Tach drive touching L36 manifold
Thread Starter
Race Director
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From: North of Toronto - Ontario
Tach drive touching L36 manifold
Earlier this summer I re-indexed my ignition wires (72 LS5) so the tach-drive pointed basically straight out the drivers side. (more or less per the service update)
I just changed the manifold to a L36 one from a 69 and when setting the timing I hit 36 degrees just as the tach cable touched a boss on the intake manifold. Everything is fine but if I did need to go farther I can't.
I could index the wires back a station but was wondering where the factory set them back in 69
Anyone with a stock setup have a pic of the distributor orientation?
Thanks
Mooser
I just changed the manifold to a L36 one from a 69 and when setting the timing I hit 36 degrees just as the tach cable touched a boss on the intake manifold. Everything is fine but if I did need to go farther I can't.
I could index the wires back a station but was wondering where the factory set them back in 69
Anyone with a stock setup have a pic of the distributor orientation?
Thanks
Mooser
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Lots of Corvette engines have had their distributors "re-clocked", depending on where timing is set. Remember, that GM set everything for low-emissions, low-performance, and low-warranty; and the factory clocked the dizzy so that everything fit nicely with that strategy.
When owners decided they wanted to get some of the 'wasted' horsepower left in the motor, that meant changing the distributor position...and, in that tight 'nest-o-snakes' back inside the ignition shielding, you either lost access to the adjustment window/screw for the points...or the tach cable bent too far...or....
Anyway, just shift all the plug wiring one position so that you can rotate the dizzy as needed and you will be fine.
When owners decided they wanted to get some of the 'wasted' horsepower left in the motor, that meant changing the distributor position...and, in that tight 'nest-o-snakes' back inside the ignition shielding, you either lost access to the adjustment window/screw for the points...or the tach cable bent too far...or....
Anyway, just shift all the plug wiring one position so that you can rotate the dizzy as needed and you will be fine.
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
I'm dialed in where I want to be right now so everything is good, but there's nothing left if I needed to go any farther (which I don't)
If I index back one I'll be sending the cable right at the dist-shield bracket so I'd need to go back two positions to clear that and then the tach-drive actually starts to get quite a bend in the cable.
I was just curious on where the people were running theirs.
Mooser
If I index back one I'll be sending the cable right at the dist-shield bracket so I'd need to go back two positions to clear that and then the tach-drive actually starts to get quite a bend in the cable.
I was just curious on where the people were running theirs.
Mooser
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
Mooser...
You can also just shift the dizzy one tooth of its drive gear. That's a little more troublesome, as you have to pull the dizzy, use a large screwdriver to offset the oil pump drive shaft a bit, and reload the dizzy in the new position. That would get you a little 'finer' offset than the 1/8th rotation that a spark plug re-clock would do. But, that's just "food for thought", if you should need it.
You can also just shift the dizzy one tooth of its drive gear. That's a little more troublesome, as you have to pull the dizzy, use a large screwdriver to offset the oil pump drive shaft a bit, and reload the dizzy in the new position. That would get you a little 'finer' offset than the 1/8th rotation that a spark plug re-clock would do. But, that's just "food for thought", if you should need it.
Thread Starter
Race Director
Joined: Apr 2011
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From: North of Toronto - Ontario
7T1
Gave the carb the once over and got some better timing results, but could not get my 36 degrees anymore so I ended up doing as you suggested and moved the dist. back a tooth.
Shoots the tach-drive behind the shield bracket and the vac-advance still behind the bracket on the other side.
Good advice, just wanted to say so.
Mooser
Gave the carb the once over and got some better timing results, but could not get my 36 degrees anymore so I ended up doing as you suggested and moved the dist. back a tooth.
Shoots the tach-drive behind the shield bracket and the vac-advance still behind the bracket on the other side.
Good advice, just wanted to say so.
Mooser
