Shortshift

Here we go:

Joe I have a really excellent set of staggered Apollo wheels (black with polished rim style) that are fitted with nearly-new Avon 'wet' tyres. I'll see if I have some images to post up but do message me on here if you might be interested. Should add, I am Warwicksire based - J15 up the M40. James

Just moved from red to blue at Stuart's recommendation whilst he was tending to the broken valve springs on my Duratec R500. But after so many years I was bored of it always being the same colour and wanted a visual under-bonnet freshening anyway. 😅 James

Yes! James

Hi Col I'd like this, please. It'll be a postal jobbie. I'll pm you as well. James

Thanks for the update James. So the cam you are using is the same as was fitted to factory-build R500s (Kent D-TEC35) and you've also helpfully identified the Raceline/Kent spring as a VS51 parallel at 41 N/mm. I've updated the table a few lines above. James

I think the photos cover all of the wheels but, in event, you get the idea. Pretty near immaculate! James

I'm selling a set of CSR 10-spoke 15" anthracite alloys (staggered and with the unique front offsets) complete with Avon CR500 tyres in old but only part worn form (and therefore likely to be quite hard but good for destroying on road or track before replacing!). The condition is really very good, as you can see in the photos. Very rare nowadays and hard to find - I don't think a set has been advertised here for many years now. Priced at £1250 for the set with shipping available at cost if necessary (but I'm open to meeting-up with a purchaser, so long as distances are reasonable given my location just outside Stratford upon Avon). James

Rog - just realised I owe you a call back on this topic. The Alps will be a fabulous destination for a Club tour - so many different areas to pick with many interesting passes and routes to enjoy. Perfect for Sevens! Regrettably I won't be able to join in 2024 but I'd certainly encourage anyone who might be considering this to show their interest to Rog - it'll be a cracking trip! James

As I feared, everyone - but with one exception. James

"Now Now. What did SL R No. 77 say" Is that a question? Whatever Stuart wrote, I think it's clear to everyone who has read or posted in this thread (well, possibly everybody - but with one exception?) who he was directing his comments to. BlatChat is mostly such a nice, friendly, non-confrontational place these days. Long may it remain so. James

"...you are in danger of becoming pompous and self opinionated who delights in controversy." Oh, the irony... James

Good luck James - I'm sure your engine will be terrific once you have it finished. And then you will also have the satisfaction of knowing that it's been personally specced, exactly as you want it to be! James

And, for completeness, I now have the car back from Stuart at Premier Power. Top job carried out (seems to be his way... 😉) and, whilst I know that memory can be unreliable, the car seems to drive better now than at any time previously in my nine years of ownership. As someone said to me - a tale of unlucky-lucky! James

That's the way! Keep us posted, Anthony - and good luck for a successful outcome. 👍 James

Just updating and reordering the spring rate table I first posted above on October 11th (have we lost post #s in the new website?), reflecting the later information provided - just for posterity and for when others come looking in the future: Kent VS60 single 33 N/mm Kent VS59 double 37 N/mm SDB double 37 N/mm Kent VS51 single parallel 41 N/mm Piper VSSDUR single 42 M/mm Ultimate Power double 43 N/mm SBD VLSK-DUR-01K double 44 N/mm Piper VDSDUR double 52 N/mm Cosworth YD0093 single tbc Ultimate Power single tbc James (Apologies for space below; can't remove it!)

Hi - I have one spare. It's a little faded in parts on the outside but otherwise perfect. Thinking £85 plus shipping at cost. Let me know if it might be of interest. James

You just beat me to all of that, James. James

Sounds nice - and sensible (given what we've been learning)! James

That sounds encouraging. And I forget; what will your max RPM be set at? James

The only comment I'd make about your choice there (above), James, is that the initial failures (from 2008 through to around 2010, when the conical VS60 spring was introduced) all occurred with straight Kent springs that are otherwise unidentified. Just make sure you're not leaping out of the pan into the fire... Maybe better to move away from Kent altogether, perhaps to the Cosworth, SBD or one of the Piper alternatives, unless you can be sure that your chosen Kent spring isn't the spec that caused the very-first failures? I know I'd not re-fit a Kent spring to my car because I'd always be worried. James

Good work, James. This is really rather fascinating. The R500 has a soft-cut at 8,500rpm and a hard-cut at 8,600rpm (well above the R400 rev limit) so enthusiastic track driving will likely result in regular operation in the 8,000 to 8,500rpm band. It seems your thoughts on resonance fit well with this, with your R400 having failed inlet springs only whereas my R500, operating at higher engine speeds, has failed both inlet and exhaust springs. I've been digging a bit too, including looking-up valve spring rate data which I table below. In some cases, the figures are as-quoted by the manufacturer/supplier; in other instances I have had to do some rough estimation from data that I have been able to access. However, even if not 100% accurate, I think the figures are good enough for comparative purposes. James Kent VS60 single 35 N/mm Kent VS59 double 37 N/mm Piper VSSDUR single 42 N/mm (242 lb/inch) Piper VDSDUR double 52 N/mm (297 lb/inch) Cosworth YD0093 single tbc Ultimate Power single tbc SBD VLSK-DUR-01K double 44 N/mm

Just measured one of my now-removed springs and, as near as I can measure with my digital calipers, all dimensions are identical to the figures you have provided, James, apart from coil count where I'd say my spring comes in at 6.5 turns, end-to-end. If these are Kent VS60 springs (and I suspect they are) then I haven't been able to find a quoted rate for them but, working from the Kent Cams spec sheet (using known free and installed lengths with their quoted installed load) then I calculate the rate to be around 36N/mm. Very close to your 40N/mm measured figure. I'll get the actual rate measured when I can but these two springs (your R400/420 and my R500) look spookily similar. James