & 8000-7800 HI-8 Digital CD Ignition Box & Engine Control | 80007800

If I wasn’t spending cash like a white in church to get my junk together I’d buy that system just to test it.

That would be fascinating to see what it does.

What’s kind of embarrassing is I’ve never seen one before you posted it. During that era I was running a mag and so were most of the guys I hung with.

I do remember when (IIRC) Holley came out with the first ignition system capable of individual cylinder timing.

I don’t remember the exact year but I’m pretty sure I was still drinking so pre 1993.

I showed up to a Pro Stock test at a tack that was local to me where they stopped between Sonoma and Seattle.

What caught my eye was that Holley showed up with their full race trailer to this little deal.

I don’t think anyone at the time was using the ignition at the National events, but they were using it on the dyno and working on how to use it in competition.

We’ve come along way since then. And went backwards in some areas sadly.

 

[9secRR]

I’m 100% positive it will retard with rpm.

What I can’t say is when it starts and how much it will retard.

I have some videos of different boxes retarding on my YouTube page.

Baldwin Carbs has (at least he used to but I haven’t looked lately) some videos of the same thing.

That’s where I first learned of slew rate and such. That’s why I bought my own test bench. It can be so bad it’s no wonder guys can “upgrade” ignition systems and lose power. The retard certainly affects power.

@92b is going to do some testing when he gets a minute to do it. I’m waiting on his results. It should be interesting.

If you are down for the cause, you can send me your box, coil and distributor and I’ll test it for free as long as you pay the freight and I can make a video and post it to my channel.

Let me know.

if i still had this setup i would send it to you to test. i ran this with the W2 engine. all different now with the current engine.

sold the ignition box and upgraded to the 7AL-3 when i rewired the entire car.

 

[RustyRatRod]

I’m 100% positive it will retard with rpm.

What I can’t say is when it starts and how much it will retard.

I have some videos of different boxes retarding on my YouTube page.

Baldwin Carbs has (at least he used to but I haven’t looked lately) some videos of the same thing.

That’s where I first learned of slew rate and such. That’s why I bought my own test bench. It can be so bad it’s no wonder guys can “upgrade” ignition systems and lose power. The retard certainly affects power.

@92b is going to do some testing when he gets a minute to do it. I’m waiting on his results. It should be interesting.

If you are down for the cause, you can send me your box, coil and distributor and I’ll test it for free as long as you pay the freight and I can make a video and post it to my channel.

Let me know.

You seem to know a whole lot about retardation.

 

[Newbomb Turk]

You seem to know a whole lot about retardation.

Yes I do. And we always say it takes one to know one lol

 

[RustyRatRod]

Yes I do. And we always say it takes one to know one lol

Now yer learnin. LOL