electrical and ignition Distributer Upgrade?

[devotion]

Im getting ready to purchase a weber 38/38 carb for my 76. I have taken off all smog related goodies already. Should I upgrade to the IE Mechanical advance distributer with electronic ignition at the same time? Motor is otherwise stock. Thanks for the advice. 

[Chamonix72]

Depends. If your distributor is in otherwise good shape (no play in the shaft or damage, etc) then it's probably not worth replacing. If the distributor is worn then the IE piece is nice or you can send your distributor out to be rebuilt.

Edited to add: electronic igniters such as Pertronix are a nice upgrade from points, but they don't cure all.

[devotion]

I guess my question was more about the mechanical advance vs stock. Is there any advantage/disadvantage with an other wise stock motor?

['76mintgrün'02]

I found this link while searching the FAQ with similar questions,

http://www.pro-touring.com/showthread.php?29320-Mechanical-advance-vs.-vacuum-advance-article

Hope it helps.

Tom

[devotion]

"For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum."

 

that pretty  much sums up the article for those of you who dont want to read the entire thing.

[jrhone]

I find that in interesting read....although maybe not exactly pertinent to the 02 engine....Is there a reason that the Tii (Ireland is a Tii clone) distributor is liked by so many for the added performance? On a stock motor you probably won't see any improvement, maybe less drivability...on a modified engine, it may be an improvement.

[Preyupy]

"For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum."

 

that pretty  much sums up the article for those of you who dont want to read the entire thing.

I don't know of anyone using a vacuum advance distributor that is hooked to "full manifold vacuum" if you hook it up that way you get advance when you are off the throttle (maximum manifold vacuum) and you loose the advance when you step on the throttle (little or no manifold vacuum) Vacuum for the advance is usually taken from a port on the carburetor that sees vacuum at the venturi under load. Some cars had a secondary vacuum "retard" that was hooked directly to manifold vacuum. If you are running a carburetor with a vacuum advance port go ahead and use a distributor with vacuum advance, if you are running Side Draft carbs, ITB's, or turbo you won't have a proper vacuum signal and need to run centrifugal only.

['76mintgrün'02]

What is the number on the distributor in your car?  My '76 came with a mechanical only (0231188002) installed and I recently purchased a vacuum/mechanical from a FAQ member (0231170164) which I believe to be the stock unit for my car.  I just got off the phoe with Jeff at Advanced Distributors in MN. http://advanceddistributors.com/  and plan on sending him the #164 to be rebuilt/recurved.  He was very helpful over the phone.  He said that the advance springs on Bosch units are weak and wear out over time, causing premature advance.  I noticed that my #002 is all in by 2400 rpm.  He will re-bush the shaft and reset the advance on the #164 to match my particular set up.  I was surprised to learn that cylinder pressures are very important information for him to dial it in.  I will do a compression test, so I can complete the rest of the worksheet before sending it in. 

[jgerock]

 He was very helpful over the phone.  He said that the advance springs on Bosch units are weak and wear out over time, causing premature advance.  I noticed that my #002 is all in by 2400 rpm.  He will re-bush the shaft and reset the advance on the #164 to match my particular set up.  I was surprised to learn that cylinder pressures are very important information for him to dial it in.  I will do a compression test, so I can complete the rest of the worksheet before sending it in. 

This is why it is important to match the distributor type and advance curve to your engine.  Just buying a new unit will not guarantee that it performs any better than the old one it replaced. 

 

Simple test for worn out advance springs:  Remove distributor from engine and quickly rotate the gear by hand in short snaps while listening for the advance weights. If they move and make noise then the (2) springs may be weak or even broken.  If no noise or movement is detected, the weights may be seized/rusted to the plate.  You may be able to revive an old distributor by spraying some penetrant on the advance mechanism.

['76mintgrün'02]

Jeff said that the turn around is four weeks right now and the cost to rebuild will be about $200, if that helps with your decision. 

 

FWIW my compression readings were all around 120 psi.  I warmed the engine up and worked from cylinder 1 to 4.  As I took the measurements the numbers consistently dropped.  I noticed that the engine had started to cool, so I warmed it up again and worked from 4 to 1.  I was relieved to learn that they were all consistent.  Engine temperature is very important for accurate readings.