Valve Spring Discussion - Who's Used What?

[philbey]

Gday

 

broke Cyl 1 exhaust valve spring this arvo, limped her home on 3 cylinders.

 

I might as well get a whole new set of springs, rather than just slap my other set of 5K ones in there. I'm running a largish duration cam on stock springs, extra lift too, so it was bound to cause trouble.

 

I just read through about 20 different threads about valve springs but there's almost nothing conclusive about what springs people have used.

I'll plot my cam curves with a dial gauge and do the numbers but it looks like the CB4A from www.performancesprings.com.au looks like the go. There's also discussion about Crow Cams but they don't list 5Kitems and the seat pressure is low, I might as well run something a bit stronger .

 

So what else have people used? Specifics people, specifics! There's already plenty of claims about "dual valve springs" or "202 springs" etc.

Who else has bought from Crow Cams or Isky before?

 

EDIT: these are a couple of the more useful threads I found.

 

http://www.rollaclub.com/board/index.php?showtopic=20044

http://www.rollaclub.com/board/index.php?showtopic=16926

Edited February 23, 2010 by philbey

[Evan G]

ive heard sr20 double valve springs fit

[irokin]

Specifics people, specifics! There's already plenty of claims about "dual valve springs" or "202 springs" etc.

ive heard sr20 double valve springs fit

 

Not really adding anything...

[Redwarf]

I have used 202 blue motor spring. Don't know the poundage, and they're a little bigger than the standards. I think I have a couple lying around if you want me to mail them to you for a trail fit.

[SLO-030]

Tom, If the afore mentioned trial fit does happen, let me know how it turns out :P

[Felix]

I have used 202 blue motor spring. Don't know the poundage, and they're a little bigger than the standards. I think I have a couple lying around if you want me to mail them to you for a trail fit.

 

Hey Rob, did you supply the valve springs that Peter Moll used on the 5k in his old ke20 club car? I remember that the cam he used was from you.

[philbey]

See how I go Rob. I've got a full set on another head so I might slap them in this weekend just to get her running again and buy some upgrades in the meantime. While it's apart, I'll take the masurements and we'll compare notes.

 

I imagine it's possible to switch springs with the head on, taking great care make sure I don't drop a valve?

[altezzaclub]

Make sure its on TDC to start with!!

 

Either a compressed air line in the spark plug hole, or a bent bit of number 8 wire in there to hold the valve up. In theory the valve stem oil seal should keep it in place.

 

Crow told me to use the Holden 202 red motor springs, which my local dealer can get for $6 each. With my lift of only 0.4" I've left them as standard.

[philbey]

Yeh I'll probably borrow the engine builders fitting, or maybe buy a leakdown tester that will have the bits.

 

EDIT: you guys got any idea what the rocker ratio on a K actually is? I'm nowhere near the car right now....

Edited February 25, 2010 by philbey

[mooseman426]

Sorry to revive an old thread, but I am wondering what we've come up with regarding this subject.

 

Is it safe to assume:

 

-Standard springs up to 0.400" - Hydraulic lifter springs preferred?

 

-Holden 202 (red or blue) springs over 0.400" for street or short term big rpms - Any machining required? Can't find anything conclusive about whether to machine or not

 

-SR20 Duals or aftermarket duals for extended big rpm

 

It would be nice to clear this one up once and for all. :jamie:

 

I'm going with a Tighe 150A cam, drag racing only mainly. Thinking of using the 202 option.

 

cheers

 

probably too late to be of benefit, but apparantly rocker ratio is 1.5:1

Edited August 31, 2010 by mooseman426

[philbey]

Sorry to revive an old thread, but I am wondering what we've come up with regarding this subject.

 

Is it safe to assume:

 

-Standard springs up to 0.400" - Hydraulic lifter springs preferred?

 

-Holden 202 (red or blue) springs over 0.400" for street or short term big rpms - Any machining required? Can't find anything conclusive about whether to machine or not

 

-SR20 Duals or aftermarket duals for extended big rpm

 

It would be nice to clear this one up once and for all. :jamie:

 

I'm going with a Tighe 150A cam, drag racing only mainly. Thinking of using the 202 option.

 

cheers

 

probably too late to be of benefit, but apparantly rocker ratio is 1.5:1

 

My lift was about .480" and the stock springs did 12 months before failure. I would suggest that the .400" is conservative.

 

I honestly wouldn't bother with either the SR20 or the 202 springs, especially if they need machining.

 

Performance CB4A's wouldn't fit in my head, the spring diameter was just slightly too large for the pocket in the head. I suspect that people install them regardless without realising this is an issue, I've seen thrashed out spring pockets in other heads.

 

I ended up using Crow Cams 4220 dual springs. They were about 120 for a set and were a much better fit in the spring pocket and also on the valve retainer. Stock ones retainers took the duals. They were a breeze to fit.

 

I checked and rechecked the rates, diameters, preload and free and compressed lengths before I settled on them, and Crow have them listed as suited for 3k/4k. The only thing I don't know is the recommended seat pressure for the cam I'm running. I've givven it plenty of hard revs and I've not noticed any valve bounce.

[TRD ke70]

We use to run the CB4's with a 1.5mm spacer and no inner.

But can't remember the installed height of the valve.

Performance springs recommended 3mm spacer with the inner installed.

personally i thought that was WAY too much seat pressure!!

 

 

This was in the old 5k rally engine that only saw 7,500rpm so the spring pressures didn't need to be very high.

Can be quite easy to put excessive pressures on the springs, i remember the 3k-B had blue valve springs that were rated at 70lb seat pressures, we used them in our 1300cc 4k rally engine which saw 8,000rpm and only replaced them once over 3 years.

 

Probably the best advice is: don't get too carried away with seat pressures and double valve springs, you can use up HP to open and close valves and also increased valve train wear.

[mighty_4k]

Brought some springs from by local cam shop for my 4k stated that they were for a12 datson fitted my 4k perfectly just singles as I thought doubles was a waste of money not like I'm planing on revving out to 9000rpm or anything lol.

[mooseman426]

There is a lot of good information in here. Would be very useful on the how to build a tough 4K page. Seems like best option for me would be new springs, just need to decide if I want duals or not. Wonder how the bottom end will like 9000rpm? :hmm:

 

Does anybody have another opinion on the high seat pressure using power topic? I fully accept that more pressure will cause more wear on the lobes. But wouldn't any power used to open the valves be returned again when they push against the cam during closing? Not saying I know or have tested this, but the theory seems sound to me. ??

Edited September 1, 2010 by mooseman426

[mighty_4k]

If your planning on revving out to something crazy like 9000rpms definatley go with duals mate.