'63-67 SB Timing Tabs (convert 6" cover to 8")

[Irby G.]

Re: '63-67 SB Timing Tabs (convert 6" cover to 8&quot

Michael, I picked up a 6" timing cover with the correct tab and I'm now going to use Joel Falk's method to remove the timing tab and spot weld it back on for the 8" balancer. My old timing cover was definitely the wrong one. What would be the best way to position the tab on the timing cover to get it into the proper place before spot welding it back on? Would you have any measurements from the approx. center of the crank hole to the tab or would there be a more accurate way to position it?
Aloha,
Irby

[Duke W.]

Re: '63-67 SB Timing Tabs (convert 6" cover to 8&quot

Irby,

The "0" on the tab is in the correct position so the only part of the rest of the marks that matters would be the one that you want to set the timing at/to.
I'll be gone for a few hours but I'll explain how to use the original when I return......

Why mess with the tab? As stated the "0" mark is in the correct position. Buy a dial back timing light or just add 2-4 degrees to whatever timing you want to run if you only have a coventional timing light. Attempting to change the tab risks screwing up the indexing or destroying the cover/tab, which is original to the engine, even though it's not properly calibrated.

Back in the sixties these engines ran best with the timing set at 16-18 on the tab, which is really about 12-14, which yields 36-38 total WOT timing with a 24 degree distributor, but modern premium fuel may not allow this much initial timing without detonation since modern unleaded premium is 2-4 RON points lower than sixties leaded premium.

Today, the best initial timing can probably by found by advancing the initial timing to the detonation limit, which is the same thing we did in the sixties. It's a matter of a little experimentation.

Duke

[Michael H.]

Re: '63-67 SB Timing Tabs (convert 6" cover to 8&quot

Michael, I picked up a 6" timing cover with the correct tab and I'm now going to use Joel Falk's method to remove the timing tab and spot weld it back on for the 8" balancer. My old timing cover was definitely the wrong one. What would be the best way to position the tab on the timing cover to get it into the proper place before spot welding it back on? Would you have any measurements from the approx. center of the crank hole to the tab or would there be a more accurate way to position it?
Aloha,
Irby

Irby,

As far as the distance from crankshft C/L to the plate, the only dimension we know for sure is the radius of the balancer. The radius is exactly 4".
I don't have an exact dimension for the gap between the balancer and the plate though but I'm sure someone here can get a dim from an original. Maybe 3/16" or so?
As far as clock position, I believe the zero line is supposed to be exactly 45* off vert. (or horiz, I guess) Off hand, I can't think of an easy accurate way to determine that. It would certainly be easier and more accurate if you had the engine out of the car with a cyl head off to establish a true TDC although the "positive stop" method could be used with the engine in the car.
If you have the tab from an old cover that used a 6" balancer, the tab may be a bit different. Not sure but when the tab was located further up/out for an 8", they may have trimmed off one corner. See pic below. The cover on the left is a correct 62-63 with 8" balancer.

Pic from the Jorjorian guy.

[Wayne M.]

Re: '63-67 SB Timing Tabs (convert 6" cover to 8&quot

Irby,


If you have the tab from an old cover that used a 6" balancer, the tab may be a bit different. Not sure but when the tab was located further up/out for an 8", they may have trimmed off one corner. See pic below. The cover on the left is a correct 62-63 with 8" balancer.

Pic from the Jorjorian guy.

Thanks for your explanations and getting those pics from "the Jorjorian guy".

Once again, my cover from a 6" balancer. I measured exactly one inch outward (aligning the zero tab mark and the crank seal hole centerline (happens to be parallel to the sides of the tab). You can see that the "footprint" of the same tab (all 6" '63 to '67 ? and maybe all 8" from '62 to '63 or Jan '64 [service]) will still fit on the cover. The edge of the tab will not be entirely on the flat surface without minor grinding, but then looking closely at RJ's pics, maybe neither does his example.

But if one was to slide the tab further up (to my dotted line) this would be sufficient for the tab outboard edge to be entirely on the flat surface. This "shift" would incorporate about a 1.5 degree error in TDC on a 6" scale, and even less on an 8" scale basis. This move would be in the "good" direction insofar as '62-63 8 inch covers were reading low in the advance direction with this "one-size fits-all' tab.

In the P&A30 catalogs I see that the 8 inch cover 3851549 was replaced by 3885048 in service, on 5-66. Anybody know what this cover / tab looks like ? Also the 6 inch # 3812994 with "double timing mark brkt" -- can't recall seeing one of these.

[Michael H.]

Re: '63-67 SB Timing Tabs (convert 6" cover to 8&quot

Once again, my cover from a 6" balancer. I measured exactly one inch outward (aligning the zero tab mark and the crank seal hole centerline (happens to be parallel to the sides of the tab). You can see that the "footprint" of the same tab (all 6" '63 to '67 ? and maybe all 8" from '62 to '63 or Jan '64 [service]) will still fit on the cover. The edge of the tab will not be entirely on the flat surface without minor grinding, but then looking closely at RJ's pics, maybe neither does his example.

But if one was to slide the tab further up (to my dotted line) this would be sufficient for the tab outboard edge to be entirely on the flat surface. This "shift" would incorporate about a 1.5 degree error in TDC on a 6" scale, and even less on an 8" scale basis. This move would be in the "good" direction insofar as '62-63 8 inch covers were reading low in the advance direction with this "one-size fits-all' tab.

In the P&A30 catalogs I see that the 8 inch cover 3851549 was replaced by 3885048 in service, on 5-66. Anybody know what this cover / tab looks like ? Also the 6 inch # 3812994 with "double timing mark brkt" -- can't recall seeing one of these.

I think I'd try to duplicate the angle grind off on the end to make it look correct for an 8" tab. You can always use the "estimated" true timing location and the car/engine will still be factory correct.

For the 66 model year, a new cover with a new design tab was released because some K19 engines actually had an "ATC/retarded timing" spec so the new tab now included several more hash marks below the "A" and also included the letter R for retarded.