distributor questions

[jmp]

The tach gear went on my 72 LT-1, wrecking the dist main shaft (well, I'm assuming -- I haven't checked yet). So, at the minimum I need a new tach gear and main shaft.

Looking through (and drooling over) my Ecklers catalog, I saw a couple of things I'd like your thoughts on.

The first is "Dura-Last Tach Cross Gear Kit"; anybody use this? What are your thoughts? Is it worth the extra $40 over the OE gear?

The second is: should I replace the distributor with the electronic version? Of course, this question leads to a bunch of others, such as:
- HEI, MSD or Mallory Unilite?
- With the MSD, you have to change the ignition box; what about the other two?
- convert to electronic tach, or stick with mech. tach?

The prices for the 3 electronic dist. listed in Ecklers are all $400+, and judging from some other posts, this is $$$$. Are there cheaper alternatives?

Thanks!

 

[Bullitt]

I've been thinking the same thing, too. I took my distributor out and have the Pertronix Ignitor. However, I want to take it to a shop and have the endplay checked and so forth. Either that or switch to an electronic tach and drop in an Accel HEI unit or equivilant. MSD's set-up is too high in the sky for my pocket book. Besides, if I'm getting a box, it's going to be digital.

--Bullitt

 

[72GSC]

I had the same problem. I rebuilt the distributor with a new main shaft, button and cross gear. I also added a ignitor breakerless ignition with a high energy coil ... life is grand and I didn't break the budget.

 

[86pacecar]

Don't know which distributer to recommend but just about anyone is cheaper than Ecklers. Try Jeg's or Summit or Pace before paying their price.

 

[Jack]

I understand from others that "The Last Detail" http://www.tld-corvette.com/ has good tach drive distributor parts & prices. I agree with Bullitt ... I'm gonna change my 71 to HEI & elec 75-77 tach ... I have the parts & pieces ... but gotta get motivated. However, if I had an original, vintage LT-1 I'd probably rebuild the original distributor. I seem to recall that some earlier LT-1 had TI (transistor ignition) thus no points ... and that the TI mainshaft is slightly different from the points type ms. Dunno if the 72's were available with TI? From outside the TI dist looks virtually the same as standard tach drive points dist. And although TI & HEI are both electronic they are not the same. You might post this on the LT-1 forum ... someone there'll know more about the TI than I do.
JACK:gap

 

[Bullitt]

Too Lazy

I think I got too much to do already, so I'm going to leave the tachometer alone and keep the stock distributor with the Ignitor. I say that now, but who knows how I'll feel once I pull the motor. I need to finish some other things up and get others sorted out, before that comes up, though.

--Bullitt

 

[jmp]

I seem to recall that some earlier LT-1 had TI (transistor ignition) thus no points ... and that the TI mainshaft is slightly different from the points type ms. Dunno if the 72's were available with TI?

I believe a 70 LT-1 had the option of transistor ignition, but that in 71 and 72 only the ZR1 had TI. Not sure though.

 

[jmp]

I had the same problem. I rebuilt the distributor with a new main shaft, button and cross gear. I also added a ignitor breakerless ignition with a high energy coil ... life is grand and I didn't break the budget.

OK, I may not get a new distributor, but I may convert to a breakerless ignition (assuming I don't already have that -- it's hard finding info on what exactly a 72 LT-1 was supposed to have and what exactly mine does have; I still haven't pulled the dist, b/c I'm waiting for winter). Now, I've seen two different systems: Ignitor (from Corvette Central for $90) and ??? (from Ecklers or Corvette America for ~$160). Anybody know the difference btwn the 2? Experiences with either?

Thx.

 

[RalleyRed]

Just so you know for sure, I just looked in my Vette-Vues fact book written by M.F. Dobbins and it states that the TI setup was available in both 71 and 72 as well as 1970.

I can't be sure the way it is written but it looks like if it's a LT-1 the TI came with it.

If there is anything else you want me to look up let me know.

Rick

 

[jmp]

Just so you know for sure, I just looked in my Vette-Vues fact book written by M.F. Dobbins and it states that the TI setup was available in both 71 and 72 as well as 1970.

I can't be sure the way it is written but it looks like if it's a LT-1 the TI came with it.

If there is anything else you want me to look up let me know.

Rick

Yup, TI was available, and in 70 it came with the LT-1, ZR1, and some other engines. But judging from the Idaho Vette site, it looks like TI only came with 71 ZR1s and ZR2s, and 72 ZR1s. Now, if only I believed what I read on web sites!

What exactly does your book say?

 

[RalleyRed]

jmp,

It says and I quote

RPO

LT-1 255hp Turbo-Fire special 350 4 bbl engine available only when 4 spd wide ratio or 4 spd close ratio transmission is ordered. Available for registration in the stae of California.
Incl. full transistor ignition system.

ZR1 255hp special purpose 350 engine (not recommended for normal traffic situations). Available for registation in the state of California. Not available when power windows, power steering, air conditioning, rear window defroster, wheel covers,or radio is ordered.Incl. special 4 spd. close ratio transmission, HD power brakes, full transistor ignition system, aluminum radiator, special springs with matching shock absorbers, special front stabilizer bar and rear wheel spindle strut shafts.

Now to make things really confusing, I just read the whole section for the 72's

On page 219 under the picture at the top of the page it says and again I quote,

"Top left side, ZR1. to help discourage street use, a fan shroud was not used, just as with the L88 cars. The earlier ZR1 cars did have shrouds. Although the eary Chevrolet literature stated that T.I. was part of the package, it was never added in production. ignition sheilding is not present as these were manatory no radio cars. Other options not available with this package were power windows, air conditioning, wheel covers.

This might be a question for the N.C.R.S. guy's..

Rick

 

[jmp]

Well, then... That clears things up, doesn't it? :confused

I have the feeling I'm only going to figure it out when I pull the distributor. Unfortunately, I wanted to order the parts (if necessary) ahead of time. Actually, I could probably figure it out just by pulling off the dist cap, correct?


Thanks, btw.

 

[RalleyRed]

I do have a picture here that shows the location of the transitor ignition amplifier.

If you open your hood and from the front of the car look down into the crack at the front of the hood. At the drivers side and over towards the fender there sound be an amplifier if you've got T.I.
It did say 68-71 amp loction, but I really doubt that it was moved for 72.
In the picture it looks like all your going to see is the headlight actuator, vacuum lines, wires and this amp.

I do agree taking your distributor cap off should tell you too.

I'm happy to help when I can, which isn't all that often

Rick

 

[jmp]

OK, I don't have TI -- no amplifier.

Also, according to 'Corvette Restoration Guide 1968-1982' by Richard Prince, no 1972 cars had TI:

"Transistor ignition was a distinct option in 1970, was available only with the LT1 and LS6 in 1971 as part of those options, and was not available at all in 1972." (page 93, emphasis mine)

So...

Well, thanks for you help. Now I know which mainshaft to order, and whether or not I should even considering converting to breakerless dist!

 

[Jack]

jmp:
Now that it seems you have a breaker points-type distributor ... you can go to a breakerless retrofit such as Pertronix Ignitor. Prices from Ignitor ONE at places like Summit & Jeg's are about $60. I've heard of many failures for the Ignitor TWO. For most folks, a points-type distributor will do all they ask for ... as long as distributor is in good shape (fresh points, condensor, rotor, cap ... no wobble in shaft-bearings ... both mechanical & vacuum advance assemblies in good condition) ... proper end-play at gear. Also, a good points-type setup's reliability is second-to-none.
JACK:gap

 

[JohnZ]

your LT-1 came with conventional point ignition; the only 1972 cars that had T.I. ignition were the ZR-1's, and there were only 20 of them built (the ZR-1 option was over $1,000.00, which was 20% of the price of the car).

 

[jmp]

points vs. no-points

In'resting... From all the posts I've read I got the impression that points were a pain in the @ss and that breakerless was the way to go. Well, HEI was the way to go, but short of that, then some kind of conversion like the Ignitor. The other posts went so far as to say the Ignitor and a new coil would increase performance somewhat.

Are you saying that this is not the case?

I'm pulling the dist anyway to replace the main shaft (damn mech tach! ), so I figured now might be a good time for an upgrade (reliability-wise and/or performance-wise).

PS. $60?! The price from the websites (Jegs, Summit, Corvette Central) are all $80+. Actually, Jegs seems to offer two different Ignitor systems for GM: the 751-1181 for $82.99 and the 751-1181LSC for $74.99. I don't really understand the difference.
Jegs Ingitor kits

 

[Jack]

jmp:
OOPS ... Prices have gone up since I last looked ... try this fellow for better pertronix prices ... Matt at Ponderosa Mustang ... October 2001 typical prices to-your-door were: P1 @ $59 (ignitor 1) & P2 @ $95 (ignitor 2). FORD6566@aol.com ... email Matt & ask for today's price for your application. Also, Smith Bros at http://rlsmithco.com/mcart2/index.cgi?ID=83793565&PID=IT486&code=13 is currently showing ignitor 1 for $57.10 plus about 6 bucks shipping.

1181 is an ignitor ONE and uses a shutter wheel affair to activate the magnet. 1181LSC is a lobe sensor ... it uses the original points' cam lobes as activators ... it is easier to install than the plain 1181. Retro Rockets at http://www.vintageperformance.com/retrorockets/ also has competitive pertronix pricing and has further info describing differences between ONE, LSC, & TWO.

What I meant is for MOST folks, points are fine. Even a good set of points will require "setting" or gapping ... but unless you drive more than 50K mile/year ... and/or the distributor is worn out ... the points shouldn't require maintenance more than once or twice a year. Points are extremely reliable. Points rarely just up and quit with no warning ... if they do ... they can be quickly adjusted/replaced. At greater frequency, electronic/magnetic/optic (LED) distributors can & do fail with little or no warning ... and their repair parts may not be so readily available. Also, a good points setup will usually perform through 7500 rpm. Don't get me wrong ... electronic/magnetic setups are great and can provide a hotter spark ... I've got a MSD 6 box triggered by a gutted (no module) HEI ... MSD coil ... Accel ferrospiral 8.8 wires. My previous point was that for MOST folks the points setup works quite well as long as distributor is in good shape and they're not pushing a huge compression motor. BTW, many stock HEI setups drop off output above 4500 rpm ... even when new. But most folks rarely push that far. Non-points usually provide a little better performance on startup and throughout its operating range. But a wore out distributor is just that ... wore out ... regardless if it's HEI, points, TI, MSD, pertronix whatever. I'm not suggesting to forego the pertronix ... if you're seeking more performance, it'll work fine ... especially in your rebuilt distributor.
JACK:gap