Balanced Camshaft?
- Thread starter Fubar
- Start date
Yes. Absolutely. As you may know we have focused much of 2011 in improving "power under the curve" with several of the TT installs. We have, IMO, been very successful to bring in full boost 1000 rpm or more SOONER which totally transforms the driveability of the cars. As such, I too await any data that shows how we could improve that even further with cam balancing, cam timing, etc. For example, one of the best TT's yet to leave our shop was at FULL boost at 3800 rpm. This car was simply incredible to drive. This was a bone-stock internals car. I look forward to see how the cars receiving some of your magic are pushing this to be even better!
MoTeC Magic
Spectator
MoTeC Magic
Spectator
Hi Gentlemen,
As for the cams... if you had them in front of you, it would be easy to see where the imbalance comes from. For those that don't have cams in front of them this may help to "see" what's going on and why this is important. Simple descriptions / terminology was chosen over more accurate / professional terminology to ease absorption by those interested and new to engine dynamics.
The image I created is pretty self-explanatory, and my description here is a little redundant of the information in the image. That said…
The firing order of the 5.4L GT and GT500 engine is 1-3-7-2-6-5-4-8. The engine cylinder numbering is 1-4 starting at the front of the block on the passenger’s side bank and 5-8 starting at the front on the driver’s side bank. If you follow the firing order and trace how the cylinder that is firing jumps from cylinder to cylinder and bank to bank… you will see that the power pulses fall in an uneven manner with regard to bank. It’s not a back and forth motion. Due to this, the cam profile and lobs follow this same pattern. Because the motor has multiple intake cams… the lobs are divided between the two banks. Because it is not a back and forth motion of cylinder power events (intake events too)... the lobs are not spaced evenly about the camshaft. There are three lobs per cam that are almost opposite of the 4th lob. This is where the balance “issues” are created.
There is no denying that this will cause vibration. The extent and result of said vibration imparted on the valve train is dependent on many variables, one of the biggest variables is speed (rpm). The higher the RPM, the higher the magnitude of the vibrational forces. To put it short and sweet this wreaks havoc on valve motion and other valve train components as many have stated within this thread.
Single camshaft motors that are even fire motors do not see near the issues because all the cam lobs are evenly spaced and balance one another. Inline, even fire engines with dual cams also see better balanced cams due to even lob spacing.
I too believe the balancing of the cams in any engine is worth the time spent, expecially on the Mod motor due to what has been described previously in this thread and what is illustrated below.
Cheers
As for the cams... if you had them in front of you, it would be easy to see where the imbalance comes from. For those that don't have cams in front of them this may help to "see" what's going on and why this is important. Simple descriptions / terminology was chosen over more accurate / professional terminology to ease absorption by those interested and new to engine dynamics.
The image I created is pretty self-explanatory, and my description here is a little redundant of the information in the image. That said…
The firing order of the 5.4L GT and GT500 engine is 1-3-7-2-6-5-4-8. The engine cylinder numbering is 1-4 starting at the front of the block on the passenger’s side bank and 5-8 starting at the front on the driver’s side bank. If you follow the firing order and trace how the cylinder that is firing jumps from cylinder to cylinder and bank to bank… you will see that the power pulses fall in an uneven manner with regard to bank. It’s not a back and forth motion. Due to this, the cam profile and lobs follow this same pattern. Because the motor has multiple intake cams… the lobs are divided between the two banks. Because it is not a back and forth motion of cylinder power events (intake events too)... the lobs are not spaced evenly about the camshaft. There are three lobs per cam that are almost opposite of the 4th lob. This is where the balance “issues” are created.
There is no denying that this will cause vibration. The extent and result of said vibration imparted on the valve train is dependent on many variables, one of the biggest variables is speed (rpm). The higher the RPM, the higher the magnitude of the vibrational forces. To put it short and sweet this wreaks havoc on valve motion and other valve train components as many have stated within this thread.
Single camshaft motors that are even fire motors do not see near the issues because all the cam lobs are evenly spaced and balance one another. Inline, even fire engines with dual cams also see better balanced cams due to even lob spacing.
I too believe the balancing of the cams in any engine is worth the time spent, expecially on the Mod motor due to what has been described previously in this thread and what is illustrated below.
Cheers
One reason I bet they changed the firing order on the new 2011 coyote motor. 15486372 This is the old pushrod firing order of 15426378 and the 8 and 2 swap has been common now in racing stuff for a few years. Also Gm started using this firing order too as there is less harmonics in engine do to the firing of the motor. MORE HP....
MoTeC Magic
Spectator
Hi BMF,
Doesn't change the cam balance issue... still has the same lob "pattern" just phased differently. You also still have one set of two successive power pulses on the same bank for all three firing orders... so one being better for cylinder filling due to less cylinder starvation isn't the answer. When you draw it out it looks like the answer is that the 15486372 firing order sets the "two consecutive, power pulse on the same bank occurrence" issue to opposing ends of the block. Whereas on the 15426378 order they happen across from each other on the back of the block and the 13726548 GT order to oppose each other at the front of the block. I can see how the Coyote firing would benefit harmonics. Only explanation as the crank is the same 4 plane arrangement. Cams are the only difference.
Ok Mark GO!...
*phone rings*
John: Hello
Fubar: I want new cams ground for my GT with the Coyote firing order
You got them on the shelf right John? :thumbsup
Cheers
Doesn't change the cam balance issue... still has the same lob "pattern" just phased differently. You also still have one set of two successive power pulses on the same bank for all three firing orders... so one being better for cylinder filling due to less cylinder starvation isn't the answer. When you draw it out it looks like the answer is that the 15486372 firing order sets the "two consecutive, power pulse on the same bank occurrence" issue to opposing ends of the block. Whereas on the 15426378 order they happen across from each other on the back of the block and the 13726548 GT order to oppose each other at the front of the block. I can see how the Coyote firing would benefit harmonics. Only explanation as the crank is the same 4 plane arrangement. Cams are the only difference.
Ok Mark GO!...
*phone rings*
John: Hello
Fubar: I want new cams ground for my GT with the Coyote firing order
You got them on the shelf right John? :thumbsup
Cheers
MoTeC Magic
Spectator
Probably has a little to do with it... I wouldn't think it is wasn't so much the "pattern" of pulsations since they all follow the same trend. Probably has to do as you suspect with moving where this "load up" of consecutive cylinders hitting on the same bank occurs relative to one another. IE (across at the front of the block, across at the back of the block, or diagonally)
This shows the "pattern" of pulses is basically the same. I think what matters is where they physically occur relative to one another in the block.
GT 1 3 7 2 6 5 4 8
You still get that [Boom Boom... same bank], Boom, Boom, [Boom Boom... same bank], Boom, Boom
Coyote 8 6 3 7 2 1 5 4
You still get that [Boom Boom... same bank], Boom, Boom, [Boom Boom... same bank], Boom, Boom
I just changed where we start the order to show the same same bank "load up"
Old Push Rod 7 8 1 5 4 2 6 3
You still get that [Boom Boom... same bank], Boom, Boom, [Boom Boom... same bank], Boom, Boom
I just changed where we start the order to show the same same bank "load up"
I could totally be wrong on this, harmonics are very complicated and I'm not a harmonics expert. I know enough to know that I don't know anything about it.
Cheers
Indy GT
Yea, I got one...too
MoTeC Magic-
Thanks again for another insightful post and I agree completely with your statement that "harmonics are very complicated". Those who profess to know the whys and wherefores are IMO blissfully uniformed.
As you are new to our Forum, there has been quite a lengthy discussion some time ago about harmonic dampers specifically on our GT's 5.4 engine. Questions of bigger, smaller, lighter, heavier, aluminum, steel, use of the GT500 damper, etc. have been discussed. I have talked at length to the Ford design engineers about the development of this specific damper and can say without reservation the design team spent considerable time on the dyno mapping multiple order dynamic responses and the damping systems necessary to attenuate each to an acceptable level. The level, degree of testing sophistication and equipment necessary to conduct this research is simply out of the reach of most if not all but the OEM’s to say nothing of the interpretation of the harmonic data.
Thanks again for you post!
Thanks again for another insightful post and I agree completely with your statement that "harmonics are very complicated". Those who profess to know the whys and wherefores are IMO blissfully uniformed.
As you are new to our Forum, there has been quite a lengthy discussion some time ago about harmonic dampers specifically on our GT's 5.4 engine. Questions of bigger, smaller, lighter, heavier, aluminum, steel, use of the GT500 damper, etc. have been discussed. I have talked at length to the Ford design engineers about the development of this specific damper and can say without reservation the design team spent considerable time on the dyno mapping multiple order dynamic responses and the damping systems necessary to attenuate each to an acceptable level. The level, degree of testing sophistication and equipment necessary to conduct this research is simply out of the reach of most if not all but the OEM’s to say nothing of the interpretation of the harmonic data.
Thanks again for you post!
MoTeC Magic
Spectator
Yep... pretty neat. Sounds like good conversation. Sitting in on the testing of the harmonics would surely be an interesting day!
Cheers
Cheers