4.6 zero tolerance?
01-06-2006, 10:27 AM
#22
3rd Gear Member
Join Date: Aug 2005
Location:
Posts: 984
RE: 4.6 zero tolerance?
ORIGINAL: SilverGTV8
Don't know how to say this but your statement is a bit flawed. There is far better technology then your local mom and pops machine shop has.
You said "You could make them to the 10 or 100 thousandth of an inch if you had the time and money". What you said is any where from .010 to .100 and if you said that to a machinest you gave a 90ths window of tolerance. He could do that with his eyes closed. What I think you were trying to say is any where from .001 to .0001 of an inch.
A typical line to line statement meaning the OD of one part nearly matched the mating ID part in dimension BUT will still go together if inserted properly. But a line to line difference is typically just into the tenths.
10ths or .010 is a common tolerance ( +/- .005), I typically work with parts that a toleranced +/- .001 (2thou swing). I have worked in the past in tenths (.0005) which is extremly small.
In the business area I work in it is not uncommon to see specs down in the tenths for critcal applications. I acuatlly use a pump that the tolerance between the drive piston and pressure housing is in to the millionths of an inch.
But you are correct it comes down to time and money.
But think about it this way. If you were to build a zero-tolerance part. Where would you fluid path be for you lubricant? But the ulitmate reason for not going line to line or zero tolerance is that metal expands and it can expand a lot when it gets hot. Making things to close tolerance often involves heat management to get the part accruate.
ORIGINAL: VARifleman
Tolerances also refer to the parts, and it is impossible to make a zero tolerance part as machines are not that accurate. You could make them to the 10 or 100 thousandth of an inch if you had the time and money, but to make them to closer tolerances than that is impossible with our technology.
ORIGINAL: SilverGTV8
All of that equals very bad.
We have the luxuary of running chains and not belts. It is quite uncommon to break a chain but common to break a belt.
It is also not commonly refered to as a "Zero-Tolerance" Motor but an "Interference" motor.
Zero tolerance implies that there is no allowable machine tolerence during assembly. If you built a zero tolerance motor it would lock-up with in minutes due to metal expansion as it heats up.
On a side note. The tolerance for the crank shaft end play is 6 to 11ths (0.006 to 0.011) and that's alot interms of machine tolerance.
All of that equals very bad.
We have the luxuary of running chains and not belts. It is quite uncommon to break a chain but common to break a belt.
It is also not commonly refered to as a "Zero-Tolerance" Motor but an "Interference" motor.
Zero tolerance implies that there is no allowable machine tolerence during assembly. If you built a zero tolerance motor it would lock-up with in minutes due to metal expansion as it heats up.
On a side note. The tolerance for the crank shaft end play is 6 to 11ths (0.006 to 0.011) and that's alot interms of machine tolerance.
You said "You could make them to the 10 or 100 thousandth of an inch if you had the time and money". What you said is any where from .010 to .100 and if you said that to a machinest you gave a 90ths window of tolerance. He could do that with his eyes closed. What I think you were trying to say is any where from .001 to .0001 of an inch.
A typical line to line statement meaning the OD of one part nearly matched the mating ID part in dimension BUT will still go together if inserted properly. But a line to line difference is typically just into the tenths.
10ths or .010 is a common tolerance ( +/- .005), I typically work with parts that a toleranced +/- .001 (2thou swing). I have worked in the past in tenths (.0005) which is extremly small.
In the business area I work in it is not uncommon to see specs down in the tenths for critcal applications. I acuatlly use a pump that the tolerance between the drive piston and pressure housing is in to the millionths of an inch.
But you are correct it comes down to time and money.
But think about it this way. If you were to build a zero-tolerance part. Where would you fluid path be for you lubricant? But the ulitmate reason for not going line to line or zero tolerance is that metal expands and it can expand a lot when it gets hot. Making things to close tolerance often involves heat management to get the part accruate.
HUH?
01-07-2006, 03:31 AM
#25
3rd Gear Member
Join Date: Aug 2005
Location:
Posts: 519
RE: 4.6 zero tolerance?
Well these are the kinds of threads I come here for... didnt know this.
When he said zero tolerance in a 4.6 I was like... maybe if they use them in a god damn f1 car... no joke though. f1 motors are built with INSANE tolerances. How the hell else can they rev to such ungodly RPMS.
Another thing I learned today, great thread
Jim
When he said zero tolerance in a 4.6 I was like... maybe if they use them in a god damn f1 car... no joke though. f1 motors are built with INSANE tolerances. How the hell else can they rev to such ungodly RPMS.
Another thing I learned today, great thread
Jim
01-07-2006, 12:21 PM
#26
4th Gear Member
Join Date: Aug 2003
Location: United States
Posts: 1,974
RE: 4.6 zero tolerance?
F1 motors are built to a tighter tolerance. They are more likly built to a +/-.002 as opposed to +/-.005. Our cars have even looser tolerances and are expected to have end play in the crank and cams. An F1 would tighten those areas up.
What people don't realize with toleranceing, is the effect of tempature. Believe it or not metal expands when hot and shrinks when cold. When you have a hole in a piece of metal when you make it hot it actually gets larger If you cool it, it wil get smaller. That is why if you have a stuck bolt they tell you to heat the area. The heat helps losen the lock point of the treads to help release the bolt. The problem is people usually heat the bolt too. But the bolt expands outwards when hot and make things worse. But all in all most of the time they come out.
That all has to be taken into consideration when building something to a tighter tolerance. F1 and all high race motors have an excellent understanding of metallurgy to ensure that the thighter tolerance don't cause issues.
A motor is never built in a drawing with zero tolerance. That print is what the motor is made too. A motor is designed with an allowable tolerance that will not affect performance or life. So motors will run at the low end some will run at the high end. But a well designed motor will run some where in the middle more often then out near the edges of the tolerance.
The high revving nature of a motor has really nothing to do with the tolerancing of the motors but with the weight of the components used in the drive train. The more mass it has the more rotational force pulling outward on the part as revs increase. This mass essenitally causes harmonics in the shaft that will eventaually hit a point that will damage the shaft unrepairbly. But a lot of what is holding back a motor is not that the rotaional mass is the issue but the valves. The valves springs will eventually reach a point where they cannot react fast enough from a compressed state to a resting position before becoming reacted on again. This is valve float and will cause damage to an interfernce motor when it occurs. But heavier springs increase weight and cause issues at low rpms where the force to move them is very difficult until the reach a harminc motion that is achived at high rpms.
What people don't realize with toleranceing, is the effect of tempature. Believe it or not metal expands when hot and shrinks when cold. When you have a hole in a piece of metal when you make it hot it actually gets larger If you cool it, it wil get smaller. That is why if you have a stuck bolt they tell you to heat the area. The heat helps losen the lock point of the treads to help release the bolt. The problem is people usually heat the bolt too. But the bolt expands outwards when hot and make things worse. But all in all most of the time they come out.
That all has to be taken into consideration when building something to a tighter tolerance. F1 and all high race motors have an excellent understanding of metallurgy to ensure that the thighter tolerance don't cause issues.
A motor is never built in a drawing with zero tolerance. That print is what the motor is made too. A motor is designed with an allowable tolerance that will not affect performance or life. So motors will run at the low end some will run at the high end. But a well designed motor will run some where in the middle more often then out near the edges of the tolerance.
The high revving nature of a motor has really nothing to do with the tolerancing of the motors but with the weight of the components used in the drive train. The more mass it has the more rotational force pulling outward on the part as revs increase. This mass essenitally causes harmonics in the shaft that will eventaually hit a point that will damage the shaft unrepairbly. But a lot of what is holding back a motor is not that the rotaional mass is the issue but the valves. The valves springs will eventually reach a point where they cannot react fast enough from a compressed state to a resting position before becoming reacted on again. This is valve float and will cause damage to an interfernce motor when it occurs. But heavier springs increase weight and cause issues at low rpms where the force to move them is very difficult until the reach a harminc motion that is achived at high rpms.
Thread
Thread Starter
Forum
Replies
Last Post
MustangForums Editor
4.6L (1996-2004 Modular) Mustang
3
10-09-2015 03:27 PM
