Timing marks in Wrong place

[Live-liner]

Hello,
Another stupid quesetion.....
1986 3.7 190, Trying to set timing, however the marks are not where they are supposed to be. What would cause this? I changed the keyway on the crankshaft a couple years ago, and have not been able to set the timing correctly since. The black mark on the picture is around wheer the mark is now. If I was off a tooth on the timing chain, would that have caused it? If so, couldn't I just find exact TDC on #1 and put a new mark on the balancer at 0. How would I find exact TDC? Usually I would do it with the mark..... Is there a gauge I could use in the spark plug hole?
Thanks

 

[Bondo]

Re: Timing marks in Wrong place

Hello,
Another stupid quesetion.....
1986 3.7 190, Trying to set timing, however the marks are not where they are supposed to be. What would cause this? I changed the keyway on the crankshaft a couple years ago, and have not been able to set the timing correctly since. The black mark on the picture is around wheer the mark is now. If I was off a tooth on the timing chain, would that have caused it? If so, couldn't I just find exact TDC on #1 and put a new mark on the balancer at 0. How would I find exact TDC? Usually I would do it with the mark..... Is there a gauge I could use in the spark plug hole?
Thanks

Ayuh,... That's a possibility, but the Cam timin' will also be Off,...

 

[achris]

Re: Timing marks in Wrong place

There's a procedure for Merc outboards, that I would look at adapting for a 4 stroke. It involves using a depth gauge, and finding the position of the flywheel at 0.464" before TDC.

Now, What I'd do is this.
Get an old spark plug and knock out the porcelain, then run a thread tap down the inside to match a suitable bolt (that will become clear in a second).
Remove all the spark plugs, put a long screwdriver in #1 hole and slowly turn the engine until the screwdriver indicates you are near the top of stroke (doesn't matter if it's compression of exhaust, we're just looking for the piston to be at the top of travel). Use the screwdriver to workout how far the top of the piston is from the plug hole (it shouldn't be very far), then select a bolt about 1" more than that. Turn the engine until the piston is more than that away from the top of stroke and put your new tool into the #1 plug hole. SLOWLY turn the engine until it stops on the bolt. Mark the balancer. Without moving the bolt in the new tool (Use a locking nut to secure it above the old plug body) remove the tool. Continue to turn the engine until the piston is now as much passed top of stroke as it was before, put the tool back in. Turn the engine SLOWLY back the other way and again mark the balancer where it stops. Now, the place on the balancer exactly between the marks is TDC....

Chris.......

 

[Live-liner]

Re: Timing marks in Wrong place

Bondo,
The boat has been running fine with timing set by ear for last two seasons so I cant imagine the cam timing is off. The balancer only goes on one way, so I can't imagine that has been installed wrong. When timing, I rotate engine by hand with finger on plug hole to find TDC on #1, then turn a little more till marks line up. I install distributer with rotor pointing at #1 hole on cap. When checking with a light, mark on balancer appears where I showed you in the picture. Timing light is adjustable, and I have to turn dial to about 30 before marks move over???? So that has had me baffled for some time, and I would like to know that my timing is set correctly.

 

[Bondo]

Re: Timing marks in Wrong place

Bondo,
The boat has been running fine with timing set by ear for last two seasons so I cant imagine the cam timing is off. The balancer only goes on one way, so I can't imagine that has been installed wrong. When timing, I rotate engine by hand with finger on plug hole to find TDC on #1, then turn a little more till marks line up. I install distributer with rotor pointing at #1 hole on cap. When checking with a light, mark on balancer appears where I showed you in the picture. Timing light is adjustable, and I have to turn dial to about 30 before marks move over???? So that has had me baffled for some time, and I would like to know that my timing is set correctly.

Ayuh,.... I don't do 470s, But,....

Like Chevy balancers, the outer ring can slip on the inner hub, when they go Bad,...

I ain't sayin' that's what happened, but it's a distinct possibility,...

 

[Live-liner]

Re: Timing marks in Wrong place

Chris,
Thanks, that makes sense. I would really like to have it line up correctly but will consider moving the mark if I can't figure out how to fix it. End results - I need to know the timing is correct.

 

[Live-liner]

Re: Timing marks in Wrong place

Bondo,
Hmmmm... I remember the balancer as being one piece of cast. Are you saying the part that goes over the shaft with keyway is actually a pressed in sleeve?? If that's true, it could have slipped inside the cast?

 

[Bondo]

Re: Timing marks in Wrong place

Bondo,
Hmmmm... I remember the balancer as being one piece of cast. Are you saying the part that goes over the shaft with keyway is actually a pressed in sleeve?? If that's true, it could have slipped inside the cast?

Ayuh,... Like I said, I don't do 470s,...

I know Chevys,...
The only Ford motor I've done much with was an ole 302 in a pickup, 'n it had an elastrometric balancer,...

 

[achris]

Re: Timing marks in Wrong place

Bondo,
Hmmmm... I remember the balancer as being one piece of cast. Are you saying the part that goes over the shaft with keyway is actually a pressed in sleeve?? If that's true, it could have slipped inside the cast?

What Bond-o is saying is that on most engines the balancer it in 2 pieces with a rubber sleeve bonded to them. That's how it's a vibration damper. But from memory (it's been a while since I played with a 470) the crankshaft pulley is a single piece. If I'm correct then the slippage of the outer on the inner that can happen with the bonded rubber units can't happen with yours.

About the only things I can think of are that the key dropped out during installation and that's allowing the pulley to move, or the key has sheared and is allowing the pulley to move.

Chris......