Cm 612 valve springs
11-29-2008, 11:13 AM
#1
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Join Date: Feb 2003
Location: Martin Mi
Posts: 715
Cm 612 valve springs
I have heard that they are prone to breakage, but I cant seem to find out why. Is it because people are using them in a to high of lift application, or is it just a sub par part? Thanks Eric L
11-29-2008, 10:06 PM
#2
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Location: Oshkosh, Wisconsin
Posts: 1,309
11-30-2008, 10:05 AM
#3
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Join Date: Aug 2002
Location: Red Oak Texas
Posts: 1,509
My guess is that the wire used in the spring is too brittle for hyd roller set ups and the springs just break even when set up properly on mild cams.
All single wound springs (other than bee hives) have a sepcific RPM that they go "hay wire" at and can't control the valve. Could be every 1600 RPM (1600, 3200, 4800, 6400 RPM, etc) or could be every 2133 RPM (2133, 4266, 6399, etc). It varies for every spring but this DOES happen.
Maybe this spring has a "hay wire" RPM that is more frequent than others or maybe it stays in this "hay wire" RPM longer than other springs or maybe the 'hay wire" RPM just happens to coincide with a popular cruise RPM and that destroys the spring. Not sure "why" they break but they do.
They are inexpensive, have good pressure and look good on paper but in the real world, they are not a good choice.
If using a mid 220 duration cam with .550 lift and spinning 6200-6300 RPM (CC 503, CC 305, GM 846, etc), I would go with these springs.
http://competitionproducts.com/prodi...p?number=98213
or a better option -
http://competitionproducts.com/prodi...p?number=98215
I would NOT use these springs on ANY XFI lobes or ANY cam spinning over 6300 RPM (CC 306, GM 847, etc). If you use these type of cams, spend the $$$ and get a better spring.
Lloyd
All single wound springs (other than bee hives) have a sepcific RPM that they go "hay wire" at and can't control the valve. Could be every 1600 RPM (1600, 3200, 4800, 6400 RPM, etc) or could be every 2133 RPM (2133, 4266, 6399, etc). It varies for every spring but this DOES happen.
Maybe this spring has a "hay wire" RPM that is more frequent than others or maybe it stays in this "hay wire" RPM longer than other springs or maybe the 'hay wire" RPM just happens to coincide with a popular cruise RPM and that destroys the spring. Not sure "why" they break but they do.
They are inexpensive, have good pressure and look good on paper but in the real world, they are not a good choice.
If using a mid 220 duration cam with .550 lift and spinning 6200-6300 RPM (CC 503, CC 305, GM 846, etc), I would go with these springs.
http://competitionproducts.com/prodi...p?number=98213
or a better option -
http://competitionproducts.com/prodi...p?number=98215
I would NOT use these springs on ANY XFI lobes or ANY cam spinning over 6300 RPM (CC 306, GM 847, etc). If you use these type of cams, spend the $$$ and get a better spring.
Lloyd
11-30-2008, 12:23 PM
#5
Registered User
Join Date: Jul 2000
Location: Three Oaks MI
Posts: 993
My guess is that the wire used in the spring is too brittle for hyd roller set ups and the springs just break even when set up properly on mild cams.
All single wound springs (other than bee hives) have a sepcific RPM that they go "hay wire" at and can't control the valve. Could be every 1600 RPM (1600, 3200, 4800, 6400 RPM, etc) or could be every 2133 RPM (2133, 4266, 6399, etc). It varies for every spring but this DOES happen.
Maybe this spring has a "hay wire" RPM that is more frequent than others or maybe it stays in this "hay wire" RPM longer than other springs or maybe the 'hay wire" RPM just happens to coincide with a popular cruise RPM and that destroys the spring. Not sure "why" they break but they do.
They are inexpensive, have good pressure and look good on paper but in the real world, they are not a good choice.
If using a mid 220 duration cam with .550 lift and spinning 6200-6300 RPM (CC 503, CC 305, GM 846, etc), I would go with these springs.
http://competitionproducts.com/prodi...p?number=98213
or a better option -
http://competitionproducts.com/prodi...p?number=98215
I would NOT use these springs on ANY XFI lobes or ANY cam spinning over 6300 RPM (CC 306, GM 847, etc). If you use these type of cams, spend the $$$ and get a better spring.
Lloyd
All single wound springs (other than bee hives) have a sepcific RPM that they go "hay wire" at and can't control the valve. Could be every 1600 RPM (1600, 3200, 4800, 6400 RPM, etc) or could be every 2133 RPM (2133, 4266, 6399, etc). It varies for every spring but this DOES happen.
Maybe this spring has a "hay wire" RPM that is more frequent than others or maybe it stays in this "hay wire" RPM longer than other springs or maybe the 'hay wire" RPM just happens to coincide with a popular cruise RPM and that destroys the spring. Not sure "why" they break but they do.
They are inexpensive, have good pressure and look good on paper but in the real world, they are not a good choice.
If using a mid 220 duration cam with .550 lift and spinning 6200-6300 RPM (CC 503, CC 305, GM 846, etc), I would go with these springs.
http://competitionproducts.com/prodi...p?number=98213
or a better option -
http://competitionproducts.com/prodi...p?number=98215
I would NOT use these springs on ANY XFI lobes or ANY cam spinning over 6300 RPM (CC 306, GM 847, etc). If you use these type of cams, spend the $$$ and get a better spring.
Lloyd
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