Rebuilding stock motor
12-07-2005, 06:39 PM
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Rebuilding stock motor Ok I need some help cause i want to get this right. To start with I plan on sprying at least a 200 shot and I just want to redo the stock block add a cam and redo the heads. ( No boring of the motor if I dont have to.)
What size pistons do I need to get?
What size rods?
As for the cam what is the best size with that big of a shot?
What kind of rings and size on them?
I plan to keep the heads stock size just upgrade the parts.
If I forgot anything just add on and any advice would be great. Thanks
What size pistons do I need to get?
What size rods?
As for the cam what is the best size with that big of a shot?
What kind of rings and size on them?
I plan to keep the heads stock size just upgrade the parts.
If I forgot anything just add on and any advice would be great. Thanks
12-07-2005, 07:58 PM
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For a start you're going to want to swap your 4.1 rear gears to something more in the range of 3.0 - 3.5 ratio for a 200hp shot if you have an automatic. It's also better to run a tighter converter specifically designed for the high torque of nitrous. If you're a manual then disreguard.
A lot of people like h-beam rods, and you have a choice in length. The piston size is going to depend on what rod length you go with, so they are inter-dependant. I would talk to the piston company first to get set up with the best affordable piston, and they will be able to help you figure the required rod length from there. Pistons come in many more sizes than connecting rods, so you'll want to shoot for a sizing range that allows you to use an off-the-shelf rod. Talk to the piston manufacturer. Work out matching sizes with them.
Most people use forged flat top pistons with small valve reliefs. I suggest polishing the tops of the pistons and rounding off any sharp edges. Some people get a piston with the first ring-land set further away from the deck to keep the rings away from the heat.
At the least get a high performance 3-angle valvejob cut on the seats and back-cut the valves. I would open the seat and throat area to 90% of the valve-head diameter and radius into the chamber. I'd also polish the chamber and valves. You can do a lot with the heads, but this is just the least I would do.
Ring gap is going to depend on a few things. Most people run a slightly wider gap on the top ring. If you get the lowered first land in your piston and you don't run your N2O system on kill at 200*F+ engine temp then you probably will not need to run a wider than recommended top gap.
If you run your engine at 200*F and then spray it with pump gas for extended periods like those highway-roll races, then you'd better run a wider gap.
For sparkplugs with a big shot, you'll need a race type plug in the engine when you intend to spray. This will be a very cold nonresistor plug... I like the Autolite AR472 personally. That's what it takes to survive the heat. You don't need them in when you're not spraying, and in fact they may tend to fowl in some cars during normal driving depending on the tune.
For the big nitrous system, direct port with a second independant fuel system is your best choice. A dry system is your second best choice.
Some people run "wet kits" at that high of power level, but I wouldn't. When you're pumping that much extra N2O and fuel into the engine, distribution is very important.
I'm sure you'll get some more input, but here is mine.
A lot of people like h-beam rods, and you have a choice in length. The piston size is going to depend on what rod length you go with, so they are inter-dependant. I would talk to the piston company first to get set up with the best affordable piston, and they will be able to help you figure the required rod length from there. Pistons come in many more sizes than connecting rods, so you'll want to shoot for a sizing range that allows you to use an off-the-shelf rod. Talk to the piston manufacturer. Work out matching sizes with them.
Most people use forged flat top pistons with small valve reliefs. I suggest polishing the tops of the pistons and rounding off any sharp edges. Some people get a piston with the first ring-land set further away from the deck to keep the rings away from the heat.
At the least get a high performance 3-angle valvejob cut on the seats and back-cut the valves. I would open the seat and throat area to 90% of the valve-head diameter and radius into the chamber. I'd also polish the chamber and valves. You can do a lot with the heads, but this is just the least I would do.
Ring gap is going to depend on a few things. Most people run a slightly wider gap on the top ring. If you get the lowered first land in your piston and you don't run your N2O system on kill at 200*F+ engine temp then you probably will not need to run a wider than recommended top gap.
If you run your engine at 200*F and then spray it with pump gas for extended periods like those highway-roll races, then you'd better run a wider gap.
For sparkplugs with a big shot, you'll need a race type plug in the engine when you intend to spray. This will be a very cold nonresistor plug... I like the Autolite AR472 personally. That's what it takes to survive the heat. You don't need them in when you're not spraying, and in fact they may tend to fowl in some cars during normal driving depending on the tune.
For the big nitrous system, direct port with a second independant fuel system is your best choice. A dry system is your second best choice.
Some people run "wet kits" at that high of power level, but I wouldn't. When you're pumping that much extra N2O and fuel into the engine, distribution is very important.
I'm sure you'll get some more input, but here is mine.
12-07-2005, 09:13 PM
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thanks very much. that is where I was head but just wanted to make sure i was going the right way. Just to let you know it is a M6 with 411 and the kit that I have is a NX dual shark kit. This is what I used last year and had no problem. But you are saying that a 200 might not work so good, and thanks agian.
12-07-2005, 09:20 PM
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Originally Posted by white2001s10
For a start you're going to want to swap your 4.1 rear gears to something more in the range of 3.0 - 3.5 ratio for a 200hp shot if you have an automatic. It's also better to run a tighter converter specifically designed for the high torque of nitrous. If you're a manual then disreguard.
A lot of people like h-beam rods, and you have a choice in length. The piston size is going to depend on what rod length you go with, so they are inter-dependant. I would talk to the piston company first to get set up with the best affordable piston, and they will be able to help you figure the required rod length from there. Pistons come in many more sizes than connecting rods, so you'll want to shoot for a sizing range that allows you to use an off-the-shelf rod. Talk to the piston manufacturer. Work out matching sizes with them.
Most people use forged flat top pistons with small valve reliefs. I suggest polishing the tops of the pistons and rounding off any sharp edges. Some people get a piston with the first ring-land set further away from the deck to keep the rings away from the heat.
At the least get a high performance 3-angle valvejob cut on the seats and back-cut the valves. I would open the seat and throat area to 90% of the valve-head diameter and radius into the chamber. I'd also polish the chamber and valves. You can do a lot with the heads, but this is just the least I would do.
Ring gap is going to depend on a few things. Most people run a slightly wider gap on the top ring. If you get the lowered first land in your piston and you don't run your N2O system on kill at 200*F+ engine temp then you probably will not need to run a wider than recommended top gap.
If you run your engine at 200*F and then spray it with pump gas for extended periods like those highway-roll races, then you'd better run a wider gap.
For sparkplugs with a big shot, you'll need a race type plug in the engine when you intend to spray. This will be a very cold nonresistor plug... I like the Autolite AR472 personally. That's what it takes to survive the heat. You don't need them in when you're not spraying, and in fact they may tend to fowl in some cars during normal driving depending on the tune.
For the big nitrous system, direct port with a second independant fuel system is your best choice. A dry system is your second best choice.
Some people run "wet kits" at that high of power level, but I wouldn't. When you're pumping that much extra N2O and fuel into the engine, distribution is very important.
I'm sure you'll get some more input, but here is mine.
A lot of people like h-beam rods, and you have a choice in length. The piston size is going to depend on what rod length you go with, so they are inter-dependant. I would talk to the piston company first to get set up with the best affordable piston, and they will be able to help you figure the required rod length from there. Pistons come in many more sizes than connecting rods, so you'll want to shoot for a sizing range that allows you to use an off-the-shelf rod. Talk to the piston manufacturer. Work out matching sizes with them.
Most people use forged flat top pistons with small valve reliefs. I suggest polishing the tops of the pistons and rounding off any sharp edges. Some people get a piston with the first ring-land set further away from the deck to keep the rings away from the heat.
At the least get a high performance 3-angle valvejob cut on the seats and back-cut the valves. I would open the seat and throat area to 90% of the valve-head diameter and radius into the chamber. I'd also polish the chamber and valves. You can do a lot with the heads, but this is just the least I would do.
Ring gap is going to depend on a few things. Most people run a slightly wider gap on the top ring. If you get the lowered first land in your piston and you don't run your N2O system on kill at 200*F+ engine temp then you probably will not need to run a wider than recommended top gap.
If you run your engine at 200*F and then spray it with pump gas for extended periods like those highway-roll races, then you'd better run a wider gap.
For sparkplugs with a big shot, you'll need a race type plug in the engine when you intend to spray. This will be a very cold nonresistor plug... I like the Autolite AR472 personally. That's what it takes to survive the heat. You don't need them in when you're not spraying, and in fact they may tend to fowl in some cars during normal driving depending on the tune.
For the big nitrous system, direct port with a second independant fuel system is your best choice. A dry system is your second best choice.
Some people run "wet kits" at that high of power level, but I wouldn't. When you're pumping that much extra N2O and fuel into the engine, distribution is very important.
I'm sure you'll get some more input, but here is mine.