LS1/LS4 Hybrid. Possible?
02-01-2014, 10:18 PM
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LS1/LS4 Hybrid. Possible? I'm putting together an LS1 to drop into a longbed Jeep Comanche pickup. I'm using an NV3550 manual 5-speed, and an NP229 transfer case.
My LS1 block is from a 2000 Corvette. It's just a bare block, but it's been honed/bored to 3.905. I bought it from a guy who briefly used it as a 383 stroker. After 8k miles with nitrous, he retired it. I'm considering rebuilding it as a "regular" 5.7.
I also have a complete 51k-mile Monte Carlo LS4. I picked up this LS4 because I was attracted to the shortness of the package, but I've been discovering that the LS4 is the embarrassing nephew nobody wants to claim. Apparently you can't feasibly put a flywheel behind it, so that's why I went looking for an LS1 block.
But I hope to use as much of the LS4 as possible, such as the heads, pan, etc. I would really like to use the crank, rods, and front accessory set-up, too. Given my overbore, I realize I need to use a larger piston. I'm new to the LSx family, so I'm all ears when it comes to good advice. I understand that the LS4 crank is 10 mm shorter on the accessory side, and 3 mm shorter at the flywheel. Is there any reason why I can't use the accessories up front as-is? Seems like it would be nice to save space on that end of the motor. Research tells me I have a big problem on the flywheel side. Novak Adapters has everything you'd need to make a flywheel & clutch work on that end, but it's all for a normal LS1 crank. I wonder if I could just have my local machinist make a 3 mm spacer that will move the flywheel bolt surface 3 mm back? My machinist says making it is no big problem, but he didn't know if the bolts holes are the same spacing between the LS1 & the LS4, or if there are any other hidden issues. I'd really like to use everything I can from the LS4 because it is low mileage and "paid for". I've priced rotating assemblies and they start around $1800. Accessory packages start around $1200. Given what I'm spending elsewhere, I'd really like to save that money on the engine. I'm no boy racer & I'm not going drag racing. I just want a stout truck that will tow my boat and haul stuff energetically.
I know I'll need new pistons & rings & main & rod bearings, but if I could use the crank and rods, that would be a huge savings. So I'm wondering if anybody is aware of any incompatibilities I'm missing. (I'm not using the LS4 block b/c it's my understanding you can't get a 168-tooth flywheel in a bell housing at the back of that motor.)
The LS1 owner I got the block from also gave me an LS2 camshaft & yellow beehive valve springs. I wonder if that is a good cam choice for a truck? I'm told I need to put something else on the end of the camshaft…? I understand if I use the LS4 crank, I'm going to have a 58-tooth crank sensor. So I'll need to go with a 4x cam sensor, right? If this LS2 cam isn't a good choice, and/or I can't make it work with a 4x control system, then what's another good cam for a truck? (I'm considering using a MegaSquirt controller.)
I skimmed the site looking for a good place to post this kind of question, but I couldn't find a better one. In fact, I didn't find the LS4 listed on any of the topic pages, even the Gen IV page. But this being a combo question, I opted to put it here. I'm a newbie here, so don't hurt me too badly if I missed a more obvious place to post it!
Thomas
My LS1 block is from a 2000 Corvette. It's just a bare block, but it's been honed/bored to 3.905. I bought it from a guy who briefly used it as a 383 stroker. After 8k miles with nitrous, he retired it. I'm considering rebuilding it as a "regular" 5.7.
I also have a complete 51k-mile Monte Carlo LS4. I picked up this LS4 because I was attracted to the shortness of the package, but I've been discovering that the LS4 is the embarrassing nephew nobody wants to claim. Apparently you can't feasibly put a flywheel behind it, so that's why I went looking for an LS1 block.
But I hope to use as much of the LS4 as possible, such as the heads, pan, etc. I would really like to use the crank, rods, and front accessory set-up, too. Given my overbore, I realize I need to use a larger piston. I'm new to the LSx family, so I'm all ears when it comes to good advice. I understand that the LS4 crank is 10 mm shorter on the accessory side, and 3 mm shorter at the flywheel. Is there any reason why I can't use the accessories up front as-is? Seems like it would be nice to save space on that end of the motor. Research tells me I have a big problem on the flywheel side. Novak Adapters has everything you'd need to make a flywheel & clutch work on that end, but it's all for a normal LS1 crank. I wonder if I could just have my local machinist make a 3 mm spacer that will move the flywheel bolt surface 3 mm back? My machinist says making it is no big problem, but he didn't know if the bolts holes are the same spacing between the LS1 & the LS4, or if there are any other hidden issues. I'd really like to use everything I can from the LS4 because it is low mileage and "paid for". I've priced rotating assemblies and they start around $1800. Accessory packages start around $1200. Given what I'm spending elsewhere, I'd really like to save that money on the engine. I'm no boy racer & I'm not going drag racing. I just want a stout truck that will tow my boat and haul stuff energetically.
I know I'll need new pistons & rings & main & rod bearings, but if I could use the crank and rods, that would be a huge savings. So I'm wondering if anybody is aware of any incompatibilities I'm missing. (I'm not using the LS4 block b/c it's my understanding you can't get a 168-tooth flywheel in a bell housing at the back of that motor.)
The LS1 owner I got the block from also gave me an LS2 camshaft & yellow beehive valve springs. I wonder if that is a good cam choice for a truck? I'm told I need to put something else on the end of the camshaft…? I understand if I use the LS4 crank, I'm going to have a 58-tooth crank sensor. So I'll need to go with a 4x cam sensor, right? If this LS2 cam isn't a good choice, and/or I can't make it work with a 4x control system, then what's another good cam for a truck? (I'm considering using a MegaSquirt controller.)
I skimmed the site looking for a good place to post this kind of question, but I couldn't find a better one. In fact, I didn't find the LS4 listed on any of the topic pages, even the Gen IV page. But this being a combo question, I opted to put it here. I'm a newbie here, so don't hurt me too badly if I missed a more obvious place to post it!
Thomas
