I have installed a LT1 from a 1993 camaro into my 1991 silverado. It ran great for over a year, but then I spun a bearing. I built the engine to a 383 stroker and with the new roller timing chain, I had to replace the distributor. After I reinstalled the engine, I had problems with it stalling intermitently. I used a GM service manual to diagnose the problem as the distributor. The problem continued; spark going into the distrubutor and intermitent spark coming out. Both distrubutors were purchased new from a GM dealer. Could I have gotten 2 bad distributors? Thanks for your help.

Welcome to the Club, LT1. Where do you reside?

The Optispark (Oops,it sparks) is not a dependable system. The location of distributor is in a very high heat area, hence, they don't last long.

Other here may have some suggestions on what to do.

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Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"

I'll drop a seed and then refer you to another site. I have a '96SS (LT1 A4) and have found the SLP site very helpful www.slpeng.com (http://www.slpeng.com) The seed is I have heard the orig optispark is prone to problems but somewhere around '95 it was redesigned and is much more reliable.

Water is it's biggest fow and it's location on the front of the block makes it an easy target. Your silverado is very open in that area if I recall and if you use it as a truck you may be subjection it to elements a street car might not... Good luck and let us know your resolve...

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...Dennis
"The '69 (http://chevelles.com/showroom/ww.jpg), the '96 (http://www.camaroslimited.com/graphics/memcars/96ss.jpg) our local club (http://camaroslimited.com/)"
and the "daily driver" (http://chevelles.com/showroom/DjD/dsc00016.jpg)

The Optispark on pre-95 LT-1 did not have a vent. Trapped moisture is a VERY common problem. Most guys convert over to the 95 and up Optipoops when theirs fail.

I never had any problems on my 96 even with running an MSD box.

Chad

OK, I was either being lazy or I just got tired of working on my own stuff. I forgot to mention that the new distributor that I installed was of the later design; that's why I was hesitant to replace it the first time. With the results of my diagnosis I knew it had to be in the optispark, but why? I took it down tonight and found that the rotor had been burnt badly down one side. Are my plugs and wires this bad? I know I need to check the resistance of the wires and the plugs are new.
By the way, I am from Alabama. I am a master ASE certified technician. After working on customers vehicles all day I get kind of burnt out. Anyway thanks for the help.

From your last post, it sounds like you may need to change plug wires. GMPP sells sets and they are good, Mine on my truck, 88 454 TBI, measured like 300 to 500 ohms depending on the length. A great improvement.

Rotor cap carbon-tracked, happens when too much resistance is in line. Usually an open wire, very lean fuel mixture, too large plug gap, wrong material rotor made. Spark plug misfire under heavy dynamic compression.

The above will also burn out a coil, as it builds up too much heat from generating the spark needed.

Food for thought.......

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Everett "OBJECTS IN THE MIRROR APPEAR QUICKLY UPON RAPID DECELERATION"

LT1
If you can get a scanner, check the injector pulse width between bank one and bank two. If you notice any difference its a bad (lazy) oxygen sensor. If your running true duals, you can tell the bad one because the exhaust sounds like it has a bad valve. Its a very common problem.

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69 convertible
LT1 4L60E

<BLOCKQUOTE>quote:</font><HR>Originally posted by Spongebob:
The Optispark on pre-95 LT-1 did not have a vent. Trapped moisture is a VERY common problem. Most guys convert over to the 95 and up Optipoops when theirs fail.

I never had any problems on my 96 even with running an MSD box.

Chad<HR></BLOCKQUOTE>

There was actually two versions of the LT1 optispark depending on the model of car. Vented & non-vented. "B" bodies used a vented one in 94', first year for this engine in this car. GM issued a service bulletin to replace the vacuum hose assembly on the vented style if you were replacing the optispark due to misfiring.

My friend has a 94' Vette and I gave him a distibutor and plug wires from a 94' "B" body and they wouldn't fit. I gave him the whole distibutor because those darn tiny 4/40 (?) steel screws that hold the cap on break off in the aluminum housing due to corrosion and you end up having to replace the distributor. I've replaced a bunch of them. He lucked out and got all the screws out which is rare, otherwise it's $300 bucks for a new distributor.

Goodluck, Drew

To the person offering parts for sale in this thread. Your post was deleted. Please list for sale items at www.camaros.net/ads (http://www.camaros.net/ads) Nothing personal, the site doesn't allow ads in the forums...

Drew,

Thanks for the correction. I was thinking only F-bod and not any of the other LT-1 variants!
DOH!!!

Chad, no problem, he did say it was an "F" body. Hard to believe GM would have two different distibutors for the same engine. Even the spark plug wires wouldn't fit my friends Vette!
I'm inclined to think this may have been an engineering mistake found out when it was too late?
I like those engines and they do make good power but they are labor intensive and parts are high dollar http://www.camaros.net/forum/eek.gif
Drew

LT1..I am in the middle of stuffing a 95 LT1 into an S10, I've read posts on some of the LT1 sites where a new optispark didn't even make it around the block...not a good track record...

FYI from some of the other posts, the accessory mounting is different from the vette to the maro ....thats why the plugwires are differert from model to model...didn't know about the different distributers tho.....