Base timing. Really ?

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AJ/FormS said:
Not just me, we're kindof a team around here. There's lots of guys here smarter than me and some to many regular contributors that have vastly more knowledge and or experience.
I only know two things in this world, maybe three, namely Bible, a street 360, and ....... um , ohchit I forgot #3. And I'm not really all that up to speed on any of them, but I muddle along pretty good.
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Agree with the muddle along pretty good !-lol
 
RustyRatRod said:
40 is a bit much. Usually small blocks like around 36 total give or take, big blocks a tick less.
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QuickDart360 said:
I set my 360 to 16° initial timing. Distributor is from fbo with limiter plate. Cam is the 292/508 mopar cam. Seems to start fine. Also runs well. Question is can I try more initial or just keep driving? Really only left this way since it came @ that setting since purchase. This distributor was used before with 280 mopar cam too.
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I would say put a vacuum gauge on it and bump up the timing 2 degrees and see if the vacuum goes up and it idles better. Than take it out and stomp on it. See if it ‘pings ‘. Go from there
 
A Body 440 WHY NOT said:
I would say put a vacuum gauge on it and bump up the timing 2 degrees and see if the vacuum goes up and it idles better. Than take it out and stomp on it. See if it ‘pings ‘. Go from there
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The only thing I would add to this is of you do this and you go mash on it and don’t hear any detonation I would still come back and take a close, hard look at the plugs to see if there was any detonation.

It will detonate and show on the plugs before it’s audible.
 
QuickDart360 said:
I set my 360 to 16° initial timing. Distributor is from fbo with limiter plate. Cam is the 292/508 mopar cam. Seems to start fine. Also runs well. Question is can I try more initial or just keep driving? Really only left this way since it came @ that setting since purchase. This distributor was used before with 280 mopar cam too.
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I once ran that cam in my 367,A833/3.55s/68 Barracuda.
It liked ;
20* cold
14* hot
32 to 34* at WOT after 3200
5*@550rpm in gear and pulling itself
56* or more at 56mph =2600 on the hiway.
The only way to cover all the bases was with a dash-mounted, dial-back, timing retard, device. Mine is a Jacob's.
That combo was; 11.3Scr with ootb Edelbrock heads,, flat top hypers at ~.034 Q, and ran about 180*F sometimes more,eventually up to 207*.
I installed a two-stage timing curve that ran to 28* at 2800, and then slowed down to 32@3200/about 34* at 3400 and done.
 
yellow rose said:
The only thing I would add to this is of you do this and you go mash on it and don’t hear any detonation I would still come back and take a close, hard look at the plugs to see if there was any detonation.

It will detonate and show on the plugs before it’s audible.
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KoiPond-fshDo-Koi-have-teeth-390x268.jpg
 
yellow rose said:
It will detonate and show on the plugs before it’s audible.
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Also,at WOT,all I can hear is the screaming dual 3inchers. And that is partly why my all-in Power-timing is 32/34 @3200/3400.
It's nice and safe, and already spins the tires
to; past the speed limit anywhere in Manitoba, and
beginning from; almost any rpm, (I haven't tried it below about 1500rpm) or any speed, in either first or second gear, even up to or more than,50 mph.
So,because of the traction issue, I have never bothered to dial it in any closer; my chassis just cannot deal with any more power. And honestly, how much power am I missing from 2800 to 3400, with my conservative timing? I could see it being an issue in Third gear, but with 3.55s, 3000 is 48mph..... and who stomps it at 48 in third? It never happens.
The bonus is, the plugs are still the same ones I installed in 1999, and they have over 100,000 miles on 'em.

For you guys running massive Power-timing at waaay early rpms; IDK how you don't cringe when you stomp it below 3000; my azz puckers just thinking about it.
 
Glad i stumbled onto this post before i made a new one. On my 440 with 284/484 cam installed 2 degrees advance, 9.4:1 compression, street dominator intake, 3000stall convertor in a 1972 dart, I have the electronic ignition with an FBO limiter plate in it and if i remember right, 1 spring in the distributor. Timing is at 20 initial and 34 total. The timing is all in by 2800. I THINK too light of a spring is the issue and after reading all this i really think it is the issue, but when laying into the throttle at lower RPM's, like under 3500 i guess, it detonates a little, but i dont hear it if i lay into it when the rpm is higher..Thoughts?
 
34 seems a little low for a bigblock unless you have close chamber heads and really goodquench .
 
mopower440 said:
when laying into the throttle at lower RPM's, like under 3500 i guess, it detonates a little, but i dont hear it if i lay into it when the rpm is higher..Thoughts?
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Yes IMO you do have too much timing below 3500. Detonation slows you down; and breaks parts; get rid of it. Better to be too slow than too fast.

The thing is; with just 9.4 Scr and that big cam, your cylinder pressure should be so low, that it should run on any crappy gas, with lots of timing, especially with a 3000stall.. The fact that it doesn't, leads me to suspect a chamber problem.
I assume you have tried best non-alcoholized gas?

Have you done a compression test?
 
mopower440 said:
Glad i stumbled onto this post before i made a new one. On my 440 with 284/484 cam installed 2 degrees advance, 9.4:1 compression, street dominator intake, 3000stall convertor in a 1972 dart, I have the electronic ignition with an FBO limiter plate in it and if i remember right, 1 spring in the distributor. Timing is at 20 initial and 34 total. The timing is all in by 2800. I THINK too light of a spring is the issue and after reading all this i really think it is the issue, but when laying into the throttle at lower RPM's, like under 3500 i guess, it detonates a little, but i dont hear it if i lay into it when the rpm is higher..Thoughts?
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Your problem is too “fast” not too much timing. At torque peak your cylinder pressure will be the highest. Delay the curve and bring in the advance later. Or as AJ does, develop a two stage curve.
 
the 2-stage works really well with a manual trans, where the tires are married to the road.
Like in direct gear at passing speed where the rpm is low, and the loading is high.
I have 3.55s and so, at 55mph, pulling out to pass a guy, still in 4th gear, The Rs will be ~2400. And I burn 87E10 exclusively. There is no KD cuz it's a manual trans, and there is no way my 367 can break traction in 4th gear. So the engine HAS to not detonate, when I floor it.
That is the type of condition I use the 2-stage for.
By experimentation I found that my engine was Ok with up to 28* at 2800 at full load/WOT, in any gear. Yours may vary.
After that I just hoped for the best, which turned out to be another 4 to 6 degrees at about 3400. That was close enough for me.
But I have heard that BBs like more, so experiment carefully.
 
AJ/FormS said:
Yes IMO you do have too much timing below 3500. Detonation slows you down; and breaks parts; get rid of it. Better to be too slow than too fast.

The thing is; with just 9.4 Scr and that big cam, your cylinder pressure should be so low, that it should run on any crappy gas, with lots of timing, especially with a 3000stall.. The fact that it doesn't, leads me to suspect a chamber problem.
I assume you have tried best non-alcoholized gas?

Have you done a compression test?
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yes, compression test is 185-190 pounds
 
TT5.9mag said:
You sure about that 9.4:1 compression?
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Been about 18 years since i built it but i believe thats what it was..? The pistons are .030 over and had a compression height of 2.062, has open chamber 452 heads and the heads have not been shaved and the block has not been decked. The head gasket, if i remember right was the thicker one, not the steel shim..
 
185/190, does not compute at 9.4 Scr and 284cam in at +2

As to that cam there are two versions; one is on a 108LSA, and the other is on a 114; So your Ica could be either 68* or 74*
Using the 74* and assuming an elevation of 900ft, the Wallace Calculator spits out a pressure of [email protected]
To get 185plus psi,the Calculator wants
more than 11.7Scr @68*, and more than 12.4Scr@74

If your pressure is accurate; and your heads are iron, then you have a big problem. Since the engine is still together after 18 years; IMA guessing the pressure is NOT accurate. And since the problem is only at below 3500, Ima guessing the Scr is NOT accurate either.
But;
just in case both the pressure and the Scr ARE correct, I tried to force the Calculator to spit out a 185psi number with a 9.4Scr, by manipulating the Ica, and had to go down to an Ica of 48*. I do not think there was ever a BBcam made with such an ICA, and I would think that if your 284 cam was advanced 20*, there is no way your engine should run ; so
IDK

Here's are some clues;
>if the pressure is correct; that thing should be a wicked beast to drive, with a tremendous amount of low-rpm grunt, that would make it scary to whack open.
> if the 9.4Scr is correct, it should feel way under-powered for a 440, even with the 3000TC.
> if the cam is advanced 20*, it should still be a bit of beast at low-rpm, but choke way too early. and I cannot imagine how it would idle, except to say that there would be a huge amount of energy still in the exhaust.
 
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mopower440 said:
Glad i stumbled onto this post before i made a new one. On my 440 with 284/484 cam installed 2 degrees advance, 9.4:1 compression, street dominator intake, 3000stall convertor in a 1972 dart, I have the electronic ignition with an FBO limiter plate in it and if i remember right, 1 spring in the distributor. Timing is at 20 initial and 34 total. The timing is all in by 2800. I THINK too light of a spring is the issue and after reading all this i really think it is the issue, but when laying into the throttle at lower RPM's, like under 3500 i guess, it detonates a little, but i dont hear it if i lay into it when the rpm is higher..Thoughts?
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20 initial , how about the vac advance ? do you use one ? That may be adding to your problem. I would also add 1 soft spring. Common set up seems to be 1 soft stock spring , ditch the thick stock spring, and install a soft aftermarket one ( mr gasket )
 
AJ/FormS said:
185/190, does not compute at 9.4 Scr and 284cam in at +2

One of those is not correct, and I'll guess it's the Scr, otherwise you would not be having a detonation problem.

As to that cam there are two versions; one is on a 108LDA, and the other is on a 114
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So you believe his act is higher ? cliser to 10-1 ?
 
TT5.9mag said:
Your problem is too “fast” not too much timing. At torque peak your cylinder pressure will be the highest. Delay the curve and bring in the advance later. Or as AJ does, develop a two stage curve.
Click to expand...
(Add a spring will delay )
 
AJ/FormS said:
185/190, does not compute at 9.4 Scr and 284cam in at +2

As to that cam there are two versions; one is on a 108LSA, and the other is on a 114; So your Ica could be either 68* or 74*
Using the 74* and assuming an elevation of 900ft, the Wallace Calculator spits out a pressure of [email protected]
To get 185plus psi,the Calculator wants
more than 11.7Scr @68*, and more than 12.4Scr@74

If your pressure is accurate; and your heads are iron, then you have a big problem. Since the engine is still together after 18 years; IMA guessing the pressure is NOT accurate. And since the problem is only at below 3500, Ima guessing the Scr is NOT accurate either.
But;
just in case both the pressure and the Scr ARE correct, I tried to force the Calculator to spit out a 185psi number with a 9.4Scr, by manipulating the Ica, and had to go down to an Ica of 48*. I do not think there was ever a BBcam made with such an ICA, and I would think that if your 284 cam was retarded 20*, there is no way your engine should run ; so
IDK
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If i remember right, it is the 284/484 with 108..it was the original grind before they came up with the second one..i know i never actually did any measuring as far as coming up with the compression ratio, i just went by the compression height of the pistons which is 2.061 which is supposed to be somehwhere around .20 down in the hole, and then the open chamber 452 heads which are 88cc i believe and the thicker head gaskets..The pistons are the TRW L2355.
 
mopower440 said:
around .20 down in the hole, and then the open chamber 452 heads which are 88cc i believe and the thicker head gaskets..The pistons are the TRW L2355.
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with those specs, 9.4 Scr is totally possible and the 108 cam in at plus2* makes for an Ica of 68*. And then the pressure cannot be 185plus. The Wallace says a tic under 140psi.
And so, I think a new compression test would be a good thing to do, but don't use the same gauge,lol.

However, in light of my previous post, and what others have said, I think just slowing the timing down, should cure the detonation.
 
AJ is right on. Something doesn’t add up. For a test you could not change a thing on it and pour in 10 gallons of 110 and see how it responds. It should run noticeably different. Is this a new problem or have you been dealing with it for 18 years?
 
TT5.9mag said:
AJ is right on. Something doesn’t add up. For a test you could not change a thing on it and pour in 10 gallons of 110 and see how it responds. It should run noticeably different. Is this a new problem or have you been dealing with it for 18 years?
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well, originally i had JB welded the advance slots, then tried it, then took it back apart and filed them some, back and forth until i had it good as long as i used 91 or higher octane pump gas. This was with the mopar ECU. I also had it dialed back to 16 degrees BTDC. Since then i have done the GM HEI module conversion hiding it in the gutted mopar ECU and also installed one of the FBO plates and am in the process of getting it right. I find it like 20* initial better than the 16 but like i was saying, it detonates slightly when nailing it under 3500 rpm and figured the timing needed to be slowed down. I know it comes all in quickly with the spring i have in it. all in before 2200.
 
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