Tuning For Detonation

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My experience with the slant, is they don't like the same amount of timing as small blocks (12/34)
If you are experiencing pinging, I believe you are using to much timming. Lowering the expectations of the thing will produce a better running motor.

I agree. I've read over and over slants don't like a ton of total timing. I really wanted to try about 20 initial and 30-32 total, but the plate is not offering that, even though it's marked to give those results. I have an email in to Don so we'll see what he says.
 
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Heat soak vs lack of heat soak is why drag racing can use more advance than most other activities. Once the the engine has enough heat combustion is quicker...
 
maybe this will help complete the picture.
Lets say the advance looks like the dotted line; And lets say you want to keep the 20* initial and 35* max.
View attachment 1715730996

Turning the long loop spring's perch or using a shorter loop will change the advance like this.
View attachment 1715731000
It only takes a few degrees out of the mid rpms and leaves the top and low rpm timing as is.
I like this idea, though I think he is already into the full advance when he tips it.
..and now iwouldn't call it ragged edge if he is doing this with 87. I'd call it motor abuse. Lol

This is for the general reader of this thread.
Knowing what you what you have read..ask yourself this...
Given the choice...why would you run 87 and detune for it...when you'll only make less power that way.
 
I like this idea, though I think he is already into the full advance when he tips it.
..and now iwouldn't call it ragged edge if he is doing this with 87. I'd call it motor abuse. Lol

This is for the general reader of this thread.
Knowing what you what you have read..ask yourself this...
Given the choice...why would you run 87 and detune for it...when you'll only make less power that way.

Well, I actually have a tank full of 90 non ethanol right this minute.
 
I agree. I've read over and over slants don't like a ton of total timing. I really wanted to try about 20 initial and 30-32 total, but the plate is not offering that, even though it's marked to give those results. I have an email in to Don so we'll see what he says.

They don't. 32 degrees full advance is where mine pulled best .
I think you should put the stock plate back in it and remove only the heavy spring leaving the light one that should give you about 18 at idle and 15 advanced left in the curve. Or screw a bolt into it and grind both sides off to eat up the advance.
 
I like this idea, though I think he is already into the full advance when he tips it.
..and now iwouldn't call it ragged edge if he is doing this with 87. I'd call it motor abuse. Lol

This is for the general reader of this thread.
Knowing what you what you have read..ask yourself this...
Given the choice...why would you run 87 and detune for it...when you'll only make less power that way.

And......I'm beginning to think it doesn't have the cylinder pressure maybe I thought, because it has the one telltale sign.....it WANTS a LOT of initial timing. I'll round up a good compression gauge and get a number.
 
And......I'm beginning to think it doesn't have the cylinder pressure maybe I thought, because it has the one telltale sign.....it WANTS a LOT of initial timing. I'll round up a good compression gauge and get a number.
Is this a three on the tree?
That's the cam, it's not as small as the lift eludes.
I'm starting to wonder a few things now after your cylinder head Extravaganza and re articulating the Chambers. Was this thing really high on the exhaust flow side
 
They don't. 32 degrees full advance is where mine pulled best .
I think you should put the stock plate back in it and remove only the heavy spring leaving the light one that should give you about 18 at idle and 15 advanced left in the curve. Or screw a bolt into it and grind both sides off to eat up the advance.

Well.....there IS no stock plate. There's nothing in stock form to limit the total advance. I heard back from Don and this is the only plate they offer. I mean really, how hard would it be to make two? A low advance and the standard one. The standard one goes from zero to 18 in 2 degree increments. It shouldn't be too difficult to make one from zero to 12 beginning with 4. Evidently this distributor is different somehow and requires different slot sizes to achieve the correct total advance.
 
Is this a three on the tree?
That's the cam, it's not as small as the lift eludes.
I'm starting to wonder a few things now after your cylinder head Extravaganza and re articulating the Chambers. Was this thing really high on the exhaust flow side

This head is totally stock, except for being milled. The closed chamber head might be what you're thinking about and I've not built that engine yet.
 
Is this a three on the tree?
That's the cam, it's not as small as the lift eludes.
I'm starting to wonder a few things now after your cylinder head Extravaganza and re articulating the Chambers. Was this thing really high on the exhaust flow side

And yes, it's three on the tree and always will be. There's a song there somewhere.
 
Well.....there IS no stock plate. There's nothing in stock form to limit the total advance. I heard back from Don and this is the only plate they offer. I mean really, how hard would it be to make two? A low advance and the standard one. The standard one goes from zero to 18 in 2 degree increments. It shouldn't be too difficult to make one from zero to 12 beginning with 4. Evidently this distributor is different somehow and requires different slot sizes to achieve the correct total advance.
I wonder what year that distributor is.
Are you using a dial back timing light?
I like to go 500 or so RPM past where it seems to full advance when I check.
 
I wonder what year that distributor is.
Are you using a dial back timing light?
I like to go 500 or so RPM past where it seems to full advance when I check.

Yeah. I don't like it, either. BUT the engine "acts" like the timing light is correct.
 
you know what's funny... is if I had directly replied to the title of this thread.... I'd tell ya spin the distributor advance till it don't turn no more , jamb close the heat flap ...and start off from every light in 3rd/1.1

Lmao great thread title!
 
you know what's funny... is if I had directly replied to the title of this thread.... I'd tell ya spin the distributor advance till it don't turn no more , jamb close the heat flap ...and start off from every light in 3rd/1.1

Lmao great thread title!

Yeah, I thought about that when I made the title....but I wanted short and sweet and knew "most" would know what I meant. LOL
 
Are you saying you're setting the timing by ear? I didn't catch if you said you what kind of timing light you were using

Oh no. I am using a dial back light. I was commenting that I don't like it, but that the engine "acts" and "runs" like the light is reading correctly.
 
Are you saying you're setting the timing by ear? I didn't catch if you said you what kind of timing light you were using

I suppose I "could" do Rob's Hillbilly Timing Tape mod and that would give me marks to check with my non dial back light. At least that'd be a second opinion. lol
 
.it WANTS a LOT of initial timing
OK. But does it have to be 20? Does it generate half decent manifold vac at anything less?

I like to go 500 or so RPM past where it seems to full advance when I check.
and every 200 or 250 rpm from as slow as I can get it up to 2250 or 2500.

I wonder what year that distributor is.
That would definately be a clue for what curve looked like.

There's nothing in stock form to limit the total advance.
See what Ray has in the bin he could send you, along with some springs.
Or the old school way.
Weld up the inside of the slots once you know what the curve looks like.
upload_2019-5-23_10-37-5-png.png

(Full description in this post)

What that does.
Lets say this was a distributor from a '69 225 ( I know its not, but it happens to be one I have specs for).
And the timing measured when initial set to 0* initial looks like this.
upload_2021-4-30_16-22-57.png


Lets say we want 32* by 4000 rpm, not 28*.
So turn this distributor to so the initial is at 4*BTC.
But with this engine we know its going to need more initial to idle decent.
Weld the inside of the slots and timing looks like this
upload_2021-4-30_16-31-3.png


That should have no problem working with the original vacuum advance.

To get the timing to advance sooner above idle rpm, turn the spring perch so there is the least tension on it.
To bring the long spring into play at a higher rpm, turn its spring perch so there is more slop.
 
Weld the inside of the slots and timing looks like this
Versus welding the outside of the slots which would result in a curve like this assuming the engine will idle down at 700 rpm.
upload_2021-4-30_16-45-12.png

Basically the same issues and solutions as when using the limiter plate.
What you might try in this case is to add a second primary spring instead of the long looped spring.
 
Oh no. I am using a dial back light. I was commenting that I don't like it, but that the engine "acts" and "runs" like the light is reading correctly.
It is. Set the total number and move the distributor till it shows zero on the balancer with the strobe. What springs, the slotted one? I think I'd lose that one and use two light springs for this.
 
You are saying it long cranks when hot trying to get it started.

You probably want to keep it original with that D, D, D, Dodge factory starter. Put a mini starter in there and it will start like it's got fuel injection.

Don't forget the mini starters don't rob juice from the ignition like the slower turning factory starters do. So you get double the juice for the ignition with the mini, quick starts.

☆☆☆
 
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