531 Bigger valves?

[barkster1971]

If you're revving the nuts off it or have a monster cam then double springs may possibly help but stock springs will be fine 99% of the time.

[davebslater(uk)]

I can put you in touch with the chap who's done my heads in the past

[rockheadrumble]

hiya mate.

I have chips with a rev limit of 7000rpm and a higher lift cam so thats the reason i was wanting to upgrade the springs.

The 531 springs are bigger but according to Crogthomas who posted a few up he said the 530 are stronger.

Thanks Crogtomas, the pinto ones are infact a very similar size to the 531 springs (i rang burton power today) but i dont know if the pinto one are stronger. I would need to know the spring rates of each. I have the info on testing the volvos springs under a certain load so if i can find the same info on the pinto ones i would have a better idea.

Cheers Carl, Iv emailed Kyrk motorsport about there springs and valves. if i hear back il be buying a full set of 8 valves is about £100. The stainless pinto ones which are 38.1mm and the same in every other aspect are £67 for the exhaust from burton power.

Crogthomas do you have any info on the springs rates for the volvo springs?

Il let you know Adie what i decide, il keep in touch as I need to get some quickly.

Thanks all.

joe

[barkster1971]

It'll all help get that Holset spinning up! Is it on yet?

[rockheadrumble]

Originally Posted by barkster1971

It'll all help get that Holset spinning up! Is it on yet?

No not yet mate, im in the process of painting up my block and engine parts then il be fitting the head, rs500 intercooler and ally rad. good job im doing it when i am as the head gasket had definitely gone, 3 cylinders have what looks like water stains on them and i always had water issues.

Im going to need all the help i can get to make it spool! No it shouldnt be that bad really, supposed to be considerably better than a hx35.

see this thread mate;

http://forums.turbobricks.com/showthread.php?t=40913

he talks about tightening up the ratio of inlet to exhaust to try and achieve 80%. he only uses 1mm bigger inlet valves (45mm) and 5mm bigger exhaust (40mm) and still doesn't quite achieve it using a ipd cam (11.9mm inlet and exhaust lift). i think 40/48 may be to much difference, i read somewhere else about 80% is best for flow and efficiency. may be b0llocks though! thats why im thinking of just going bigger exhaust valves, i have a stage 2 RSI cam that will tighten the ratio up. also on this site it talks of tightening up the ratio

http://people.physics.anu.edu.au/~am...ad_531_530.htm

i have chips to rev to 7000rpm and the exhaust lift is 11.93mm, i wanted uprated spring for piece of mind really. i might do the occasional skid which means il be bouncing of the rev limiter! what do you think?

Originally Posted by davebslater(uk)

I can put you in touch with the chap who's done my heads in the past

Yes please, could you let me know Dave whos done your heads in the past.

Thanks

Joe

[crogthomas]

Originally Posted by rockheadrumble

Crogthomas do you have any info on the springs rates for the Volvo springs?

The 531 springs are 32.5mm OD. Weight 58g.
Free length is 45.9mm
Seat pressure at 38mm (installed height) is 31kg/68lbs
Pressure at 26mm (approx max lift for a Volvo cam) is 86kg/190lbs
From that you can work out the spring rate to be about 260lbs/in.
These are approximate figures measured using rudimentary equipment (bathroom scales) on very old valve springs.
Others have measured similar though:
http://turbobricks.org/forums/showthread.php?t=248250

The 530 springs are 29mm OD. I have not measured their seat pressure, but I can tell you from their dimensions (wire dia, etc) that they are slightly stiffer. Probably not much in it. But they are also slightly lighter in weight (47g) which will reduce valvetrain mass and help prevent float.

Originally Posted by rockheadrumble

I have the info on testing the volvos springs under a certain load so if i can find the same info on the pinto ones i would have a better idea.

What figures do you have then?

[rockheadrumble]

hiya mate.

the onfo i have is taken from an penta engine build manual. it says;

full spring length= 47.6mm
+ 44N (+/- 6n)= 32mm
+61 (+/- 6N) = 26mm

I have no idea how to convert or compare this though! I figured if i could find a similar test for the pinto springs i could compare them.

I can ask at burton power what the original spring rate of a pinto spring is.

thanks for the info mate.

joe

[smithy]

I use kent cams uprated springs in my head .good for over 8k rpm no probs even though I won't go that high mine will be 6k .im only after 140 bhp .

[rockheadrumble]

Originally Posted by smithy

I use kent cams uprated springs in my head .good for over 8k rpm no probs even though I won't go that high mine will be 6k .im only after 140 bhp .

i was waiting for your input mate. do you know what springs they are for mate/ what car they are for?are they single or double and did you use your original retainers?

joe

[smithy]

Originally Posted by rockheadrumble

i was waiting for your input mate. do you know what springs they are for mate/ what car they are for?are they single or double and did you use your original retainers?

joe

They are single uprated ones for a b230ft/fk .and yes original containers