The opti spark system on the old LT1's are garbage at best and a pain to replace esp on a vette.
LS1 vs. LT1
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Rusty Nutz said:
Very true. Yet, there are a few options to eliminate the opti spark. One in particular is to use the opti spark's optical sensor to trigger a DIS coil pack system. 2 companies sell a kit to do that. The next is to adapt the LS1's 8 coil system. One company sells a kit to do that. The next few are aftermarket systems from MSD, Accel, Mallory, and Pertronix. All have crank trigger systems that can replace the opti spark and then use what you like.
The opti spark's optical sensor is actually very accurate. The rotor and cap are the culprits in that system. They can't handle the stresses of being sideways and definitely can't handle high rpms. The decision of GM not to use the DIS system was a stupid one.
T
Lt1 is a whole cheaper and if your good with the lack of support you still can make good power vs a stock ls1. LS1 is old news now compared to the ls2, ls3 swaps done now a days... ls has a lot more support and more capable hp gains, even with simple bolt ons, but as said before once you get past the normal "bolt on" stage it gets expensive!!
So much misinformation about LT1s is out there constantly spread about that it boggles my mind. I have a 94 Vette powered by an LT1 that makes near 500 HP, gets 20 MPG, runs bone reliable and has never had any issues at all with the opti spark. Nearly everything you need to build an LT1 is the exact same part you need to build a standard small block chevy. Cranks, Rods, Pistons, Rockers, Cams headers etc. So there is plenty of aftermarket support. Aftermarket Heads and manifolds are there as well, but the beauty of it is that they are not even needed. My motor is still running ported factory heads and intake. There is literally no part needed to upgrade an LT1 that is not available from multiple manufacturers and at a reasonable cost. Tuning software is available from multiple sources either cheap or free, and converting to a 4 barrel intake can be done for the computer impaired.
The LS1 is a great motor and has considerably more power potential than an LT1, but everything, and I mean everything is substantially more money for it once you start buying hard performance parts. Where this reputation that this is a cheap motor to build comes from I just dont know. You can get by inexpensively by swapping in a relatively stock 5.3 iron block and still make gobs of fuel efficient hp up to about the 400 HP mark. Tuning software is expensive, although it is quite sophisticated.
Bottom line is that they are both great motors, but with complete LT1 motors available for a song, it is dollar for dollar the better value.
Roy
The LS1 is a great motor and has considerably more power potential than an LT1, but everything, and I mean everything is substantially more money for it once you start buying hard performance parts. Where this reputation that this is a cheap motor to build comes from I just dont know. You can get by inexpensively by swapping in a relatively stock 5.3 iron block and still make gobs of fuel efficient hp up to about the 400 HP mark. Tuning software is expensive, although it is quite sophisticated.
Bottom line is that they are both great motors, but with complete LT1 motors available for a song, it is dollar for dollar the better value.
Roy
Fastmax32168 said:
Yes a whole lot of misinformation. Even though your not having opti spark issues, It is a fact that the opti spark is problematic. I built a 580 horse LT1 on a 3 grand budget. The highest cost items were in the rotating assembly, the valve train, and the exhaust. (I ported the stock heads) Replaced the opti spark twice and went through 3 starters (one was a Vette starter and it cracked the housing!) due to failing opti sparks. The engine has a lot more in it but due to lack of High flow intakes, It wont reach the cam's rpm ceiling of 7500. It starts to fall off at about 6500. If I can find or convert a intake and ignition system to handle the rpms, it probably will be making close to 600 hp or higher.
550 hp from a LS1 can be attained with a little over 2 grand. So I've been told. I never built one to see if that's true. Yet... But i have checked out the prices for parts to get that HP and it's not impossible to do.
T
Rusty Nutz said:
Yes, the early optispark set up was known for failure due to condensation and lack of appropriate venting but I've been running one of these on the LT1 in my truck for over 15 years with no issues. Far from garbage in my opinion. The early optispark modules can be modified for better venting if one chooses to do it for peace of mind. No need to spend the farm on aftermarket ignition systems......
Anubis said:
Ok, I need to clear this up. The opti spark is great for a DD car that hardly ever sees 5000 rpm. But even the vented second style opti spark fails on serious street/strip cars. I've personally seen rotors get ground down and arching cross fire tracks created by heat (Even on the vented caps). But these cars are run hard!!! some are running 11, 10, and 9 second 1/4 mile times. The motor I built is running 12.5:1 compression and others have been running as high as 14:1. At these pressures a misfire is damaging, even at first start up. That's how LT1 starters get broken.
So I stand on the opti spark being problematic for performance use.
T
The sleeves are cast in the block, can't just press them out like with normal sleeved engines. The bad sleeve would have to be bore out and the block machined to accept a press in sleeve. Iron block is a safer bet when buying a used motor.[/quote]
Yes but I would not consider that a cost effective way to fix an ls1 block. I don't know how much the machining would be but at least in my area its pretty expensive to get any engine machine work done.
Yes but I would not consider that a cost effective way to fix an ls1 block. I don't know how much the machining would be but at least in my area its pretty expensive to get any engine machine work done.
I agree it would not be cost effective to replace a LS cylinder sleeve, way too much expensive machine work. Just finding another motor would be the cheapest route if you end up with a bum LS. That is why I said buying an used iron block motor is safer over a used aluminum block motor. Iron block you can just rebore if need be.
jetsetw31 said:
I see nothing in the OPs post to lead me to believe he wants to build a 7500 RPM or a 550 Hp motor. He has asked for something he can do basic bolt ons to that is affordable. So I stand by everything I typed, and we will simply just disagree.
Roy
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