billybob6110

I been fighting a issue with my car and I believe its timing related. I found true tdc last night and its nowhere near what the balancer reads. what do I do to fix this? timing tape from new spot?do I have to redo distributor for new tdc?

sofakingdom

iTrader: (1)

Timing tape is a good idea. Don't expect it to be permanent though; the blob of spooge that loosely associates the ring that the mark is on, could just as easily up and decide to move again tomorrow, with no more warning than it did yesterday.

Yes you need to make the distributor match the position of the internal parts of the engine, rather than some "mark". The engine does not care one whit about some "mark"; all it cares, is when the spark occurs, in relation to the piston motion and valve position. Which you can find by making it occur where the engine runs the best. THE ENGINE knows, all ya gotta do is LISTEN to it.

You may have seen me recommend frequently to people having trouble with their "timing", that they verify the agreement (or most often, the lack of it) of the mark with the actual engine position; now you know why.

billybob6110

its a brandnew balancer, it has the timing mmarks engraved on it. so set tdc new mark pull dist reset dist and retime?

sofakingdom

iTrader: (1)

Doesn't too much matter, eh??

Yup, they usually do, for what it's worth. Personally, not sure why they bother.

Yup, pretty much; but don't count on th emark staying accurate. Since you ALREADY KNOW it's moved itself once, there's no reason to have anyconfidence it won't move again.

I'd suggest, as always, that you IGNORE the mark, and set the timing to where THE ENGINE tells you it wants it. Which it will do, by running the best. It's real simple: get the car to run. Advance the timing a bit. Is it better, or worse? (to some extent you have to be the judge of what's better: more power, cripser throttle response, better gas mileage, cooler operating temp, etc. that come from more advance, vs pinging or starting trouble that come from too much) If it got better, do the same thing some more. If it got worse, go back where it was, plus a bit more. Better/worse? if better, do it some more. Repeat until it's as good as you can make it. When you get it like that, then THAT'S where the timing belongs, REGARDLESS of some "mark" and/or what YOU THINK it should be. THE ENGINE knows better than you do. LISTEN to it and GIVE IT WHAT IT ASKS FOR instead of what most people do.

billybob6110

I was setting it by ear and feel and more I advance the better it sounded and got better response. threw timing light on it and it was off the chart with mark. so I put it back. ill take your advice and set it how it wants to be set.

Orr89RocZ

iTrader: (20)

Brand new balancer shouldnt have moved timing unless it was defective. Are you sure its designed for your timing cover's pointer position?

billybob6110

i have the correct pointer one of them cheap chrome ones. i mean the tdc is 1/4 of the balancer past where factory markings are. that's y i wasn't sure if i had to change distributor position and stuff

billybob6110

http://www.summitracing.com/parts/sum-161358/overview/ I have this balancer
http://www.summitracing.com/parts/sum-161358/overview/ I have this pointer.


do I need this one instead? http://www.summitracing.com/parts/sum-g6316-8

Orr89RocZ

iTrader: (20)

If it is true tdc on compression stroke, then pointer should be close to the balancers 0 mark. Is it the pointer location or is balancer just that far off? Lol i agree piece of timing tape should do the trick and set your distributor pointing at cyl 1 at tdc and set timing from there.

I just use basic L98 factory timing cover and pointer location at approx 2 o'clock and has worked for both my old romac balancer and my ati unit

billybob6110

I was told im on the wrong stroke, exhaust so ill have to double check after wrk. I hate timing ****

Jonesyfxr

iTrader: (2)

If you're on the compression stroke both valves will be closed on the cam base circle and if you can put a finger in #1, then as you approach TDC you'll feel a rush of air past your finger.

cardo0

Most owners do all kinds of cam work and never bother to verify TDC. Reality is they dont really know if there timing pointer lines up and if they are reading the correct advance. BTW all u need is a pointer - though most chevys have a tab with degree marks for BTDC and ATDC. Heck u can use a fixed coat hanger as long as it pointer to the dampner mark at TDC.

So u need a pointer or tab but u will also need a piston stop. The finger over the hole method works on aircraft where u can rotate the propeller a dozen times to nail TDC by air out the plug hole. But cranking a V8 by hand is not going to fly here.
Since u have 60* marks BTDC on your dampner i would use a tape measure and match those marks on ATDC side of dampner TDC mark. This will save u from buying and installing a degree wheel.
Now with a piston stop u dont want to turn the engine by battery/starter as u will damage the piston crown. U need to install the piston stop in the plug hole and slowly turn by hand until the p-stop does its job - write this number down where the pointer points on the dampner marks. Now slowly turn engine by hand the other way utill the p-stop does its job again and write this number down where the pointer is pointing on the dampner marks.

So now if your counter clockwise p-stop mark was 13*BTDC and your clockwise p-stop mark was 33* ATDC where do u think your TDC location is? Yes (13+33)/2=23ATDC! So remove the p-stop then move/crank engine by hand so pointer is pointing at 23*ATDC - now u can move the timing tab to zero or just line up your pointer to the dampner mark and u have it at TDC. Thats why its important to use a rigid pointer/tab so its move after driving. And again dont adjust it until the crank is lined up on that calculated mark (23* here).

One more thing is i found most vendor p-stops are aluminum and bend easily so i make my own out of and old spark plug. I knock out the center electrode and insulator, cut off the side electrode and thread the inside for a 3-4" stove bolt. Be careful as the plug case is kinda thin now and can crush in vice when u tap it for stove bolt.

Whew! Thats enough for now. Let us know if it helps Billy - feedback helps us all.

sofakingdom

iTrader: (1)

Problem with ANY pointer is, the "mark on the damper is NOT CONNECTED TO THE ENGINE. It is merely loosely associated out at the far end of a blob of spooge.

All that has to happen for the whole "mark" crap to go down the toilet, and take all your careful "tape" and "pointer" and "piston stop" and EVERY BIT OF THE REST OF THAT along with it, is for the spooge to let go. Which it ALWAYS does.

Total waste of time messing with all of that.

Set the timing to where the engine runs the best.

Indulge yourself with the following mental exercise...

Start point: engine with unknown "timing"

End point: engine with "timing" set to IDEAL

OK, so what's the shortest distance between these 2 points???

How about, adjust the timing until the engine runs the best it canbe made to run by adjusting the timing?

What does all that other crap ADD that you can introduce in between Start and End? All of that "stop", "tape", "mark", "pointer", "light", etc. etc. etc.? Does ANY of that make the engine run better? Does ANY of it know where THE ENGINE wants the timing to be set, any better than THE ENGINE does?????

Then why EFFF with it? It's a complete waste of time and effort.

Set the timing to where THE ENGINE asks you to set it, which is will TELL YOU, in no uncertain terms, by RUNNING THE BEST IT CAN. Go straight to the horse's mouth and LISTEN.

cardo0

If u dont index/reference your TDC then all your timing numbers on your timing curve are just "relative" and to what yor ears tell u. If u ever want to time the cam or advance the cam intake center line u have to know the correct location. I dont think correcting your TDC mark is crap at all as without it youll never know if the timing has shifted due to whatever reason or if the dampner is slipping.

sofakingdom

iTrader: (1)

EXACTLY.

So what difference does it make what some "number" is?

You're obviously pretty young, so I'm going to reach back probably before you were born here...

When GPS receivers first became available to the American public, they were like the 8th wonder of the world. You could buy this little box, (actually, wasn't so "little" back then), set up an antenna, wait about 5 or 10 minutes, and it would tell you EXACTLY where you were, within 50' or so. Magic!

Problem was, that's ALL it would tell you. It wouldn't tell you how to get to the Kroger down the street, wouldn't even tell you where the Kroger WAS, let alone what streets went there or which direction to drive. To do any of THAT, you needed a map and a compass to go along with your $$$$GPS receiver$$$$.

A "timing mark" is ALOT like that, except worse... it would be kinda like the GPS receiver from the late 80s with no maps or database, except like if the GPS receiver's 0° latitude (equator) and longitude (Greenwich Meridian) just moved to wherever they felt like whenever they felt like it, and didn't tell you about it.

I think finding TDC is GOLDEN when building an engine or assembling a distributor to it. That has NOTHING WHATSOEVER to do with "mark". I find NO USE AT ALL for a "mark". They're ALWAYS wrong, and subject to randomly being differently wrong unpredictably. AT BEST, a "mark" will tell you where the engine (or spark) IS, but won't tell you A DAMN THING about where the spark NEEDS TO BE. Therefore, when you're working on getting the spark to occur at the right place/time, a "mark" is simply THE WRONG TOOL. Messing around with it at that time for that reason is CRAP.

Orr89RocZ

iTrader: (20)

I'll disagree with that. All my motors have matched tdc with the 0 mark on balancer using L98 cover pointer.

I want to know where i am starting at so i know where i am goin when i go make changes to make the engine run best.

And idle timing really varies. Motor can seem to run "best" by ear at 16 deg total, or it could be 26 or 32. I dont think anyone can tell a difference on most typical cam combos.
Now i am not a carb guy but those that are setting total advance at a certain rpm so they know what their total wot timing number is, i find that critical information. I wont tune blind. Over 50+ years of sbc existence its common knowledge what range of timing values they run best at, so why not know your base line so you can then test to find where it runs best?

sofakingdom

iTrader: (1)

"Know your baselinse" sounds TERRIFIC, in principle...

Until you realize that the thing you're basing your baseline on, CAN AND DOES MOVE.

One of those minor little details that cause "principle" and "practice" to be 2 different things.

To go along with, of course, that it doesn't matter IN THE SLIGHTEST how accurate you know where your timing IS; that "mark" STILL won't tell you A DAMN THING about where it OUGHT TO BE INSTEAD.

cardo0

Well the post title is "true tdc". I spent good amount of time trying to get the OP what he requested. No thats not crap, thats the way its done. The OP didnt ask for shade tree mechcanic ways to find tdc or even tune. He asked for "true tdc". And i dont think your much older than me and if u are u should know its rude to call someone efforts "crap" when its actually accurate information - not shade tree hack tricks.

Enough, let the OP decide for himself.

sofakingdom

iTrader: (1)

The OP is concerned about his distributor and ignition timing. Read his post.

Enough. You've shown us that you're not willing to listen to common sense, but instead would rather change the topic to one that suits your point of view instead of helping the OP fix his perceived driveability problem, whatever it is which he hasn't told us, without a useless detour of effing with his "mark". Dinking around with "mark" is CRAP in this situation.

It's real simple: think you've got a timing problem? CHANGE IT. One of 3 things will happen: nothing, or it will get better, or it will get worse. "Mark" doesn't enter into the picture. This just isn't rocket science after all, it's just a car.

Quit trying to tell the OP that his "mark" matters with respect to making his car run right.

cardo0

I did read his post again and he asks how to fix his reading to match the balancer. Nothing 'bout shadetree tricks to locate the best running timing. I didnt say advancing by trial and error wont or doesnt work. I didnt mention that at all. Im sure a lot of owners that are very familiar with their cars can do a good job with it. But again thats not what the OP asked and if u think locating the actual TDC is of no use i cant help u either.

No actual TDC is not CRAP and is used by 99% of owners, maybe not u but 99% of owners when they map their timing curve or when they dial in the cam or make changes.
Yes that is enough!

sofakingdom

iTrader: (1)

Enough.

You just don't GET IT, do you? You're WRONG, you're NOT HELPING, you're just NOISE AND DISTRACTION, you're not even talking about what the OP asked about, but it hasn't sunk in yet.

I never said TDC was CRAP. What I DID say was, using timing marks to set timing is CRAP; especially when you don't know if they're right, and you don't know what timing THE ENGINE WANTS in the first place. Which of course is what this whole discussion (everybody except you of course) is talking about... TIMING.

You're right, you can't help. The OP needs to establish whether he has a "timing" problem, which he can do by simply CHANGING IT and seeing what happens. No "mark" required. No "TDC" required. No pointer required. Just a simple experiment, see what it does, do some more if you like it, go back to where it was plus some more if it's worse, put it back and leave it alone if nothing happens. No "mark" required for ANY of that.

cardo0

But i do get it. Your setting the timing by your hearing and driving impressions not knowing what happen to the entire timing curve/map. What "feels/sounds" best at idle under load at WOT could put the motor into detonation and make some serious damage. But why should u care, its not going to cost u a dime? Poor OP has to pay the bill for a shadetree mech hack trick. Show us one shop manual that says to set initial timing by sound and feel, just one?

IMHO the guy thats calling everything crap is the one making it. Most likely to lazy to do it any accurate way or even doesnt understand how to so its easier to label a functional method crap and claim to the uniformed that the lazy man method is what needs to be used. Thats some of the biggest crappy advice there is.

Orr89RocZ

iTrader: (20)

This is why the mark matters. It didnt line up cuz theres a good chance it wasnt on the right stroke to begin with

When everything is right, at true tdc the balancer should read close to if not exactly 0 on the pointer. Set it there, install the distributor and proceed to start car and set actual base timing once its running.

I dont understand how hard this is to understand?

And again you need that mark to set timing at full advance for wot. Guys hold 3000-3200 ish rpm and check timing with a light. There is no way you can accurately do it without a light and accurate balancer, or else a dyno to measure changes

billybob6110

Im not picking side on whats right and what wrong. all I did was what sofakingdom said to do was advance till ran good and it did. I did the timing light for hell of it and it was at 30* so whether balancer is wrong or right, car runs idles had 15hg of vacuum and has a lot of power there.

Orr89RocZ

iTrader: (20)

Thats typical for an idle of a cammed car. 20-30

Did you ever recheck to verify if the balancer was at zero at tdc on the right compression stroke?

Sounds like its not off afterall if motor is at 30

billybob6110

30 at idle isn't to much for a car? that would be 30 inital

sofakingdom

iTrader: (1)

If it RUNS good, it IS good.

That's all you need to know.

Now that the car runs right, feel free to sort out the "mark" location... now that you're confident that getting the car running right isn't being held hostage to a leisurely or futile mental exercise in curiosity.

You don't need the "mark" to get the engine running right.

Orr89RocZ

iTrader: (20)

Eh not really. Stock tpi cars run 20-22 initial. Big cam cars need alot more along with increased rpm for vacuum brakes. 28-30 isnt bad at all. Also depends on head chamber. Vette 113 heads for instance love timing. We had 30 at idle and just off idle 1000-1200 rpms we had 41

Now just make sure max timing for wot doesnt exceed 34-38, whereever it runs best. Not sure what dizzy you have and what kind of advance it is capable of.

billybob6110

when I was having issues with the car It never went over 36* so ill have to double check it again

anesthes

iTrader: (12)

That was a fun read.

I don't think I've used a rubber isolated damper in 20 years. 1pc steel dampers are cheap, and they don't move. If they do, it is because you hit a wall at 200mph.

I find TDC with a mag base and dial caliper.

TDC is TDC regardless of stroke. The crank has absolutely no idea what the cam is doing, and doesn't care. TDC is when the piston is all the way UP in the bore. It will point to zero even if the cam is 180* out.

If your 30 year old, stock, rubber isolated "balancer" 'spun' throw it in the trash and replace it with a 1pc steel damper. (fluid damper, etc)

-- Joe

skinny z

But if the engine isn't running right despite whatever timing you through at through trial and error, then at the very least, it would be helpful to know what the timing is (and accurately so) as a diagnostic tool.

-=Z28=-

iTrader: (3)

Right. Sofakingdom isn't saying the mark is junk, or there is no use for it. Think he is saying to get the motor purring, you don't need the mark. (It is prob off anyways) grab the dizzy and play with it. see where it runs best. I know an old timer, who used to run circle-dirt back in the 60's-70's. He said they would tie strings on the dizzy and while ripping around, adjusting the timing to what was best for that Engine. Nothing to do with a mark or tdc. Use your senses. You will know when its right.

-Dan

sofakingdom

iTrader: (1)

Why?

What's the difference between not knowing what the timing is but it doesn't matter where it's set, and knowing what the timing is but it doesn't matter where it's set? If it doesn't matter what it is, then it also doesn't matter whether you know what it is. Put it back wherever it was and leave it alone and find THE REAL problem and FIX IT, and then MAYBE return to trying to tune the engine with timing settings AFTER fixing whatever ails it.

This is so logical it hurts. I can't for the life of me understand why people can't understand it.

Conversely, if it DOES matter what it's set to, and you set it to where the engine runs the best it can at any setting, then what difference does it make what that is?

"If it RUNS good, it IS good". LISTEN TO THE ENGINE AND LET IT TELL YOU WHAT IT WANTS. It's just way too simple I guess.

It all comes right back down to this intellectual superiority complex some people seem to have, where they think they're able to somehow predict what their engine is going to want before they even try it: "I know that my engine needs {fill in the blank} timing so I'm going to set it just exactly there according to my light and mark and pointer and and close my mind to any further observation". NEVER MIND that the engine might want some COMPLETELY OTHER timing than whatever you've prejudiced yourself into trying to force down its throat; or that your light mark & pointer might be WRONG; or that you don't know what you're doing in the first place. (like expecting a FI motor to stay at the static setting with the EST plugged back in, or not understanding that "total" timing on a mech dist is without vac adv)

The same thing goes for carb settings. "I think my jets are too {large small staggered whatever} so I'm going to use {smaller larger all the same whatever} ones instead." They should be, WHAT THE ENGINE WANTS. The engine doesn't read the number on them, and pooh-pooh it, and run bad; all it cares, is that they're giving it the right amount of fuel. If you put smaller ones in and it runs better, then it needs SMALLER ones. PERIOD. In that case, put in EVEN SMALLER ones, and keep on doing it, until you reach the peak running condition and start to decline on the other side: at that point, you know what THE BEST is. Eff the number on them.

novaderrik

one of my rituals when i get a new (to me) car with a small block in it is to check where true tdc is with a piston stop, and in the 25 or so years that i've been playing with small block Chevies i've only ever had 1 where the mark on the balancer wasn't within a degree or so pf true TDC as found with a piston stop- and that was only because the outer ring was only being held onto the hub by the crank pulley.


it is important to know where true TDC is so you can know if you are changing things in the right direction and to be able to refer back to where you had it previously if you need to go back- something called "repeatability". but in order for that mark to mean anything, you need to have a balancer that is properly marked for the pointer you are using. if you are using a balancer for a car that has the tdc mark at the 2 o'clock position when at tdc, then you will be way "off the charts" if your pointer is for a balancer that has the tdc mark at about the 12 o'clock position- which is a situation that i ran into on the 350 that some genius put in my girlfriend's 64 Chevy truck before she got it. since (i assume) that same genius managed to break off the timing cover bolts where the proper pointer needs to go, i just used my piston stop to figure out where the balancer was sitting when at tdc and using a paint pen to make a mark that lines up with the pointer... this allowed me to figure out that the initial timing was about 10 degrees atdc- which is somewhere near 25 degrees off from where i know a healthy 350 likes to be for initial timing.. i used my handy Craftsman dial back timing light to set the timing to 15btdc and the truck instantly ran about 1000% better, but i did have to move the distributor over a tooth to allow me the room to do that... i could have chased my tail for a long time if i didn't know where true tdc was on that engine..

so if you are in the "advance it until it detonates and/or starts hard, then pull it back a bit" school of tuning, good luck with that. i'll use hard numbers and decades of experience to tell me where to start and where i'll likely need to end up. i'll be out driving and having fun with my car while you are in your driveway trying to figure out why you can't get your car to run right..

skinny z

It's very easy to understand your simple concept however it goes beyond that.

IF THE ENGINE RUNS LIKE CRAP YOU HAVE TO DETERMINE WHY.
If I show up at your shop and you're struggling with a tune up, I'll ask something SIMPLE like, what do you have the timing set at? And you'll answer, "I don't know."....that is not the least bit helpful. If, in your diagnostics, you actually measured the timing and saw that the engine ran best with 2 degrees of total advance, wouldn't you be suspicious? Or maybe it took 50 degrees of timing so it would idle? Those examples are abnormalities (when talking about a SBC) and you owe it to yourself to get the information you need.

I'll go back over my build notes and see that engine "A" ran best with "X" amount of timing. I can say that absolutely because I observed it. Then I can make a comparision to engine "B" should I need to (and I have).

Don't get me wrong and I totally understand what you're saying.
Sure, you can go to the dragstrip and tune without knowing the jet sizes and without knowing the timing and without knowing the air pressure in your tires, etc, etc. But where does that leave you in terms of any changes you may want to make in one direction or the other the next time you're out? Start again from scratch? No thanks.
It reminds me of one of the guys at work who will blindly stab at an operating console until he gets the result he's after. I'll ask him how he got that result and his reply is "I don't know". The next time he's at the same console, he's poking buttons in the same random approach he did before. Isn't it just easier to make some notes?

To each his own I guess however in my world, the more information the better.

cardo0

Well i was ready to pull my posts in this thread as i just tried to answer the question in the title then became attacked for it. I thought the OP needed a method to verify his timing tab and he was unaware of how to find "true tdc" with hand tools. I made no implication of "how it runs". My posts was called "crap" went it actually answers the question though some here dont understand the difference. BTW true tdc may or may not be where it runs the best - it would only be coincidence. Fudging with "how it runs" is finding the sweat spot for intitial timing and has nothing with what i was trying to say or #1 cyl TDC and the dampner mark. It seems the OP now is more happy with "how it runs" and thats fine but not what he asked in the title. I can read he and others here dont see the difference between "how it runs", cam timing and crank damper postion and so my efforts went unappreciated and even attacked/labeled as "crap". Again i cant seem to help those that cant understand that. As far as im concerned "how it runs" would be "off topic" for a "true tdc" topic.

If the mods want to wipe my posts on this thread i wouldnt mind that in the least.

anesthes

iTrader: (12)

The old school of thought was 'set it by ear, give it what it wants' and that is fine for old stuff.

On modern stuff, I tend to set my initial advance to 6 or 10 degrees (depending on the cam profile I'm using), and then I build a base spark map in the software. I fire the thing up and I adjust fuel and spark until I've given it "What it wants".

I still like to know what my baselines are, and I have certain targets I use for my base maps that are educated guesses based on the components I'm using to build the engine.

On my old farm tractor, I'd just turn the dizzy until the thing hauled stuff out in the field without pinging under a load. On a 10 second race car I'm a bit more critical.

Anyway, like I said earlier, and I think Sofa said as well - the balancer spun. It happens with the stock ones. Replace it, then re-evaluate the tune.


-- Joe

FRMULA88

A quality harmonic balancer cannot slip on the inner hub like a worn-out high mileage OEM piece does. This is what throws off the timing marks OR you left the dist. hold down clamp too loose and the dist. slipped and threw off the timing.

with quality parts, properly installed
35 degrees of total advance should read 35 degrees, no if, ands, or buts