Motor philosophy
01-09-2007, 04:16 PM
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Motor philosophy
If one is going to set up a B series DOHC Honda motor, I have some questions:
1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).
2) Can one replace the rotating rotating asembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.
3) If this all works out, does there need to be any modification to the block or the cyliders? Will the 2mm longer stroke affect anything?
4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotaing internals versus GSR rotating internals?
5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.
What are your thoughts?
1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).
2) Can one replace the rotating rotating asembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.
3) If this all works out, does there need to be any modification to the block or the cyliders? Will the 2mm longer stroke affect anything?
4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotaing internals versus GSR rotating internals?
5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.
What are your thoughts?
01-09-2007, 06:27 PM
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If one is going to set up a B series DOHC Honda motor, I have some questions:
1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).
2) Can one replace the rotating rotating asembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.
3) If this all works out, does there need to be any modification to the block or the cyliders? Will the 2mm longer stroke affect anything?
4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotaing internals versus GSR rotating internals?
5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.
What are your thoughts?
1) If you have an installed B18C1 block, normally the correct rotaing assembly is also inside. (GSR crank, rods, and pistons).
2) Can one replace the rotating rotating asembly with an LS crank (89mm stroke versus 87mm GSR stroke) and LS rods (5.394 inches versus 5.430 inch GSR rod length)? If so, do you retain the GSR pistons? I would think you can if the deck heights of a B18C1 block and and an LS B18B block are the same.
3) If this all works out, does there need to be any modification to the block or the cyliders? Will the 2mm longer stroke affect anything?
4) Basically, I'm trying to assess the validity of the ever popular LS VTEC build. If all other things are equal (GSR head, GSR cams, P72 GSR ecu, etc.), then is there any real gains of LS rotaing internals versus GSR rotating internals?
5) Forged pistons versus OEM pistons? If the car is more of a street car, and not so much a drag or track car, is there any benefit of forged versus OEM pistons? The motor would immediately have small power adders such as header, ECU upgrade, mild cams, etc. I may want to boost it 6-8 psi in the future. Yet I want the motor to have as much longevity as close to OEM Honda as possible.
What are your thoughts?
The main benefit of the longer stroke is a gain in low to mid range torque.
If you plan on boosting, you might as well spend the extra $700 +/- on forged pistons & rod's. For anything under 400 whp, Eagle rods are a popular choice.
If you want my advice:
a) Since an LS block is considerably cheaper than a GSR block, why don't you just use an LS block and a vtec head? Golden Eagle makes an oil supply kit which eliminates the need to tap the block. It will save you money in the long run. I see this as the cheapest option, whether you stay NA or go FI.
b) If you are planning to boost and must have a GSR block, then I would scratch the LS crank. Just use forged piston's and rods, and with proper tuning you could make between 300 & 400 whp. The additional torque provided by the LS crank won't be missed in a FI application, unless your talking serious power. IMO anyway.
01-09-2007, 07:12 PM
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Yes, you can use an LS Crank & Rod's in a GSR block. You might have clearance issues with the Oil Squirter's, but don't quote me on that. The engine will run fine without them, and they are useless if you choose forged pistons.
The main benefit of the longer stroke is a gain in low to mid range torque.
If you plan on boosting, you might as well spend the extra $700 +/- on forged pistons & rod's. For anything under 400 whp, Eagle rods are a popular choice.
If you want my advice:
a) Since an LS block is considerably cheaper than a GSR block, why don't you just use an LS block and a vtec head? Golden Eagle makes an oil supply kit which eliminates the need to tap the block. It will save you money in the long run. I see this as the cheapest option, whether you stay NA or go FI.
b) If you are planning to boost and must have a GSR block, then I would scratch the LS crank. Just use forged piston's and rods, and with proper tuning you could make between 300 & 400 whp. The additional torque provided by the LS crank won't be missed in a FI application, unless your talking serious power. IMO anyway.
The main benefit of the longer stroke is a gain in low to mid range torque.
If you plan on boosting, you might as well spend the extra $700 +/- on forged pistons & rod's. For anything under 400 whp, Eagle rods are a popular choice.
If you want my advice:
a) Since an LS block is considerably cheaper than a GSR block, why don't you just use an LS block and a vtec head? Golden Eagle makes an oil supply kit which eliminates the need to tap the block. It will save you money in the long run. I see this as the cheapest option, whether you stay NA or go FI.
b) If you are planning to boost and must have a GSR block, then I would scratch the LS crank. Just use forged piston's and rods, and with proper tuning you could make between 300 & 400 whp. The additional torque provided by the LS crank won't be missed in a FI application, unless your talking serious power. IMO anyway.
I am currently running a GSR motor. But it is an old one and will need a rebuild soon. So since I will be investing money, that's why I was seeing if an LS rotating assembly was a way to go. I know that a VTEC head and LS block are often mated together, but they were never meant to be mated together. I've heard too many horror stories of LS Blocks and VTEC heads causing blown head gaskets, oil leaks, compression problems, yadda yadda yadda. I figure, build an LS VTEC correctly with a B18C1 outer shell........so to speak, with the LS rotating assembly. The head will bolt on perfectly and no oil lines or conversion kits necessary.
Again the car is a street car that will not be fully raced. Is the extra torque (2mm more stroke) worth the changeover to LS rotating internals? Also would I need to go with LS pistons or stick to GSR pistons? My common sense tells me that I can stick to GSR pistons due to the same block deck height between a B18C and B18B............unless I'm wrong.
When I choose pistons, are forged pistons absolutely necessary for mild upgrades or mild boost? OEM motors and internals have always seemed to do just fine with mild upgrades.
01-10-2007, 04:51 AM
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FYI,
I am currently running a GSR motor. But it is an old one and will need a rebuild soon. So since I will be investing money, that's why I was seeing if an LS rotating assembly was a way to go. I know that a VTEC head and LS block are often mated together, but they were never meant to be mated together. I've heard too many horror stories of LS Blocks and VTEC heads causing blown head gaskets, oil leaks, compression problems, yadda yadda yadda. I figure, build an LS VTEC correctly with a B18C1 outer shell........so to speak, with the LS rotating assembly. The head will bolt on perfectly and no oil lines or conversion kits necessary.
Again the car is a street car that will not be fully raced. Is the extra torque (2mm more stroke) worth the changeover to LS rotating internals? Also would I need to go with LS pistons or stick to GSR pistons? My common sense tells me that I can stick to GSR pistons due to the same block deck height between a B18C and B18B............unless I'm wrong.
When I choose pistons, are forged pistons absolutely necessary for mild upgrades or mild boost? OEM motors and internals have always seemed to do just fine with mild upgrades.
I am currently running a GSR motor. But it is an old one and will need a rebuild soon. So since I will be investing money, that's why I was seeing if an LS rotating assembly was a way to go. I know that a VTEC head and LS block are often mated together, but they were never meant to be mated together. I've heard too many horror stories of LS Blocks and VTEC heads causing blown head gaskets, oil leaks, compression problems, yadda yadda yadda. I figure, build an LS VTEC correctly with a B18C1 outer shell........so to speak, with the LS rotating assembly. The head will bolt on perfectly and no oil lines or conversion kits necessary.
Again the car is a street car that will not be fully raced. Is the extra torque (2mm more stroke) worth the changeover to LS rotating internals? Also would I need to go with LS pistons or stick to GSR pistons? My common sense tells me that I can stick to GSR pistons due to the same block deck height between a B18C and B18B............unless I'm wrong.
When I choose pistons, are forged pistons absolutely necessary for mild upgrades or mild boost? OEM motors and internals have always seemed to do just fine with mild upgrades.
01-10-2007, 10:39 AM
#5
been there done that
FYI,
I am currently running a GSR motor. But it is an old one and will need a rebuild soon. So since I will be investing money, that's why I was seeing if an LS rotating assembly was a way to go. I know that a VTEC head and LS block are often mated together, but they were never meant to be mated together. I've heard too many horror stories of LS Blocks and VTEC heads causing blown head gaskets, oil leaks, compression problems, yadda yadda yadda. I figure, build an LS VTEC correctly with a B18C1 outer shell........so to speak, with the LS rotating assembly. The head will bolt on perfectly and no oil lines or conversion kits necessary.
Again the car is a street car that will not be fully raced. Is the extra torque (2mm more stroke) worth the changeover to LS rotating internals? Also would I need to go with LS pistons or stick to GSR pistons? My common sense tells me that I can stick to GSR pistons due to the same block deck height between a B18C and B18B............unless I'm wrong.
When I choose pistons, are forged pistons absolutely necessary for mild upgrades or mild boost? OEM motors and internals have always seemed to do just fine with mild upgrades.
I am currently running a GSR motor. But it is an old one and will need a rebuild soon. So since I will be investing money, that's why I was seeing if an LS rotating assembly was a way to go. I know that a VTEC head and LS block are often mated together, but they were never meant to be mated together. I've heard too many horror stories of LS Blocks and VTEC heads causing blown head gaskets, oil leaks, compression problems, yadda yadda yadda. I figure, build an LS VTEC correctly with a B18C1 outer shell........so to speak, with the LS rotating assembly. The head will bolt on perfectly and no oil lines or conversion kits necessary.
Again the car is a street car that will not be fully raced. Is the extra torque (2mm more stroke) worth the changeover to LS rotating internals? Also would I need to go with LS pistons or stick to GSR pistons? My common sense tells me that I can stick to GSR pistons due to the same block deck height between a B18C and B18B............unless I'm wrong.
When I choose pistons, are forged pistons absolutely necessary for mild upgrades or mild boost? OEM motors and internals have always seemed to do just fine with mild upgrades.
unless you're trying to make 400+whp you can boost fine with the stock internals as long as the engine is still healthy and you have a good tune to back it up.
01-14-2007, 08:13 AM
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This is all great info. Thanks.
GSR pistons Sounds like a no brainer. Since the block deck heights are the same between a B18C and a B18A/B, I want to keep the OEM 10.0:1 compression using my existing GSR head.
LS rods I will probably get a set of Eagle rods for the B18A/B.....AKA the LS motor. These are shorter than the GSR rods because of the longer LS crankshaft stroke. Will LS rods whether OEM or forged have any compatibility issues with wristpins or sizing with GSR pistons whether they are OEM or forged?
LS crankshaft Like the posts here say, as well as other people I've talked to, I will have to get a stock LS crankhaft worked to allow clearance for the VTEC oil squirters. Of course the other work will need to be done also........things like micropolishing and balancing. What's the cost for getting these 3 items done? Would it be better for me to just buy an Eagle LS crank? These can be found for about $500 brand new. Apparently, the Eagle cranks are ready to install? Or do you have to slightly balance them even more? Do they already come ready to clear the VTEC oil squirters?
GSR pistons Sounds like a no brainer. Since the block deck heights are the same between a B18C and a B18A/B, I want to keep the OEM 10.0:1 compression using my existing GSR head.
LS rods I will probably get a set of Eagle rods for the B18A/B.....AKA the LS motor. These are shorter than the GSR rods because of the longer LS crankshaft stroke. Will LS rods whether OEM or forged have any compatibility issues with wristpins or sizing with GSR pistons whether they are OEM or forged?
LS crankshaft Like the posts here say, as well as other people I've talked to, I will have to get a stock LS crankhaft worked to allow clearance for the VTEC oil squirters. Of course the other work will need to be done also........things like micropolishing and balancing. What's the cost for getting these 3 items done? Would it be better for me to just buy an Eagle LS crank? These can be found for about $500 brand new. Apparently, the Eagle cranks are ready to install? Or do you have to slightly balance them even more? Do they already come ready to clear the VTEC oil squirters?
01-14-2007, 10:06 AM
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01-14-2007, 12:04 PM
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been there done that
LS rods I will probably get a set of Eagle rods for the B18A/B.....AKA the LS motor. These are shorter than the GSR rods because of the longer LS crankshaft stroke. Will LS rods whether OEM or forged have any compatibility issues with wristpins or sizing with GSR pistons whether they are OEM or forged?
LS crankshaft Like the posts here say, as well as other people I've talked to, I will have to get a stock LS crankhaft worked to allow clearance for the VTEC oil squirters. Of course the other work will need to be done also........things like micropolishing and balancing. What's the cost for getting these 3 items done? Would it be better for me to just buy an Eagle LS crank? These can be found for about $500 brand new. Apparently, the Eagle cranks are ready to install? Or do you have to slightly balance them even more? Do they already come ready to clear the VTEC oil squirters?