unixfreak

Hello everyone, last night Bank 2 Intake Camshaft was broken at the sensor side ( bottom of camshaft ), I will disassemble it and repair but need to make it clear why it happened? anyone have some answers ? thank you

dkmura

iTrader: (64)

My suggestion is to closely examine the camshaft itself. You may need to wait until the disassembly is complete and look at the fracture line carefully. If there's signs of a imperfection in the casting and a stress riser in the surface, it could come back to a production defect. But Nissan is typically very good about QC with power components and this not at all typical of VQ engines. You'll also need to examine other timing components to see if there was a catastrophic event that stressed that part of the drivetrain.

How many miles were on this Z car? Anything else going on to describe when the cam broke?

THIRZTY

Yikes. Being a Revup (I have one) my first suspicion would be damage from lack of oil. Maybe not by you... but it just finally gave up. My Revup was in very sad shape internally when I rebuilt it at 160k. All bearing surfaces throughout the engine were smoked...

unixfreak

Oil pressure issues can cause this guys? Engine was rebuilt year ago but we didn’t touched heads

dkmura

iTrader: (64)

Unless oil pressure dropped to zero at some point, it's hard to imagine it caused that fracture. Why did you have to rebuild the shortblock? How many miles were on the rev-up and how was bearing wear when you changed them out?

unixfreak

When I bought this car it has 130k in KM it's a JDM Z, seems old owner didn't watched oil and indeed it had oil consumption issues because of piston rings design and one day it screwed up, then I changed crank and bearings ( bearings were in very bad condition ), now mileage is 180K KM. Cam broke on 6th cylinder that matters?

dkmura

iTrader: (64)

If the previous owner didn't watch oil consumption, you've got your cause right there. Oil has to be pumped up to the head and without adequate lubrication, caused cam bearings to run with increased friction until something broke. I hope you also changed out rod bearings and rings while you rebuilt this engine.

THIRZTY

Sorry man but this is why... do it right or do it twice. Rebuilding a bottom end that's in sad shape and not checking the heads over was a mistake. Live and learn.

unixfreak

Thank you guys, I have almost ideal DE heads (non revup) , only difference is sensor hole? I am digging into FSM and I don't see any major difference?

and yes I changed rod bearings and piston rings as the cause was Piston rings as they were buggy. ( installed OEM piston rings for VQ35 NonRevup )