Merc 4.3l timing question, BTDC mark

[soulhawaii]

This will probably be a dumb question, but in the image BTDC is on the side where the 6 is correct? I ask because I need to see the timing to 10 BTDC but why would there not be a mark for 10 on that side, but one on the other side?

 

[soulhawaii]

To add, on my timing gun there's an advance option, when I set it at 10, with the pulley showing 0, when I set the gun to 0, the pulley goes to 10, on the right of the 0 mark, but everything I read online says BTDC is on the left when looking at the engine, not sure why I'm confused by this

 

[alldodge]

The 10 is BTDC and the 6 on the left is ATDC

The motor is standard left hand rotation and that is determined facing the flywheel, so facing the motor it rotates clockwise (RH). The 10 comes up before TDC

 

[Scott Danforth]

first, AD has you straighted out on the timing tape and RH vs LH motors.

secondly, post #2 would indicate that you did not shunt the two wires and put the motor in base timing mode.

 

[Scott06]

To add, on my timing gun there's an advance option, when I set it at 10, with the pulley showing 0, when I set the gun to 0, the pulley goes to 10, on the right of the 0 mark, but everything I read online says BTDC is on the left when looking at the engine, not sure why I'm confused by this

You re just seeing the timing light adding and removing ten degrees of advance hence why it goes to 10 BTDC with no advance in the light, and zero with ten degrees advance.
mist stock balancers have only TDC and what ever base timing is. So you use an advance light to program in ‘X’ advance, this will make the light flash when the tdc mark is at the pointer. Say you wantto verify you have 30 degrees total advance at 2500 rpm. Set the light for 30 degrees, this will offset the light to flash when tdc on the balancer is at the pointer.
as scott mentioned you likely have to set the ignition in base mode - required if you have a delco est or thunderbolt 5

 

[Bondo]

This will probably be a dumb question, but in the image BTDC is on the side where the 6 is correct? I ask because I need to see the timing to 10 BTDC but why would there not be a mark for 10 on that side, but one on the other side?

Ayuh,..... On older motors the timin' tab was mounted on the block, which puts the Btc on the left,.....
With the timin' tape on the balancer, the Btc is on the right,.....

 

[soulhawaii]

Thank you everyone for the replies, makes sense now, just wanted to make sure I didn't screw up ign timing. I set it at 10 BTDC at 650rpm, seems to be running well.

 

[Lou C]

It’s a little confusing because on the older engines the scale was on the timing tab and the mark was on the balancer (still is) now what they are using is a single mark on the timing chain cover and the scale in degrees on the balancer. Kind of what Ford used on their V8s. This changed probably because with the newer ignition systems you couldn’t set timing anymore so they eliminated the timing tab on the timing chain cover. So glad you got it figured out.

 

[nola mike]

You re just seeing the timing light adding and removing ten degrees of advance hence why it goes to 10 BTDC with no advance in the light, and zero with ten degrees advance.
mist stock balancers have only TDC and what ever base timing is. So you use an advance light to program in ‘X’ advance, this will make the light flash when the tdc mark is at the pointer. Say you wantto verify you have 30 degrees total advance at 2500 rpm. Set the light for 30 degrees, this will offset the light to flash when tdc on the balancer is at the pointer.
as scott mentioned you likely have to set the ignition in base mode - required if you have a delco est or thunderbolt 5

No base timing mode on a TB 4

 

[Scott06]

No base timing mode on a TB 4

Correct but there is on a TB5. Wasnt sure if you were just pointing out diff between 4 and 5, not sure if OP specd a year or ignition system, just wanted him to be aware of the need If he has EST or TB 5

 

[nola mike]

Correct but there is on a TB5. Wasnt sure if you were just pointing out diff between 4 and 5, not sure if OP specd a year or ignition system, just wanted him to be aware of the need If he has EST or TB 5

Yeah, he didn't specify. Just so he knows he may or may not need base mode.