lightweight pulleys worth having?
10 February 2014, 04:44 PM
#33
All I can say is I have been running light weight pulleys for over ten years with no adverse affects.i brought my pulleys from RCM and I asked him the same question about the damper and olley said to me do you think I would sell parts that would damage engines with the reputation RCM have to up keep.I never worried myself after that,and got them fitted
.SJ.
.SJ.
10 February 2014, 04:46 PM
#34
All I can say is I have been running light weight pulleys for over ten years with no adverse affects.i brought my pulleys from RCM and I asked him the same question about the damper and olley said to me do you think I would sell parts that would damage engines with the reputation RCM have to up keep.I never worried myself after that,and got them fitted.SJ.
.SJ.
10 February 2014, 04:59 PM
#35
Just because the pulley does not break, does not mean it is not causing an issue elsewhere.
Why was the centre thrust position moved to the rear then Chris?
Maybe it's a better idea to ask the engineers, rather than the salesmen.
Why was the centre thrust position moved to the rear then Chris?
Maybe it's a better idea to ask the engineers, rather than the salesmen.
10 February 2014, 05:13 PM
#37
Ren, I am not even going to bother with your comments anymore,. trying to get a rise out of me won't work - I just don't have the time
7 years ago ? , when they was first designed maybe - which we paid for regardless of blame and if they was indeed tightened up correctly - but we are not even talking about these pulleys,.
I am trying to get the point across that our pulleys are safe to run,... if they are not going to cause problems after 10 years then that's good enough for me!
I am trying to get the point across that our pulleys are safe to run,... if they are not going to cause problems after 10 years then that's good enough for me!
10 February 2014, 05:39 PM
#38
Maybe this thread will just give pause for thought before an owner decides whether or not fitting lightweight pulleys is the kindest thing they can be doing to a 90,000 mile STI 5 engine.
Last edited by Ren77; 10 February 2014 at 05:40 PM.
10 February 2014, 05:59 PM
#41
10 February 2014, 06:58 PM
#44
Scooby Regular
iTrader: (23)
Join Date: Jul 2008
Location: In the fast lane
Posts: 3,458
Likes: 0
Received 0 Likes
on
0 Posts
The thread wasn't aimed at him, his company, or his product directly, but he chose to defend his product.
However it must be said that the supporting evidence he has produced is only historical and anecdotal:- it works therefore it must be right.
The documentation I have posted is well founded on research and established principles of engine operation. The Fuji paper was written by engineers who registered patents on behalf of that company, and the ATI paper was written by Steve Dinan who develops race engines for use in Grand Am and Daytona prototypes.
If firm evidence (not opinion) exists to contradict the facts supported by those papers then I for one will be glad to see it and will promptly place an order for a set of Chris's pulleys, if he'll let me
However it's difficult to argue with this...
"Every time a cylinder fires, the force twists the crankshaft. When the cylinder stops firing the force ceases to act and the crankshaft starts to return to the untwisted position. However, the crankshaft will overshoot and begin to twist in the opposite direction, and then back again. Though this back-and-forth twisting motion decays over a number of repetitions due to internal friction, the frequency of vibration remains unique to the particular crankshaft."
10 February 2014, 07:20 PM
#45
Surely the rotational force using a lightweight pulley is a lot less on the crank, and the rubber can't absorb all of the force on the standard crank pulley. So wouldn't any difference between the 2 be negligible anyway? Hence why not many, if any engines have suffered damage due to a lightweight pulley. I'm probably completely wrong, but that'd be my uneducated opinion.
10 February 2014, 07:31 PM
#46
Scooby Regular
iTrader: (11)
Join Date: Feb 2011
Location: Newcastle upon tyne
Posts: 2,750
Likes: 0
Received 0 Likes
on
0 Posts
^
Correct to within scope ( blueprinted & crafted engines more so ...
Mass produced units offer a much wider scope ...
I'm neither for or against , personal choice really
But as above personally I think 99% of day to day road cars would cope just fine as they offer a greater scope for margin & tolerance .
Then again , iv said it before
"Anything can fail "
Correct to within scope ( blueprinted & crafted engines more so ...
Mass produced units offer a much wider scope ...
I'm neither for or against , personal choice really
But as above personally I think 99% of day to day road cars would cope just fine as they offer a greater scope for margin & tolerance .
Then again , iv said it before
"Anything can fail "
10 February 2014, 07:50 PM
#47
Steve is right, I have nothing on paper to support what I am saying. Only experience with the parts
I did write to Subaru three weeks ago by hand when the thread started on 22b, only because certain people were telling customers to stay clear of my products because they will "wreck" their engine ,. so that got my goat a bit. If they do finally reply I will scan it on here,. whether I am right or wrong
I did write to Subaru three weeks ago by hand when the thread started on 22b, only because certain people were telling customers to stay clear of my products because they will "wreck" their engine ,. so that got my goat a bit. If they do finally reply I will scan it on here,. whether I am right or wrong
10 February 2014, 08:06 PM
#50
Scooby Regular
iTrader: (41)
Join Date: Nov 2003
Location: in the woods...........555 Wagon Sqn
Posts: 13,347
Received 56 Likes
on
42 Posts
(almost) Nobody is demonising Chris...he is a top man, this is just a discussion around his post
Anyways I was chatting to my dad earlier about this and he is a retired automotive engineer...so thought Id share this...
"The crankshaft pulley is used to dampen high frequency vibration in the crankshaft generated by cyclic load variation during each rotation. *The crank being an iron alloy is elastic so will vibrate and I think the pulley is turned to the natural frequency of the crank; it's what is known as an harmonic damper. *
Anyways I was chatting to my dad earlier about this and he is a retired automotive engineer...so thought Id share this...
"The crankshaft pulley is used to dampen high frequency vibration in the crankshaft generated by cyclic load variation during each rotation. *The crank being an iron alloy is elastic so will vibrate and I think the pulley is turned to the natural frequency of the crank; it's what is known as an harmonic damper. *
10 February 2014, 08:06 PM
#51
thank you
10 February 2014, 08:14 PM
#52
QUOTE :
. *The crank being an iron alloy is elastic so will vibrate and I think the pulley is turned to the natural frequency of the crank; it's what is known as an harmonic damper.
Hence why arrows , don't point to the centre rubber bonded part
10 February 2014, 09:12 PM
#53
Out of interest, could this vibration you speak of also be apparent after fitting a lightweight flywheel.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
10 February 2014, 09:14 PM
#54
10 February 2014, 09:19 PM
#55
I run a set of RCM pulleys on mine along with a lightened flywheel & they have been fine for the last 3 years. My engine builder told me that they can give the shells a harder time due to lack of damping but most people still run them due to the increased responsiveness & power gains. RCM wouldn't sell these if they were engine wreckers, but there are advantages & disadvantages so it's a personal decision.
10 February 2014, 09:20 PM
#56
Scooby Regular
iTrader: (41)
Join Date: Nov 2003
Location: in the woods...........555 Wagon Sqn
Posts: 13,347
Received 56 Likes
on
42 Posts
Out of interest, could this vibration you speak of also be apparent after fitting a lightweight flywheel.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
10 February 2014, 09:26 PM
#57
Out of interest, could this vibration you speak of also be apparent after fitting a lightweight flywheel.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
I had a fidanza light fly in my car and on overrun I had an awful vibration, Ren above came out with me to help diagnose it.
I ended up grabbing a standard flywheel off Ren and swapped the lightweight one, hey presto, no noises or vibrations after the standard flywheel was fitted.
10 February 2014, 09:27 PM
#58
Scooby Regular
iTrader: (23)
Join Date: Jul 2008
Location: In the fast lane
Posts: 3,458
Likes: 0
Received 0 Likes
on
0 Posts
With all due respect, I suspect this is a mis-quote...
"The crank being an iron alloy is elastic so will vibrate and I think the pulley is turned to the natural frequency of the crank; it's what is known as an harmonic damper."
How can a pulley be turned to a frequency? Aren't most pulleys turned in the normal course of manufacture? The exceptions being forged, cast or moulded. Surely Chris's pulleys are turned, not moulded, forged or cast. Surely tuned is the word.
And I doubt that they are tuned, although he may well wish to correct me on that score and explain how this is achieved for each of the 1000's of pulley sets supplied.
The full quote also acknowledges my point about the necessity for vibration damping...
""The crankshaft pulley is used to dampen high frequency vibration in the crankshaft generated by cyclic load variation during each rotation. "
and...
" and I think the pulley is turned" This hardly constitutes anything more than an opinion.
"The crank being an iron alloy is elastic so will vibrate and I think the pulley is turned to the natural frequency of the crank; it's what is known as an harmonic damper."
How can a pulley be turned to a frequency? Aren't most pulleys turned in the normal course of manufacture? The exceptions being forged, cast or moulded. Surely Chris's pulleys are turned, not moulded, forged or cast. Surely tuned is the word.
And I doubt that they are tuned, although he may well wish to correct me on that score and explain how this is achieved for each of the 1000's of pulley sets supplied.
The full quote also acknowledges my point about the necessity for vibration damping...
""The crankshaft pulley is used to dampen high frequency vibration in the crankshaft generated by cyclic load variation during each rotation. "
and...
" and I think the pulley is turned" This hardly constitutes anything more than an opinion.
Last edited by Blue by You; 10 February 2014 at 09:28 PM.
10 February 2014, 09:37 PM
#60
Scooby Regular
iTrader: (41)
Join Date: Nov 2003
Location: in the woods...........555 Wagon Sqn
Posts: 13,347
Received 56 Likes
on
42 Posts
typo...clearly should be tuned
Granted every engine is unique and to get the optimal benefit you would ideally balace each one individually....but like any other mass produced part they will have been designed to be the best compromise given the limitations of the particular manufacturing process. I think that constitutes tuned.
Granted every engine is unique and to get the optimal benefit you would ideally balace each one individually....but like any other mass produced part they will have been designed to be the best compromise given the limitations of the particular manufacturing process. I think that constitutes tuned.
Last edited by trails; 10 February 2014 at 09:43 PM. Reason: dropped the as!