why can't I time my truck??

[Ed ke6bnl]

Hi, I went to check the timing on my 80 chevy dually crewcab 454, when I hook up the timing light and try to check the timing I can not see the timing mark till I turn the advance all the way to 50* and even then it does not line up with the plate on the block.  I tried a second timing light with the same results.  I am on number one plug on the driver side front and I tried differant locations along the wire thinking of other wire could cause interferance, no change,  Does this mean possible the damper pulley has turned OR Could the timechain have slipped only about 60,000 on the motor double roller chain.  The truck idles and run ok not any power house but I think that year was hp derated and low compression motor.  the motor is stock, stock hei, and quadrajet carb, has a edelbrock intake and an Rv cam what ever that means. runs smoothly, will I need to time it by ear and advance till there is not sign of pinging, has never pung b4 even on low octane fuel thanks for your advice,  Ed ke6bnl

[1FATGMC]

I think for starters I would pull the plug and put your finger in the hole and run it up on comprssion (feeling for the air to come out).  Then carefully put something in there and get as close to TDC as you can by rotating it back and forth by hand.  

Then check that with the TDC mark on the timing tab to see if the damper has turned.

If it hasn't then I'll let someone else go on from here  :? .

c ya, Sum

[HOTRODSRJ]

First, I have NEVER seen a balancer turn on the crank without falling off! So, that's not it.  Secondly, I have NEVER seen a droller jump either.

But, what you may be seeing is the vacuum advance can giving you all kinds of grief.  Do you have vacuum advance and is it mechanical or electrical?  A mechanical advance can give you a torrent 35 degrees of advance.  So, is your timing measurement with or without VA?

[Ed ke6bnl]

First, I have NEVER seen a balancer turn on the crank without falling off! So, that's not it.  Secondly, I have NEVER seen a droller jump either.

But, what you may be seeing is the vacuum advance can giving you all kinds of grief.  Do you have vacuum advance and is it mechanical or electrical?  A mechanical advance can give you a torrent 35 degrees of advance.  So, is your timing measurement with or without VA?

I disconnected the vacuum advance  and plugged the vacuum source and it still did not come anywhere near the timing mark.  a couple of years back I had a shop tune the dist for my truck and gearing.  I guess it is possible that he mechanical advance is causing this conditions and that would seem to be only if the springs were missing and the weights were not held back. its a possibility.  Ed ke6bnl

[WZ JUNK]

I have never had a problem with a Chevy harmonic balancer but my slant 6 race engine (not a joke) has had 3 bad ones.  The rubber between the inner and outer ring looses its grip and the outer ring moves.  I did what Sumner said and made an indexing tool out of a spark plug and then I found true TDC.  I remarked the outer balancing ring and timed the engine.   If the ring on your harmonic balancer has slipped, I would replace the balancer.

[tomslik]

First, I have NEVER seen a balancer turn on the crank without falling off! So, that's not it.  Secondly, I have NEVER seen a droller jump either.

i have.
lot's of 'em(percentage-wise)

[Dave]

First, I have NEVER seen a balancer turn on the crank without falling off! So, that's not it.  Secondly, I have NEVER seen a droller jump either.

But, what you may be seeing is the vacuum advance can giving you all kinds of grief.  Do you have vacuum advance and is it mechanical or electrical?  A mechanical advance can give you a torrent 35 degrees of advance.  So, is your timing measurement with or without VA?

The balancer doesnt turn on the crank the rubber goes bad and the ring turns on the balancer. I remember a blazer with a 4.3 that every time you shut er off it made a ringing noise... Yep rubber went bad and she was loose.
Dave

[enjenjo]

There is another possibility here. The timing mark was moved several time during production, so if your timing tab doesn't match the damper, the timing marks can be way off. For instance, early tab, late damper.

[1FATGMC]

There is another possibility here. The timing mark was moved several time during production, so if your timing tab doesn't match the damper, the timing marks can be way off. For instance, early tab, late damper.

I had that problem when I first fired my motor.  Timing tab on the side, but the balancer was setup for a top timing tab.  This was a SBC and when I had the rotating assembly balanced I forgot to take my balancer and he used a different one that used the top timing tab. I used it on the motor.  To get it to run the timing showed up as way off as I wasn't aware of the differences in the balancer's timing marks.

I couldn't figure out what was going on until I checked the TDC like I mentioned in my first post and made new marks on the balancer like John mentioned.

c ya, Sum

[Stakebed]

One other thing to check is the advance weights. I have seen HEI distributers get rusty enough that the weights stick in the advanced position and the springs can't pull them back.  ( Though I doubt this if you had it worked on recently, but you never know.)

[EMSjunkie]

I have used a vacuum gauge in the past to time my sprint car motors.
adjust timing till you get maximum vacuum at idle.  of course, in a sprint car, "normal operation" was wide open throttle. get kinda itchy this time of year, want to strap on the fire suit and go play in the mud. then I look at the scar on my right shoulder from the surgery to repair the damage the last time I played in the mud.

good luck with your motor, keep us posted, I'm curious to know what is up.


Vance

[Dave]

I have used a vacuum gauge in the past to time my sprint car motors.
adjust timing till you get maximum vacuum at idle.  of course, in a sprint car, "normal operation" was wide open throttle. get kinda itchy this time of year, want to strap on the fire suit and go play in the mud. then I look at the scar on my right shoulder from the surgery to repair the damage the last time I played in the mud.

good luck with your motor, keep us posted, I'm curious to know what is up.


Vance

Ahhh Sprint cars.... Love em as I told you before. Im off to the fastest 1/2 mile pavement track in the usa. Winchester Indiana sunday. Winged sprints. I need a good race with all the crap going on in my life lately i need a day at the track! The need for speed......
Dave

[EMSjunkie]

I have used a vacuum gauge in the past to time my sprint car motors.
adjust timing till you get maximum vacuum at idle.  of course, in a sprint car, "normal operation" was wide open throttle. get kinda itchy this time of year, want to strap on the fire suit and go play in the mud. then I look at the scar on my right shoulder from the surgery to repair the damage the last time I played in the mud.

good luck with your motor, keep us posted, I'm curious to know what is up.


Vance

 I need a good race with all the crap going on in my life lately i need a day at the track! The need for speed......
Dave

NO KIDDING     if anybody needs a break its you buddy!!

in my line of work, you are considered a "fecal magnet"
here lately you seem to attract the crap  :x

hope things get better for you.

I wanted to build another sprinter, but the Mrs said I wouldn't have enough money after the divorce to build one. who can argue with logic like that!

Vance

[Ed ke6bnl]

One other thing to check is the advance weights. I have seen HEI distributers get rusty enough that the weights stick in the advanced position and the springs can't pull them back.  ( Though I doubt this if you had it worked on recently, but you never know.)

I will check the advance weights, the timing marks have worked in the past I have timed it in the past with no problems, I even have a new dist I may plug in and see what happens.  I just wanted to get the most out of the motor with as much advance that works without pinging and ready the truck for my vacation.  thanks for all the advice Ed ke6bnl

[Ed ke6bnl]

Well I spent some more time on the timing, the mechanical advance works and as you rev the motor you can see the timing mark move also the weights are free to move and return to the center, I removed the dist cap and rotor, I turned the engine over well my boy did and felt for compression stroke and for the rotor to point to the number one plug as it did I looked for the timing mark no were to be found at least not near the tdc pointer and the piston was near the top I can not get an exact tdc on the piston till I can get the truck on the lift and turn the flexplate back and forth till I get the highest point for the piston, but it is obviously not where it belongs.  So all indications are that the harmonic balance has slipped on the the crank pulley.  That is all I can come up with and I thank all of you for your help and suggestions and I will need to find the time to replace the damper pulley.  Thanks Ed