Recommended total engine timing

[Jax]

I know is difficult to suggest the ideal timing, however would like to know what you guys are running.

I am currently experiencing some misfiring, and I think it has to do with timing and fuel Octane relation.

This is my set up:

Engine Cubic Inches: 410
Compression Ratio: 11.5
Intake Manifold Brand: Indy Performance 360-3R
Intake Manifold Bolt Pattern: Single 4150
Cylinder Head Type: Indy 360 H1 Aluminum Heads
Intake Valve Diameter: 2.100
Exhaust Valve Diameter: 1.65
Fuel Type: Gasoline and Race Fuel mix ( 2:1) 2 Gallons 95 octane pump gas, 1 gallon VP race C12 or C14 fuel
MSD Digital Ignition with 38 Degrees Ignition Timing
Fuel Pump: Electric
Fuel Pump GPH Rating: 140
Camshaft - Intake Duration @.050: 255
Camshaft - Exhaust Duration @.050: 263
Camshaft - Intake Lift at Valve: .670
Camshaft - Exhaust Lift at Valve: .670
Lobe Separation: 106
Header Diameter (List size for stepped header in space provided.): 1 7/8"

What is your setup and how much timing and fuel are you running?

 

[Garrett Ellison]

First question is, are you running with the timing locked out at 38 degrees static all the time? If not, how much baseline and when is your total timing all the way in? I honestly can't see that needing much more than 35 degrees of total timing on a good day...

 

[Jax]

First question is, are you running with the timing locked out at 38 degrees static all the time? I not, how much baseline and when is your total timing all the way in? I honestly can't see that needing much more than 35 degrees of total timing on a good day...

My distributer is locked (MSD) and my timing comea in full at 3500 rpm

 

[Jax]

First question is, are you running with the timing locked out at 38 degrees static all the time? I not, how much baseline and when is your total timing all the way in? I honestly can't see that needing much more than 35 degrees of total timing on a good day...

Wich compression ratio and fuel are you running?

 

[RustyRatRod]

My distributer is locked (MSD) and my timing comea in full at 3500 rpm

If your timing "comes in full at 3500 rpm" then you don't have locked out timing. I think you need to double check and let us know. Locked out timing would mean you have 38 degrees advance at idle and 38 degrees advance at every RPM. Also 38 degrees advance sittin in the driveway not running at all. In other words 38 degrees EVERYWHERE. So we need some clarification.

 

[Garrett Ellison]

Also, just curious, your location is Aruba, so you're probably not much over 500 feet above sea level are you?

 

[teringer]

I would try to get all the timing in by 1800 to 2000 rpm maybe cut it back to 35deg

 

[Jax]

If your timing "comes in full at 3500 rpm" then you don't have locked out timing. I think you need to double check and let us know. Locked out timing would mean you have 38 degrees advance at idle and 38 degrees advance at every RPM. Also 38 degrees advance sittin in the driveway not running at all. In other words 38 degrees EVERYWHERE. So we need some clarification.

Indeed, my distributor is locked so I have 38 degrees timing all across.

 

[Jax]

Also, just curious, your location is Aruba, so you're probably not much over 500 feet above sea level are you?

Yesss.. we are just above 300 ft

 

[RustyRatRod]

Two things. With aluminum heads and under 12:1 with that cam, there's no way in heck you need locked out timing and at 38 degrees. Secondly, there's no way you need race gas. You're wasting your money with a bad tune.

 

[TT5.9mag]

the Indy 360-1 heads are pretty damn efficient. They are based on the W2 design. I will not recommend timing numbers but 38 is likely too much AND probably not causing your misfire problem. I do recommend backing the timing down to 30 and then TEST to see what the engine actually likes. Add a degree, make a pass. Faster? Slower? Repeat. Stop adding when the car slows down.

 

[Jax]

Thanks for the feedback guys. Will try to lower the timing and see how it reacts.

Any other ideas what can be causing the misfiring? It doesn't happen all the time during the run..

 

[RustyRatRod]

Thanks for the feedback guys. Will try to lower the timing and see how it reacts.

Any other ideas what can be causing the misfiring? It doesn't happen all the time during the run..

At this point, the high and locked out timing would be suspect.

 

[Newbomb Turk]

I know is difficult to suggest the ideal timing, however would like to know what you guys are running.

I am currently experiencing some misfiring, and I think it has to do with timing and fuel Octane relation.

This is my set up:

Engine Cubic Inches: 410
Compression Ratio: 11.5
Intake Manifold Brand: Indy Performance 360-3R
Intake Manifold Bolt Pattern: Single 4150
Cylinder Head Type: Indy 360 H1 Aluminum Heads
Intake Valve Diameter: 2.100
Exhaust Valve Diameter: 1.65
Fuel Type: Gasoline and Race Fuel mix ( 2:1) 2 Gallons 95 octane pump gas, 1 gallon VP race C12 or C14 fuel
MSD Digital Ignition with 38 Degrees Ignition Timing
Fuel Pump: Electric
Fuel Pump GPH Rating: 140
Camshaft - Intake Duration @.050: 255
Camshaft - Exhaust Duration @.050: 263
Camshaft - Intake Lift at Valve: .670
Camshaft - Exhaust Lift at Valve: .670
Lobe Separation: 106
Header Diameter (List size for stepped header in space provided.): 1 7/8"

What is your setup and how much timing and fuel are you running?

I’m going to be the hard *** and tell you to not mix race fuel with pump fuel.

At your compression ratio you do not need race fuel and it is most likely costing power.

So don’t do that.

Then we have 38 degrees of timing. Is it locked out. If so, that’s bad.

If not, what is the initial timing and at what rpm?

At what rpm does the distributor start adding timing?

At what rpm does full advance occur?

Until we know that no one can even guess at a curve.

I will say that if you have 38 degrees of timing at less than 7500 rpm you most likely have too much timing at peak power. And you definitely have too much timing at peak torque.

That is unquestionable.

 

[Newbomb Turk]

I would try to get all the timing in by 1800 to 2000 rpm maybe cut it back to 35deg

 

[Newbomb Turk]

Indeed, my distributor is locked so I have 38 degrees timing all across.

You are killing torque and power like crazy.

You need to stop what you are doing, get it off the race fuel and get a curve in the distributor.

And a “curve” that is all in by 2500 isn’t a curve. I consider that locked out.

Now we need to know you car weight, transmission, converter stall speed, rear axle ratio and hopefully you had it on an engine dyno so you know your torque and power peaks.

 

[Demonracer]

You need to do all of the above, as well as read the plugs and tune the jetting and power valve(s) in the carburetor.

 

[Jax]

Will get back to you guys on the initial timing, for the rest this is the remaining info:

car weight: 2735 lbs'
Trans: A904 with transbrake
converter stall speed: 4500
rear axle ratio: 4.10

 

[Newbomb Turk]

Will get back to you guys on the initial timing, for the rest this is the remaining info:

car weight: 2735 lbs'
Trans: A904 with transbrake
converter stall speed: 4500
rear axle ratio: 4.10

Shift rpm?

 

[Jax]

Shift rpm?

5600

 

[TT5.9mag]

4500 stall with a 5600 rpm shift? Did you mean 7600? Or 6600?

 

[Bewy]

Strange isn't it. For decades, hot rodders found that if their ign timing was LOCKED, they ran quicker, ran cooler & had better tip in response. Assuming the total timing is correct for the engine.

 

[Newbomb Turk]

Strange isn't it. For decades, hot rodders found that if their ign timing was LOCKED, they ran quicker, ran cooler & had better tip in response. Assuming the total timing is correct for the engine.

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.

 

[Valman]

Indeed, my distributor is locked so I have 38 degrees timing all across.

Total mechanical advance shouldn’t be anymore more than around 32-34 especially with the stroker & good comb.chamber/ quench.

 

[Newbomb Turk]

Total mechanical advance shouldn’t be anymore more than around 32-34 especially with the stroker & good comb.chamber/ quench.

At what rpm? Without rpm your numbers make zero sense