Danster76

iTrader: (2)

I'm about to order a cvh turbo newman cam and wanted to know what springs people are using and having reliable use from.

I will be using the solid lifters and am thinking their single 190 poundage springs would be the ones to go for.

Advice please.

Thanks.

little bram

Wouldnt think you will need double mate singles will be good enuf

Danster76

iTrader: (2)

The newmans 190 pound singles or standard fords?
I thought I read somewhere people advising to use standard ford springs??

project rs

i'm currently on the kent uprated ones, tried the doubles newman do and had trouble so went back to the kents and been fine believe the ford ones are good too

Canada1

What trouble did you have with the Newman doubles?
It would be great to know others experiences.

Cheers

Karlos G

iTrader: (4)

Stock Ford springs is what I run as per Karl Norris's (NMS) advice, he said to use nothing else.

Danster76

iTrader: (2)

This is what I heard, hence my question.
Talk about conflicting info!
I have just called newmans and they say fit their double springs
I called NMS and just got the standard answer phone msg saying they're on holiday till 5th September!

Karlos, are you 100% nms say use standard ford springs? If thats their advice thats the advice I'll follow i think.

I need to get this ordered today so any advice appreciated.

Karlos G

iTrader: (4)

Yes 100%, my head came from them at a cost of Ł1000 (with Newman cam) and Karl was quite insistent that only stock springs are to be used if there was any chance of the cam lasting.
I have now been running for just over a year of daily use (10'000 miles approx) and all is still well

Danster76

iTrader: (2)

Thats the info I needed. Thanks.

I said to the guy at newmans so double springs is what nms would suggest seeing as they were involved during development...No, Karl doesn't get his springs from us, was his reply.

So, did you adjust the solid lifters yourself or was this done by nms as part of the 'package'.

Danster76

iTrader: (2)

Karlos, are you using this cam?

FORC/276/409T PH4 http://www.newman-cams.com/pdf/ford.pdf

Does/did your car have any idle issues on this cam?
I'm on stand alone efi mgt if it makes any odds.

Rogeyboy

iTrader: (2)

I ran kent double springs for aorund 20k with no issues on a CVH32 cam from them.
Dunno if that helps!?

muz

When I ordered my cam direct from Newman, I spoke to David and he told me not use their springs. He said standard Ford ones were best.

essexRSTSouthend

how funny is that.They supply these double springs but even David says don't who works for them.How strange i must say.

So basically from what is above,if you want your cam to last use ford items...

Danster76

iTrader: (2)

My thoughts exactly. Confusing from a customer point of view.

Anyway, I've ordered up the cam and solids from Matt Lewis Motorsport which will be here tomorrow. Standard springs it is.

Karlos G

iTrader: (4)

All I got was the head, ported/flowed, bronze guides, SS valves and the cam/lifters seperately so yes I fitted and adjusted them.
Yes thats the one, it's the only RST Cam they do off the shelf (other one is for ZVH), no trouble idleing at all.

muz

I'm not sure why the make a ZVH cam either. When I phoned and gave them the spec of my car, which in all fairness is a pretty well spec'd engine as far as ZVH's go, they advised me to go with a CVH spec cam not the ZVH. Maybe David had a few brandies on his lunch break

Karlos G

iTrader: (4)

TBH after speaking to Christian (APT) and Karl (NMS) I think Newman are more of a machine shop than a Cam developer, they dont know much about Cam design but given the specs can produce the goods as needed, so Davids advice is probably not the best! lol

haz87

Running standards Ford springs on my newman and regularly see nigh on 8,000 rpm. (i'm n/a CVH tho and not turbo) Not had a single problem yet *touches wood*

Canada1

Hello Karlos,

I really think it is unfair to call Newmans just a "machine shop".
Speccing the open and close timing of a camshaft for a specific application
doesnt make one an expert in cam design.
There is much more to camshaft lobe design than the usual specs we see published.
Camshaft opening ramps and velocities are much more important design features.
I doubt Christian and Karl know much about the physics of camshaft design - velocity, acceleration, jerk, etc... much more than a valve opening at 24 Deg BTDC and closing at 72 deg ABDC.

Rogeyboy

iTrader: (2)

Haz, was u running the newman cam last year on way to FITP when i saw you on the A120?
Thought you pushed it hard, didn't realise you gave it 8,000rpm tho!

haz87

Nooo, that was still on a cvh32 and a nasty misfire, lol. I really should have killed it that day! Engine spec has had a total change and build since then

Edit: Was only hitting about 7k as it was on hydraulics at that time (still pushing the limits a little some might say,lol)

rstdave

iTrader: (3)

100% don't bother using their single springs if you want to rev the car over 5.5k as they're far too weak and nowhere near their stated 190 pound (i tested them)......i had issues with valve bounce after david newman insisting i use their springs with a new cam i bought after wearing one out, and was down to the springs being far too weak!
I obtained a set of standard ford springs through nms and karl also advised me that the ford springs were what to use......they were nearer the 190 pound newman claim theirs to be and worked perfectly with no issues revving to 7k (you could see straight away by the thickness of the coils that the ford were far stronger than the newmans).

project rs

when we tested the doubles they were giving us a missfire and were having trouble with holding boost as in too soft so getting valve lift

Rogeyboy

iTrader: (2)

Haz, mine was on a CVH32 then... Yours is MFi isn't it? What diff did the newman cam make?
Yeah i think 7,000rpm from a CVH is asking alot isn't it - let alone 8,000rpm!
If and when i change my cam for a performance one (was thinking kent cvh35) i'll re-use my kent double springs... Should factor out and valve bounce or boost lift issues!

haz87

Yer i'm MFI. Newman cam just totally opened up my top end. The only thing that i had to spend alot of time doing was recurving my distributor (imported some springs/weights from the US) and then modified a Porsche fuel warm up regulator so i had more fuel! With those sorted and a load of other bits sorted its turned it into a bit of a rev monster
Maybe our paths will cross on the a120 again at some point,lol

Karlos G

iTrader: (4)

Perhaps, it wasnt really ment as in insult just to illustrate what I was saying really.
Christian may not know much about the physics behind cam design but Karl Norris certainly does.

Rogeyboy

iTrader: (2)

Yeah another "meeting" on the A120 should be good, i had a gearbox, 4 shocks & springs and an orion exhaust system in the car aswell as 3 people last time - extra ballast lol!
Haz u should look at EFi management for it next or bike carbs etc...?
Maybe if your about on the 4th May in the evening, we could meet up down at southend n have a chat about the motors!?

Canada1

Just out of curiousity - has anyone actually measured the different valvespring options?
What are the closed pressure and open pressures (at full lift)?
It looks like the standard Ford single spring has more closed pressure and open pressures
than most Newman, Kent or Piper springs.
I do know that spring pressure is vital to an engines ability to rev - NA or boosted.
Boosted even requires more pressure.
When valves bounce so do the lifters on the cam. This would destroy cam and lifters
very quickly.
Too little spring pressure will surely destroy camshaft and lifters probably faster than too much pressure?

The standard Ford spring in Canada is 94 lbs closed and 200 lbs at .400" lift.
For my turbo build I am using 110 lbs closed and 225 lbs at .440" lift.

Rob_DOHC

iTrader: (4)

With certain springs people have seen valve bounce at as little as 5000rpm which i agree will destroy cams and cam gear very quickly. BUT, wear will increase dramatically with a spring rate which is too high, valves and valve seats also suffer a shorter life with a high spring rate.

I think people generally just find the stock ford springs to be a good compromise, people still rev to 7000rpm with out valve bounce.

And in all fairness, ford did have a substantially larger development budget (even in the early 80's) than kent, piper and newmans combined, their standard rev limit was around 6500, which IMO isn't far off the mark for a road going cvh.



Rob,

Karlos G

iTrader: (4)

My initial rpm limit was 7200rpm with stock springs and there was no issues, it's since been lowered to 6600rpm as my turbo runs out of puff at high rpm's so is pointless having it so high.

Rob_DOHC

iTrader: (4)

Core, i bet you clenched the first time you took it to 7200 Karlos Must be like that first start up feeling.

Canada1

Hello Rob,

Good to hear from you too!
Valves and the lifters on the cam will start to become unstable well before the point you cannot rev any higher.
Fords development budget is large - yes!, but not for performance reasons. It is to produce an automobile with the lowest costs possible - maximize profits.
Porsche and Ferrari back in the day looked at performance issues first, certainly not Ford or GM - although I still love my Fords

Regarding valve spring pressures wearing out valves and valve seats faster? I do not agree at all. Control of valvetrain harmonics (and bounce issues) leads to extended parts life.
I have a street driven car - well over 10,000 kms that has 250 lbs closed pressure and 800 lbs open pressure - solid roller camshaft .750" lift. I have never had any valve or valve seat problems.
Too much pressure is far better than not enough to control the valvetrain.

If one is only intending on a 5000 rpm limit, then softer springs may be sufficient. Most
users on this forum tend to like the higher rpm ranges - at least I do.

Rob_DOHC

iTrader: (4)

Hiya Perry,

Dont forger that although ford want to make things cheap, they also want them to last for the 3 years guarantee they give... So if a stock rev limit of 6500 +/- 300 rpm the ford spring in my opinion will be the most suitable, with regards to wear vs. performance.

Yes i agree, my definition of valve bounce is just that, the valve bouncing off the seat not so much the point where the engine cannot rev any higher, there are a few slow motion videos about showing spring harmonics, that are very interesting, in all honesty im not too sure how going out of phase would effect things?

I will dig some info out regards to valve seat and valve damage cause by excessive spring pressures, but granted the spring rates used in road cars will not approach what im talking about, i believe it is also a problem with desmodromic setups, the action of the hot valve closing with too much force cases deformation of the valve head/stem leading to micro fractures. (i think thats how it went! ill find it because its interesting!)

Any way, wheres your build thread Perry!

Rob,

Yes,

Karlos G

iTrader: (4)

I did a little yes, was in 4th gear doing 130mph too so was up there for quite some time!

Regards your above post, very interesting subject any links or info you can dig out I look forward to reading mate!

Canada1

Hello Rob,

Excessive spring pressure issues with Desmodromic (Ducati) setups is not applicable to regular camshaft and follower engines. Who has Desmo valvetrains anymore?

The valve closing event is controlled entirely by the camshaft lobe. More spring pressure does not make the valve shut any quicker. The only issues occur when the lifter (in a cam/lifter engine) does not follow the cam lobe. This happens when valvetrain harmonics exist - usually a result of too low spring pressures - or a very poorly designed cam lobe where acceleration and or jerk is too high.

Please find the Desmo info - it sounds like fun reading.

Cheers

Regarding my build - it just snowed here again 15 more cms of snow.
High temperature of +3C
I do not have a heated garage - waiting for warmer weather.

How may still believe in the Global Warming Hoax?
I do not!!!

Rob_DOHC

iTrader: (4)

Its still snowing! friends just moved out to canada, i'll have to give him a call and tell him about our sunny weekend


This is all very true Perry, however i believe some sort of desmodromic setup is still used in f1? I think i read a paper on valve design and failure modes related to this, im still searching!

In all honesty, i've never really thought too deeply about it, valve float/bounce and cam wear has never been a problem for me

but a quick (very) search did show this site,

http://www.bassoassist.com.ar/ingles/esrecom02.htm

Its not very conclusive, but it does list high closing force as a cause for distortion of the valve/failure.

Although a valve will not close any faster with a higher spring pressure, the force used to close the valve is higher, meaning the impact of the valve on the valve seat is greater. At high rpm the valve can be 'thrown' off the lobe, essentially leaving it close in a manner un controlled by the lobe.

**EDIT** i see what you mean, weak springs or poorly designed cam profile!!!! The weak valve spring can actual invoke a larger closing force due to 'float', but a badly designed cam shaft (or excessive RPM) with a very stiff spring is even worse

Here is another quick link,

http://www.mlcmotorfactors.co.uk/Tro...rs/ValveTT.pdf



http://www.youtube.com/watch?v=_REQ1PUM0rY

And this is a quick video that shows valve float, i guess it shows how the harmonic frequency of a spring effects its performance, i suspect its actually no where near its natural frequency, probably more like A 5th harmonic (pure guess!).

Any way, night!

Rogeyboy

iTrader: (2)

S surely double valves springs offer a greater closing pressure and are a benefit? Altho they offer standardish opening pressure as they are progressively wound and the 2nd spring doesnt operate throughout the whole valve travel. Reducing excess wear on camlobes but keeping the valves firmly shut?

Rob_DOHC

iTrader: (4)

I have no idea mate, i don't know how the double spring set up works. I always assumed double springs was for a higer spring rate.

but if every one uses the ford springs with out issue, and they perform well enough i still think they are the best options.

Rob,

essexRSTSouthend

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??)

pee vee

RST dave on here ran a newman cam with their solid lifters and springs.
got valve bounce at anything above 5500 rpm when being mapped IIRC

NMS sorted him with a set of standard ford springs, and the problem was gone!

measuring them, the ford springs were heavier duty than the newman ones anyway (obviously lol)

EDIT: Doh, didnt see RSTdaves post above! LOL