Timing request 100 shot 360

360moparjunkie

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Hello FABO its been a while. My Dart is back on the road!!

Looking for technical advise on retarding my timing for 100 shot plate system. My engine, while freshly machined, has enough run time imo to introduce spray. Would like to know where the safe zone is.

My set up:
73 swinger @ 3,240# w/o me in it
Calvert 90/10 up front, tubular A arms, Adj strut rods
8-3/4" spool w/ 4:56 gears & 275/60 M/T ET Street SS tires
Slapper bars to modded steel gussets w/ welded frame connectors
727 & Hughes 4,000 rpm stall
.030 360 w/ kb107's standard stroke @ 10.7 comp w about 40 hrs run time
rhs heads from brian @ imm (2.02 stain valves, bee hive springs, bowl work..how he sets em up)
prw 1.6 stainless roller rockers
.600" valve lift int/exh dur @ .006 295 int & 307 exh w/ 108 lobe sep. set @ 2* advanced
billet cam gear double roller chain w/ v6 tensioner installed
TTI 1-5/8-1-3/4" step headers to dual 3" exhaust w/ dynomax super turbos
Weiand x-celerator 7545 open pl intake
Elelbrock 750 cfm carb running 100 octane low lead fuel
Plate system N2O....I have nozzles for 75, 100 & 140 shots
msd 6al ignition
msd pro billet distributor w/ 36* all in

I believe timing should be 30* to maybe 32*@ full advance for 100 shot to be safe. PLEASE ADVISE FABO as I do not want to damage what is a sweet running little power plant.

Motive:
I have an old acquaintance w a 06 gto 6.0 trick flow heads, cam, stall, big throttle body, 3:73 & sticky tires who looks to run my dart. His car weighs 3,725# vs my 3,240# He claims he makes 500hp. Just seeing his car run looks faster than mine i must admit. I think i need the juice to have a shot to run on his level.

thx in advance for all your input!
 

360moparjunkie

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Forgot to mention ring gap....I did not get quantitative # for distance of ring gap when my engine builder assembled it. I did request like 4x to use the maximum gap option when custom fitting them. Judging by the amount of blow by my motor makes at an idle I believe top ring gap is adequate. Blow by is noticeable from both valve covers. Currently no pvc.
 

360moparjunkie

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Thank you oldkimmer for your input. I am learning as I go. Doing research on this and looks like I will be pulling my plugs and learning to read them after a pass.
 

j par

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I think the rule of thumb is supposed to be two degrees for every 50 horsepower of nitrous. I set up an entire Nitrous system that I have not used yet but I bought the timing start retard that piggybacks on to the MSD... It's pretty slick when you hit the button or whatever activates you nitrous solenoid can also send a low voltage to the start step retard and you can dial it back to anything you want... I have a hundred shot set up right now so I have it set at 4 degrees.. it only sees that when I hit the button... "When" again is the optimal word because I haven't had any track time to try it...
 

j par

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For nitrous anything under 150 shot they're really not recommending having to do ring gaps and special Pistons....
 

360moparjunkie

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I think the rule of thumb is supposed to be two degrees for every 50 horsepower of nitrous. I set up an entire Nitrous system that I have not used yet but I bought the timing start retard that piggybacks on to the MSD... It's pretty slick when you hit the button or whatever activates you nitrous solenoid can also send a low voltage to the start step retard and you can dial it back to anything you want... I have a hundred shot set up right now so I have it set at 4 degrees.. it only sees that when I hit the button... "When" again is the optimal word because I haven't had any track time to try it...

TY j par, I will look into the potential addition of the timing start retard. For now we are giving the distributor a twist. I believe they make an msd box with that built in. I'm just not familiar with that one at the moment. Again, still learning.
 

360moparjunkie

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For nitrous anything under 150 shot they're really not recommending having to do ring gaps and special Pistons....
For nitrous anything under 150 shot they're really not recommending having to do ring gaps and special Pistons....
We are surely in the lower spray category. My piston choice, I learned, have the potential to break the top ring land under extreme punishment. KB assembly guide gives recommendations on ring gap depending on your use from tight to loose when filing your rings to fit. I believe I chose maximum gap as though it would be severe duty such as tow truck application or such.
 

j par

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This is what I have..
Screenshot_20200728-221511.png
 

flyfish

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I would pull 4° to be safe, but you probably only need to pull 2°. Years ago when my car was bottle fed, I ran 28° locked out with a 150-180 shot...ran it for ~ 8 years like that, no issues.
 

j par

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I keep saying "they say" because I haven't tried it yet, but timing is critical and it's better to be safe and creep up on it..
 

360moparjunkie

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I would pull 4° to be safe, but you probably only need to pull 2°. Years ago when my car was bottle fed, I ran 28° locked out with a 150-180 shot...ran it for ~ 8 years like that, no issues.
Mr. flyfish, I am currently at 36* total. Respectfully, pulling 2-4* would put me at 32* to 34*. Can I have that much timing and not damage my kb 107 hypereutectic pistons?
Another question...were you running forged pistons in your 8 year success motor?
TY!
 

340doc

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Make sure your fuel system is up to the task. Most damage done by the bottle is caused by the fuel leaning out. I always flow the fuel side of the plate over a bucket to make sure the fuel pressure is good. Are you running an electric pump?
 

flyfish

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Mr. flyfish, I am currently at 36* total. Respectfully, pulling 2-4* would put me at 32* to 34*. Can I have that much timing and not damage my kb 107 hypereutectic pistons?
Another question...were you running forged pistons in your 8 year success motor?
TY!
I built that particular motor for nitrous use with JE forged pistons, and the appropriate nitrous ring gap (~ 22-24 thousands if I recall correctly). I missed the part that you are running Hypers....supposedly "they" say you can get away with a small shot on hyperutectic pistons, but I have never ventured down that road....I'm not sure I would spray it with those pistons (I'm pretty conservative), but thats just me. Like any cast type piston, it can fracture when sprayed. If you must spray it , as Jpar said, pull more timing than needed and creep up on the tune. Maybe start at 28-30°...it will make it a bit of a dog running NA, but on the bottle it will make good steam.

For what its worth, my old 360 nitrous motor (in Colorado at Bandimere, 5800') would run ~13.8 NA and 11.0 on the bottle.
 

360moparjunkie

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I built that particular motor for nitrous use with JE forged pistons, and the appropriate nitrous ring gap (~ 22-24 thousands if I recall correctly). I missed the part that you are running Hypers....supposedly "they" say you can get away with a small shot on hyperutectic pistons, but I have never ventured down that road....I'm not sure I would spray it with those pistons (I'm pretty conservative), but thats just me. Like any cast type piston, it can fracture when sprayed. If you must spray it , as Jpar said, pull more timing than needed and creep up on the tune. Maybe start at 28-30°...it will make it a bit of a dog running NA, but on the bottle it will make good steam.

For what its worth, my old 360 nitrous motor (in Colorado at Bandimere, 5800') would run ~13.8 NA and 11.0 on the bottle.

Many thanks. I'm thinking I will start at 28* then. Wow. huge difference for your old nitrous motor. 11.0 is fast imo. 13.8 pretty good too.
 

j par

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Many thanks. I'm thinking I will start at 28* then. Wow. huge difference for your old nitrous motor. 11.0 is fast imo. 13.8 pretty good too.
Remember he said in Colorado at 5800 feet lol... Motors are starving for air up there and nitrous provides it...
What are you doing for your fuel side as mentioned...??...
 

360moparjunkie

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Make sure your fuel system is up to the task. Most damage done by the bottle is caused by the fuel leaning out. I always flow the fuel side of the plate over a bucket to make sure the fuel pressure is good. Are you running an electric pump?
Remember he said in Colorado at 5800 feet lol... Motors are starving for air up there and nitrous provides it...
What are you doing for your fuel side as mentioned...??...
Gr8 point. We are running holley 12v high pressure 110 GPH pump with 1/2" fuel line to a regulator / splitter.
 

j par

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I have an activation switch that that has to be turned on that sends electricity to a momentary switch/button on my shifter that sends 12v to timing retard and the full throttle switch which sends juice to a relay which is grounded through a low pressure switch and a window switch LOL... And if all those things are in play the nitrous and the fuel solenoids open...
 

j par

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TY looks like alot of help you received. I will read more carefully once my work tasks are caught up.
Like most of my threads there's probably a bit of banter to slice through. I can help by telling you to disregard anything that 318 will run said or I quoted him and said back to him..
 
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