hey guys,

I just switched my LT1 to a rear mount distributor. I need to go pick up a timing light to double check that I've got the distributor set in the right place. Are there any timing lights that you guys would recommend? Something that I could pick up locally at a Sears or NAPA or Checker or somthing? Any features that I need to get? Thanks guys.

 

I use the Craftsman "professional timing analyzer" for all our cars. I likew the heavy metal construction (doesn't melt) and the ability to check advance with the know on the back.

 

Timing lights are pretty simple devices. You could probably use one from any source, Sears et al without a problem. The only thing I would recommend is that you get one with an inductive pick up on the no. 1 plug wire.

On a different note, what did you do to your LT-1 to convert it to a regular rear mount distributor?

Larry

 

Sounds like the sears light isn't a bad thing then. I sent my intake to lt1intake.com and had him drill a hole in the back of the intake and put on the spacers and such that the dist clamp needs.

I'm running an Accel Gen 7 so they make a slick distributor that allows me to go to full sequential fuel injection. No more Opticrap for me, yeay *happy dance*

I even bypassed the stock ignition module so its running with just the dist, an MSD and a coil.

 

If all you work on is computer cars, don't spend any extra for a "dial back" timing light. They are great for checking the mechanical and vacuum advance in conventional distributors, but are pretty much worthless with an ECM controlled distributor. An inductive pick up for the secondary wiring, is invaluable.

RACE ON!!!

 

I agree with the above to the extent we are talking
about checking initial timing at low RPM. In this case
you want something with the inductive pickup, a bright
light, rugged construction and quality leads that
can withstand heat and abuse.

OTOH If you intend to be checking timing advance at
elevated RPMs then you ought to be particular about
ensuring the light has the accuracy necessary to provide
useful information at 5,000+ RPM.

In the latter category, MSD comes to mind. They
make a powered light (#8990) that is rated for use
up to 8,000. If you have relocated the battery, they
also offer a self-powered light (#8991) that is said
to be good through 5,000. Note that neither MSD
light has the 'Dial-back' feature - IIRC, it is felt to
be a point of failure and inaccuracy.

In some MSD literature produced a number of years
ago, they write about acccuracy and discuss results
testing their and other mfr's lights. They give
honorable mention to the Craftsman (not Sears)
#2134 light. I believe they found it was accurate
to 6,000?

Chris Jacobs has a section on lights in his book
"Performance Ignitions Systems" (1999, HPBooks).
In tests, his people liked Snap-On and Fox Valley
for accuracy but no model #'s are given. They did NOT
care for Kal Equipment product at the time.

Jacobs wrote that he offered a 'Dial-back' light but
a check of the Jacobs website didn't turn up a current
hit for the light. Perhaps it isn't listed or maybe
it was dropped.

.

 

That's alot of info. I'm just looking to find something to check base timing to make sure the dist is in the right way. I'm using the computer to set the timing on the upper rpms, as long as the computer has the base timing to adjust it from I should be ok.

 

Incidently, I have a Craftsman #2134.

I checked their site to see whether this is still
available and found it does not appear to be.

Closest number is the #2137. This shows the quick-disconnect
cable but it appears to have a plastic housing/body
- unlike my 2134 which is chromed 'metal'.

There is also the #21027. More money,
chrome metal case, no 'Dial-back' advance, does not
appear to have the quick-disconnect cable.

Finally, there is the #21023 light that has the 'Dial-back' advance
feature (0-60º). This has the metal case, as well as the
quick-disconnect cable.

Bottom line: the unit MSD liked is no longer available.
I don't know how well the new models perform at
elevated RPMs - if that doesn't matter, then I'm sure
any one of these is more than adequate for setting
initial timing.

.

 

I picked up a Sears inductive pick up timing light on ebay for $7.00. Works fine! I even lent it to the fellow I bought it from!

 

Like the dial back feature, the ability to check the timing at high rpms is pretty useless with computer controlled timing. Because it would be difficult if not impossible to input WOT conditions to the ECM from all the sensors, there is no point in attempting to check the timing curve, as we used to in the olden days.

RACE ON!!!

 

Obviously you've built a serious performance engine. As well as knowing when and at what rate total advance comes in, you will want to know that it is stable at high RPMs. Make sure you get a good quality tool that will be reliable to your limit. Doesn't have to be the most expensive one, just not a $25 cut-rate parts store POS.

 

Alright, Wait a Minute! I tried using the timing light just now and I can't even get close to seeing my timing marks and block mark thing. There's too much in the way, and idler pulley and belt mostly but I can't see it.

My mechanic had a timing light that gave a digital read out. I'm not exactly sure how that works, but I'd like to see if I could try one of those. Anybody know of one?

 

Does your LT engine even HAVE a mark on the damper and a timing tab? If so...WHY???

That digital read out just sounds like dial back timing light with LEDs instead of a meter.

RACE ON!!!

 

I've seen aftermarket dampers for the Ltx engines with marks but yes, if you've still got the stocker, it's going to be worthless for this purpose. You could make marks on it but that too would be worthless once you R&R it one time, unless it's been keyed.

 

The hub is keyed, and there is a mark on the pulley. I'll have to fine another way of doing it I guess.

 

I've been thinking about this and I think I came to this conclusion.

Since I only have a TDC mark on my pulley I need the timing light to flash at 0* of timing. So I have to have a car that idles at 0* in stead of the 20-30* that it likes. OR I could buy the timing light that has the adjustable dial and turn it up to 25 and freeze the timing at 25* and then I should see the TDC mark line up properly. Is this right or am I still missing how a timing light works??


I forgot to freeze the timing at a certain value so I think that may be why I couldn't see anything, not to mention the fact that I was up to 30*'s off what I think I was going to see.

 

That is how all SBCs and most engines are set up. The damper, or in your case the pulley, has a mark on it that lines up with the timing tab bolted to the engine. The timing tab is marked with the different positions of the engine rotation. The single mark on the pulley isn't the problem, it's with what ever it lines up with. Of course there is no reason you couldn't have the pulley or damper degreed, and work from it.

What are you using for a distributor? Is it mechanical or computer controlled? If computer controlled, is there an ESC wire to disconnect to set base timing? If all you can reference is TDC, you WILL need a dial back timing light. Dial the gauge on the timing light to 6° BTDC with the ESC disconnected and turn the distributor so the TDC timing marks line up.

RACE ON!!!

 

The tab that bolts into the engine only has one slice on it, no degrees.

I'm running an Accel Gen 7 DFI with an Accel Dual Sync distributor, I freeze the timing at whatever value I want if I use the laptop while I'm doing this.

I'm pretty sure that if I freeze the timing at 20* or so and dial the light gun to 20 then my TDC mark should line up with the mark on the reference tab, Right?

 

I don't know what a "Dual Sync distributor" is.

If I understand the DFI, as I think I do, can't you set the "base" timing at any value, even zero, and program that into the software? Wouldn't that be just as easy as trying to subtract 6° or 12° or 20° from all the other numbers you have to deal with?


YES. As I said in my last post, dial the advance in the timing light to 20° (or whatever you like) and set the timing to zero on the timing marks. BUT, be sure that DFI isn't adding or subtracting any timing while you're doing this. That is why pre LT computer engines have to have the ESC wire disconnected before setting the base timing.

RACE ON!!!

 

The dual sync is just a distributor looking thing with a cam and crank sensor built into it and a cap and rotor on the top.

I could just remove 6 or 12 or 20 degrees from my timing tables, but I still need a reference as to how much to pull out. Since I don't have any degree marks I'm pretty well out on that idea. It's easier to set the distributor correctly.

I could set the base timing to zero and use a non-dial light, but I don't think the car will idle at that low of a timing advance.