SUPPOSED TO BE A TIRE BURNER

[DENNYSCARS]

I AM SURE OTHERS HAVE HAD SIMILAR PROBLEMS BUT I CAN'T FIND ANY POST STATING THE PROBLEM OR THE SOLUTIONS. NO TIRE BURNING FROM THE LINE.  THE TIMING IS SUPPOSED TO BE GOOD AND SET UP PER FBO DON GOULD.  14* INITIAL TIMING, 18*@16" (VAC) AND 20* @ 3200.  I DONT KNOW WHY AND FBO SAID IT SHOULD BE A TIRE SMOKING MACHINE.....SUGGESTIONS?

I HAVE A 68 383 CHARGER THAT IS PUNCHED TO .060. LINE BORED, DIAMOND PISTON .0045, RINGS T.017 - S.015, MAIN BRG .002-0025, ROD BRG .002-0023, END PLAY .007, REAR MAIN DEFLECTION @ .025-,035. DEGREED IN CAM .001 ADV, VALVE ADJ .040 PRELOAD, OIL PRESS @ 80 PRIMED, PISTON TO VALVE +.200.
RACER BROWN EH 220 .474 lift 220 at 50 1.5 rockers PRW SS ROLLER ROCKERS
2500-2800 Convertor
904 HEADS PORTED
STK VALVES
Mighty Demon  750
Performer RPM 383 Intake
FBO A688D Ignition Kit w/ Distributor
Carter Ported Fuel Pump
TORQUEFLIGHT
GEAR VENDORS
3:55 SURE GRIP
26 IN OD TIRES
NO HEADERS, FACTORY HP EXHAUST MANIFOLDS WITH    


   

[Ghoste]

How wide are the tires?

[DENNYSCARS]

I BELIEVE 8 OR 9 INCHES.  I FORGOT TO FINISH, THE EXHAUST IS H PIPE 2 1/2" MAGNA-FLO

[FLG]

Should light em up!

What happens when you mash the gas from a stop? We need some info.

[DENNYSCARS]

A LITTLE SCREECH AND TAKES OFF, GREAT PICK UP AFTER IT GET SOME RPM.  EVEN IF I ROLL IN REVERSE AND DROP IT IN 1ST IT REALLY DOESNT BREAK THEM LOOSE.  I HAVE HAVE THE CARB PRETTY WELL SET WITH O2 SENSOR IN THE DRIVER SIDE EXHAUST.  AROUND 14 =/- ON IDLE AN AT 2500 ON THE ROAD IT AVERAGES 11-12.  I AM STUMPED AS WELL AS DON GOULD @ FBO.

[RallyeMike]

14* INITIAL TIMING, 18*@16" (VAC) AND 20* @ 3200.

Not sure I am following the last part of this ....

Has anyone checked mechanical timing advance? With vacuum detached, rev to 2500-3000 and check/set for around 36 degrees total. You may need timing tape or extra markings.

[Cooter]

You do reallize the 383 Mopar has a shorter Stroke than a 350 Chebby right? Huge Bore and no torque...TORQUE is what "Burns tires"...Try using your "Caps lock" button and turning it off, looks like your yelling...Although, you might be being that your car won't burn tires....

[skip68]

20* at 3200    You need more timing.   It should be 36* by about 3000 rpm.  You're advance curve is way slow.   

[DENNYSCARS]

Sorry about the caps lock.  Use it at work cause all the techs have Treos and are blind and cant read the emails...   The total timing is the 20* + the intial at 14* = 34*   Can a rear end be set up too tight?  Had new gears put in and was just wondering?  Also, isnt a stall converter supposed to "slip" some at idle?  What I mean is I put it in gear and it jumps in.  No slip unless I have just started it after setting for a few days then is slips a little to get it moving until its been engaged for a few secs. I have had everything checked out by a shop and the guy had run 383's in his Cuda drag car for years.  He hasnt really found anything either.  Has to be something not quite right... valve springs, adjusted too tight, degreed wrong, ??

[Ghoste]

I don't think you could set a rearend that tightly and still drive for any length of time.  It isn normal for the converter to "engage" at an idle.  It is also normal for the converter to need a few seconds after the car has sat for a couple of days, in that instance you might want to let the car warm up a few seconds with the selector in the neutral position (not park) and let the pump refill the converter before putting it in a driving position.
When you apply the brakes and step on the throttle, does the converter slip then?  And it will of course, but that is how they work.  
When you say a 2500 to 2800 converter, how do you kow this?  Did you have an aftermarket converter maker build you one based on cam specs or is it "out of the box", or is it just what you were told or...?

[DENNYSCARS]

The converter was part of the recommendation by FBO on the build. Its a 10" Dynamic with a full face flex plate.

[Ghoste]

Like Cooter says, the 383 isn't a torque monster but even so, I have a much milder build than that and my 383 is breaking a wider tire loose when you nail it from a dead stop with a healthy bark going into 2nd as well.
Carb tuned properly?

[Chryco Psycho]

possibly just a bad converter not allowing the stall to be reached or an internal problem in the trans eating power

[Ghoste]

Or a really good working suspension.  Was the suspension set up for you?  After all, spinning tires aren't really a desirable feature compared to forward motion.

[Chryco Psycho]

A stall converter should allow you to flash the rpm to 2400 before power is transmitted into the trans .
If you do a brake stand holding the car with the brakes the rpm will stop climing at a given rpm , this should be the stall speed or close to it

[DENNYSCARS]

Well I was supposed to get around 400 HP from this build.  The suspension is mostly rebuilt with the stock parts with good shocks and new bushings.  I will check the converter in high on the highway to see of it ramps up.  Dont think it does though.  I need to know what is too much timing for the engine.  I have always "felt" that it was too retarded.  Started good, ran strong on the highway, temp fine, yada yada yada.  Just had the sound at idle of a retarded engine. Have timing tape on balancer and have used set back timing light to get it at 34*.  How do you know if its got too much timing? 

[John_Kunkel]

A LITTLE SCREECH AND TAKES OFF, GREAT PICK UP AFTER IT GET SOME RPM. 

Count your blessings.

[RallyeMike]

You didnt say what your compression was or what fuel you run. I would still take it to 36 degrees. It will ping when hotter or loading if its too much. Your plugs will tell you the same.  I don't think 2 more degrees is going to turn it into a tire-boiler though.

As was mentioned, 383s are great engines but not torque monsters. With ported heads you will lose flow at low rpm but make it up on the high side. Who/what/how were the 906s ported? Done wrong they could be worse than stock heads. Also, the stock exhaust is hurting ability to maximize the use of cam and head work. Finally, how are you launching?: Stand on the brake, take it up a couple thou, stomp at gas and reduce the brake at the same time.

As John stated..... you have a car that hooks? Lucky you! 

[Lunger]

you should be able to roast them. Ok going back to my youth and some of the mistakes i made. Check to make sure you didn't bend the pushrods. Are the valve springs able to take the lift of the cam? I changed the rocker arms once and when i tightened up the rocker arm shaft bolts, i messed up and bent a pushrod, tell you what that 440 would not turn the tires over then either.

I looked up the rockers arms you used-- did you adjust them right?    they may be too loose or to tight
all the stainless steel ones i saw for a 383 where 1.6 ratio brings the lift up a ways.   

betting yopu have bent push rods after doing some checking

[maxwellwedge]

What is your total mechanical advance (with vacuum advance disconnected) and by what RPM?

How many RPM's can you get your tach up to with the car in Drive and your foot firmly on the brake (do this in a safe area!!) ?

[DENNYSCARS]

UPDATE:  I went to adjust the timing up yesterday and found the timing tape fell off at some point. In addition my digital RPM/timing light decided to crap out.   So I decide to set the timing like I use to back in the day (way back).  Ran RPM up to about 3000 and adjusted for the fastest and smoothest RPM.  Lcked it down and let it set for a few and cranked it.   No kick back and it fired up without hardly turning over.  Took it out and stomped it from a dead stop and laid down a pretty good strip.  Tried it again this time with it in first and power braked it and let er rip....shifted around 5K and smoked it in second for a bit then wound it out till I had to slow down.  Didn't note any engine breakup just kept pulling.   My concern is how much is too much timing and shouldnt the motor be the judge? I don't want to deal with the dreaded detonation.  I picked up a new timing light today and will see just how much it is.  I am pretty sure its going to be more that 38*-40*  Oh, the compression is around 9.2-9.3 and I run a half tank of 110 octane and half Sunoco w/o corn.

[Ghoste]

I can't even begin to pretend to have the knowledge that Chryco Phsyco does but I can tell you that he typically tunes by ear and you're right, the engine is often the judge.

[Challenger340]

A 9.2 or 9.3CR  383, will require more initial stall to boil the balonies.
383 engine are inherently WEAK off the line !
As mentioned, the same thing that makes them GREAT revvers, is EXACTLY the same thing that makes them so POOR at lower rpm's, even with a small camshaft.
The STROKE is the bottom end characteristic, think of it as the LENGTH of the wrench you are trying to undo a TIGHT bolt. The longer from center the force is applied(longer wrench), MORE TORQUE.
The shorter the wrench, you need more and more force required.

Your problem is relatively low force applied with the lower CR on the Iron Heads.......no amount of magic tuning will ever compensate for what is "built in"
so,
Get a Torque Convertor that will provide an HONEST 3400-3500 rpm stall, and let the "wee-83" get rolling, you won't be sorry !

[Chryco Psycho]

As stated above I time by ear , threw out my timing light decades ago , the only reason to use one is so you have a reference point to set back to AFTER you get the timing set by ear

[oldschool]

UPDATE:  I went to adjust the timing up yesterday and found the timing tape fell off at some point. In addition my digital RPM/timing light decided to crap out.   So I decide to set the timing like I use to back in the day (way back).  Ran RPM up to about 3000 and adjusted for the fastest and smoothest RPM.  Lcked it down and let it set for a few and cranked it.   No kick back and it fired up without hardly turning over.  Took it out and stomped it from a dead stop and laid down a pretty good strip.  Tried it again this time with it in first and power braked it and let er rip....shifted around 5K and smoked it in second for a bit then wound it out till I had to slow down.  Didn't note any engine breakup just kept pulling.   My concern is how much is too much timing and shouldnt the motor be the judge? I don't want to deal with the dreaded detonation.  I picked up a new timing light today and will see just how much it is.  I am pretty sure its going to be more that 38*-40*  Oh, the compression is around 9.2-9.3 and I run a half tank of 110 octane and half Sunoco w/o corn.

also, dont use any race gas. with that low of compression, your killing power with it.

[Ghoste]

Not being a chemist I have to ask, how so?

[maxwellwedge]

True - The gas will only hurt his wallet.

[Ghoste]

The price part is a for sure, but how does it affect performance negatively in a low compression engine?  Would it not just be a case of of the engine not being able to take advantage of what the high octane can offer?

[Troy]

Not being a chemist I have to ask, how so?

Octane is a detonation inhibitor - ie it makes gas harder to burn.

Troy

[idahogrumpy]

Advance the the cam shaft 4 degrees. Set the timing at 38 degrees total, all in by 3200 rpm. Readjust carb. Do a power run and check plug color, sounds rich to me.  
Grumpy

[Ghoste]

Not being a chemist I have to ask, how so?

Octane is a detonation inhibitor - ie it makes gas harder to burn.

Troy

That makes sense I suppose,  But at what compression ratio does it become detrimental.  I don't have what I consider to be a high squeeze in my car (10.5 to 1) and when I dump a tank of 104 or 110 in the car it makes a difference.  The car even becomes easier to start and idles much smoother.  In fact, you can hear the engine note change when you are driving and the good stuff finally reaches it.

[oldschool]

Not being a chemist I have to ask, how so?

The higher the octane of the fuel the slower it burns.  Anymore octane than required to prevent detination, will slow the combustion process.  As an example, my 580 CI motor has 14.16 cr.  When I put in on the dyno I first tried 116 race gas, the EGT's were very low but air fuel and everything else was good.  I then tried 110, the EGT's went up to where they should be and the motor picked up about 20 hp.