• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

DM6A Distributor Question

Share this page

P

PeterB

Senior Member
Country flag
Offline
Having a little hard time timing my BJ7. My timing marks on the pointer and pulley are aligned and the attached pics show how my distributor was set up by guy who rebuilt it. I hear about rotor pointing to #1. Would that be plug or wire where it connects to cap? I am using a adjustable timing light and it looks if I am in the high 20 to 30 for timing. Does the rotor on the distributor look pointing in right direction if pointer and notch on pulley are aligned?

thanks,
pete
 

Attachments

  • 1703BE71-7F6C-4CDD-8599-52EFC1BB3ACB.jpeg
    1703BE71-7F6C-4CDD-8599-52EFC1BB3ACB.jpeg
    91.7 KB · Views: 194
  • image.jpg
    image.jpg
    64.5 KB · Views: 196
Pete;

The rotor looks to be about 180 degrees out. The attached is what I took before I had my DM6A in our BT7-II rebuilt. Cylinder No. 1 is at TDC (both valves closed) and the timing mark is 'near' the pointer.

BT7-II rotor.jpg

Regards,

Paul
 
screenshot.2164.jpg
screenshot.2163.jpg

Two possibilities. Per the Manual, section B4 & 5.
This is with the engine TDC and both #1cyl valves closed:

1) the Tachometer Spindle (upper component) is correctly oriented per the pic above:
Your distributor drive gear is 180* out and you'll need to drive out the pin and rotate the gear 180*.

2) tach spindle is 180 out:
Undo the housing from the lower Distributor Drive flange and rotate the tach spindle 180* so it looks like the picture above.

According to the manual, the Distributor Drive is symmetrical.
If it's the original solid pin be sure to drive from the dimpled side - not the "mushroomed" side. The pins are single-direction.
 
If that’s the case, I am wondering if I can pull the distributor out rotate the rotor 180 degrees and set it back in and that may help me. I too thought the distributor drive looked right but rotor was off.

Thank you
 
Ok so I took the off the tachometer spindle and rotated the gear inside 180 degrees so when I put it Back together with the smaller part of the offset in the downward position. When I put the distributor, the rotor now points to #1 cylinder when the timing arrow and notch are lined up as it should. Now it won’t start.
 
Make sure you're at TDC on #1 with both valves closed. You may have to take off the valve cover and make sure you can jiggle both #1 rockers a little. Then set the points and time it. Section B2 in the manual.

screenshot.2165.jpg
screenshot.2166.jpg


Can't do much without the manual:
screenshot.2167.jpg
 
Did you confirm initially that you were TDC of the compression stroke w/both valves closed?

Is it possible your initial pictures were at TDC on the exhaust stroke rather than the compression stroke? ​

The timing marks align at the top of the compression stroke and again at the top of the exhaust stroke which is why, as Steve said above, you may need to take the valve cover off to be sure the valves of #1 are closed.

If it started before you rotated the tachometer spindle drive 180*, it couldn't have been 180 out. Did you remove the tach drive spindle when the dizzy was rebuilt? If not, then it probably was right.

I apologize if I'm misunderstanding you.

Dave
 
Assuming you have spark to the plugs--easy to test for--try putting in more advance )Clockwise rotation) while cranking.
 
I haven't done static timing for decades but pretty sure this is it:

With the engine at TDC with both #1 cyl valves closed...

Static timing BJ7 is 10* before TDC. That would be a mark on the pulley .55" to the right of the TDC mark when viewed from the front. Based on a pulley diameter of 6.25"; circumference of 19.625". 1/36 of 360* = 10* = .55"

Move the car back and forth in 3rd gear to align the pointer with your mark.

Hook up a 12V test light or VOM between the wire going from the coil to the distributor and a good ground. Turn ignition ON.

Loosen the distributor clamp and rotate the distributor clockwise a ways and the light should come on.

Then rotate it counter-clockwise until the light just goes out. That's when the spark occurs.

Tighten the clamp being careful not to disturb the setting. Turn ignition OFF.

Now it should run.
 
Last edited:
Thank you everyone for the help. I have it running well now! I am embarrassed to say, I was on the exhaust stroke rather than the compression. Should have looked under the valve cover better. Also there was a little groove on my distributor when you tried to turn it, it was getting hung up on the mounting plate making it difficult to turn.
 
Back
Top