Chevy Nova Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
30 Posts
Discussion Starter #1
so I've got this SBC currently in my car starting and runs Halfway decent. Not a driver yet. the question is I throw a timing light on it and the timing mark is showing at the TOP of the balancer no where near the timing pointer. but the motor is humming right along.

Can the timing be this far off and running halfway decent?
is this the wrong balancer?
WTF?

I believe I can set #1 TDC and the mark should be at 0 on my pointer correct?
So I should be able to do that and make my own timing mark if this is not the right balancer?

help!!
 

·
Registered
Joined
·
188 Posts
Yes find TDC on#1 and verify that the mark on the balancer and the timing tab are lined up. You can make your own mark but I'd also find out if they don't line up why. The balancer is probably right, maybe the wrong timing tab but who knows what somebody before you put on there though. I've seen all sorts of stuff. A picture of them would help.
 

·
Registered
Joined
·
145 Posts
The other thing to remember is timing advance. Make sure the vacuum advance is disabled so you are actually measuring base timing before you check or try to set the timing. You can simply pull the vacuum line off and plug it.

Typically, a sbc base timing is around 12 degrees. I’ve seen engines run up to 16 degrees of vacuum advance at idle, which would put it way off the timing marks.




Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
198 Posts
Timing Mark Question

G.M. crate motors come with bolt on timing tabs so if yours is off to the drivers side keep this in mind. Balancers had marks for those tabs as well as for the tabs at 12 oclock behind the water pumps. As stated above, make sure you remove the Hose to the vacuum advance cone to check base timing. Balancers can become defective when the outside ring slips on the rubber---this is a long shot though. #1 piston at TDC & a look at the balancer mark should tell you what's going on. I have a handfull of bolt on tabs from the GoodWrench Mexican Engines in my garage---for different diameter balancers . You never know whose been there before you.:yes:
 

·
Registered
Joined
·
30 Posts
Discussion Starter #6 (Edited)
no change

update...

so when i roll the motor to TDC (ish) the factory timing mark is just under the timing pointers.

pull the vacuum line to the advance, throw the timing light on it at the mark is up on top of the balancer still. running but running roughish. still baffled, i can advance it super far and get the timing mark closer but to get it where it needs to be is clearly too much advance and will die

is it possible the distributor is off like 1 tooth?
guy said it had a cam...possible cam degreed and throwing this off?
im pulling like 10 inches manifold vacuum.
 

·
Registered
Joined
·
1,079 Posts
Be sure you are putting the timing light probe on the number one plug wire.:yes:
 

·
Registered
Joined
·
188 Posts
No but you could be 180 out but then it wouldn't run. What kind of distributor? Have you checked the advance weights and springs. Like said light hooked up to #1? Your pic is an X.
 

Attachments

·
Registered
Joined
·
30 Posts
Discussion Starter #9 (Edited)
Update#2

Well for the heck of it i restabbed the distributor...checked the weights...one of the studs for the weight looked loose...taped it back in...pulled all the wires and re put them in the correct order...

still have the timing mark well above the pointer....i have heard there are some balancers in the 70s that were on top of the balancer...

i wouldn't think the motor would run this decent if it was timed like it says it is...
[/IMG]
 

·
Registered
Joined
·
947 Posts
I seem to remember some engines that timed almost dead straight up. I'm not sure what they came in but I do recall this years ago. I would buy a aftermarket balancer and start from scratch. I can't remember how many times I've said it on this forum but unless you know your timing marks are correct you don't have a clue what your timing really is. The number one thing to start with is finding true top dead center. You can do it with the head on or off the engine but you have to know your pointer is pointing at zero when your engine is at top dead center. To do it right you need to have some kind of piston stop and a degree wheel or good timing tape is almost a must. Moroso has it going on with their adjustable timing pointers.
 

·
Registered
Joined
·
608 Posts
so I've got this SBC currently in my car starting and runs Halfway decent. Not a driver yet. the question is I throw a timing light on it and the timing mark is showing at the TOP of the balancer no where near the timing pointer. but the motor is humming right along.

Can the timing be this far off and running halfway decent?
is this the wrong balancer?
WTF?

I believe I can set #1 TDC and the mark should be at 0 on my pointer correct?
So I should be able to do that and make my own timing mark if this is not the right balancer?

help!!
I think the key is that you said it's not a driver yet. You think it is running ok but you have not put it under a load at this point. Sounds to me that the distributor is installed of a tooth or two off. Timing light is telling you where in the rotation that the distributor is firing. It really has nothing to do with the balancer at all. The only way to know for sure is to put the motor at #1 TDC (firing). There are two positions for #1TDC. One for compression and one for exhaust. Make sure it is at #1 TDC for compression and make at mark on you balancer where the pointer says 0 degrees when the motor is at #1 TDC compression. Another way to check is once you know you have the motor in #1 TDC compression, look at the relation between the distributor rotor and the number #1 spark plug wire on the Distributor cap. Hope this helps.
 

·
Registered
Joined
·
547 Posts
As others have indicated, my guess is that this is a timing tab issue. Get a new timing cover and balancer that match. Double check mechanical advance and put back in the motor ensuring it's hitting cylinder one at the cap.

Set timing with no vacuum advance (static) anywhere from 8-14 degrees. Hook vacuum back up and call it a day.
 

·
Registered
Joined
·
196 Posts
I've also had the outer ring on the balancer slip out of place and move the timing mark. It happens when the elastomer band gets old and shrinks/breaks apart. find true top dead cylinder by pulling out the number 1 spark plug and rotating engine to tdc verify with either long straw in plug hole or wood dowel rod. Then mark 0 on the balancer. I'm sure the balancer is marked for different tab or slipped out of 0.
 

·
Registered
Joined
·
799 Posts
First,verify your balancer ring isn't loose and spinning.Sounds to me like an incorrect pointer also.For the engine to idle OK with 10 inches of vacuum you have to be in the ball park.Doesn't matter if the distributor is out one tooth,two teeth or 5.To make the engine run you just need to be able to rotate the distributor body far enough to line up the rotor with number one wire on the cap at your desired timing number.Usually that's not possible if you're on the wrong tooth because of the vacuum pot,plug wires or something else getting in the way preventing the distributor body physically rotating far enough so the rotor has to be moved forward/backward a tooth or two to get #1 over it.Engine simply will not start or backfire if you're way off.To stab in the distributor requires a TDC mark on the balancer at the correct spot in relation to your pointer.You need a solid piston stop and rotate the engine by hand till it touches,mark the balancer at the pointer,rotate back till it touches again,mark the balancer at the pointer.Halfway between the 2 points is TDC and to hell what the balancer is stamped.Timing tape is a good idea since factory markings are usually short to check total timing anyway.I have put a piece of thin tape over the factory timings marks,rubbed it with a pencil and moved it to the far end where the factory marks stop to get the range required to check total timing.I wanted a better layout for plug wires so I have the rotor rotated far from normal,5 or 6 teeth,on both my motors and installed the plug wires accordingly.
 

·
Registered
Joined
·
20,113 Posts
.Doesn't matter if the distributor is out one tooth,two teeth or 5.To make the engine run you just need to be able to rotate the distributor body far enough to line up the rotor with number one wire on the cap at your desired timing number..
Amen, could put it in blind if you wanted and then simply rotate engine to compression stopping at your desired initial advance. Where ever it's pointing is now #1.
 

·
Registered
Joined
·
878 Posts
Timing mark locations
Repointer posts a real good example of how the location of the tabs has changed over the years. Be mindful that the location of the timing mark on the balancer has also changed relative to the location of the key slot on the balancer. Example, the key slot on a 327 balancer has a much different location to the key slot that is found on a 350 balancer.
So, unless you want to find true TDC using a piston stop (and then correct the tab using an adjustable tab) you must make sure the timing cover and the balancer come from the same generation of engine.
 

·
Registered
Joined
·
799 Posts
I have a cheapie,cast aluminum aftermarket front cover and the factory pointer for my balancer would not fit so I made one.Since your marks seem to be so out of whack I would use the piston stop method to find TDC,make a pointer and apply timing tape.Way simpler,super accurate,probably cheaper,and then everything you do from here on in will be bang on.Again,assuming your balancer isn't moving around.For a stop I broke the porcelain out of a spark plug and tacked in a heavy piece of rod.Even with a correct,matched balancer/pointer it doesn't hurt to verify TDC with the stop method.Trust but verify I say and that applies to absolutely everything.
 

·
Registered
Joined
·
239 Posts
Use a timing gun with a degree dial on it. Use that for setting timing, then hit the spot where the timing marks should be on the engine.
 
1 - 19 of 19 Posts
Top