JE 12:5 piston hit valves with X-4 cam

[1badazz_700r]

I have recently oppted to install the +5mm styroker crank. Its a goodthing i tore it down. Iam going to have to disagree with anyone that say JE pistons will work with larger cams, the reliefs just dont seem to be big enough . Here is the proof. im lucky it didnt cause any damage

[machelis]

Are you sure it wasn't just a valve clearance issue this time? Or have you heard of and dealt with this type of situation before?

[1badazz_700r]

I would say it was a valve clearence issue. they open to far with the larger type cam.also when i told kenny i was running a JE before i ever took it apart he asked if there was any issues with the valves hitting the piston.At that point i said no,why? he said its been known to happen with the larger cams and JE pistons. all the work done to the head was done by velociraptor and assembled by him cam and all. So i know it was assembled correctly and have no reason to question that end of it at all.

[NVMYZ28]

Sheesh!

I'm planning on doing a 105mm bore, and 5mm stroke, with a Web4 cam, using a CP 12:1 piston - think I'll run into issues?  I planned on doing a clay test to be sure - but would hate to get that far into the build and then get stuck for a bit 

[1badazz_700r]

I think the cp's are fine but i would ask the pro's Im just trying to make people aware of the issue that i had to save people hastle and money

[Troy]

I would say it has to be the bigger +1 valves.  An x4 with stock valves will clear a JE 12.5:1 piston, or at least it did with no problems on the build I just tore down.  I know the valve reliefs aren't as big as the other brands.  Good thing you checked it out   Just out of curiosity, did the head get milled at all to clean it up or did the cylinder get milled any?

[1badazz_700r]

nothing was milledat all Its the first time the urge for spending more money to get more power actually saved me alot of money

[Troy]

LOL, that almost never happens.  I know I was warned before with the JE 12.5:1 pistons me and a buddy put in not to run it with big cams.  We ran my buddy's with an x4 cam with no problems, but it was a stock valve size head.  When I sent my head to Racer's Edge I ended up doing the x4, new valves, big bore piston, cylinder shaved, etc.  I had no worries on my build because the CP's have enough valve relief.  So what kind of piston are you going to go with?  There are alot of really good options out there now a days.

[1badazz_700r]

im going with the diamond 12:5 piston

[Troy]

Sheesh!

I'm planning on doing a 105mm bore, and 5mm stroke, with a Web4 cam, using a CP 12:1 piston - think I'll run into issues?  I planned on doing a clay test to be sure - but would hate to get that far into the build and then get stuck for a bit 

I have a 105 bore, 5mm stroke, 13:1 CP piston, shaved down cylinder and an x4 now with no issues.  I will be testing the Web 4 and a custom grind cam in two weeks so I can tell you at that point if it all works out for me.  Keep in mind I'm running a shaved cylinder, I think it was shaved .040" and a bigger profile piston that you are thinking so you should be just fine.  I 'll let you know how it works out for me.

[NaturalRaptor]

nothing was milledat all Its the first time the urge for spending more money to get more power actually saved me alot of money

Wow, I need to use that as an excuse next time I tear it down. Sounds like you got lucky, so good luck on the next build! 

[tonyrt44]

I have stated, on the other forum, that X4 cam will have clearance issues on stock bore builds.

for ya'll running the 105mm bore, it's all good