rb25 vtc-cam failure!!

[supersayianjim]

so the weirdest thing happend to me this past saturday night.. fired up the rb 25 and drove a distance to kansas city from my garage for ths first time since i finished my swap. you know to get the bugs out and what not. then this happend.














Heres some back cliffs. when i replaced the old oil pan, and while cleaning the oil pickup there were 3 small pieces of aluminum shavings on the oil pickup. i thought nothing of this, but this may have played a part in what to come.



i finished my swap started up the engine. ran good no knocks or lifter tick. mind you i got a brand new n1 oil pump. so thankfully i had my harness done the right way so my oil pressure sender unit/dash oil light worked. never had any oiling problems untill this night.



i used dino-oil and a cheapo fram filter to just get a feel for the engine and planned on using synthetic later on(that didn't work out).



so iam driving around. working on my tune using nistune. i was copying and mimicing my stock fuel map that i uploaded through consult. i got a happy medium of 14-15 afr idle and about 15-16afr crusing mixture.



there are sensors on nistune/consult screen and the vtc window would blink but wouldn't go into red. (the fuel temp sensor was apparently busted). but other than that there weren't any notacable problems.



i didn't really get on it much as i was still breaking up above 15psi(i needed a pro tune). I wasn't bouncing off the rev limiter, just a little throttle here and there.



so them my dash oil light came on. great, so i went to walmart and got some more oil. on my way there when i was in throttle the light would go off, and flicker but i still got 2qt's to be safe.



put the 1st one in. and the light went off. then later on that night after starting the car. i had a damn lifter tick!!! WTF!!!



IT got louder as i went. so i added the other qt of oil, it sounded like it was getting better. then on the highway i hear a loud "CLANK"!! i get like maybe 5 more engine revs and like a couple more hundred feet to roll and thats sll she wrote. engine will crank but won't tuen over. sounds like there something stopping the rotation process!!!



and on top of that i see oil leaking out the bottom of the engine so my initial suspect was a bad oil pump. seeing as ive had a bad run-in prior with the n1 oil pump.



but a few days later and after a teardown and inspection heres what i found!!!






looks like the timing teeth were skipping a beat!!!



went to pull off the timing gear and violia!!!

[supersayianjim]

the intake cam seal looked like toasted ****. it appears that the cam siezed in the head!!

[supersayianjim]

and can't explain it but the exhuast cam looks equally shitty!!!

[Skym]

Jaw drops.

[supersayianjim]

so i pull the intake valve covers and what do i find?? not gold!! looks more like the bits i picked out of the pickup screen when i had the oil pan off, foul play???










so this is where things seem to be kinda fishy!! the front of the shaft is bone dry(explains the oil leakage before the final shutdown). but the back of the shaft has some oil, albeit not that much but more than the front!!

[supersayianjim]

and onto the camshaft retainers, these guys have seen better days iam sure.

[supersayianjim]

and here is the intake camshaft and the now sprinkled with awesome aluminum head bit cam shims.





yep, thats oil starvation!!












yep, my head's effed!!!!

[supersayianjim]

so when i get some time iam going to drain my oil and cut my filter in half to see if this snow is i my crank-case. knowimg my life it is and i need to pull this engine again and build it!!!



so i ask the community what the hell went wrong?? could not timing or the vtc itself could had caused this?? does the vtc have any effect on the oiling of these cars??



i thghtened the vtc cam gear to 50ft-lbs because i couldn't find the tq specs for the life of me. could this be a contributing factor??



i need a rb25s2 head if anyone has one let me know!!!

[speedfreak]

Maybe something blocked the oil passage from the block into the head.

[DatsunZ31]

Maybe something blocked the oil passage from the block into the head.

As I was reading this is what i thought to my self. the only way to find out is to pull the crank girdle and see how the engine bearings look like. if their fine but the head is toast for sure theres a block-age some where.

[zac3ne2nr]

Just so I get my bearings right, this was a VTC head swap you finished up on your S2-25. I assume you got the head from someone used doing a part out, rawbrokerage perhaps?
It would be interesting to see what the filter looks like. If there is residue it could be post and an effect not a cause. What DatsunZ31 says though about looking at the bearings would know if one or more of the ports got blocked. But then again you might only be able to make an inference as to which came first.

[Skym]

Pull the exhaust cam and see if it's the same. If it is, maybe oil starvation problems. Sometimes cams can be put in and tightened down on a warped head (can snap cam or get low oil pressure). Usually you line bore where cam goes (if head has warped in the past) to make sure it's straight. Same with block where crank goes if it has run a bearing or got very hot (enough to warp the block, should be obvious when bores are not straight, etc).

Also the front cam seal is known to fail on these engines (why Nissan recommend to change the front intake cam seal, front exhaust cam seal, front crank seals when changing cambelt at 110,000kms). Nissan usually has the front cam x2, front crank seals in cambelt kit.

You can get blockages in the block, head from metal (machining), casting sand, etc (with rebuilds, always clean oil, water galleries out before using block, head, especially if has been machined).

[supersayianjim]

Just so I get my bearings right, this was a VTC head swap you finished up on your S2-25. I assume you got the head from someone used doing a part out, rawbrokerage perhaps?
It would be interesting to see what the filter looks like. If there is residue it could be post and an effect not a cause. What DatsunZ31 says though about looking at the bearings would know if one or more of the ports got blocked. But then again you might only be able to make an inference as to which came first.

no there was no head swap, the head was never removed(by me) i just took off the cam gear to replace the cam seal.


but i got the engine from this guy.

http://www.japaneseengineimport.com/

[DatsunZ31]

no there was no head swap, the head was never removed(by me) i just took off the cam gear to replace the cam seal.


but i got the engine from this guy.


http://www.japaneseengineimport.com/

I'm sure a bad engine is common here and there. it's impossible to ensure everyone get's a good engine, if you have not touched the engine internally I would contact them and ask for a replacement if it is still within the warrenty period.

If I buy another RB it would only be through Raw brokerage, I read to many horror storys about bad engines and stuff to buy outside. at least RB will do whatever they can to satisfy you.

[amnash]

did you have an oil restrictor installed? making me hesitant to buying one and fitting to my rb20 block.. normally the head is over oiled on the RB's... weird