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Topic Review (Newest First)
01-24-2013 05:26 PM
oldbogie
Quote:
Originally Posted by bowtie44s View Post
Hey guys, I have been reading htis site for quite a while. It has been very helpful. I have a problem that i can't figure out and I was hoping someone on here could help.

I have built 2 engines, a 383 and a 454. They both run pretty good. I couldn't get the timing right on either one, so I timed them by ear. When I put the light on the timing is reading around 60 degrees.

I must be doing something wrong but have no idea what. I checked true TDC by using a piston stop and rotating clockwise, put a mark then ccw and put a mark and scribed the middle of the 2. One motor was right on, the other was 2* off. I have the firing order 18436572, have timing light on #1 plug wire, yes i'm on #1. I have tried 3 distributors on one motor and I tried 3 timing lights, 2 of the lights showed the same, one showed 3* different. If I put the light on cylinder 6 it shows the exact same thing.

If it really was 60* I don't see how it could actually run, let alone start. If I slow the timing down to where it should be it dies before I get there. What am I doing wrong?

I thought for sure it was me because it's 2 motors and 3 lights. I told a buddy that builds dirt track motors to set the time. He said why can't you, i said just see what you come up with. He did use one of my lights. He was under the hood for 15 minutes and he said I HAVE NO IDEA WHAT'S GOING ON.

Sorry for the length and thanks in advance.
Read through this, I get three possibilites;

- First Chevy uses number one on the drivers side as the number one cylinder that timing is checked from, I'm assuming your light is hooked to this, if not this would be the thing to do.

- Second would be you've got a high resistance ignition wires which cut off part of the ignition signal (a thing they're supposed to do) which delays the inductive coupling of the timing light from forming enough voltage to trigger the light when it's needed in a timely fashion for accurate measurement. things happening fast a small delay within the inductive coupling can be a lot of crank degrees.

- Third, the cam is a tooth or two out of time and needs a lot of advance from the ignition to operate the engine.

Bogie
01-24-2013 04:27 PM
71nova355
Hold your head up

Have you tried restabbing your distributor? somthings off cause I dont believe your actually running those numbers. You said you got it running by ear right? So it must have been sounding normal, then you checked and it was off right? well I dont think it would ever sound normal at 60.

So, here is what we can assume.
Either your distributor, balancer, TDC, timing light,...
thats about it. One of those isnt right. I know its a bummer to continue to do things over and over but since its not right you have no choice.
Just try going at it on a fresh day, and re-stab your distributor. This has to be perfect and there is a ton of videos on you tube showing tricks and common issues. double check everything make sure the clamp that is attached to the number one wire from the timing light is facing the right direction. make sure the vacuum advance is plugged at both ends. make sure you are using the correct timing tabs, I know this has been stated already but you would get a 60 reading at the 2 oclock spot if you were really needing to be at 12 oclock. (maybe). Most likely its not running at 60 and the numbers your getting are incorrect. which is a bummer but better than having an engine running at 60 advanced.

Ive seen guys put heavier springs in the distributor when checking initial just so they know they are not getting a false reading cause by mechanical advance showing face while its idling. Then put lighter springs back in so you know its opening all in by 3000. I actually use one med. and one light in the final product. just seems to work good for my set up. I also have vacuum advance and after reading all kinds of stuff online about how its a must in street driven vehicles, I took some advice and plugged it for driving and it accelerates much better and now never exceeds 34 degrees. Even sounds better when accelerating.

Hopefully, this msg will get your spirits up a lil, I know how frustrating it can be. Hell, I bet we all have been there one time or another so we want nothing more than to help. Im no pro either, just this last year I have been through this many times, and I continually resort back to these forums or you tube for help.
01-24-2013 12:56 PM
bowtie44s Like i said, I have used 3 timing lights. With the piston stop, the mark on the balancer lines up with the 0 on the timing pointer. I do not have a MSD box.
01-24-2013 12:20 PM
cobalt327
Quote:
Originally Posted by bowtie44s View Post
I've used 2 carbs. The one i'm using now is a 750 holley vacuum secondary. I closed the secondary throttle blades and cracked them 1/4 turn so they don't stick. I have the idle set at 750 with the primary blades. I never did see how the primary throttle blades look on the transition slots but I don't see how that would cause my timing problem. The carb is exactly how it came out of the box except idle mixture screws, float level, and i did lighten the secondary spring.

Could the spark plug really be firing when the crank is 60 degrees btdc at idle? I wouldn't think it could run let alone start. I'm just wondering if it's actually firing at 12 or 14 and somehow i'm coming up with 60.
Is the timing light equipped w/a "dial back" feature? This type of light usually has two buttons at the trigger. This type of light will sometimes be inaccurate if used w/MSD boxes. With a dial back light you need to always use the "0" degree line on the tab aligned to line on the damper.

I know you said you used a piston stop to verify TDC, but if this is a sbc engine you're working with, there are several different combos of timing tabs/damper lines, so you might want to double check what you have.
01-24-2013 11:38 AM
bowtie44s
Quote:
Originally Posted by cobalt327 View Post
So it idles w/60 degrees BTDC and then the mechanical advance adds to that? Yikes!!

As long as you've confirmed TDC, firing order, etc. like you have, unless the carb is way out of tune/faulty/"modified", there's no way it should need anywhere near that kind of timing. So I'd start w/the carb:

As long as the carb is working right and not too far from factory specs, I'd start by baselining the transfer slots of whatever carb you're using. Then use initial advance and idle bypass air to get it to idle w/o the primary throttle blades being open too far. This can be done in several ways depending on the carb; a Holley can use the secondary throttle shaft adjustment screw to tip them open a little. If bad enough (although this is rare) holes can be drilled in the primary blades, but that's only as a last resort.
I've used 2 carbs. The one i'm using now is a 750 holley vacuum secondary. I closed the secondary throttle blades and cracked them 1/4 turn so they don't stick. I have the idle set at 750 with the primary blades. I never did see how the primary throttle blades look on the transition slots but I don't see how that would cause my timing problem. The carb is exactly how it came out of the box except idle mixture screws, float level, and i did lighten the secondary spring.

Could the spark plug really be firing when the crank is 60 degrees btdc at idle? I wouldn't think it could run let alone start. I'm just wondering if it's actually firing at 12 or 14 and somehow i'm coming up with 60.
01-22-2013 01:03 PM
cobalt327
Quote:
Originally Posted by bowtie44s View Post
I have the small block cam retarded 4 degrees, the big block is straight up. I haven't messed with the small block for a while. I am adjusting initial timing. I don't know when the mechanical advance starts but i would assume after 750rpm. I have the vacuum advance unhooked and when i slow the timing much below 60 it starts idling rough and will die.
So it idles w/60 degrees BTDC and then the mechanical advance adds to that? Yikes!!

As long as you've confirmed TDC, firing order, etc. like you have, unless the carb is way out of tune/faulty/"modified", there's no way it should need anywhere near that kind of timing. So I'd start w/the carb:

As long as the carb is working right and not too far from factory specs, I'd start by baselining the transfer slots of whatever carb you're using. Then use initial advance and idle bypass air to get it to idle w/o the primary throttle blades being open too far. This can be done in several ways depending on the carb; a Holley can use the secondary throttle shaft adjustment screw to tip them open a little. If bad enough (although this is rare) holes can be drilled in the primary blades, but that's only as a last resort.
01-22-2013 12:47 PM
bowtie44s I have the small block cam retarded 4 degrees, the big block is straight up. I haven't messed with the small block for a while. I am adjusting initial timing. I don't know when the mechanical advance starts but i would assume after 750rpm. I have the vacuum advance unhooked and when i slow the timing much below 60 it starts idling rough and will die.
01-21-2013 04:26 PM
cobalt327
Quote:
Originally Posted by bowtie44s View Post
I will do the piston stop again. This weekend. That makes sense but it seems strange that it lined right up with the factory balancer mark. I'm out of ideas so it's worth a try. I'll post back when I do and let you know what i find.
Your whole problem is you're adding total timing to get the engine to run right, but all it needs is more INITIAL timing. Add the initial it needs, then limit the mechanical timing to keep the total timing from being so high.

Read this, and then if you have any more questions just ask.
01-21-2013 01:38 PM
cdminter59
weird timing issue

You know it sounds like to me that you do not have the crankshaft gear set straight up. It's probably one of those crankshaft gears that have 3 keyway settings. One keyway has a dot, the next has a square, and the other has a triangle.
01-21-2013 12:18 PM
bowtie44s I will do the piston stop again. This weekend. That makes sense but it seems strange that it lined right up with the factory balancer mark. I'm out of ideas so it's worth a try. I'll post back when I do and let you know what i find.
01-21-2013 11:52 AM
ssmonty You obviously have a fudimental problem with your timing mark or light. If you have 60* initial and an aditional say 24* mechanical advance there is no way it could run with 84* advance unless you were using candle wax for fuel.
"There is 45* distributor rotation between cylinders so the rotor should be almost to the #8 plug."
The rotor should be pointed right at or just after #1 terminal on cap at TDC.
If you rotate the engine to say 12* before TDC, the rotor should be pointed directly at the #1 terminal if your using close to stock advance.
Any chance the balancer ring has rotated on its hub(happens all the time).
Any chance that when you used a piston stop that the engine got stuck in its rotation before the piston hit the stop in either foward or reverse rotation making you think it hit the stop(stopping in its foward rotation would result in an over advanced "zero" indication if I'm not mistaken). Did you unscrew the stop a little and see if the you got the same results?
Any chance that you put your mark on the opposite side of the balancer between the two marks? If you had the piston stop screwed in to far it could be an easy mistake. I really think you should try the piston stop method of finding your TDC mark again! I know your certain thats not the problem, and thats where your having so much diffuculty. I agree that its probably not 3 different lights, although I've had severe problems with a dial back light on my MSD 8365 HEI.
I was an electronic technician for over 20 years, and one of the 1st things I learned about troubleshooting a problem for someone else is not to take their word for a diagnostic step they found to be ok as that was often incorrect and the reason they couldn't fix the problem.
FWIW,
ssmonty
01-21-2013 11:37 AM
bowtie44s Haven't checked the compression, the shortblock is stock. The heads shouldn't have upped the ratio any so i'm guessing around 8:1.

@.050 218int/228exh lift .500/.500 lsa 114 so fairly mild cam for a big block.
01-21-2013 11:16 AM
lmsport How much compression and what are the cam specs.
01-21-2013 11:07 AM
bowtie44s I have timing tape on my 8" balancer and the mark lines up at tdc. The pointer is at around 2 oclock. I checked the mark so it's right.
01-21-2013 08:54 AM
cdminter59
weird timing issue

If you are standing in front the vehicle. Looking at the timing chain cover and the top of the crankshaft, where is the timing scale located. Use the postion of the hands on a clock. Is it at 12:00 or at 2:30?
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