47 degrees initial time? help!!!

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MoparOrNokar said:
Ok so i have my new engine in and running. 360 .04 over xe274 cam msd al6. Now that th engine is broke in i decided to check some timing numbers and see what works best. Hit it with the light and it says 47 at 1000 rpm and dizzy unhooked. I checked the balancer mark with a piston stop and it is dead nuts on. Gears and chain were put on spot on. Car fires right up hot or cold. Could it be somethi g with the msd messing me up?
Click to expand...
Just to review post #1
A lot of oem balancers wobble;just like old men,there comes a time...
The transfers need to be more than just peeking or you will have driveability issues, like hesitation on tip-in. The just peeking indicates you have too much idle timing, and you have closed the curb-idle for compensation. Read my sig.I can think of absolutely no advantage to running more idle-timing than neccessary, and at least one to run less.OOps, make that two.
 
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AJ/FormS said:
Just to review post #1
A lot of oem balancers wobble;just like old men,there comes a time...
The transfers need to be more than just peeking or you will have driveability issues, like hesitation on tip-in. The just peeking indicates you have too much idle timing, and you have closed the curb-idle for compensation. Read my sig.I can think of absolutely no advantage to running more idle-timing than neccessary, and at least one to run less.OOps, make that two.
Click to expand...
Whats your sig mean AJ? Hope thats not a dumb question lol
 
At the Bottom of my posts, is a little blurb on how to set your T-Port sync. This is probably one of the most important things to do, when starting your tune, right behind setting the float level.
Let's talk about float level for a bit.Every carb is designed to work at a certain float level and pressure differential across all the discharge ports. When you set it wrong, everything is wrong. If it doesn't stay where you put it it gets worse. If you are not at standard temperature and pressure, ie you operate the car at some other altitude or mean temperature than what the carb was designed to operate at, then some kind of compensation is/may be required. So saying something like the fuel level is good, or my fuel pressure is good, is nearly useless information.
The carb doesn't even care what your fuel pressure is. It only cares that the fuel level is at exactly what the designer called for, and that it stays exactly there under all driving conditions. Every circuit is designed to work at that level, and at STP,( Standard Temp and Pressure). The fuel pressure only needs to be high enough to ensure that the floatbowl stays at the design level under all conditions
-Then let's talk about the low speed circuit a bit.Most of that circuit is hidden from sight. The parts that you have control over is the T-Port synchronization, and the idle mixture.
There are two discharge ports per venturi. The long slot one is to provide fuel from idle to when the other circuits come on line. The little round one is to provide additional fuel at idle, cuz at idle the engine needs the extra bit. You, the tuner, get to balance this circuit with the sync.Every combo is a lil different, so my blurb is a starting point. But if you stray too far from it, you will have driveability issues.
If you set the idle-advance too high,then the transfer port will end up nearly closed.You will have tip-in problems, cuz the T-ports may have nearly stopped flowing, and then you get issues like you are having.
If you set the idle-advance too low, then to keep the engine running,the butterflies will end up being too far open. The idle speed may be too high and,the mixture screws will be unresponsive,and air going around the plates will pull too much fuel out, compounding your idle issues with a huge burn-your-eyes-out stink coming out the tailpipe.
Keep on asking,that's what we're here for.
 
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You need to change the mechanical advance in the distributor, NOT back down the initial timing so the total is still in bounds.

See where the car start with difficulty, if that's at 20+ so be it. Set the initial timing there or close and tailor mechanical to hit your total, NOT the other way around!
 
crackedback said:
You need to change the mechanical advance in the distributor, NOT back down the initial timing so the total is still in bounds.

See where the car start with difficulty, if that's at 20+ so be it. Set the initial timing there or close and tailor mechanical to hit your total, NOT the other way around!
Click to expand...
I see what u mean. What would be a good total to aim for on a 360? I always here che*ys like 34* about the same area for mopar? Thanks for all the help guys. Im learning alot
 
Turn your sig display on.
Top right of the page click on your name,scroll down and click on preferences, scroll down near the bottom, put a checkmark(by clicking) in the box for sig display.Come back to this thread and reload it.Voila

You can make your own signature from the same do-it center, except click on signature,and type in anything you would like to have appear on every post that you make. Space is limited. I think they increased it though, cuz I recently updated mine and it seems to allow a bit longer message.
If you still can't get it, here it is
Transfer-Port sync; 1)set the transfers down to about square under the plate, to a little taller than wide. 2)Adjust the idle speed with bypass-air,and idle-timing. 3)Limit your power-timing. 4)Bring in the advance at a rate that the engine accepts and likes. 5)Vacuum advance; If it pings under light acceleration,you may have too much idle-timing,too fast a curve,or too fast a V-can rate.Cans are adjustable.Typical street-cammed SBMs may run about 16* to 20* initial, and 32*to 36* power, and up to a theoretical 60*for cruising with the vacuum advance having brought it's load in. This is usually abreviated as 18/34/60.
If 60 sounds like a lot, it is. But it's highly unlikely your engine can achieve it. You would have to be cruising at an rpm after the mechanical is all in, but also with a ported vacuum signal high enough to bring in all that the can has to offer. The two are mutually un-exclusive. With 3.55s and an all-in timing of 3400rpm, this would be 76 mph. But at this speed, the ported vacuum signal may have fallen to a point where only 10 comes in by V-can, so the cruise timing might only be 34 plus 10 =44, a nice number to be sure.
At slower speeds say city cruising at 2800rpm; the all-in mechanical might be 28* and the V-can now bringing all it's got of up to 26*(if modded), so the total could be 28 plus 26 =54. Perhaps a tad high;perhaps not. That's for you to establish.Perhaps the MSD will get by with less. My combo likes 28 plus 22 =50*with an old Accell Super Coil fat-boy;Kettering at it's finest.IMO at least.
 
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crackedback said:
You need to change the mechanical advance in the distributor, NOT back down the initial timing so the total is still in bounds.

See where the car start with difficulty, if that's at 20+ so be it. Set the initial timing there or close and tailor mechanical to hit your total, NOT the other way around!
Click to expand...
^^Right on as always^^

MoparorNokar-I had that cam in a 360 and it idled at 700 in drive. I had the distributor modified to only have 12 degrees of advance so I set the timing at 22 with 34 total. When you don't have enough initial timing (like yours) the idle will be nastier and have to be turned up higher. Do as Rob says and it'll idle better (a little smoother and lot lower rpm) and be snappier when you gas it and make sure you hook the vac advance up to the ported port. If you hook it up to a straight vac port it'll be cantankerous and drop a lot more rpm when you drop it in gear. A/J also has good points abotu carb tuning

BTW: do you know what power valve your carb has in it? You probably need a 5.5 with that cam. The carb (if it's a Holley) probably came with a 6.5 which will open a little to early
 
fishy68 said:
^^Right on as always^^

MoparorNokar-I had that cam in a 360 and it idled at 700 in drive. I had the distributor modified to only have 12 degrees of advance so I set the timing at 22 with 34 total. When you don't have enough initial timing (like yours) the idle will be nastier and have to be turned up higher. Do as Rob says and it'll idle better (a little smoother and lot lower rpm) and be snappier when you gas it and make sure you hook the vac advance up to the ported port. If you hook it up to a straight vac port it'll be cantankerous and drop a lot more rpm when you drop it in gear. A/J also has good points abotu carb tuning

BTW: do you know what power valve your carb has in it? You probably need a 5.5 with that cam. The carb (if it's a Holley) probably came with a 6.5 which will open a little to early
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Thanks for the info. Remember guys im a noob so i appreciate all the help i can get. I double checked the T slots last nite. They are about 3 times as tall as they are wide. Still have to check the power valves. I was questioning that too. Where the car is running now the vac gauge is about 9. The builder who did my carb said he thinks they were 6.5 in it. Couldnt remember. Now ported vac would be on the metering block correct?

So correct me if im wrong. Im going to set the timing a bit higher into the 20 range for initial and then see what the total is. If its too higj or too low the dist needs changed to get the desired total time?

Also do any of you guys have experience with the non vac distributors from Skip White. All the things i have read and i dont see any negative. I would like to ditch the stock dist bit a name brand is just out of the question right now.
 
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MoparOrNokar said:
Thanks for the info. Remember guys im a noob so i appreciate all the help i can get. I double checked the T slots last nite. They are about 3 times as tall as they are wide. Still have to check the power valves. I was questioning that too. Where the car is running now the vac gauge is about 9. The builder who did my carb said he thinks they were 6.5 in it. Couldnt remember. Now ported vac would be on the metering block correct?

So correct me if im wrong. Im going to set the timing a bit higher into the 20 range for initial and then see what the total is. If its too higj or too low the dist needs changed to get the desired total time?

Also do any of you guys have experience with the non vac distributors from Skip White. All the things i have read and i dont see any negative. I would like to ditch the stock dist bit a name brand is just out of the question right now.
Click to expand...
Yes ported vac is the one on the metering block. Ur also correct on the total timing. Shoot for 34 degrees. No exp the skip white dist but I've found by experience if it's cheap & made in China it's most likely junk. Another thing, vacuum advance is good on a street car. Helps keep the plugs cleaner and helps fuel mileage. IMO the stock dist works fine, just needs the advance slots welded up to limit total advance. Another option if I don't have a welded is to buy a limiter plate from FBO. I think their about $38
 
fishy68 said:
Yes ported vac is the one on the metering block. Ur also correct on the total timing. Shoot for 34 degrees. No exp the skip white dist but I've found by experience if it's cheap & made in China it's most likely junk. Another thing, vacuum advance is good on a street car. Helps keep the plugs cleaner and helps fuel mileage. IMO the stock dist works fine, just needs the advance slots welded up to limit total advance. Another option if I don't have a welded is to buy a limiter plate from FBO. I think their about $38
Click to expand...
Well i guess since im a welder and have a tig machine here in the garage im on to more learning lol. I might get some garage time today and ill set that initial and see what the dist is throwing for total then i will report back. Any good links for modifying the dist advance would be great. Thanks again
 
from post 59
"So correct me if im wrong. Im going to set the timing a bit higher into the 20 range for initial and then see what the total is. If its too higj or too low the dist needs changed to get the desired total time?"
yes and no
You are going to reset the T-port first, and defeat the vacuum advance(note4). Then you will twist the dizzy up to some undetermined number LIKE in the range of 14* to 22*, so it will stay running during the warm-up period;and then hit the starter. After the engine has warmed up, you will set the idle speed with idle air bypass(note1) and timing.(note2)You will not touch the idle speed screw again.(note3)

-Note1)Idle air bypass is simply air that you introduce into the engine almost anywhere, EXCEPT through the primary butterflies. This will be a controlled vacuum leak. The most common place to let air in is through the secondaries via the cracking screw. The PCV is another. Certain carbs have a built-in idle-air bypass screw.There are also other ways.
-Note2) It may end up that 20* is perfect. But to to arbitrarily choose 20*, is to invite futzing with the speed screw again! After the idle timing is determined, then the power-timing may have to be limited, and the rate of advance dialed in.
-Note3)if you cannot get a stable, smooth idle, with the above system, and with the idle mixture screws in, near the center of their normal range, then it is permissible to add or subtract a little transfer fuel.It may be that the arbitrary sync that you initially chose, was not quite spot on. But don't stray far from the initial setting. Of course if you do futz with the speed screw, you get to re-start the bypass air adjustment.
-Note4) at some future date, after you have the mechanical timings(plural) sorted, THEN you can re-introduce the V-can.

You need to give this process more consideration. This is not a slam it in and done deal. If you move ahead too fast, you are inviting endless driveability issues that will make commuting less than pleasurable. Probably something like 70 or 80 or more percent of the driving experience will be on this tune.

ALL streeters should have a well tuned vacuum advance system.It adds so much.The oem distributor would have to be really worn out to consider replacing it.There is a guy on FABO that makes timing limiter plates. I think that was already mentioned in this thread.
 
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AJ/FormS said:
from post 59
"So correct me if im wrong. Im going to set the timing a bit higher into the 20 range for initial and then see what the total is. If its too higj or too low the dist needs changed to get the desired total time?"
yes and no
You are going to reset the T-port first, and defeat the vacuum advance(note4). Then you will twist the dizzy up to some undetermined number LIKE in the range of 14* to 22*, so it will stay running during the warm-up period;and then hit the starter. After the engine has warmed up, you will set the idle speed with idle air bypass(note1) and timing.(note2)You will not touch the idle speed screw again.(note3)

-Note1)Idle air bypass is simply air that you introduce into the engine almost anywhere, EXCEPT through the primary butterflies. This will be a controlled vacuum leak. The most common place to let air in is through the secondaries via the cracking screw. The PCV is another. Certain carbs have a built-in idle-air bypass screw.There are also other ways.
-Note2) It may end up that 20* is perfect. But to to arbitrarily choose 20*, is to invite futzing with the speed screw again! After the idle timing is determined, then the power-timing may have to be limited, and the rate of advance dialed in.
-Note3)if you cannot get a stable, smooth idle, with the above system, and with the idle mixture screws in, near the center of their normal range, then it is permissible to add or subtract a little transfer fuel.It may be that the arbitrary sync that you initially chose, was not quite spot on. But don't stray far from the initial setting. Of course if you do futz with the speed screw, you get to re-start the bypass air adjustment.
-Note4) at some future date, after you have the mechanical timings(plural) sorted, THEN you can re-introduce the V-can.

You need to give this process more consideration. This is not a slam it in and done deal. If you move ahead too fast, you are inviting endless driveability issues that will make commuting less than pleasurable. Probably something like 70 or 80 or more percent of the driving experience will be on this tune.

ALL streeters should have a well tuned vacuum advance system.It adds so much.The oem distributor would have to be really worn out to consider replacing it.There is a guy on FABO that makes timing limiter plates. I think that was already mentioned in this thread.
Click to expand...
I like your style. What is the proper way to set the T-port these are the slots that peak at the butterflies right?
 
Where they appear as little squares... If the engine requires more throttle opening than that you may need a PCV valve with more bypass, drilled bypass holes in the primary throttle plates or adjust secondary opening stop if carb is so equipped.
 
^^ That is the starting point.... you may have to adjust it a couple of times to optimize it and it may not be square anymore at the best operating setting. Replace the adjusting screw with an allen head and it will be easier to adjust without pulling the carb each time.
 
Secondary adj screw was messed right up. Tapped in a 1/4-20 with a hex head for easy adjustment without removing carb the T-ports are set at about .o35 using a piece of weld wire

20160514_112543.jpg


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Just double checked everything after tweaking the carb. 22* initial and she purs like a kitten. Distribitor pegs at 50* total at about 4000rpm. Going into the distributor now to weld the slots. Gonna shoot for 34* so i need 12* advance. Vac gauge is still running about 9. Still the best i can get it. Ill post back after modding the dist
 

Good job. 34 total is a pretty safe number for an iron headed SB. It may take more as you get things sorted out. You might want to figure out if it will take 24 or 26 initial to give you some wiggle room. Say the engine likes 36 or 38 total... you need to either bust back into the distributor or twist in a little more initial. :)

Contrary to a lot that is written, I like to do the inside limit points when welding them up. Sometimes help to slow the advance a bit with faster advancing springs like the MRG units.
 
crackedback said:
Good job. 34 total is a pretty safe number for an iron headed SB. It may take more as you get things sorted out. You might want to figure out if it will take 24 or 26 initial to give you some wiggle room. Say the engine likes 36 or 38 total... you need to either bust back into the distributor or twist in a little more initial. :)

Contrary to a lot that is written, I like to do the inside limit points when welding them up. Sometimes help to slow the advance a bit with faster advancing springs like the MRG units.
Click to expand...
This is an interesting option that also depends on your choice or assortment of springs and rotor indexing. Limiting the slot inside or outside can keep your rotor closer to the pole in the cap under advance and is a good way to help solve this issue if the rotor is getting farther from the contact than you like. If you have an old cap to cut open or drill holes in and inspect rotor alignment this will tell you which method is better for your application.
 
Generally in LAs you'll fall between 32-36. Maybe a little more or less. Less means you're getting great flame travel. More means you might wanna see if you can improve your spark. Make sure you're not running rich either. Or it will want more timing.

You always want as much initial as it can take. Keep turning up the initial until it starts to give you trouble on hot starts (kicking against the starter and such). Then back it down a couple degrees. Then shoot for your total. And adjust that based on where it makes most power. And as always listen for pinging/detonation. Sounds like you're on your way there!
 
Just welded the slots. Put it back together and checked time. 22* initial again and it totaled at 30* put a little too much weld in. Good new is i put a little more initial in and i doesnt mind so now im at about 25* 33* and its all in at 2200. Man it feeps good to learn all of this new stuff. Thanks for all the help guys
 
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