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Author Topic:   Timing (is this right?)
Doran
Dirt Roller

Total posts: 21
posted April 09, 2005 07:20 PM  
Running in purestock class my rookie year. Running a 1980 Regal with a pretty much stock 305. Just finnished rebuilding the motor and have very little idea how to properly time it. I should say that the engine has been started and seems to run great with minimal tweeking of the distributor. This is what I know so far, I beleave you get her to TDC on the compression stroke then mark the balancer (with chalk). After that, from what i have read in previous posts, you rev her to 3000 rpms and shoot the timing light lining up your mark with 0 on the tab by moving distributor. Is this correct? Any help would be appreciated.

Thanks

Raceman17
Dirt Maniac

Total posts: 165
posted April 09, 2005 08:24 PM  
Heres what you do. First I am going to explain it using a expensive timing light that has the dial on the back of it. You turn the dial to whatever reading you want (somewhere between 30 to 36 degree depending on your preference) Now when you turned the motor over to TDC, there should have been a line scribed into the balancer. If not then your balancer has slipped and you need to get another one. (the old rubber lining that holds the two pieces together has deterioated) But anyways, you should mark that TDC line with chalk. Now your vaccum advance should be welded up also. If not, do that also. So fire her up and plug the light into the #1 plug wire and fire the light down to the tab. If you have the dial set at 30 to 36 degrees you want to line the line on the balancer to the line on the tab that says 0 degrees or TDC. You move the dirtribitor back and work until the line hits zero. Tighten the distribitor up and recheck the timing again to make sure you havent moved it a little.

Now if you dont have the better light its gonna take some work. All stock balancers only go to about 10 degree Before TDC. So you need to have a line somewhere between 30 and 36 degrees on the balancer (keep in mind that your balancer only has it marked to 10 degrees before TDC. So what you need to do is get a piece of tape and use that like a measuring tape. Make it go from 0 degreess TDC to the 10 degrees before TDC mark on the balancer. Cut the piece of tape on the exact mark. Then carefully remove the tape place it at the 10 degrees Before TDC and measure it out to 20 degrees Before TDC (It should be the length of the tape. Make a scribe on the balancer and slowly remove the tape. Then go from 20 degrees Before TDC to 30 Degrees Before TDC and make another scribe. remove the tape and do it one more time. From 30 degrees to 40 degrees. Now after you are done you should take a hacksaw blade or and bandsaw and cut a small grove in the balancer where the 30 and 40 degrees Before TDC marks are. Then put everything beack together and fire her up and put the light on the #1 plug. Rev the motor up and try to get the line somewhere between the 30 degree Before TDC and the 40 degrees Before TDC mark. THen button her up and recheck to see if it moved slightly. You can also do this if you have a instrument that reads 360 degrees. Just mark the line at the 30 to 40 Degrees BTC measured from the TDC mark thats there from the factory. You can also buy this tricked out cover from speedway motors that slips over your balancer and already has all the line marked. They cost about 30 bucks but it is worth the hassle if you have a few extra bucks laying around. Im sorry for the book but I hope this hepls.
Later

Doran
Dirt Roller

Total posts: 21
posted April 09, 2005 09:16 PM  
Okay, I think I understand but have a couple more questions. You said that stock balancers only go to 10 degrees, does that mean the original line on the balancer at TDC is actually 10 degrees? If I have this right I measure out a piece of tape that is 10 degrees long and keep moving it and marking the balancer right? Last question, how do measure degrees like that? Thanks

Raceman17
Dirt Maniac

Total posts: 165
posted April 09, 2005 09:28 PM  
quote:
Originally posted by Doran:
Okay, I think I understand but have a couple more questions. You said that stock balancers only go to 10 degrees, does that mean the original line on the balancer at TDC is actually 10 degrees? If I have this right I measure out a piece of tape that is 10 degrees long and keep moving it and marking the balancer right? Last question, how do measure degrees like that? Thanks


If you look on the stock balancer you can see the deep scribed line. This line is at TDC. My balancer had marks on it at ten degrees so , you could measure it out and then move the piece of tape aroud until you get to 30 and 40 degrees. But if your balancer doesnt have anymore lines or marks on it you can get me the diameter of the balancer. (The more exact measuremet you give me the better it will be) I need to go get a book to find the formula for arc length (BUT I NEED THE EXACT DIAMETER OF THE BALANCER) for it to work. I will post back in a second. If you have anymore questions please shoot them this way.\
Later

Raceman17
Dirt Maniac

Total posts: 165
posted April 09, 2005 09:59 PM  
Take notes cause theres gonna be a test at the end of this

Ok are you ready for a little math lesson. What we are going to do is find the arc length of 30 and 40 degrees. Arc length is defined as the distance around the outside of a circle measured in radians. (kinda like if you look at you balancer and ask the question (how many inches is it halfway around the balancer ) But anyways I hope you understand that little example. So for this deal we are going to find the arc length for 30 degrees and 40 degrees. (keep in mind that you need to get the diameter of your balancer (the better the measurement the better the degreeing will go)) So the eqation that we need to use is arc length=diameter/2 times the degrees we are going to measure(The degrees need to be converted to a measurement of radians first) So i will do that for you now. I know that
1 degrees = 0.0174532925 radians
so if we have 30 degrees that is eqal to
0.0174532925 radians x 30 = .523598775 radians. This mease that 30 degrees = .5235 radians. I will do the same for 40 degrees now.
0.0174532925 radians x 40 = .6981317
This mease that 40 degrees = .6981317 radians.

Now here is your part that you need to do. For example, if your balancer measures 5.75 inches to find the arc length of 30 degrees we would take 5.75/2= 2.875 inches
That means the the radius of your balancer is 2.875 inches. Now multiply this number by the numbers we got by converting 30 degrees to radians.
2.875 x .523598775 = 1.50 inches So if you cut a piece of tape 1.5 inches long and place it on a balancer that is 5.75 inches in diameter, the end of the tape will be at 30 degrees if you placed the start of the tape at TDC.
Now i will do this for the 40 degree mark.
To find the arc length of 40 degrees we would take 2.875 x .6981317 = 2.00 inches. So this means that if you cut a pice of tape 2 inches long and place the end at 0 TDC on the balancer, the other end would be at 40 degrees. You got it?

So now here is the final summary. You need to find you diameter of your balancer and devide that number by 2. Then to find the length for the 30 degree make you would multipy that number you got by .523598775. This number would be the length of the tape at 30 degrees. Now do the same for the 40 degrees. Take the diamter of the balancer and divide it by 2 then multiply that number by .6981317. This number would be the length of the tape at 40 degrees. I hope you got this and if you need something else, let me know.
Later

rico 08
Dirt Forum Champ
Total posts: 1139
posted April 10, 2005 06:44 AM  
Make sure you rev up the motor to at least 3000 rpm while timing it if it has the stock advance weights in it...i always wing it up to 5000 once to make sure it doesn't advance any more also.

Doran
Dirt Roller

Total posts: 21
posted April 10, 2005 07:52 AM  
Raceman17, I will get the total diameter and use that formula to mark the balancer. I will post back after I do the math. I really appreciate all the help!!!!
Thanks

racer17j
Dirt Forum Champ
Total posts: 5390
posted April 10, 2005 08:28 AM  
quote:
Originally posted by racer17j:
guys use the wonderfull tool box in the menu on here they have a caculator you put in the balancer size and the timing you want and it tells you how far you want to make the new mark from your tdc mark. kiss is how i always like to do it

Well, how I showed Doran how to do it is exactly how that little calculator works. Now you know how it works. Its based on an arc length.
Later


fordracer90x
Dirt Roller

Total posts: 18
posted April 10, 2005 05:29 PM  
racer17j.....let me break this here thread down for ya..if ya don't mind a little crtitisism from an xsperienced driver. What raceman17 is doing is splainin the proper way to measure..in radians...the balancer. Now if you already now how, then gyou should move on to another thread, ya hear..otherwise be coorgle to those who are readin and learn how its done engineerikly speaking. I learned a whole lots from readin this one. why I've already got mine balanced and purrin in my lil johnny sponsored Licoln. just from readin this thread. Raceman17, i apreciate your help cuz I was needin some in help in that area. the belts I got from auotzone aren't that good and I need a good balancer to help them equal the pull even at tdc, hince...BALANCER! duh yall! I got mine set at 48.25 degrees...+ or - a degree or 2. This lesson has workred well for me.
fordracer90x...so to speak..

Raceman17
Dirt Maniac

Total posts: 165
posted April 10, 2005 05:36 PM  
quote:
Originally posted by fordracer90x:
racer17j.....let me break this here thread down for ya..if ya don't mind a little crtitisism from an xsperienced driver. What raceman17 is doing is splainin the proper way to measure..in radians...the balancer. Now if you already now how, then gyou should move on to another thread, ya hear..otherwise be coorgle to those who are readin and learn how its done engineerikly speaking. I learned a whole lots from readin this one. why I've already got mine balanced and purrin in my lil johnny sponsored Licoln. just from readin this thread. Raceman17, i apreciate your help cuz I was needin some in help in that area. the belts I got from auotzone aren't that good and I need a good balancer to help them equal the pull even at tdc, hince...BALANCER! duh yall! I got mine set at 48.25 degrees...+ or - a degree or 2. This lesson has workred well for me.
fordracer90x...so to speak..


Dude you got me rollin in the floor. Keep up the humor. Its good to laugh every once in a while.
Later

Doran
Dirt Roller

Total posts: 21
posted April 10, 2005 07:14 PM  
Well...got her timed (using Raceman17`s forumla) and broke in. Runs and sounds great!! I did notice a difference in the way it idled after I timed it. When I first started it last week after the rebuild I tweeked the cap til she ran smooth and now after dialing it in today it idles a little more rough. When in the R`s it is very smooth, and could tell the difference when timing it around 3000 RPM. I do have one more question though, when timing it I unplugged ,what I assume is the timing advance (a vaccum line from the carb to the mechinism on the side of the distributer cap), and the timing suddenly went out of wack @ 3000 RPM, whats up with that? Thanks again!!

racer17j
Dirt Forum Champ
Total posts: 5390
posted April 10, 2005 07:34 PM  
quote:
Originally posted by Doran:
Well...got her timed (using Raceman17`s forumla) and broke in. Runs and sounds great!! I did notice a difference in the way it idled after I timed it. When I first started it last week after the rebuild I tweeked the cap til she ran smooth and now after dialing it in today it idles a little more rough. When in the R`s it is very smooth, and could tell the difference when timing it around 3000 RPM. I do have one more question though, when timing it I unplugged ,what I assume is the timing advance (a vaccum line from the carb to the mechinism on the side of the distributer cap), and the timing suddenly went out of wack @ 3000 RPM, whats up with that? Thanks again!!

My first question to you is do you have access to a mig welder? You need to get rid of that vaccumn advance. But like most stock classes, the rules say that you have to keep the vaccumm advance on the side of the distribitor. To fix this and still look legal, you need to remove the vaccumn advance off the side of the distribitor. There is two small screws and a little "c-pin clip" that is conneected to a metal rod that needs to be removed and disconnected before the you can pull the vaccum advance off. So once you get it off if you turn the advance over and look at the bottom side, there is a rod that slides back and forth. This rod moves back and forth depended on the amount of vaccumn the motor pulls. This works great on a street car but it really ***** on a race car. So to fix this, you need to place a small tack weld on the underside of the rod that advances and retards the timing. Just put a small tack weld on the rod and plate. This will lock the timing and will not let it adjust. If you dont have a welder, you maybe can use epoxy but, just try to get it welded. Now once you get it tack up, put her back together and see still looks like the advance is connected and working properly but, it is locked and wont be adjusted with the vaccumn advance. This is perfect for racing. Now just reset the timing and your ready to race.
The reason why the timing went to wack when you removed the rubber line is because you removed the vaccumn from the vaccumn advance which moved the small rod which in in turn adjusted the timing. I hope this helps.
Later


fordracer90x
Dirt Roller

Total posts: 18
posted April 10, 2005 09:12 PM  
racer17j
well if i could get your belt tightner i wouldn't need a balancer then would i? i think i'll just stick with what raceman says. i think he knows what he's sayin. ain't barkin up no tree a yours, just like to see us folks get the info we need to git our car up to the front where it belongs. i ain't seen any other treads where you asked any questions. you must know everything already. you still race? if so how would you figer timin your car without knowing there's a calculator on this site? splain that if you would...i'm interested. also one more thing. what you mean movin a motor forward to git the carb to open up more? that don't make no sence. just put a whole in the floor to push the pedal ferther in....thanks for ya input...
fordracer90x...so to speak

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted April 10, 2005 09:27 PM  
fordracer90x's post about carb problems was a joke...

and racer17j does know his stuff, he was just pointing out there was a calculator in the tool box to do what raceman17 was saying. I'd rather spend a little bit of money on a timing light and make sure my stuff is right rather then be cheap and measure my balancer, even thought it is a good idea to do both

powerglides
Dirt Freak

Total posts: 374
posted April 11, 2005 08:43 AM  
My balancer degree formula in 4 EASY steps. Find the exact diameter of the balancer. Multiply that by pi (3.1416) to get the circumference.
Divide that number by 360 to get the length of 1 degree.
Multiply by that number of degrees you want and thats it.

[This message has been edited by powerglides (edited April 11, 2005).]

fordracer90x
Dirt Roller

Total posts: 18
posted April 11, 2005 09:50 AM  
you're right X. sorry, this is getin old anyway. I'll use it the way its supposed to be used if it could apply to asphalt. you guys keep up the good talk. I'm out..
fordracer90x....with a knife in his neck, so to speak....

Doran
Dirt Roller

Total posts: 21
posted April 11, 2005 04:46 PM  
Raceman17,
I do have a small stick welder that may work for that. I am on my way to the garage to give her a try. I`ll post back, thanks again!!!!

Doran
Dirt Roller

Total posts: 21
posted April 11, 2005 07:47 PM  
Had the welder set alittle too hot and burned one of the rods off, but luckly that was a practice run. I was able to goober weld the rod and reinstall it. I retimed her and know ( just like raceman17 said ) the time stays the same at idle or at 3000 RPM. Seems to run as good too.
My thoughts.... right or wrong? The reason eliminating the vaccum advance is important is #1 better response and #2 eliminat timing headaches? Thanks agian!!

Raceman17
Dirt Maniac

Total posts: 165
posted April 11, 2005 08:40 PM  
quote:
Originally posted by Doran:

My thoughts.... right or wrong? The reason eliminating the vaccum advance is important is #1 better response and #2 eliminat timing headaches? Thanks agian!!

Right on the money. Also if the vaccum advance ever got stuck where it would not move then your timing would just stay where ever it got stuck at, also its one less moving part that could fail and cause a problem. I'm glad I could help.
Later

DirtMirt
Dirt Roller

Total posts: 20
posted April 21, 2005 09:26 AM  
I have a question on welding the vaccum advance. The class, that I'm running in, rules state that the vaccuum pressure may not be less than 14.00 inches at 1000 RPM before or after the race (no tolerance).
Will welding the advance help or hurt the vaccum pressure? Right now I'm using a stock 305(probably won't matter with this engine) while I build a 350. I will need help with cam specs, which heads to use and piston type, but that is for another thread.
Thanks, DM

[This message has been edited by DirtMirt (edited April 21, 2005).]

Raceman17
Dirt Maniac

Total posts: 165
posted April 21, 2005 11:35 AM  
Welding the vaccumn advance will do nothing to the vaccumn of the engine. The vaccumn of the engine is what the tech guys will be checking on your motor. The vaccumn advance on the distribitor just runs off teh vaccumn from the engine and since you are going to weld that up, it wont matter what the vaccumn from the engine is. Hope that helps,

racer17j
Dirt Forum Champ
Total posts: 5390
posted April 21, 2005 08:27 PM  
some of the last model hei's had no vaccume advance or swing weights and you can unplug the extra wires form the module.

JohnG
Dirt Maniac

Total posts: 137
posted April 24, 2005 11:40 AM  
17j, you dont need to buy any plate, you just unscrew the advance and straighten out the part where the rod went thru that is still on the distributor, then clip the very end of it open and put one of the screws that held the advance plate in thru the slot you now made down into the rear screw hole where the plate was and its locked for "FREE" and in about 3 minutes!!

Then of course install it in your car or if it was allready in reset the timing..

DirtMirt
Dirt Roller

Total posts: 20
posted April 25, 2005 10:56 AM  
This seems pretty obvious to me but i have to ask anyway. When welding the rod on the vaccum advance which position should it be. "In" towards the center of the distributor or out towards the vaccum hole. My guess would be...when you remove the distributor the vaccum is not pulling and it is in the correct place. However if you turn the distributor over will the rod flop back and forth or will it stay in the non suction position. PS..I hope that I asked this porperly and not confusing!

Raceman17
Dirt Maniac

Total posts: 165
posted April 25, 2005 11:28 AM  
quote:
Originally posted by DirtMirt:
This seems pretty obvious to me but i have to ask anyway. When welding the rod on the vaccum advance which position should it be. "In" towards the center of the distributor or out towards the vaccum hole. My guess would be...when you remove the distributor the vaccum is not pulling and it is in the correct place. However if you turn the distributor over will the rod flop back and forth or will it stay in the non suction position. PS..I hope that I asked this porperly and not confusing!

When you weld it up it doesnt matter what position it's in. Just after you weld it up it needs to be connected to the part of the distribitor that advances the timing when a vaccumn is pulled. Other wise you just have a rod that is welded not holding anything in place.


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