C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Tach drive distributor options

Thread Tools
 
Search this Thread
 
Old Sep 1, 2015 | 06:09 PM
  #1  
TMU's Avatar
TMU
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,623
Likes: 22
From: Boise Idaho
St. Jude Donor '09-'10, '15, '17
Default Tach drive distributor options

I currently have an Accel 37100A which was apparently a dual point, but has been switched to electronic. It still has separate coil.

I see there are inexpensive new HEI tach drive distributors available, but I am not sure what's involved in changing over. What are my best options as far as replacing my current distributor?

Engine is a mild performance 350.
Reply
Old Sep 1, 2015 | 06:26 PM
  #2  
Big2Bird's Avatar
Big2Bird
Le Mans Master
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
Default

Originally Posted by TMU
I currently have an Accel 37100A which was apparently a dual point, but has been switched to electronic. It still has separate coil.

I see there are inexpensive new HEI tach drive distributors available, but I am not sure what's involved in changing over. What are my best options as far as replacing my current distributor?

Engine is a mild performance 350.
This one is good, has smaller cap, but needs an MSD box:
http://www.msdignition.com/Products/...m_Advance.aspx

This one is good, does not need a box, but has the larger HEI cap:
http://performancedistributors.com/p...acuum-advance/

You CAN order it with/without vacuum advance.

I have worked on both. Both are good units.
Reply
Old Sep 1, 2015 | 06:39 PM
  #3  
doorgunner's Avatar
doorgunner
2026 Loser of the Year
Supporting Member
10 Year Member
Veteran: Army
Photogenic
Photoriffic
 
Joined: Sep 2013
Posts: 36,573
Likes: 7,016
From: New Or-leens Loo-z-anna
Default

From my learning experience/failures........here is something that MUST be done to avoid early electric component failure.......

First......make sure your cable-driven tachometer works properly before you invest in a new distributor.....you can connect a good tach cable to the tach.....then drive the other end of the inner cable with an electric drill set to LOW SPEED!

Buy a "decent/dependable" aftermarket distributor (FYI: internal parts alone cost $125+.....add the cost of a tach driven housing.....you are looking at $200 for a tach-drive distributor (maybe less if you buy a "NEW ITEM" meaning a manufacturer is offering a "first-run" off the production line to get sales started)

The firewall ignition wire from INSIDE the firewall engine harness connector all the way to the coil/distributor MUST be removed and replaced with a 10 or 12 ga. copper strand wire unless the wiring harness already has a copper-strand ignition wire (the original ignition wire in older cars is a special RESISTOR steel stranded wire that will not supply the correct voltage/amps to the upgraded distributor).

A new tach cable is needed.

Allow an hour or two to make the change-over.....especially if the ignition wire at the firewall has to be replaced.

Other members will post replies if I forgot anything.
Reply
Old Sep 1, 2015 | 07:03 PM
  #4  
TMU's Avatar
TMU
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,623
Likes: 22
From: Boise Idaho
St. Jude Donor '09-'10, '15, '17
Default

Originally Posted by doorgunner
From my learning experience/failures........here is something that MUST be done to avoid early electric component failure.......

First......make sure your cable-driven tachometer works properly before you invest in a new distributor.....you can connect a good tach cable to the tach.....then drive the other end of the inner cable with an electric drill set to LOW SPEED! Tach works good now

Buy a "decent/dependable" aftermarket distributor (FYI: internal parts alone cost $125+.....add the cost of a tach driven housing.....you are looking at $200 for a tach-drive distributor (maybe less if you buy a "NEW ITEM" meaning a manufacturer is offering a "first-run" off the production line to get sales started)

The firewall ignition wire from INSIDE the firewall engine harness connector all the way to the coil/distributor MUST be removed and replaced with a 10 or 12 ga. copper strand wire unless the wiring harness already has a copper-strand ignition wire (the original ignition wire in older cars is a special RESISTOR steel stranded wire that will not supply the correct voltage/amps to the upgraded distributor).

A new tach cable is needed. I cannot just plug in my current cable?

Allow an hour or two to make the change-over.....especially if the ignition wire at the firewall has to be replaced.

Other members will post replies if I forgot anything.
Wish I could just replace with another electronic tach drive distributor, but they seem to more rare and much more expensive than the HEI tach drive units.


Thank you doorgunner

Last edited by TMU; Sep 1, 2015 at 07:05 PM.
Reply
Old Sep 1, 2015 | 10:11 PM
  #5  
TimAT's Avatar
TimAT
Le Mans Master
15 Year Member
Liked
Loved
 
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Default

What is your goal? Are you having problems with the Accel distributor or tach drive?

I'm running a MSD tach drive that has a pickup coil in it (no points) and the original K-66 GM TI amp and coil. I also have a Mallory CD ignition box mounted and wired, just not plugged in. Nothing like backup.
Reply
Old Sep 1, 2015 | 10:54 PM
  #6  
doorgunner's Avatar
doorgunner
2026 Loser of the Year
Supporting Member
10 Year Member
Veteran: Army
Photogenic
Photoriffic
 
Joined: Sep 2013
Posts: 36,573
Likes: 7,016
From: New Or-leens Loo-z-anna
Default

Originally Posted by TimAT
What is your goal? Are you having problems with the Accel distributor or tach drive?

I'm running a MSD tach drive that has a pickup coil in it (no points) and the original K-66 GM TI amp and coil. I also have a Mallory CD ignition box mounted and wired, just not plugged in. Nothing like backup.
OOOPS! I just ASSUMED that he did NOT have a tach drive attaching point on his current distributor!

Reply
Old Sep 1, 2015 | 11:28 PM
  #7  
TX-Techman's Avatar
TX-Techman
Racer
10 Year Member
 
Joined: Aug 2008
Posts: 413
Likes: 22
From: Justin TX
Default

I upgraded to a Mallory SSI and had Redline convert my Tach to electronic. They use your original faceplate and needle so it looks stock and works great without the hassle of the cable and components for the tach drive. I also converted all the instrument panel lamps to LED during the process.
Reply
Old Sep 1, 2015 | 11:48 PM
  #8  
TMU's Avatar
TMU
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,623
Likes: 22
From: Boise Idaho
St. Jude Donor '09-'10, '15, '17
Default

Originally Posted by TimAT
What is your goal? Are you having problems with the Accel distributor or tach drive?
Had a pinging problem develop and have ruled out just about everything but the distributor. As its some kind of electronic retro fit frankenstein distributor I figured probably best to replace it. Just hoping for a reasonably simple solution
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-1

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-2

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-3

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-4

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-5

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-6

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-7

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-8

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-9

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
Old Sep 2, 2015 | 09:55 AM
  #9  
TimAT's Avatar
TimAT
Le Mans Master
15 Year Member
Liked
Loved
 
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Default

Do a full check of your timing- initial advance, advance curve (when advance starts to come in) and what the total advance is. If the mechanical advance is stuck, you could be running full advance all the time. And that could get you a ping. Too much initial advance could too. Most of the electronic retrofit (points eliminator) systems are pretty good. Unless it's installed so it's advanced, but that would show with a check of the timing.
Reply
Old Sep 2, 2015 | 02:34 PM
  #10  
TMU's Avatar
TMU
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,623
Likes: 22
From: Boise Idaho
St. Jude Donor '09-'10, '15, '17
Default

Originally Posted by TimAT
Do a full check of your timing- initial advance, advance curve (when advance starts to come in) and what the total advance is. If the mechanical advance is stuck, you could be running full advance all the time. And that could get you a ping. Too much initial advance could too. Most of the electronic retrofit (points eliminator) systems are pretty good. Unless it's installed so it's advanced, but that would show with a check of the timing.
I could not see the hole in the side before because the coil was in the way. I am assuming the adjustment screw is for the advance? As the distributor was tight and the screw had not been moved why would it suddenly cause pinging and should I even try to adjust it?

These are ebay pics, but its the same model as mine and looks like mine




Reply
Old Sep 2, 2015 | 02:50 PM
  #11  
jstrime's Avatar
jstrime
Instructor
10 Year Member
 
Joined: Apr 2008
Posts: 159
Likes: 4
From: Olympia WA
Default

I put a Mallory Unilite with the tach drive on my '72 LT-1 and no issues whatsoever. LOVE it!
Reply
Old Sep 2, 2015 | 03:16 PM
  #12  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,692
Likes: 2,572
Default No points

Originally Posted by TMU
I could not see the hole in the side before because the coil was in the way. I am assuming the adjustment screw is for the advance? As the distributor was tight and the screw had not been moved why would it suddenly cause pinging and should I even try to adjust it?

These are ebay pics, but its the same model as mine and looks like mine




You said you have no points so the screw in the picture may not exist on your distributor. Accel has precalibrated that distributor for 24 degrees of advance plus setting your initial for 12 will give you the correct 36 degrees total. The link below explains how the timing is set in the distributor when new. On the other hand this was intended to be a race only distributor, it has no vacuum advance which is highly beneficial for a street driven vehicle.
http://prestoliteperformance.com/med...tor_37000A.pdf
Reply
Old Sep 2, 2015 | 05:43 PM
  #13  
TMU's Avatar
TMU
Thread Starter
Melting Slicks
10 Year Member
 
Joined: Jun 2007
Posts: 2,623
Likes: 22
From: Boise Idaho
St. Jude Donor '09-'10, '15, '17
Default

Originally Posted by MelWff
You said you have no points so the screw in the picture may not exist on your distributor. Accel has precalibrated that distributor for 24 degrees of advance plus setting your initial for 12 will give you the correct 36 degrees total. The link below explains how the timing is set in the distributor when new. On the other hand this was intended to be a race only distributor, it has no vacuum advance which is highly beneficial for a street driven vehicle.
http://prestoliteperformance.com/med...tor_37000A.pdf
I removed the top as described in the document and its a dual point. I feel like an idiot because I had not seen one with a cover over the points and assumed it was electronic. So now I am assuming whole pinging issue could be caused by dirty or bad points. Do I replace or try to clean? I'll need to get a dwell meter.
Reply
Old Sep 2, 2015 | 06:46 PM
  #14  
redvetracr's Avatar
redvetracr
Race Director
25 Year Member
Photogenic
Photoriffic
Shutterbug
 
Joined: Aug 1999
Posts: 18,126
Likes: 174
From: WI
Default

there is nothing wrong with a well set-up factory tach drive distributor.
Reply
Old Sep 3, 2015 | 11:37 AM
  #15  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,692
Likes: 2,572
Default Points

Originally Posted by TMU
I removed the top as described in the document and its a dual point. I feel like an idiot because I had not seen one with a cover over the points and assumed it was electronic. So now I am assuming whole pinging issue could be caused by dirty or bad points. Do I replace or try to clean? I'll need to get a dwell meter.
The points aren't going to cause pinging themselves. The only effect they would have is if the dwell is off enough to advance the timing. Set the dwell and then set the timing to 12 degrees.
Reply
Old Jul 11, 2017 | 10:33 AM
  #16  
AIP's Avatar
AIP
2nd Gear
 
Joined: Jul 2017
Posts: 2
Likes: 2
Default Options

Here are all the popular electronic options for Corvettes using mechanical tachs, you'll need to do some homework to determine which will be the best fit depending on your specific needs:

HEI Distributor (Large Cap) with tach drive:
PROS - Easy all in one stand alone system, replaces entire existing
ignition, allows for connection of the mechanical tach cable, mid range
cost, most reliable.

CONS - Factory Chrome shield no longer fits, non-factory look, requires
new plug wires 8mm or larger with female style boot terminals for male
style cap.

Here is a good example:

ZIP Products HEI

Electronic Conversion kit for OEM distributor:
PROS - Retain factory look, low cost, replaces points without changing
other parts.

CONS - Worn metal moving parts inside distributor remain same.

Here is a good example:

Pertroix Electronic Conversion Kit

Performance Electronic Distributor (Small Cap):
PROS - Retain factory shield, best performance, allows for connection of
the mechanical tach cable.

CONS - Expensive, requires an external box and 12 volt coil, longer
install time, requires new plug wires 8mm or larger with female style
boot terminals for male style cap.

Here is a good example:

MSD Performance Distributor


Performance Electronic Distributor (Small Cap) with built in control module:
PROS - Retain factory shield, best performance, Easy install, allows for
connection of mechanical tach cable, low cost.

CONS - requires an external 12 volt coil, requires new plug wires 8mm or
larger with female style boot terminals for male style cap.

Here is a good example:

AIP Dragon Fire Performance Distributor
Reply
Old Jul 11, 2017 | 11:54 PM
  #17  
Big2Bird's Avatar
Big2Bird
Le Mans Master
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Dec 2006
Posts: 8,837
Likes: 1,028
Default

All? Nope. Not all.
Reply
Old Jul 12, 2017 | 11:45 AM
  #18  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,692
Likes: 2,572
Default

thread was two years old
Reply
Old Aug 25, 2021 | 01:17 PM
  #19  
1960's Avatar
1960
Instructor
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2009
Posts: 150
Likes: 14
From: Sidney Ohio
Default

Originally Posted by doorgunner
From my learning experience/failures........here is something that MUST be done to avoid early electric component failure.......

First......make sure your cable-driven tachometer works properly before you invest in a new distributor.....you can connect a good tach cable to the tach.....then drive the other end of the inner cable with an electric drill set to LOW SPEED!

Buy a "decent/dependable" aftermarket distributor (FYI: internal parts alone cost $125+.....add the cost of a tach driven housing.....you are looking at $200 for a tach-drive distributor (maybe less if you buy a "NEW ITEM" meaning a manufacturer is offering a "first-run" off the production line to get sales started)

The firewall ignition wire from INSIDE the firewall engine harness connector all the way to the coil/distributor MUST be removed and replaced with a 10 or 12 ga. copper strand wire unless the wiring harness already has a copper-strand ignition wire (the original ignition wire in older cars is a special RESISTOR steel stranded wire that will not supply the correct voltage/amps to the upgraded distributor).

A new tach cable is needed.

Allow an hour or two to make the change-over.....especially if the ignition wire at the firewall has to be replaced.

Other members will post replies if I forgot anything.
WHY do you have to replace the tach cable ?
Reply

Get notified of new replies

To Tach drive distributor options





All times are GMT -4. The time now is 07:16 AM.

story-0
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-1
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-2
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-3
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-4
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-5
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-6
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-7
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-8
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-9
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE