Correct Distributor Orientation for L79
Thread Starter
4th Gear
Joined: Apr 2015
Posts: 4
Likes: 0
Correct Distributor Orientation for L79
I have a 68 with L79 and a 4 speed tranny. My tach cable is hitting the firewall when I try to advance the ignition. I read somewhere that #1 plug wire on the dizzy should be vicenity of the 2 o'clock position to prevent this.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
just rotate all Plug wires on top - 1 cylinder,
this will allow tach cable to rotate away from firewall, then turn Dist. for new timing.
#1 can be physically inwhere you want, I adjust #1 to best position for tach cable.
this will allow tach cable to rotate away from firewall, then turn Dist. for new timing.
#1 can be physically inwhere you want, I adjust #1 to best position for tach cable.
Team Owner
Joined: Sep 2006
Posts: 31,221
Likes: 4,312
From: Westminster Maryland
Hi n,
I believe the distributor's 'body' needs to be 'clocked' so the vacuum hose to the 'advance can' passes to the rear of the right side distributor shielding support.
This allows the tach drive connection to be at the proper angle to receive the tach cable as it exits the firewall.
This puts the distributor at a different position than on sb engines in steel bodied models.
Regards,
Alan
I believe the distributor's 'body' needs to be 'clocked' so the vacuum hose to the 'advance can' passes to the rear of the right side distributor shielding support.
This allows the tach drive connection to be at the proper angle to receive the tach cable as it exits the firewall.
This puts the distributor at a different position than on sb engines in steel bodied models.
Regards,
Alan
Thread Starter
4th Gear
Joined: Apr 2015
Posts: 4
Likes: 0
Hi n,
I believe the distributor's 'body' needs to be 'clocked' so the vacuum hose to the 'advance can' passes to the rear of the right side distributor shielding support.
This allows the tach drive connection to be at the proper angle to receive the tach cable as it exits the firewall.
This puts the distributor at a different position than on sb engines in steel bodied models.
Regards,
Alan
I believe the distributor's 'body' needs to be 'clocked' so the vacuum hose to the 'advance can' passes to the rear of the right side distributor shielding support.
This allows the tach drive connection to be at the proper angle to receive the tach cable as it exits the firewall.
This puts the distributor at a different position than on sb engines in steel bodied models.
Regards,
Alan
Thanks for your response. Let me ask you this, I'm trying to determine my total timing. So once I get the initial timing set on this L79, which i believe should be 10*, how do I know what my total is? I mean the timing tab is the AOR kind and it only has about 16 or so degrees on it to play with and there is only one mark on the balancer. Not too sure how to determine this using an inductive timing light.
Team Owner
Joined: Sep 2006
Posts: 31,221
Likes: 4,312
From: Westminster Maryland
Hi n,
I'm not much of a mechanic…. but Lars is.
This is what I use.
I hope it helps!
Regards,
Alan
http://www.corvette-restoration.com/...ine_Timing.pdf
I'm not much of a mechanic…. but Lars is.
This is what I use.
I hope it helps!
Regards,
Alan
http://www.corvette-restoration.com/...ine_Timing.pdf
Burning Brakes
Joined: Mar 2014
Posts: 904
Likes: 46
From: Crestline CA
Best way to check total timing is with a "dial-back" timing light. Set the light to whatever you want total timing to be(34-36 is typical), disconnect the vacuum advance and rev the engine till it stops advancing(may want to remove one advance weight return spring if you have the stock springs) and turn the distributor till the mark lines up with 0 on the tab.
Also couldn't hurt to verify the accuracy of the timing mark on the balancer.
Sears sells some nice timing lights, I bought a digital one with a built in tach, comes in handy when setting the advance curve, rev engine till full advance, hit the tach button and instantly know at what rpm the the timing is "all in" at, pretty slick.
Also couldn't hurt to verify the accuracy of the timing mark on the balancer.
Sears sells some nice timing lights, I bought a digital one with a built in tach, comes in handy when setting the advance curve, rev engine till full advance, hit the tach button and instantly know at what rpm the the timing is "all in" at, pretty slick.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
If you re-curve the distributor for 'performance', "initial" timing is irrelevant. When you set up the weights/springs to get proper mechanical timing action, initial timing is whatever it checks. Usually, initial timing checks in the range of 12-16 degrees advanced.
To set the dizzy correctly, do a SEARCH for Lars "timing" papers. Those will detail the entire process. Or you can send an e-mail request to him at V8FastCars@msn.com.
GM's "initial" timing setting was their way of detuning the engine for "Least Warranty Expenses".
To set the dizzy correctly, do a SEARCH for Lars "timing" papers. Those will detail the entire process. Or you can send an e-mail request to him at V8FastCars@msn.com.
GM's "initial" timing setting was their way of detuning the engine for "Least Warranty Expenses".
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