Someone please explain "single" vs "double" springs for ported heads
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Someone please explain "single" vs "double" springs for ported heads
Advantages/disadvantages between the 2 for port/polish heads?? Any info why one is better than the other would be great. What's the story with CompCam 941 springs?? If you warm up your car properly, are springs a big deal?? Any info/suggestions/experiences would be great. :cheers:
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Re: Someone please explain "single" vs "double" springs for ported heads (JWSchmidt3)
Springs have to be matched for cam AND valves used. They also have to be installed properly. It's easy to not install springs properly and create an early fatigue failure. I know of some people who are using the 941s no problem and I know of someone else who is having spring afer spring issues with his Iskys or KMotions..whatever MTI used on his stage I heads. Don't look upon it as disadvantages or advantages of either one, each combo should dictate the spring you need to use.
The lift of the cam and weight of the valves are two important factors.
Tony :cheers:
The lift of the cam and weight of the valves are two important factors.
Tony :cheers:
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Re: Someone please explain "single" vs "double" springs for ported heads (JWSchmidt3)
What spring to use is usually dependant on what lift the camshaft you are using has. I think I would recommend going with dual springs on most 400rwhp head/cam cars.
I currently have CompCams 941 springs in my car and did break ONE about 5000 miles after the install of the package. Everything has been fine since but I have heard of many others having worse luck with them. Letting the car properly warm up is an important factor with single springs and I always follow it pretty decently. I never move my car before the coolant temp is over 130. I then do not take the car over 2500rpm until it is up to 160. I have had great luck since that one failure.
However, this winter my heads will definitely be getting dual springs put in them as they are reworked before they are bolted on my new stroker/bored bottom end.
Dual springs do raise the cost of heads slightly because of the extra cost of the springs and the machining necessary to put them in an ls1 head.
I currently have CompCams 941 springs in my car and did break ONE about 5000 miles after the install of the package. Everything has been fine since but I have heard of many others having worse luck with them. Letting the car properly warm up is an important factor with single springs and I always follow it pretty decently. I never move my car before the coolant temp is over 130. I then do not take the car over 2500rpm until it is up to 160. I have had great luck since that one failure.
However, this winter my heads will definitely be getting dual springs put in them as they are reworked before they are bolted on my new stroker/bored bottom end.
Dual springs do raise the cost of heads slightly because of the extra cost of the springs and the machining necessary to put them in an ls1 head.
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Re: Someone please explain "single" vs "double" springs for ported heads (rschiltz)
So it sounds like dual springs are the safe way to go?
ARE's Stage II heads come standard now with Dual Springs.
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Re: Someone please explain "single" vs "double" springs for ported heads (Nilla Ice)
Nilla is on the right track. You need to pay attention to the weight of the valves, retainers, locks, springs themselves, the install height, cam profile, etc.
The advantages to single springs are a lighter, more stable valvetrain assembly at high RPM. This can add more RPM and extend the HP curve.
Most of the people that are breaking the 941's either have them set up wrong(shimmed to high) or are using them with a very agressive cam. There is definitly a point where the 941 spring needs to be set aside. This does not mean go to a double, just a different spring, and yes, there are situations where double are a very good idea!
One of our camshafts(226/226 .598/.598) is too much cam for the 941 and should/will be upgraded! On the other hand, some of our more tame cams have hapily lived for years with the 941's.
We personally do not use the 941's any more. Unfortunately, this is due to advertising and the bad rep that the 941 has gotten, not because it is not a good spring....
[Modified by 2FST4U, 1:13 PM 10/31/2001]
The advantages to single springs are a lighter, more stable valvetrain assembly at high RPM. This can add more RPM and extend the HP curve.
Most of the people that are breaking the 941's either have them set up wrong(shimmed to high) or are using them with a very agressive cam. There is definitly a point where the 941 spring needs to be set aside. This does not mean go to a double, just a different spring, and yes, there are situations where double are a very good idea!
One of our camshafts(226/226 .598/.598) is too much cam for the 941 and should/will be upgraded! On the other hand, some of our more tame cams have hapily lived for years with the 941's.
We personally do not use the 941's any more. Unfortunately, this is due to advertising and the bad rep that the 941 has gotten, not because it is not a good spring....
[Modified by 2FST4U, 1:13 PM 10/31/2001]
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Re: Someone please explain "single" vs "double" springs for ported heads (2FST4U)
I learned this morning, the problem with the 941 spring was/is the dampener. They have been installing them without the dampener and has since had no problems. These springs would be going on a Stage I head (about 305cfm flow) with extra polishing and a mild cam (114) without too much lift. Peak hp probably around 6200-6400. In addition, would 1.8 roller rockers help or hurt?? Would it be a total waste to include them, or would I get at least some durability benefit from them?? :cheers:
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Re: Someone please explain "single" vs "double" springs for ported heads (JWSchmidt3)
Damper :) :)
I would not bother with the 1.8 RR's. You are adding quite a bit of side load and consequention wear.
Please explain 114 cam?!?! Is that a 114* LSA. If so, that really does not say anything about the agressiveness of the cam. Lift and duration, jerk, ramp rate, etc will determine whether the cam is agressive.
BTW...Who the heck would install the spring without the damper?!?! That is just plain silly!!!
Be afraid, be very afraid...
I would not bother with the 1.8 RR's. You are adding quite a bit of side load and consequention wear.
Please explain 114 cam?!?! Is that a 114* LSA. If so, that really does not say anything about the agressiveness of the cam. Lift and duration, jerk, ramp rate, etc will determine whether the cam is agressive.
BTW...Who the heck would install the spring without the damper?!?! That is just plain silly!!!
Be afraid, be very afraid...
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Re: Someone please explain "single" vs "double" springs for ported heads (JWSchmidt3)
On its own, there is no specific merit to dual springs. For a given cam profile you need a specific amount of force to close the valve. On higher lift and longer duration cam profiles the valve has to travel a longer distance in a shorter time. To do this requires more spring tension. At a given diameter the only way to do that is to increase the size of the wire. If you increase the wire size you limit the amount it can travel before it is solid. For a good spring life you would never compress it to solid so the only alternative is to add additional springs to achieve the mount of tension and travel that you need. On some high lift long duration cams there are 3 springs required to create enough force.
Tom
Tom
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Re: Someone please explain "single" vs "double" springs for ported heads (MattG)
Like matt, said. A lot of people that just do a cam, probably need the double springs. But you have to pull the head to machine it to accept the larger springs. That is a cost just cammers dont want to do, so they go for the best singles.
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Re: Someone please explain "single" vs "double" springs for ported heads (TomC5)
To do this requires more spring tension. At a given diameter the only way to do that is to increase the size of the wire. If you increase the wire size you limit the amount it can travel before it is solid. For a good spring life you would never compress it to solid so the only alternative is to add additional springs to achieve the mount of tension and travel that you need. Tom
There is a lot more to this topic, but not much more that most people want/need to know. :)
If anyone does want more info on springs and such, feel free to contact me. I would be more than happy to help.
Thanks,
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Re: Someone please explain "single" vs "double" springs for ported heads (2FST4U)
I have a question about upgrading vavle springs on stock heads/cam. I have heard of people putting the 01 zo6 springs on the stock c5 heads. Is that a good upgrade? I have 150hp NX and am getting the computer programmed to add additional rev limit (6500) on my A4. I'm changing the pushrods soon and am considering changing the springs, retainers, etc while I'm in there. Any suggestions? Thanks
