Reliability... (both lightly modded/heavily modded)
Thread Starter
Registered User
Joined: May 2003
Posts: 116
From: Menlo Park, CA
Originally posted by Cmr0z28
the optispark is the distributor
the optispark is the distributor
why can't we use the ones like you'd see on another, less technically advanced sbc? is it computer controlled?
Banned
Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
Originally posted by Cmr0z28
the optispark is the distributor
the optispark is the distributor
its an electronic distributor with an optical sensor.
For years the big gripe about chevys was that the distributor was driven off the back of the cam- this would cause the cam to torque a bit and effect timing at high RPM's.
This optispark was GM's great idea poorly executed.
PRO's:
maintinance free 85k-100kmile expetancy
extreemly accurate timing
relativly powerful. HEI would be good to about 4800 rpms where as the opti doesn't have any serious issues till you really start spinning
almost instantious knock retard.
Cons-
Expensive- about $200 a pop on a good day
Placement- under the waterpump and behind the crank pulley.
Waterpump leaks from weep hole and there goes an opti. Also to change it the crank pully and water pump have to come off. a good 6-8 hr job.
93 and 94 units were VERY prone to failure due to exposure to wetness. 95+ has a vented unit that helps a GREAT deal. Still not perfect but still much better.
the LS1 motor (which i'd advise you to get) has individical coil packs for every cylinder which makes for a more powerful spark, a more reliable spark and easier maintinace. down fall is you have to replace 8 coils
which is still probobly cheaper than 1 optispark.Beware, the optispark is the red headed step child of the LT1. The opti will be blamed instantaniously for ANY problems. Misfires, running rich, running lean, poor power, slow track times, burnt out tail lights, speeding tickets, flat tires- you name it!
about 30% of the time when its an ignition issue on the 95+ its the opti. people tend to forget that wires burn out over headers, plugs and coils go bad, coil wires go bad and they also dont install the opti propperly causing the infamous "i have a low RPM stumble and replaced everything! why is my car running like crap" threads
Moderator
Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
Trey: "red headed step-child" LOL. Very literate! You are learning, my young Jedi 
"Ghettoraid" needs to decide what he is asking about. A performance rebuild vs. freshening up a stock motor that is tired. Whole different ballgame.
As far as "reliability" goes, there is a relationship between how fast you want to go and how long it will last. The stock LS1 is your best bet for a reliable, fast car. When you start talking mods, it's hard to do more than generalize as I did above - the faster you go the more it will break and the more it will cost. As some have suggested, spending a lot of money is a partial solution to this conundrum*. But be careful here too. Many high buck performance parts are designed for high performance and not longevity. An extreme example would be aluminum connecting rods, and similar exotica. Very light weight pistons are a more prosaic* example.
Anyway, if you want to rebuild an LT1 for good reliability at a low cost, go OEM parts with the exception of the pistons. For these, either get a set of premium hypereutectics (like the KB's) or a set of good forged pistons (JE/SRP). You can build a reliable forced induction LT1, but it will cost you big dollars. Ask me how I know.
A "basic" LT1 shortblock rebuild with new pistons should run in the $1,500 range not including the motor R+R. If you want to start replacing other things like the Opti, waterpump, etc. that's the time as there is no additional labor involved. The parts will cost you though.
*vocab words for Trey
Rich Krause
"Ghettoraid" needs to decide what he is asking about. A performance rebuild vs. freshening up a stock motor that is tired. Whole different ballgame.
As far as "reliability" goes, there is a relationship between how fast you want to go and how long it will last. The stock LS1 is your best bet for a reliable, fast car. When you start talking mods, it's hard to do more than generalize as I did above - the faster you go the more it will break and the more it will cost. As some have suggested, spending a lot of money is a partial solution to this conundrum*. But be careful here too. Many high buck performance parts are designed for high performance and not longevity. An extreme example would be aluminum connecting rods, and similar exotica. Very light weight pistons are a more prosaic* example.
Anyway, if you want to rebuild an LT1 for good reliability at a low cost, go OEM parts with the exception of the pistons. For these, either get a set of premium hypereutectics (like the KB's) or a set of good forged pistons (JE/SRP). You can build a reliable forced induction LT1, but it will cost you big dollars. Ask me how I know.
A "basic" LT1 shortblock rebuild with new pistons should run in the $1,500 range not including the motor R+R. If you want to start replacing other things like the Opti, waterpump, etc. that's the time as there is no additional labor involved. The parts will cost you though.
*vocab words for Trey
Rich Krause
Last edited by rskrause; Jun 9, 2003 at 12:00 PM.
Thread Starter
Registered User
Joined: May 2003
Posts: 116
From: Menlo Park, CA
Originally posted by rskrause
Trey: "red headed step-child" LOL. Very literate! You are learning, my young Jedi
"Ghettoraid" needs to decide what he is asking about. A performance rebuild vs. freshening up a stock motor that is tired. Whole different ballgame.
As far as "reliability" goes, there is a relationship between how fast you want to go and how long it will last. The stock LS1 is your best bet for a reliable, fast car. When you start talking mods, it's hard to do more than generalize as I did above - the faster you go the more it will break and the more it will cost. As some have suggested, spending a lot of money is a partial solution to this conundrum*. But be careful here too. Many high buck performance parts are designed for high performance and not longevity. An extreme example would be aluminum connecting rods, and similar exotica. Very light weight pistons are a more prosaic* example.
Anyway, if you want to rebuild an LT1 for good reliability at a low cost, go OEM parts with the exception of the pistons. For these, either get a set of premium hypereutectics (like the KB's) or a set of good forged pistons (JE/SRP). You can build a reliable forced induction LT1, but it will cost you big dollars. Ask me how I know.
A "basic" LT1 shortblock rebuild with new pistons should run in the $1,500 range not including the motor R+R. If you want to start replacing other things like the Opti, waterpump, etc. that's the time as there is no additional labor involved. The parts will cost you though.
*vocab words for Trey
Rich Krause
Trey: "red headed step-child" LOL. Very literate! You are learning, my young Jedi
"Ghettoraid" needs to decide what he is asking about. A performance rebuild vs. freshening up a stock motor that is tired. Whole different ballgame.
As far as "reliability" goes, there is a relationship between how fast you want to go and how long it will last. The stock LS1 is your best bet for a reliable, fast car. When you start talking mods, it's hard to do more than generalize as I did above - the faster you go the more it will break and the more it will cost. As some have suggested, spending a lot of money is a partial solution to this conundrum*. But be careful here too. Many high buck performance parts are designed for high performance and not longevity. An extreme example would be aluminum connecting rods, and similar exotica. Very light weight pistons are a more prosaic* example.
Anyway, if you want to rebuild an LT1 for good reliability at a low cost, go OEM parts with the exception of the pistons. For these, either get a set of premium hypereutectics (like the KB's) or a set of good forged pistons (JE/SRP). You can build a reliable forced induction LT1, but it will cost you big dollars. Ask me how I know.
A "basic" LT1 shortblock rebuild with new pistons should run in the $1,500 range not including the motor R+R. If you want to start replacing other things like the Opti, waterpump, etc. that's the time as there is no additional labor involved. The parts will cost you though.
*vocab words for Trey
Rich Krause
It would be a while before the supercharger would ever serve under my hood, so I'd have to run around with low compression/lower performance... which is where I thought the cam would come in and save me/bring me back around stock levels...
But once again I'll probably have to go over there and get more details.. heh
Moderator
Joined: Dec 1969
Posts: 10,745
From: Buffalo, New York
Originally posted by Ghettoraid
If I go with custom pistons, won't I want lower compression?
It would be a while before the supercharger would ever serve under my hood, so I'd have to run around with low compression/lower performance... which is where I thought the cam would come in and save me/bring me back around stock levels...
But once again I'll probably have to go over there and get more details.. heh
If I go with custom pistons, won't I want lower compression?
It would be a while before the supercharger would ever serve under my hood, so I'd have to run around with low compression/lower performance... which is where I thought the cam would come in and save me/bring me back around stock levels...
But once again I'll probably have to go over there and get more details.. heh
When you start talking "bloweer" and "reliable" you are talking big $$$. But yes, you want low CR forged pistons for a blower. A bigger cam and lower CR may not be a great combo. If you are sure you are doing a blower, you need to more than upgrade the pistons anyway.
It's a long subject, if you want one of my essays, just ask
. But you may be better off doing a search and reading over some old threads in the Forced Induction section.Rich Krause
Registered User
Joined: Dec 1999
Posts: 2,248
From: Houston, TX
Originally posted by treyZ28
Let explain this a bit further
its an electronic distributor with an optical sensor.
For years the big gripe about chevys was that the distributor was driven off the back of the cam- this would cause the cam to torque a bit and effect timing at high RPM's.
This optispark was GM's great idea poorly executed.
PRO's:
maintinance free 85k-100kmile expetancy
extreemly accurate timing
relativly powerful. HEI would be good to about 4800 rpms where as the opti doesn't have any serious issues till you really start spinning
almost instantious knock retard.
Cons-
Expensive- about $200 a pop on a good day
Placement- under the waterpump and behind the crank pulley.
Waterpump leaks from weep hole and there goes an opti. Also to change it the crank pully and water pump have to come off. a good 6-8 hr job.
93 and 94 units were VERY prone to failure due to exposure to wetness. 95+ has a vented unit that helps a GREAT deal. Still not perfect but still much better.
the LS1 motor (which i'd advise you to get) has individical coil packs for every cylinder which makes for a more powerful spark, a more reliable spark and easier maintinace. down fall is you have to replace 8 coils which is still probobly cheaper than 1 optispark.
Beware, the optispark is the red headed step child of the LT1. The opti will be blamed instantaniously for ANY problems. Misfires, running rich, running lean, poor power, slow track times, burnt out tail lights, speeding tickets, flat tires- you name it!
about 30% of the time when its an ignition issue on the 95+ its the opti. people tend to forget that wires burn out over headers, plugs and coils go bad, coil wires go bad and they also dont install the opti propperly causing the infamous "i have a low RPM stumble and replaced everything! why is my car running like crap" threads
Let explain this a bit further
its an electronic distributor with an optical sensor.
For years the big gripe about chevys was that the distributor was driven off the back of the cam- this would cause the cam to torque a bit and effect timing at high RPM's.
This optispark was GM's great idea poorly executed.
PRO's:
maintinance free 85k-100kmile expetancy
extreemly accurate timing
relativly powerful. HEI would be good to about 4800 rpms where as the opti doesn't have any serious issues till you really start spinning
almost instantious knock retard.
Cons-
Expensive- about $200 a pop on a good day
Placement- under the waterpump and behind the crank pulley.
Waterpump leaks from weep hole and there goes an opti. Also to change it the crank pully and water pump have to come off. a good 6-8 hr job.
93 and 94 units were VERY prone to failure due to exposure to wetness. 95+ has a vented unit that helps a GREAT deal. Still not perfect but still much better.
the LS1 motor (which i'd advise you to get) has individical coil packs for every cylinder which makes for a more powerful spark, a more reliable spark and easier maintinace. down fall is you have to replace 8 coils
which is still probobly cheaper than 1 optispark.Beware, the optispark is the red headed step child of the LT1. The opti will be blamed instantaniously for ANY problems. Misfires, running rich, running lean, poor power, slow track times, burnt out tail lights, speeding tickets, flat tires- you name it!
about 30% of the time when its an ignition issue on the 95+ its the opti. people tend to forget that wires burn out over headers, plugs and coils go bad, coil wires go bad and they also dont install the opti propperly causing the infamous "i have a low RPM stumble and replaced everything! why is my car running like crap" threads
Banned
Joined: Aug 2001
Posts: 3,505
From: looking for a flow bench so Brook and I can race
Originally posted by 96-speed
Where was this plagiarized from?
Where was this plagiarized from?
it was just easier for me to retype it than to do a search, find it, copy paste ect...
not like i didn't have it memorized
I did write it
Registered User
Joined: Oct 2002
Posts: 856
From: Denver
Re: Reliability... (both lightly modded/heavily modded)
Originally posted by Ghettoraid
One of the reasons I'm switching from a turbocharged import to a Z28 is because of reliability. I'll have similar power, but with a lot less complexity, and fewer components which can go "bad" with regular day to day driving.
Is a Z28 really the right car? My plans are to buy a high mileage 95-97, obd2. Drive it for maybe 8-10,000 miles (probably a lot fewer) for my commutes to school, then rebuild it with low compression pistons, nicer cam, guess a few other basic items.. for $3,500.
Will a properly rebuilt LT1 last me, with all the basic maintenance performed regularly? (I'll change all the fluids as soon as I've got it in my driveway)
What usually goes wrong with these cars, what can I look forward to hassling with on a higher mileage (100k range) obd2 LT1?
What happens once you get into forced induction? Will the car spend more time in the shop than on the road? If I boost more conservatively, will it be more reliable? What should I tell the shop to do/not to do, in general, when they perform the rebuild, considering the fact that reliability is a major issue?
It's also my understanding that properly cared for T56's will last 300,000 miles... Fair assumption?
Thanks in advance!
One of the reasons I'm switching from a turbocharged import to a Z28 is because of reliability. I'll have similar power, but with a lot less complexity, and fewer components which can go "bad" with regular day to day driving.
Is a Z28 really the right car? My plans are to buy a high mileage 95-97, obd2. Drive it for maybe 8-10,000 miles (probably a lot fewer) for my commutes to school, then rebuild it with low compression pistons, nicer cam, guess a few other basic items.. for $3,500.
Will a properly rebuilt LT1 last me, with all the basic maintenance performed regularly? (I'll change all the fluids as soon as I've got it in my driveway)
What usually goes wrong with these cars, what can I look forward to hassling with on a higher mileage (100k range) obd2 LT1?
What happens once you get into forced induction? Will the car spend more time in the shop than on the road? If I boost more conservatively, will it be more reliable? What should I tell the shop to do/not to do, in general, when they perform the rebuild, considering the fact that reliability is a major issue?
It's also my understanding that properly cared for T56's will last 300,000 miles... Fair assumption?
Thanks in advance!
Take a look at my website it has what you need for a $3800 blower motor 355. Thats from crank to heads. Reliability will come over time as you learn these cars. The more power the more breaks. Stay under 500rwhp and you should be fine. Drive line upgrades are needed.
Thread
Thread Starter
Forum
Replies
Last Post
dbusch22
Forced Induction
6
Oct 31, 2016 11:09 AM
