8BA timing mark

RalphG

RalphG

Well-known member
Finally got a chance to hook up a timing light to the 52 Merc. Its running fine but I just wanted to see where the timing was and if it could be improved on. Results were inconclusive in that I could not see any timing marks with the timing light on the idling engine. I had found the little dot on the crank pulley and even marked it with white but there was no sign of it with the engine running. https://youtu.be/VHPxDjQKsX4
 
A couple of pictures below. With the timing cover pin aligned with the dimple in the crankshaft pulley, it is supposed to be 2° BTDC. You may have to uses the zip tie method to accurately determine TDC and then mark your pulley, in alignment with the pin.

568589


568602


Glenn
 
Last edited:
glennpm said:
A couple of pictures below. With the timing cover pin aligned with the dimple in the crankshaft pulley, it is supposed to be 2° BTDC. You may have to uses the zip tie method to accurately determine TDC and then mark your pulley, in alignment with the pin

Glenn
Click to expand...

Yes I have the pointer and dimple just like in the pictures but for some reason the timing light does not pick it up. Is it possible the old spark plug wires are giving too much induction and causing a false readout? I know this car puts out a lot of static on the shop am radio. The engine runs great. I did try a slight advance on the distributor but that caused kickback on the starter so I set it back a little.
 
RalphG said:
Yes I have the pointer and dimple just like in the pictures but for some reason the timing light does not pick it up. Is it possible the old spark plug wires are giving too much induction and causing a false readout? I know this car puts out a lot of static on the shop am radio. The engine runs great. I did try a slight advance on the distributor but that caused kickback on the starter so I set it back a little.
Click to expand...

Perhaps #1 isn't #1 anymore. It's pretty easy to install the distributor a tooth or two off and make up for it by moving the wires a hole or two in the cap. The engine will run fine this way, but the original timing marks are way off.

#1 should be at 6 o'clock on an 8BA.
 
What tubman said, and my old t light isn't very visible outside. Better in the shade of the garage. Still love the Ole Merc Ralph.
 
Another possibility is your initial timing is more like 10 to 12 degrees. This would be the reason your not seeing the dot anywhere near the timing pin on the front cover.
Ronnieroadster
 
tubman said:
Perhaps #1 isn't #1 anymore. It's pretty easy to install the distributor a tooth or two off and make up for it by moving the wires a hole or two in the cap. The engine will run fine this way, but the original timing marks are way off.

#1 should be at 6 o'clock on an 8BA.
Click to expand...
Could be possible as this engine was apart back about 1980 for a minor overhaul. Although #1 does appear to be at 6 o clock. I see at the Van Pelt page they recommend 2 degrees btdc for initial timing.
 
I was a mechanic for 30-years (not recommended). If you can't see the timing marks with the light, chances are the plug wires are placed wrongly on the cap, or the distributer is installed wrong. I would start from the beginning, disconnect the vacuum line from the vacuum advance and plug it. Pull the #1 plug and crank it until it blows compression out of it, then line up the timing marks on the #1 compression stroke and see that the rotor is pointing at #1 on the cap. Check the firing order, flatheads are not numbered like some other engines. Look up the firing order and make sure number #1 is where it's supposed to be and the rest follow in the correct FLATHEAD firing order. Some engines are 1234 down one side and 5678 down the other. Other engines are 1357 down one side and 2468 down the other. Some people automatically think they know firing orders, flatheads are different. Look up the correct order for a flathead, find #1 and start there. Make sure you know the direction that the distributor rotates and then install the wires one at a time in the correct firing order. I had a stroke so every time I answer a question, I have to question myself, one of my wires burned out, but I'm pretty sure I'm correct???

If anybody buys a timing light, make sure it is an "adjustable" one. Then if have one timing mark like a flathead, has you can still read your maximum advance using the adjustable light. You can't do this with a standard timing light.
 
Flathead Fever said:
I was a mechanic for 30-years (not recommended). If you can't see the timing marks with the light, chances are the plug wires are placed wrongly on the cap, or the distributer is installed wrong. I would start from the beginning, disconnect the vacuum line from the vacuum
If anybody buys a timing light, make sure it is an "adjustable" one. Then if have one timing mark like a flathead, has you can still read your maximum advance using the adjustable light. You can't do this with a standard timing light.
Click to expand...

Thanks for the reply. I don't know if this light is standard or adjustble but will check. I got all the tune up specs from the Van Pelt site re: firing order and cylinder numbers. I think the next step might be to remove spark plug #1 and determine true top dead centre to see how it relates to the pointer and mark on the pulley.
 
If the engine is running, #1 piston is getting it's spark within 30 degrees of the pointer. The distributor is just there to share the spark around. You don't have to alter the distributor.
If you connect the timing light to #1 or #6 the mark will be close.
Try laying the light on the engine with ignition on and turn the engine over by hand until you see the light flash, you might have to turn it over 720 degrees. Now check to see where the timing dimple is.
 
Morning update on the Merc. I tried the zip tie idea and found tdc which co-incided with the pointer on block and the dimple on the pulley. Plus #1 spark plug wire is at the 6 o clock point. Checked the dwell at 33 degrees which is a bit high but I left it as is for now.
 
High dwell indicates the points are closing up, probably from rubbing block wear. This also affects timing, making it lower because the point open later in the revolution.

Reset the points/dwell and then check for visible marking on the dot.
 
You must log in or register to reply here.
Back
Top