Newmans Camshaft...Which springs???
#41
Too many posts.. I need a life!!
Hello Rob,
What part of Canada did your friend move to?
Desmodromic was used by a few teams in F1 - I think Ferrari in the early 90's?
I think only Ducati made Desmo valvetrains for the general public.
I have looked at the Kent and Piper catalogs, and the recommended single and dual valve springs for the cvh seem very weak - in fact lower spring presures than the Ford single.
No wonder NMS and others recommend new Ford springs.
It would be very interesting for someone - maybe a shop - NMS or Jano, to measure the different recommended spring pressures - Kent single and double, Piper single and double, and Newman single and doubles and Ford standard springs.
The installed (closed) pressure, and the pressure at .400" lift.
A proper valvespring comparo would be uber usefull!
I will start:
std Ford (Canada) cvh spring - closed 90 lbs, open (0.400") 200 lbs.
I always measure valve spring pressures (closed and open) for my engine builds.
Did it with the Cosworth 3 liter 4 cyl engines I built, the 2 Porche 6's I built, and both big block ford V8's I assembled. This is one detail you should not overlook.
Cheers
What part of Canada did your friend move to?
Desmodromic was used by a few teams in F1 - I think Ferrari in the early 90's?
I think only Ducati made Desmo valvetrains for the general public.
I have looked at the Kent and Piper catalogs, and the recommended single and dual valve springs for the cvh seem very weak - in fact lower spring presures than the Ford single.
No wonder NMS and others recommend new Ford springs.
It would be very interesting for someone - maybe a shop - NMS or Jano, to measure the different recommended spring pressures - Kent single and double, Piper single and double, and Newman single and doubles and Ford standard springs.
The installed (closed) pressure, and the pressure at .400" lift.
A proper valvespring comparo would be uber usefull!
I will start:
std Ford (Canada) cvh spring - closed 90 lbs, open (0.400") 200 lbs.
I always measure valve spring pressures (closed and open) for my engine builds.
Did it with the Cosworth 3 liter 4 cyl engines I built, the 2 Porche 6's I built, and both big block ford V8's I assembled. This is one detail you should not overlook.
Cheers
Last edited by Canada1; 16-04-2011 at 02:43 PM.
#42
PassionFord Post Whore!!
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Thats a good video Rob.With all this talk.I had trouble getting into gear which caused high rpm when giving it the beans.Got it into gear and about couple minutes later my exhaust valves hit my pistons.Would i be right in saying that i had some serious float going on?
I would also think having double coiled springs would be designed for higher rev range ( bigger power equals more stress??)
I would also think having double coiled springs would be designed for higher rev range ( bigger power equals more stress??)
#43
PassionFord Post Whore!!
iTrader: (4)
Hello Rob,
What part of Canada did your friend move to?
Desmodromic was used by a few teams in F1 - I think Ferrari in the early 90's?
I think only Ducati made Desmo valvetrains for the general public.
I have looked at the Kent and Piper catalogs, and the recommended single and dual valve springs for the cvh seem very weak - in fact lower spring presures than the Ford single.
No wonder NMS and others recommend new Ford springs.
It would be very interesting for someone - maybe a shop - NMS or Jano, to measure the different recommended spring pressures - Kent single and double, Piper single and double, and Newman single and doubles and Ford standard springs.
The installed (closed) pressure, and the pressure at .400" lift.
A proper valvespring comparo would be uber usefull!
I will start:
std Ford (Canada) cvh spring - closed 90 lbs, open (0.400") 200 lbs.
I always measure valve spring pressures (closed and open) for my engine builds.
Did it with the Cosworth 3 liter 4 cyl engines I built, the 2 Porche 6's I built, and both big block ford V8's I assembled. This is one detail you should not overlook.
Cheers
What part of Canada did your friend move to?
Desmodromic was used by a few teams in F1 - I think Ferrari in the early 90's?
I think only Ducati made Desmo valvetrains for the general public.
I have looked at the Kent and Piper catalogs, and the recommended single and dual valve springs for the cvh seem very weak - in fact lower spring presures than the Ford single.
No wonder NMS and others recommend new Ford springs.
It would be very interesting for someone - maybe a shop - NMS or Jano, to measure the different recommended spring pressures - Kent single and double, Piper single and double, and Newman single and doubles and Ford standard springs.
The installed (closed) pressure, and the pressure at .400" lift.
A proper valvespring comparo would be uber usefull!
I will start:
std Ford (Canada) cvh spring - closed 90 lbs, open (0.400") 200 lbs.
I always measure valve spring pressures (closed and open) for my engine builds.
Did it with the Cosworth 3 liter 4 cyl engines I built, the 2 Porche 6's I built, and both big block ford V8's I assembled. This is one detail you should not overlook.
Cheers
Hi Perry, he moved just out side of Toronto.
Im not sure any Jano or NMS would have the equipment to measure spring pressure....?
I guess you could measure its length then load it with a know mass untill you are @ .400" but it wouldn't be too accurate.
Rob,
#44
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Yes mate.was driving normally after woulds,as i came off the main road up the slip road,was rough as hell ( 3 cylinders ).No compression on all 4 cylinders,found to be all four exhaust valves bent.Inlets were fine.dents on the pistons just exhaust side.was very strange.I thought exactly that rob,belt slip or valve float.The worst thing was it was set up the day before it happend!
#45
OCD Victim
Yes mate.was driving normally after woulds,as i came off the main road up the slip road,was rough as hell ( 3 cylinders ).No compression on all 4 cylinders,found to be all four exhaust valves bent.Inlets were fine.dents on the pistons just exhaust side.was very strange.I thought exactly that rob,belt slip or valve float.The worst thing was it was set up the day before it happend!
Brand new top-end rebuild using a Kent Cams CVH22. Used their cam, tappets, springs, the whole lot. Steel adjustable vernier pulley set at 0 degrees until run in. Car did 100 miles or so, then, while down-shifting from 3rd to 2nd at about 3000rpm max under light throttle, it just started sounding terrible. Pulled the car over to the side of the road and it cut out. Restarted again using a lot of throttle and constant revs. Drove it home, let it cool down and there was no compression on any cylinders.
Took the top off and 7 out of 8 valves had hit the pistons. Timing belt was timed up perfectly, nothing had moved or slipped. Put 8 new valves in (no point messing around with the 1 remaining good one), "pocketed" the pistons slightly with an angle grinder and put it back together with some normal Ford valve springs and another new belt and it ran fine ever after. Redline was somewhere near 7k as well afterwards and it used to find it often.
The only thing I can put it down to was one of the valve springs "binding" slightly for a second, causing the valve to stay open slightly longer than it should, which would allow it to hit the piston. This then had a domino-effect on the others.
#46
Too many posts.. I need a life!!
Hello Iansoutham,
Wow!
Certainly severe valve float. When valve springs are too light the valves literaly are not in control of the camshaft any longer. Kissing pistons is what happens.
I am still at a loss as to why UK camshaft maufactures recomend valvesprings with too
little pressure. The Ford cvh has a very heavy valvetrain - lifters and steel rocker arms;
The 2.0 Pinto does not have lifters and heavy rocker arms, yet one still runs 80 lbs closed pressure on those engines for 7000 rpm use.
Wow!
Certainly severe valve float. When valve springs are too light the valves literaly are not in control of the camshaft any longer. Kissing pistons is what happens.
I am still at a loss as to why UK camshaft maufactures recomend valvesprings with too
little pressure. The Ford cvh has a very heavy valvetrain - lifters and steel rocker arms;
The 2.0 Pinto does not have lifters and heavy rocker arms, yet one still runs 80 lbs closed pressure on those engines for 7000 rpm use.
#47
Ask me a question!
iTrader: (1)
I have access to equipment that measures any pressures you would want to know. My good friend and engineer has millions of £ worth of equipment. Their main line of work is for keloggs, tate and lyle, sainsburys to name a few of their clients. He basicly makes all of their tools and machines. So measuring spring pressure is one of the simple things that can be done along with more involved testing like air flow or flow rates etc etc.
You must remember that we are in the heart of the Engineering areas in Essex with everything you could ever want and need within a 20 mile radius.
If i cant do what i want in house then it will be done on the best available equipment.
You must remember that we are in the heart of the Engineering areas in Essex with everything you could ever want and need within a 20 mile radius.
If i cant do what i want in house then it will be done on the best available equipment.
#49
PassionFord Post Whore!!
iTrader: (4)
I have access to equipment that measures any pressures you would want to know. My good friend and engineer has millions of £ worth of equipment. Their main line of work is for keloggs, tate and lyle, sainsburys to name a few of their clients. He basicly makes all of their tools and machines. So measuring spring pressure is one of the simple things that can be done along with more involved testing like air flow or flow rates etc etc.
You must remember that we are in the heart of the Engineering areas in Essex with everything you could ever want and need within a 20 mile radius.
If i cant do what i want in house then it will be done on the best available equipment.
You must remember that we are in the heart of the Engineering areas in Essex with everything you could ever want and need within a 20 mile radius.
If i cant do what i want in house then it will be done on the best available equipment.
Valve springs are fairly unique, in their size vs spring rate, the equipment used to measure them will probably be pretty unique too, any company that makes springs (die springs especially) should have a suitable piece, especially any firm who makes valve springs!
Rob,
#50
OCD Victim
#51
Too many posts.. I need a life!!
Hello Jano,
I own a valvespring test gauge also, but do not have access to the different valvesprings that Newmans, Kent and Piper recommend for cvh use.
There are several different types of testers. Some are more costly, and of course higher quality for a shop to use. I use the type that can be used in a shop vise.
Kent Springs: VS22 and VS42
Piper Springs: VSSCVH and VDSCVH2
Newmans: single and double (not sure if there are part numbers?)
The catalogs do not give close and open pressures for any of these springs.
Seated or closed pressures are important for setting up valve springs (one can shim the spring to increase pressure to where the builder wants).
Open pressure will depend on camshaft valve lift and the specific spring rate of the spring.
Closed pressures have very little impact on camshaft life - but have a huge impact on valve float rpm.
In any case you must measure installed valve spring height with any brand spring you use. You could run into valve spring bind or too low spring presures - with anyones valve spring.
This is the type I use.
I own a valvespring test gauge also, but do not have access to the different valvesprings that Newmans, Kent and Piper recommend for cvh use.
There are several different types of testers. Some are more costly, and of course higher quality for a shop to use. I use the type that can be used in a shop vise.
Kent Springs: VS22 and VS42
Piper Springs: VSSCVH and VDSCVH2
Newmans: single and double (not sure if there are part numbers?)
The catalogs do not give close and open pressures for any of these springs.
Seated or closed pressures are important for setting up valve springs (one can shim the spring to increase pressure to where the builder wants).
Open pressure will depend on camshaft valve lift and the specific spring rate of the spring.
Closed pressures have very little impact on camshaft life - but have a huge impact on valve float rpm.
In any case you must measure installed valve spring height with any brand spring you use. You could run into valve spring bind or too low spring presures - with anyones valve spring.
This is the type I use.
Last edited by Canada1; 18-04-2011 at 02:30 PM.
#53
Too many posts.. I need a life!!
Hello Rob,
The type you show is a high quality tester.
For shop use at an engine builder - to be used 1000's of times.
The lower cost ones work well for the average home builder.
One can calibrate the smaller ones - they are actually quite good.
Cheers
The type you show is a high quality tester.
For shop use at an engine builder - to be used 1000's of times.
The lower cost ones work well for the average home builder.
One can calibrate the smaller ones - they are actually quite good.
Cheers
#55
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I'd already mentioned i HAD measured the springs but no one took any notice lol
The newman's were nowhere near what they were supposed to be, and the ford ones were what the newmans were supposed to be hence why they work.....simple
The newman's were nowhere near what they were supposed to be, and the ford ones were what the newmans were supposed to be hence why they work.....simple
#57
Too many posts.. I need a life!!
Hello rstdave,
Tell us your measured results!
What were the closed and open pressures of the Newman spring vs. the Ford springs.
Also what did you use as the closed height? 37mm (1.46")?
That info would explain for everyone.
Cheers
Tell us your measured results!
What were the closed and open pressures of the Newman spring vs. the Ford springs.
Also what did you use as the closed height? 37mm (1.46")?
That info would explain for everyone.
Cheers
#60
OCD Victim
You are talking S1, I am talking XR3i n/a.
#61
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Don't know whether anyone has mentioned a few reasons why people are getting valve bounce with uprated valve springs vs the standard ford ones but i thought i'd have a go with my two penneth and join in from what i sort of know.
thickness of the spring wire dictates the preload and the lift. uprated valve springs made out of thinner steel give the correct lift but dont generate the right preload. the higher the preload, the faster the valve closes - if the preload isnt high enough the valve can leave the contact surface of the cam lobe and cause issues. did somebody mention bending valves?
hence the use of double valve springs
the other issue stated below concerns double valve springs being fitted to the cvh. they tend to go coilbound unless the inner spring is located properly.
http://www.pumaracing.co.uk/CVH.htm
most of my knowledge is from this above.
personally i will be modifying my NA EFI CVH but am undecided on what cam to go for. i want to go for something like a CVH33 but am unsure of what springs to go for due to the issues illustrated by people on this thread and in the article above.
interesting point in this article about the exhaust valves on a CVH... lol
thickness of the spring wire dictates the preload and the lift. uprated valve springs made out of thinner steel give the correct lift but dont generate the right preload. the higher the preload, the faster the valve closes - if the preload isnt high enough the valve can leave the contact surface of the cam lobe and cause issues. did somebody mention bending valves?
hence the use of double valve springs
the other issue stated below concerns double valve springs being fitted to the cvh. they tend to go coilbound unless the inner spring is located properly.
http://www.pumaracing.co.uk/CVH.htm
most of my knowledge is from this above.
personally i will be modifying my NA EFI CVH but am undecided on what cam to go for. i want to go for something like a CVH33 but am unsure of what springs to go for due to the issues illustrated by people on this thread and in the article above.
interesting point in this article about the exhaust valves on a CVH... lol
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