Hey All...I was wondering if anybody can tell me if there is a corelation between the harmonic balancer keyway position (1 o' clock..or 12 o'clock etc.) and what plug # the rotor should be pointing at when it's at that position?...I have a rebuilt 66 327 4 bbl with an HEI dizzy...appreciate any replies.....LK66
A somewhat confusing question. The simple answer is NO. The rotor must point at the cylinder it is going to fire ONLY when that cylinder is just finishing its compression stroke. Basically, the keyway will also be in that exact same position also when reaching end of the exhaust stroke.
Let me try this again. Take cylinder #1 for example, when it is almost at TDC (and ready for that plug to be lit) the keyway will be in "X" position ... BUT the keyway will also be in that same "X" position at the end of the exhaust stroke as well. If you are trying to "time" the motor in preparation for installing the dist ... I would suggest that simply (and only) using the position of the keyway is NOT the way to do it.
Hey...I appreciate the info...I thought I'd heard of somethin like that in the past But I guess not...Thanks LK66
I am trying to time this motor...I've done everything the way I think it should have been done..1. made certain that #1 was on its way up on compression stroke..2. turned the motor over by hand until the 0 degrees marks lines up..set the dizzy in (dropped right in) so that the rotor turned into the #1 firing order on the cap..put everything back together..and it still wont fire unless I turn the dizzy COUNTER CLOCKWISE almost to the point that I run out of room..WTF am I missing? LK66
There are two balancers for SBC engines. Sounds like you might have an early balancer and a later timing tab or vice versa. On one balancer the mark will be at something like 2:00 (maybe) at TDC and the other balancer will have the mark at TDC #1 pointing straight up I believe. I'm betting your timing tab is the wrong one for the balancer you have.
Try this ... pull all the plugs to allow easier turning of the engine ... turn the engine over until you reach TDC on #1 cylinder (you should be able to look in the spark plug hole and see the top of the piston). Once you have verified visually that you have reached TDC on #1 (there are other ways to do this than looking in the plug hole if that is not an option for you) NOW take a look at the mark on the balancer. I am willing to bet that TDC on the piston and 0 on the balancer do not line up.
If you determine that the timing tab does not match the balancer, you have three option I guess .... find the correct (bolt on) timing tab .... mark your existing balancer for the "new" 0 degrees .... or change the balancer for one that matches your timing tab (it IS an option but certainly not nec).
You turned the engine over by hand till the 0 lined up ... I get it ... but, did you verify that 0 on the balancer was really TDC in the cylinder? It will be if you have the correct timing tab for that balancer .... it WON'T be if your using the incorrect timing tab for the balancer you have. Best of luck Dammit ... he logged off without reading my suggestion. Oh well.
to answer your question...the keyway is in line with the first crank throw, so it will be clockwise 45 degrees from straight up, when #1 is at TDC.
Dont use zero for setting up distributer. The motor doesnt run there. Use 6 or 8 degrees if you have a distributer with auto advance. Use 25 or 30 for a locked out advance. See if that doesnt get you the clearence you need to set timing.
Squirrel, that kind of information you always add never ceases to amaze me.. thats a tidbit thats pretty cool to know. I have just never thought about it or looked at it that way.
The other thing you could try is move the plug wires over one tower on the cap. Turn the new #1 position back to the rotor and see if it will time that way. As long as the wires are in the right order and the rotor is lined up it doesnt mater where they are on the cap.
It is best to find true TDC no matter what kind of engine you have. You need a piston stop, a timing pointer, and someting to mark the balancer/pulley with. !) Remove all the spark plugs to make rotating engine by hand easier. 2) Rotate engine so that #1 piston is close to BDC 3) Install piston stop in #1 cylinder. 4) Install a timing pointer, pointing at an easy to see and get to place on your balancer/pulley. You can use the existing timing tab if you have one. 5) Rotate engine clockwise by hand until the #1 piston contact the piston stop. No need to lean on it, just make firm contact with stop. 6) Now make a mark on your balancer/puller to line up with your timing pointer, or zero on your existing timing tab. 7) Rotate engine counter clockwise until the #! piston hits the stop again. 8) Make a mark on the balancer/pulley as in step #6. 9) You now have two marks on your balancer/pulley. True Top Dead Center is exaclty 1/2 way between those marks. Make a new mark there. Erase the other two marks. The new mark is TDC lined up with your pointer or zero on your timing tab to indicate #1 TDC. Doing this means you don't need to be concerned whether you have the right balancer/ tab combination. It is also a good idea to make marks that show the alignment of the outter ring of the balancer and the inner hub. Although probably covered up by the front pulley, it is a way to check wether or not the outter ring has slipped on the inner hub in the future. When building an engine, you should do this when degreeing in the cam. To set ignition timing you can use your timing tab, a timing tape on the balancer, or use a dial-back timing light with the TDC mark and timing pointer.
Are you just building this engine or has it run before? Have parts been changed on it? How many degrees do you have to turn it to make it run? I always find the easiest way to make sure #1 is coming up on compression is to have the spark plug out, put my thumb on the hole and crank the engine until it pushes my thumb out. I put a chalk mark on the damper so I know which side I want near the timing mark.
The thumb over the spark plug trick is just fine on a chevy...don't try it on an older ford with the big 18mm plugs, you can really hurt your thumb when it ****s it in If it's easy to get the valve cover off, the two valves won't be moving when it's time to fire that cylinder, you can see pretty easily if it's in the right place, or 180 degrees out.
I don't think he's 180 out. He claims he can get it to run if he turns the dist enough, but then runs out of room. That suggests to me that he is out but not 180 out. Being out but not 180 sounds like he's got the wrong timing tab for the balancer he is using or the outer ring has spun slightly. I agree that he should find TDC, and I agree with the piston stop method. But in this case, if he can actually see the top of the piston, he can get close enough to actual TDC to check to see if the timing tab and balancer line up. I'm betting he changed the balancer to a newer one but didn't change the timing tab. Or he changed the timing chain cover to a chrome one and installed the wrong timing tab. Or changed the timing cover to a newer one that has the wrong tab on it for his balancer. Unfortunately he has logged off so we can't find out he if did change anything. I still stand behind my "simple answer of no" to the original question, because that alone is not enough to determine piston position when "timing" an engine for plug wire installation ... If more factors are involved then the answer becomes "yes" ... the other factor being that the piston in question is at the end of compression stroke and not the end of exhaust stroke.
Another tidbit. If you're using a used harmonic balancer, it's always good to check with above to find out if the outer ring has slipped. This is common. Misaligned timing tabs are common. Even if you don't have a degree wheel, you can check both cylinder heads on or off with a piston stop and a Sharpie to mark both of how to find halfway and true TDC for the next mark. You might find how good or bad your good parts stash or s**** pile really are. You will also find out how inaccurate some "Gotta have this to have this degree thingee" parts are. My old small harmonic balancer has it's ring positioned to the chu rome stamped Mr Gasket timing tab that shows one of them is two degrees advanced. If the ring is spun, the timing mark would show the timing mark to be retarded==after TDC.
Here are balancer differences which do you have? Notice the key way and timing mark differences. The orange one is most common the other requires the timing tab in a different area.Hope this helps. Tig
I think there is yet another one, too....with the mark in line with the keyway. I think it was used on the pre-1969 engines.
you said it trys to fire when rotated in one direction.move wires over one on cap see if that helps.did you get the motor rebuilt or did you build it??if you built it how did you adj valves properly.i thought you used timing mark to adj vaves
GM used different keyway locations for different engines. You are still going to fire the #1 cylinder when it is time to fire the #1 cylinder. The difference in keyway will only affect the timming marks on a specific harmonic balancer, if you have the wrong balancer the timming marks will be wrong. Get yourself an adjustable pointer, roll your engine up on TDC and then adjust the pointer accordingly.
Hey Guys..really appreciate all the knowledge here.Weirdest thing of it all is that it ran great when I pulled it in the garage to change the plugs and wires..No...I didn't do them one at a time cause I can do em in my sleep..as I'm sure all of you can..I didn't touch the dizzy at all..replaced the plugs and wires..changed out the valve covers and thats the last time she ran...I did verify that #1 piston was at tdc...I did have it set up initially to fire at 8 degrees advanced..but got to looking at someones YOU TUBE VIDEO and decided to set it up at zero..I have the second balancer that you showed (not the orange one) and no crank snout bolt..but I got it to turn by hand with the plugs out...can a timing chain go out overnight.? I'm gonna go back out there again in the morning and do what you all suggested. Again...I thank you for all the time spent answering my H.A.Q. on the H.A.M.B....LK66
The second damper (not the orange one) is for the van engines and whatnot that had the timing pointer at the top, behind the water pump. Won't work too well if you try to time it with that one, using a timing tab that's on the side.
That's for sure where is your timing marker located?? You will not get it lined up unless the marker is from same combo. Sounds like you are trying to line up timing marks and it is the wrong combination.With that combo lining up the marks it will not be top dead center compression on #1.When you line up your mark and the timing tab look in the crank snout and tell us where the key way is? Down around 4 o'clock or further? If so that is wrong it should be approx 2 o'clock or so.Look at pic this is where the Eng. is at tdc regardless of dampener make sure you are on compression and not exh. Tig
What engines in a small block family use a different crank gear because of key way location that would be a nightmare because what timing set would you use how could you tell what eng the crank came from there would be a huge combination of timing components. eg 67 to 95 small block all take the same crank gear s 391 comes from dynagear cat. If there is a different crank what is it from?
Mine is a little bitty skinny s.o.b..not hefty like these..now that I see the difference between the keyway locations and the timer mark..I gotta go and take a look to see..but I have to remove all the belts and the lower pulleys to see it..Think I'll let it kool off a bit outside...I think it's about 102 here with 90% humidity...it's nasty..I really appreciate you guys....LK66
Is it 5/8" thick? http://www.damperdoctor.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=DD&Category_Code=CHE only 8 for a 327 good luck Tig
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