Maintenance 101 --Understanding your tCs' engine--
01-31-2007, 01:59 AM
#1
Senior Member
SL Member
Thread Starter
Join Date: Dec 2006
Location: San Diego, CA
Posts: 284
Maintenance 101 --Understanding your tCs' engine--
Okay... This post is for first time buyers, new drivers, potential tuners, newcomers to the forum (n00b's). Hope this information provides useful.
*Note* Most information will be referenced from other websites. I will notate at the end of the article for references.
Engine
The scion tC is a 2.4 DOHC (dual overhead cam) VVT-i (Variable Valve timing intelligence) 16-valve 4 cylinder engine with 161hp and 162 lb-ft of torque. The compression ratio is 9.6:1.
-Understanding how the motor works-
This is an example of a 4-stroke combustion engine. You'll notice the intake valve on the top right, the piston inside the cylinder, and the exhaust valve on the top left. Above each valve is the camshaft. (Notice the lobes on the camshaft working with the valves, keeping everything synchronized.) The spark plugs between the valves, (where the spark flame comes from.) The bottom end contains the crankcase containing the crankshaft. The piston is connected to the crankshaft via piston rods.
The stages are
Stage 1 is intake - air entering the cylinder.
Stage 2 is compression - fuel and air is mixed and the cylinder compresses them together causing an explosion. (Notice the spark plug in between the valves creating a spark when the piston travels up)
Stage 3 is power - The explosion from stage 2 thrusting the piston down to it's lowest point.
Stage 4 is exhaust - remaining gases are expelled from the cylinder through the exhaust valve into the exhaust manifold.
On a 4 cylinder engine, this process is occuring 4 times, once in each cylinder. Never the same stage at the same time though. It may seem like 1 and 4, and 2 and 3 are on the same stage, but they are not, look closer, one is on intake, one is on compression, one is on power, and one is on exhaust, this process is constant.
-A bit on VVT-i-
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.
VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. In 1998, "Dual" VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza's 3S-GE engine. Dual VVT-i is also found in Toyota's new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Other Dual VVT-i engines include the upcoming 1.8L 2ZR-FE I4, which will see implementation in Toyota's next generation of compact vehicles. By adjusting the valve timing, engine start and stop occur virtually unnoticeable at minimum compression, and fast heating of the catalytic converter to its light-off temperature is possible, thereby reducing HC emissions considerably.
*Courtesy wikipedia.org*
-Understanding Octane and Compression-
A low octane fuel, like 87, has a high tendancy to autoignite and 87 octane can handle the least amount of compression before igniting. This means that once 87 octane has reached a certain compression, it will autoignite.
Pre-ignition - When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine.
Detonation - After combustion, if there is a remaining mixture of air/fuel it can be ignited by heat and pressure from the the advancing flame front. If this occurs for a certain length of time, detonation occurs.
It is also possible for Pre-ignition to lead to detonation and vice-versa.
This is why certain engines have a specific compression ratio and required a specific octane. Everything is predetermined so that when air/fuel are mixed, at the same time the flame-front from the spark plug causes combustion (stage 3) inside the cylinder.
The tC is designed to run on 87 octane unless the compression ratio is changed. This only happens when you replace the stock pistons with high compression pistons to get more power out of the motor. With a N/A, Natural Aspiration high compression motor, a turbochager, or a supercharger, you need to use a higher octane because if you use a lower grade octane like 87 or 89, you will experience pre-ignition or detonation.
Imagine with the image above, that the explosion occurs before the piston reaches the point where the explosion should occur. The reason is the 87 octane fuel cannot be compressed as much as 91 octane can be.
So, in an engine with a high compression like 11.0:1, and using 87 octane, there is less volume in the cylinder, and since 87 octane can only be compressed to a certain point, the explosion occurs prematurely.
versus
An engine with a low compression like 9.6:1, where there is more volume in the cylinder, using, say, 87 octane is alright because at the point of compression where 87 octane is supposed to ignite it does.
Does all that make sense?
High compression engines can produce more power. Take the tC motor and compare it to a RSX Type-S motor. I think its 10.1:1. This engine is smaller (I think 2.0L) but has a higher compression ratio, resulting in higher rev, and more power.
In a nut shell... The more volume there is in the cylinder the lower the compression will be, where-as the less volume you have in the cylinder, the higher the compression will be. (A couple ways to change the compression is to change the pistons, bore the cylinders, increase/decrease the stroke of the pistons, and changing the head gasket.)
-Breaking in your engine-
This is very controversial, but since the tC is not a high performace engine, we are going to go the recommended way in the manual. Most people say that drive it hard and drive it fast, and of course the manual says otherwise. The reason it's important to break your engine in slow and easy is because Everything in the motor is working together and certain things need to mold, and certain things need to set. For example, it's very important that the rings on the piston set in the cylinder so that you don't end up burning oil. Same reason that when you first start up your car, you want to let it warm up for a few minutes so that the engine can run at it's proper temperature, before driving it around.
Here are some important things to remember if you're breaking in your car.
- Don't over rev the engine if you can help it. Remember the rings need to set.
- When you're on the highway try not to maintain a constant speed. If your driving at 80, after a few minutes speed up to 90, or slow down to 70. Don't let your engine get used to being at a certain speed. City driving is preferred over highway driving for the first 1000 miles.
- (5 speed owners only) When you are driving, for the first 300 miles shift at lower RPM's, then at 400 miles shift a little higher. The idea is to progressively increase your shifting RPM.
- Use the proper fuel rating.
- Maintenance your car at regular intervals. (First 3,000 or 5,000 miles depending on manufacturer and driving.)
- Finally when you start up your car allow it to warm up. Wait for the temp neddle to move, or for the RPM idle to drop to about 900.
-Oil-
Alot of people discuss what oil to use, high performance this, heavy weight that. Keep in mind that oil is very complex and very specific just like octane. Don't go using a heavy weight oil because someone said it's better, and don't go using a lighter weight because someone else said it's better. Depending on where you live (temperature), and the performance level of your car should determine the type of oil you use.
I'm not going to get into the huge bit about what oil to use for your car because someone already wrote an impecible articl on oil. The link is included at the end of this topic. The one thing I will tell you is that synthetic oil is a good idea. The reason for this, and I will quote since some are too lazy to read the article...
"The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendancy to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justifed in your application."
Here's a breakdown.
Superior high temp oxidation resistance means that, it is not prone to oxidization. -Oxidation is the loss of electrons by a molecule, atom or ion.- High film strength means that even though the oil is spread thin, like between the cylinder and piston, it will stay in tact better, less chance of it breaking apart. Very low tendancy to form deposits means you have cleaner oil, for a longer time resulting in less oil changes. A stable viscosity base means the strength of the oil to maintain a certain amount of stress. And low temperature flow characteristics means that the oil can spread more easily even at lower temperatures.
To read up on this topic more here is an excellent article... http://www.howstuffworks.com/framed....nfo/oiled.html
-Changing your Oil-
It is recommended for soft/easy drivers to change their oil every 5,000 miles, while people who are harder drivers, or put alot of stress on their motors change their oil every 3,000 miles.
Search the forum to see what others say about changing oil.
*The information above is in my opinion. Some may agree, some may disagree*
Here's two links about warranties.
https://www.scionlife.com/forums/vie...=warranty+info
https://www.scionlife.com/forums/vie...=warranty+info
Remember... If you have a problem with your car and it is under warranty, TAKE IT TO THE DEALERSHIP. Have a tech ride with you so you can SHOW them the problem rather than explain it to them.
I hope this was useful... and I hope that it gets sticky'd.
Even if for a little while!
And don't forget to
Hope this all helped.
*Info pulled from howstuffworks and wikipedia. Dummied down by me.*
*Note* Most information will be referenced from other websites. I will notate at the end of the article for references.
Engine
The scion tC is a 2.4 DOHC (dual overhead cam) VVT-i (Variable Valve timing intelligence) 16-valve 4 cylinder engine with 161hp and 162 lb-ft of torque. The compression ratio is 9.6:1.
-Understanding how the motor works-
This is an example of a 4-stroke combustion engine. You'll notice the intake valve on the top right, the piston inside the cylinder, and the exhaust valve on the top left. Above each valve is the camshaft. (Notice the lobes on the camshaft working with the valves, keeping everything synchronized.) The spark plugs between the valves, (where the spark flame comes from.) The bottom end contains the crankcase containing the crankshaft. The piston is connected to the crankshaft via piston rods.
The stages are
Stage 1 is intake - air entering the cylinder.
Stage 2 is compression - fuel and air is mixed and the cylinder compresses them together causing an explosion. (Notice the spark plug in between the valves creating a spark when the piston travels up)
Stage 3 is power - The explosion from stage 2 thrusting the piston down to it's lowest point.
Stage 4 is exhaust - remaining gases are expelled from the cylinder through the exhaust valve into the exhaust manifold.
On a 4 cylinder engine, this process is occuring 4 times, once in each cylinder. Never the same stage at the same time though. It may seem like 1 and 4, and 2 and 3 are on the same stage, but they are not, look closer, one is on intake, one is on compression, one is on power, and one is on exhaust, this process is constant.
-A bit on VVT-i-
VVT-i, or Variable Valve Timing with intelligence, is an automobile variable valve timing technology developed by Toyota. The Toyota VVT-i system replaces the Toyota VVT offered starting in 1991 on the 4A-GE 20-Valve engine. The VVT system is a 2-stage hydraulically controlled cam phasing system.
VVT-i, introduced in 1996, varies the timing of the intake valves by adjusting the relationship between the camshaft drive (belt, scissor-gear or chain) and intake camshaft. Engine oil pressure is applied to an actuator to adjust the camshaft position. In 1998, "Dual" VVT-i (adjusts both intake and exhaust camshafts) was first introduced in the RS200 Altezza's 3S-GE engine. Dual VVT-i is also found in Toyota's new generation V6 engine, the 3.5L 2GR-FE V6. This engine can be found in the Avalon, RAV4, and Camry in the US, the Aurion in Australia, and various models in Japan, including the Estima. Other Dual VVT-i engines include the upcoming 1.8L 2ZR-FE I4, which will see implementation in Toyota's next generation of compact vehicles. By adjusting the valve timing, engine start and stop occur virtually unnoticeable at minimum compression, and fast heating of the catalytic converter to its light-off temperature is possible, thereby reducing HC emissions considerably.
*Courtesy wikipedia.org*
-Understanding Octane and Compression-
A low octane fuel, like 87, has a high tendancy to autoignite and 87 octane can handle the least amount of compression before igniting. This means that once 87 octane has reached a certain compression, it will autoignite.
Pre-ignition - When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine.
Detonation - After combustion, if there is a remaining mixture of air/fuel it can be ignited by heat and pressure from the the advancing flame front. If this occurs for a certain length of time, detonation occurs.
It is also possible for Pre-ignition to lead to detonation and vice-versa.
This is why certain engines have a specific compression ratio and required a specific octane. Everything is predetermined so that when air/fuel are mixed, at the same time the flame-front from the spark plug causes combustion (stage 3) inside the cylinder.
The tC is designed to run on 87 octane unless the compression ratio is changed. This only happens when you replace the stock pistons with high compression pistons to get more power out of the motor. With a N/A, Natural Aspiration high compression motor, a turbochager, or a supercharger, you need to use a higher octane because if you use a lower grade octane like 87 or 89, you will experience pre-ignition or detonation.
Imagine with the image above, that the explosion occurs before the piston reaches the point where the explosion should occur. The reason is the 87 octane fuel cannot be compressed as much as 91 octane can be.
So, in an engine with a high compression like 11.0:1, and using 87 octane, there is less volume in the cylinder, and since 87 octane can only be compressed to a certain point, the explosion occurs prematurely.
versus
An engine with a low compression like 9.6:1, where there is more volume in the cylinder, using, say, 87 octane is alright because at the point of compression where 87 octane is supposed to ignite it does.
Does all that make sense?
High compression engines can produce more power. Take the tC motor and compare it to a RSX Type-S motor. I think its 10.1:1. This engine is smaller (I think 2.0L) but has a higher compression ratio, resulting in higher rev, and more power.
In a nut shell... The more volume there is in the cylinder the lower the compression will be, where-as the less volume you have in the cylinder, the higher the compression will be. (A couple ways to change the compression is to change the pistons, bore the cylinders, increase/decrease the stroke of the pistons, and changing the head gasket.)
-Breaking in your engine-
This is very controversial, but since the tC is not a high performace engine, we are going to go the recommended way in the manual. Most people say that drive it hard and drive it fast, and of course the manual says otherwise. The reason it's important to break your engine in slow and easy is because Everything in the motor is working together and certain things need to mold, and certain things need to set. For example, it's very important that the rings on the piston set in the cylinder so that you don't end up burning oil. Same reason that when you first start up your car, you want to let it warm up for a few minutes so that the engine can run at it's proper temperature, before driving it around.
Here are some important things to remember if you're breaking in your car.
- Don't over rev the engine if you can help it. Remember the rings need to set.
- When you're on the highway try not to maintain a constant speed. If your driving at 80, after a few minutes speed up to 90, or slow down to 70. Don't let your engine get used to being at a certain speed. City driving is preferred over highway driving for the first 1000 miles.
- (5 speed owners only) When you are driving, for the first 300 miles shift at lower RPM's, then at 400 miles shift a little higher. The idea is to progressively increase your shifting RPM.
- Use the proper fuel rating.
- Maintenance your car at regular intervals. (First 3,000 or 5,000 miles depending on manufacturer and driving.)
- Finally when you start up your car allow it to warm up. Wait for the temp neddle to move, or for the RPM idle to drop to about 900.
-Oil-
Alot of people discuss what oil to use, high performance this, heavy weight that. Keep in mind that oil is very complex and very specific just like octane. Don't go using a heavy weight oil because someone said it's better, and don't go using a lighter weight because someone else said it's better. Depending on where you live (temperature), and the performance level of your car should determine the type of oil you use.
I'm not going to get into the huge bit about what oil to use for your car because someone already wrote an impecible articl on oil. The link is included at the end of this topic. The one thing I will tell you is that synthetic oil is a good idea. The reason for this, and I will quote since some are too lazy to read the article...
"The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendancy to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justifed in your application."
Here's a breakdown.
Superior high temp oxidation resistance means that, it is not prone to oxidization. -Oxidation is the loss of electrons by a molecule, atom or ion.- High film strength means that even though the oil is spread thin, like between the cylinder and piston, it will stay in tact better, less chance of it breaking apart. Very low tendancy to form deposits means you have cleaner oil, for a longer time resulting in less oil changes. A stable viscosity base means the strength of the oil to maintain a certain amount of stress. And low temperature flow characteristics means that the oil can spread more easily even at lower temperatures.
To read up on this topic more here is an excellent article... http://www.howstuffworks.com/framed....nfo/oiled.html
-Changing your Oil-
It is recommended for soft/easy drivers to change their oil every 5,000 miles, while people who are harder drivers, or put alot of stress on their motors change their oil every 3,000 miles.
Search the forum to see what others say about changing oil.
*The information above is in my opinion. Some may agree, some may disagree*
Here's two links about warranties.
https://www.scionlife.com/forums/vie...=warranty+info
https://www.scionlife.com/forums/vie...=warranty+info
Remember... If you have a problem with your car and it is under warranty, TAKE IT TO THE DEALERSHIP. Have a tech ride with you so you can SHOW them the problem rather than explain it to them.
I hope this was useful... and I hope that it gets sticky'd.
Even if for a little while!And don't forget to
Hope this all helped.
*Info pulled from howstuffworks and wikipedia. Dummied down by me.*
01-31-2007, 03:13 AM
#2
Senior Member
SL Member
Team ScioNRG
Join Date: Sep 2005
Location: Norwalk, CT
Posts: 3,201
very nice. very useful. Its great when people actually understand that machine thingy that they paid 20K for lol.Now we need something like this for a clutch system so people begin to understand pressure plates, flywheels, etc
01-31-2007, 04:11 AM
#4
Senior Member
SL Member
Thread Starter
Join Date: Dec 2006
Location: San Diego, CA
Posts: 284
^Thanks guys. I think I can do a write up on the transmission and clutch system. I just need to sit down, read and translate to n00b-friendly language. That one took me about 2 hours. I just want to make sure they are sticky'd b/c I dont want them to be a waste of time. It is important that people understand instead of just doing something they don't get. That's why i'm pro-DIY! haha.
01-31-2007, 05:18 AM
#5
Senior Member
Scikotics
SL Member
Join Date: Nov 2004
Location: Minneapolis, MN
Posts: 9,731
Piston hitting the valve because of octane??? Absolutely NOT!
The "knock" associated with pre-ignition or detonation is due to the way the flame front interacts with the position of the pistons movement as well as the cylinder wall
A knock on the crank is either on the crank to rod interface or at the wrist pin. A knock on the cam is due to issues with the cam bearings or valve to cam interface and should be half crank speed. A "slapping" type of knock which is not even with engine speed and may sound more random can be piston slap. Those are the only knocks spoken of. If the piston hits the valve, you are done driving.
The only way a piston will contact a valve is if the timing chain breaks on an interference engine. The tC is a non-interference engine, so this will not happen. The piston is moving with the crank.. period. The only way the timing can be off between the valves and the piston is if the timing chain breaks, is SEVERELY worn, or the vvti is not being controlled correctly, none of which will cause a valve to contact the piston on this car.
A ROD is the part that connects a piston to the crank and has nothing to do with the valve.
Please get rid of that info! Write ups should be screened so people not knowing any better are not misled.
You cut and pasted some true info and then destroyed it with some very false info.
The "knock" associated with pre-ignition or detonation is due to the way the flame front interacts with the position of the pistons movement as well as the cylinder wall
A knock on the crank is either on the crank to rod interface or at the wrist pin. A knock on the cam is due to issues with the cam bearings or valve to cam interface and should be half crank speed. A "slapping" type of knock which is not even with engine speed and may sound more random can be piston slap. Those are the only knocks spoken of. If the piston hits the valve, you are done driving.
The only way a piston will contact a valve is if the timing chain breaks on an interference engine. The tC is a non-interference engine, so this will not happen. The piston is moving with the crank.. period. The only way the timing can be off between the valves and the piston is if the timing chain breaks, is SEVERELY worn, or the vvti is not being controlled correctly, none of which will cause a valve to contact the piston on this car.
A ROD is the part that connects a piston to the crank and has nothing to do with the valve.
Please get rid of that info! Write ups should be screened so people not knowing any better are not misled.
You cut and pasted some true info and then destroyed it with some very false info.
01-31-2007, 05:32 AM
#7
Senior Member
Scikotics
SL Member
Join Date: Nov 2004
Location: Minneapolis, MN
Posts: 9,731
You should also explain the difference (or look up a definition) between pre-ignition and detonation if you are even going to start trying to define things.
Pre-ignition occurs when "hot spots" of some type or another ignite the fuel as it comes in.
Detonation occurs when the initial flame front causes the rest of the charge to ignite all at once rather than smoothly.
Pre-ignition occurs when "hot spots" of some type or another ignite the fuel as it comes in.
Detonation occurs when the initial flame front causes the rest of the charge to ignite all at once rather than smoothly.
01-31-2007, 05:34 AM
#8
Senior Member
Scikotics
SL Member
Join Date: Nov 2004
Location: Minneapolis, MN
Posts: 9,731
Sorry to sound rude before, but I am a firm believer that if you are going to post up a "teaching thread" you should post because you know the info yourself rather than stuff that is cut and pasted in. When you do that, you pass on incorrect info like your original post.
And besides, you are cut and pasting directly from wiki. So really it is better off to just link people to that. Wiki is set up with so many internal links that people can just get the same info there.
And besides, you are cut and pasting directly from wiki. So really it is better off to just link people to that. Wiki is set up with so many internal links that people can just get the same info there.
01-31-2007, 05:41 AM
#9
Senior Member
SL Member
Thread Starter
Join Date: Dec 2006
Location: San Diego, CA
Posts: 284
I didn't cut and paste, I do know what i'm talking about but when I was writing it I was doing it on my down time at work. So I got some things mixed up and didn't properly edit. When I saw your post I went back to that area and saw the errors. It's ok that you came off harsh, I do the same, I believe that these threads should be 100% accurate too but at the same time I want new people to understand things in a simple explination rather than the technical stuff.
And not all the information above is wrong. There were some spots that needed to be corrected. Just point them out so it can be corrected, and try to do it w/o being rude. It's offensive when you state the information above is incorrect, rather than you saying there are parts that need to be reviewed because they're not accurate. I spent a good amount of time doing this, I didn't copy and paste, I used images, and cut and pasted the VVT-i part, (hence the *Courtesy Wikipedia*) but... that explains itself. Everything else I broke down and tried to make easy to understand for everyone else.
People on this forum would rather post and ask questions than search the net. But maybe this will help.
Why are you so hell bent on bashing me taking time to write this up? Anyone can look half the stuff on here up on the web, but... they do it here instead.
And not all the information above is wrong. There were some spots that needed to be corrected. Just point them out so it can be corrected, and try to do it w/o being rude. It's offensive when you state the information above is incorrect, rather than you saying there are parts that need to be reviewed because they're not accurate. I spent a good amount of time doing this, I didn't copy and paste, I used images, and cut and pasted the VVT-i part, (hence the *Courtesy Wikipedia*) but... that explains itself. Everything else I broke down and tried to make easy to understand for everyone else.
People on this forum would rather post and ask questions than search the net. But maybe this will help.
Why are you so hell bent on bashing me taking time to write this up? Anyone can look half the stuff on here up on the web, but... they do it here instead.
01-31-2007, 06:20 AM
#10
Member
SL Member
Join Date: Jan 2007
Posts: 79
Originally Posted by TrueSlide
I didn't cut and paste, I do know what i'm talking about but when I was writing it I was doing it on my down time at work. So I got some things mixed up and didn't properly edit. When I saw your post I went back to that area and saw the errors. It's ok that you came off harsh, I do the same, I believe that these threads should be 100% accurate too but at the same time I want new people to understand things in a simple explination rather than the technical stuff.
And not all the information above is wrong. There were some spots that needed to be corrected. Just point them out so it can be corrected, and try to do it w/o being rude. It's offensive when you state the information above is incorrect, rather than you saying there are parts that need to be reviewed because they're not accurate. I spent a good amount of time doing this, I didn't copy and paste, I used images, and cut and pasted the VVT-i part, (hence the *Courtesy Wikipedia*) but... that explains itself. Everything else I broke down and tried to make easy to understand for everyone else.
People on this forum would rather post and ask questions than search the net. But maybe this will help.
Why are you so hell bent on bashing me taking time to write this up? Anyone can look half the stuff on here up on the web, but... they do it here instead.
And not all the information above is wrong. There were some spots that needed to be corrected. Just point them out so it can be corrected, and try to do it w/o being rude. It's offensive when you state the information above is incorrect, rather than you saying there are parts that need to be reviewed because they're not accurate. I spent a good amount of time doing this, I didn't copy and paste, I used images, and cut and pasted the VVT-i part, (hence the *Courtesy Wikipedia*) but... that explains itself. Everything else I broke down and tried to make easy to understand for everyone else.
People on this forum would rather post and ask questions than search the net. But maybe this will help.
Why are you so hell bent on bashing me taking time to write this up? Anyone can look half the stuff on here up on the web, but... they do it here instead.
ha ha he's just ____y cuz he didn't do it, don't worry i liked it, lol although he was right about, my 1998 cavalier was NOT a non interferance motor.. haha timming belt broke... MY GOD
can you say boom
01-31-2007, 06:25 AM
#11
Senior Member
SL Member
Thread Starter
Join Date: Dec 2006
Location: San Diego, CA
Posts: 284
yea, i do admit that I had some incorrect information but I changed it. Everything should be accurate and hopefully easier to understand.
I'm not bashing on you engifineer but not all of us have a family owned shop and are surrounded by it almost all the time.
I'm not bashing on you engifineer but not all of us have a family owned shop and are surrounded by it almost all the time.
01-31-2007, 07:32 AM
#13
Senior Member
Big Sky Scion
SL Member
Join Date: Dec 2005
Location: six-two-six
Posts: 4,120
I think you should just remove the break-in and oil bits myself - or just point to the threads and leave it at that.
It's not really good info and not backed up with data - it's wishy-washy, if you get my drift.
The rest is good basic info, and good for folks new to this stuff.
Don't take that as a jab, it's just that break-in and oil are WAY to complex and your text is not good data - like the other bits are.
Good job.
Scott
It's not really good info and not backed up with data - it's wishy-washy, if you get my drift.
The rest is good basic info, and good for folks new to this stuff.
Don't take that as a jab, it's just that break-in and oil are WAY to complex and your text is not good data - like the other bits are.
Good job.
Scott
01-31-2007, 01:21 PM
#15
Senior Member
SL Member
Scion Evolution
Originally Posted by MJVsTC
Include something about the bearings and why so many people have spun them in their '05's.
01-31-2007, 01:35 PM
#16
Senior Member
SL Member
Join Date: May 2005
Location: Central PA
Posts: 2,840
Originally Posted by soros151
Originally Posted by MJVsTC
Include something about the bearings and why so many people have spun them in their '05's.
I didn't realize that I made it sound like it was a ginormous problem. It's not a huge problem that affects hundreds of tC's. Nonetheless, it's still a problem and I thought it may be a good idea to include an explanation of the issue.
Everyone on this thread needs to chill out.
01-31-2007, 01:46 PM
#17
Senior Member
SL Member
Scion Evolution
Since we may only know that there are a few documented cases, I can't seem to see what info could be used to explain that, expept a bad batch of bearings. I can't seem to find any other explanation.
01-31-2007, 02:18 PM
#18
Senior Member
Scikotics
SL Member
Team ScioNRG
Join Date: Jul 2006
Location: Peru, NY
Posts: 135
Imagine with the image above, that the explosion occurs before the piston reaches the point where the explosion should occur, you're going to experience pre-ignition because the 87 octane fuel cannot be compressed as much as 91 octane can be. Even though the high-compression piston is designed to travel further than the factory piston, it doesn't due to early explosion.
01-31-2007, 02:59 PM
#20
Senior Member
SL Member
Join Date: Mar 2006
Location: Quincy, MA
Posts: 195
Originally Posted by Jayjr
Imagine with the image above, that the explosion occurs before the piston reaches the point where the explosion should occur, you're going to experience pre-ignition because the 87 octane fuel cannot be compressed as much as 91 octane can be. Even though the high-compression piston is designed to travel further than the factory piston, it doesn't due to early explosion.
I believe what he was trying to say was that the piston would travel a shorter distance prior to combustion, continuing its pre-determined stroke through the explosion.