Have you checked your cam cap clearances? They might be worn. Are you moving upto a 30 series turbo? Let me know I'm also thinking of upgrading mine.
the Heads were bought brand new from Nissan ...they have under 2000km on them GTX2863R its a direct bolt to my current set up .. .
Any machining to fit the JUNs? Maybe a glitch in someone's calculations? basically the only possible explanation other than the springs or just the worst luck.
The only machining for the jun cam install is a clearance issues to clear the lobes. -It's a pretty straight forward die grinder job so no implications there
If you like a lag monster then sure and plan on redoing the sump, pick up point, girdle and actually choking them out with the dumps and manifolds Sure (P.S. A lot of the US figures are manipulated. Ask me how I know Can make 500rwkw on e85 with a correct set up (like Blackbeasts)
ZEDZY .... 30 series Turbos don't need to be "lag monsters", I have 3071's making 24+psi by 4500rpm ... They do however take a bit extra to fit. If want some more details pm me.
Bit of a long shot ... but have you checked that there is no valve spring binding ? would only have be slight to cause a problem.
my cam lift is 9.5mm coil bind is over 15mm one of these engines that have been meticulously calculated ,this is why nothing makes sense of the possible cause.
I now don't believe its the valve springs ...just found out from machine shop the springs are just over 70lb+ seat pressure not the rated 80lbs. ???? from memory stock is around 55-60lb not a spring problem so all that's left is the gears that is the common item on the 2 engines its happened on . new gears are on their way just to make sure.. and going to lighten and balance them . nothing more I can do .
I've only just purchased my pair. Might ask Brett on what can be done and if it's as simple as putting them on a lathe and seeing what surfaces can be lightened.
That's disappointing re spring pressure. If I ever get around to pulling the motor I'll see what the JUN springs actually measure out to. No problem with JUN cams & springs and BDE series 2 cam gears, suppose it's just a matter of eliminating variables until it stops breaking.
correct me if im wrong, apologies if I am speaking out of place, however are these the same cam gears your send back last time for reconditioning? perhaps there is a flaw in your specific gears of somekind that keeps being overlooked ? I use JWT400+ cams JWT HD springs BDE s2 gears, no issues (yet) touch wood it sucks that your ÄGAIN" in this situation but im curious to find out the eventual cause
That's why they're being swapped I'm pretty sure. I'm starting to get the impression the Rob must have run over a gypsy in his Z at some point, obviously some voodoo black magic going on since there's no engineering explanation for it.
ok just gone through all my emails . I recently sent the gears back and was confirmed that it wasn't the repaired one so its the same cam gear on the broken cams. The one I had repaired that was off centre wasn't on the broken cams. I mean ,sure I CAN ASSUME THATS THE PROBLEM ...nothing else adds up. ________________________________________ Rob, This must be the sprocket that came loose on you? Both the inner hub and the cog are extremely worn where they interface ? and this is what allowed the cog to become off center. I have some spare parts that I can use to get it back to good, but I?ll need a until this weekend to get everything put back together. Regards, Brett Dempsey Brett Dempsey Engineering (253) 230-8205 bde-performance.com From: robxtreme@optusnet.com.au [mailto:robxtreme@optusnet.com.au] Sent: Wednesday, July 25, 2012 10:36 PM To: 'Brett Dempsey' Subject: RE: BDE GEARS PROBLEM ----------------------------------------------------------------------------- Hi Brett This is not the cam gear which the cam snapped with as the other one has wear marks on the anodising from rubbing a hole through the cam covers. This is the cam gear where the adjustment screws came loose for a day when I first installed them after purchasing from you .(if thats what you mean). Thats fine about waiting til weekend. Thanks Rob From: Brett Dempsey [mailto:brett@bde-performance.com] Sent: Thursday, 26 July 2012 12:53 PM To: robxtreme@optusnet.com.au Subject: RE: BDE GEARS PROBLEM ------------------------------------------------------------------------------ Rob, Yes, I meant the sprocket that had the adjustment screws come loose. Regards, Brett Dempsey Brett Dempsey Engineering (253) 230-8205 bde-performance.com ---------------------------------------------------------------------- Brett Dempsey <brett@bde-performance.com> Jun 17 I emailed to you on 6/11 the following: Robert, I finally found the time to inspect your VTCs? The one you marked with an X and had the broken cam end in it is not the one that I repaired last time. Everything else on both sprockets checks out normal. Regards, Brett Dempsey Brett Dempsey Engineering (253) 230-8205 bde-performance.com
So is that it then? Dodgey cam gear internals moving the gear off centre, swinging around like a ballast and causing vibration that lead to the cam snapping? Or is it just a new question now of "what caused the cam gear internals to wear?"
NO .....re read . wasn't the repaired one ... was the other one both times no proof only what is the common part on both occasions .. will never really know . but have a new set of gears to eliminate the possibility of being the gear. .
I'm sorry, I don't think I understand. I was going off of when Brett said the wear allowed the cog to go off centre.