petert 588 Posted July 14 There’s little information regarding fitting double springs or experiences on this forum, so I thought I’d share my recent experiences in fitting the Catcam kit, as sold by Pug1off. I had two heads to build and the owners had both purchased the kits without advice. Pug1off will openly warn buyers that the kits are not for the inexperienced engine builder. The kits contain three parts. The double springs, retainers and spacers (or bottom retainers). I’ll detail the bottom first, as this was identical in both heads I built. The tops differed, as one head had XU9 valves, the other XU10. The spacer is designed to fill the spring base cavity, creating a new flat platform. Once they drop in, they’re hard to remove, so beware. Whilst the spacers are made from anodised aluminium, you can’t allow the springs to sit directly on that. Additionally, the inner spring would sit on the casting aluminium. Neither ideal. Thus you need to add a thin hardened shim, which both inner and outer spring can sit on. Next issue is that there is nothing now to locate the bottom of the springs. They’ll wander around and create havoc. Pug1off advise to turn up steel rings, which slip over the guide and locate the inner spring. The seal is then fitted which retains the ring in place. Share this post Link to post Share on other sites
petert 588 Posted July 14 (edited) Fitting with XU9 Valves The first head was a normal D6B head, fitted with new, oversize stainless steel valves. With the thin base shim fitted and new Catcam retainers, the fitted spring height came in nicely at approx. 95lbs of seat pressure. All good there. However, it soon became apparent that an extremely thin valve clearance shim would be required if oem buckets were used with the oem camshaft base circle. After some researching, I found a BMW S14 bucket which has a thinner pad and uses a smaller and thinner shim. This worked out perfectly, as this head needed new buckets anyway. Edited July 14 by petert 1 Share this post Link to post Share on other sites
petert 588 Posted July 14 (edited) Fitting with XU10 Valves The owner of the second head, in this case a Grp A casting, wanted to use low mileage XU10 valves & buckets he had. I hadn’t really given it much thought and it provided unexpected challenges. When using the Catcam retainers, the top of the XU10 valve is extremely low. This means it’s impossible to fit a normal shim. The shim would sit on the retainer recess, not the tip of the valve. After much deliberation, I concluded that it was impossible to use the Catcam retainers with XU10 valves & collets. The solution was to turn a small step in the oem retainer to locate the inner spring. The outer spring locates perfectly on the standard retainer. I turned up a 7º mandrel to hold the retainer and used a small tungsten carbide tool. High speed steel won’t cut it. It’s not over yet however. With the top and bottom of the springs located satisfactorily, I could now measure installed spring height. Unfortunately, it was too high and I had to add more shim at the base to obtain acceptable seat pressure. Edited July 14 by petert 2 Share this post Link to post Share on other sites
SRDT 182 Posted July 14 6 hours ago, petert said: After some researching, I found a BMW S14 bucket which has a thinner pad and uses a smaller and thinner shim. This worked out perfectly, as this head needed new buckets anyway. Those are aftermarket "shim under" buckets right? Genuine BMW S14 buckets have the shim on top like some Italian and Japanese cars. Share this post Link to post Share on other sites
petert 588 Posted July 14 Yes, I found them in the Supertech catalogue. Share this post Link to post Share on other sites
LucasDunkley 0 Posted December 11 Excellent write up @petert, just what I was looking for. I have got a few more queries though. Did you machine a collar on the valve guide to locate your inner spring locating rings? And then valve stem seal sits on top? What was your concern with using a thinner OE shims and the OE buckets? Was it purely availability of the thinner shims or did the CATCAMS retainer prevent fitting the larger diameter OE shims? Thanks Share this post Link to post Share on other sites
petert 588 Posted December 11 I didn't machine the guides. The OD of the guide locates the inner spring locator. Order of intsallation, as per pic: 1. Install Catcam supplied spacer 2. Install aftermarket spring shim 3. Install inner spring locator 4. Install valve seal. The lip of the seal body retains the inner spring locator. The shim thickness needed with the oem buckets was <1.5mm. It may differ with yours. You can't determine that until you've done a trial assembly. Share this post Link to post Share on other sites
LucasDunkley 0 Posted December 11 9 minutes ago, petert said: I didn't machine the guides. The OD of the guide locates the inner spring locator. Order of intsallation, as per pic: 1. Install Catcam supplied spacer 2. Install aftermarket spring shim 3. Install inner spring locator 4. Install valve seal. The lip of the seal body retains the inner spring locator. The shim thickness needed with the oem buckets was <1.5mm. It may differ with yours. You can't determine that until you've done a trial assembly. Thank you @petert, looks like I’ll be biting the bullet and purchasing the kit. Hoping that I can stick with the OE buckets and shims as Supertech S14 buckets are not cheap! I’m assuming the shim washers that sit under the spring are a custom affair? I’ve got a friend with a laser cutter who should be able to knock some up if so. Thanks again, reply is much appreciated. Share this post Link to post Share on other sites
petert 588 Posted December 12 (edited) The hardened shims are just an off the shelf item, approx. 0.015” thick from memory. I can dig up the part number if you want. Who will make the inner spring locators for you? Until you have the shims and sacrificed a seal, you can’t really work out their height. It’s fiddly and time consuming but worth the effort. Edited December 12 by petert Share this post Link to post Share on other sites
LucasDunkley 0 Posted December 12 47 minutes ago, petert said: The hardened shims are just an off the shelf item, approx. 0.015” thick from memory. I can dig up the part number if you want. Who will make the inner spring locators for you? Until you have the shims and sacrificed a seal, you can’t really work out their height. It’s fiddly and time consuming but worth the effort. @petert if you could dig out the part number it would be greatly appreciated thank you. I’ve got access to a lathe so should be able to turn up the inner spring locators fairly easily once I’ve figured out the OD, ID and height. Thanks again Share this post Link to post Share on other sites
LucasDunkley 0 Posted December 12 20 minutes ago, petert said: CompCams 4717-16 Thank you @petert, I’ll take a look. Share this post Link to post Share on other sites
