Andrei

iTrader: (7)

This is very disappointing. This changes my opinion from a favorable one to a very unfavorable opinion of the VQ35DE. This thread will be posts from all members who broke stock cams. Post what VQ, year, mileage, redline, and where it broke.

2006 Non-Revup motor with 53k miles, broke intake cam on bank 2 before the last lobe. 7200 redline occasionally peaking at 7250 in Cipher logs. Camshaft sensor gets 0 readings and there is no cam above the sensor inside the cylinder head. Can be checked through camshaft sensor port.

Also a member PMed me with this same exact problem.

2bad240

iTrader: (6)

wannabuy350z

iTrader: (27)

have had this happen on a customers car before, 2005 vq35de twin turbo

2bad240

iTrader: (6)

I just tore mine apart today and installed revup intake cams

kacz07

iTrader: (15)

I had a 2006 vq35de revup JWT C8R cam break. It broke at the sprocket. Redline 8k. Built motor.

tcode

iTrader: (7)

Ouch . Set redline on mine to 6900, thought to move it bit further for a couple of 100 rpm's but now I'm very unsure.

Andrei

iTrader: (7)

I think and this is just a guess, that the tolerances between the camshaft caps and the camshafts are too large and the frequency of the vibration as the cams revolve, matches the structural frequency of the camshafts at certain RPM causing the cams to break. It's a hit and miss with every camshaft, but spend enough seconds or fractions of a second at the right RPM to cause the vibration frequency that matches the structural frequency of the cams, and they break instantly.

Andrei

iTrader: (7)

I was wrong that is not the cause^. I'm in the process of replacing mine now. I talked this over with Z1 Motorsports and it seems that this is another mechanic design flaw. Apparently the end of the camshaft is the first to drain of oil after the motor sits for a period of time. It drains past the last camshaft cap and the tolerances are actually too small between both, not large, and because there is no oil there is more friction between the cap and camshaft, and the last lobe breaks off when it hits the valve lifter and mine broke on start up. That is why it breaks after the last cap and before the last lobe.

It does not happen because of high RPM as much as it happening on start up, though the last cap is also the last one to get oil (even if oil pressure should be equal after start up) so higher RPM will stress it more. I also noticed that the journal of the camshaft where last cap sits on top, shows more wear then the journals in the front, but that could be caused on start up or both.

This all makes sense because apparently even aftermarket $1200 billet cams break. I did not have enough common sense to figure that out^. Credit goes to Rob at Z1 Motorsports. He also mentioned that it's just bad luck since it happens rarely, but I believe in mechanical flaws not luck.

I also had oil burning on start up with this problem but that was because oil that was shooting out of the broken end of the camshaft and right into the PCV port of the baffle plate on the valve cover and got sucked into the intake. I have aluminum Pathfinder valve covers and the baffle plate port is right at the end of the intake camshaft on bank 2. This does not happen if the cam is intact because the end is capped off to create oil pressure inside the cam for the caps and journals.

I always said I would not part out the car or sell it, but because this is another mechanical flaw that cant even be revised easily and does not happen often enough for Nissan to revise the caps/cams, it leaves me no choice. I cant swap the HR because of the risk of bad main bearings and a slightly high price, and I cant swap the VQ37VHR because of the ridiculous price of used parts.

ehaalandtluk

iTrader: (1)

This makes me cry.

Andrei

iTrader: (7)

This could be avoided maybe if the car is parked on an incline for the front to sit higher than the rear, to keep oil in the back of the camshaft. Maybe Lucas oil additive will reduce the risk as well and I did stop using it with this new motor to cut back on cost. I parked my car on inclines where the rear was higher at work and home and there is days when I only drive in the morning for less than 10 miles to work and wont drive it again until the next morning for work again. Also before this happened I used to start and shut off the car at least 12-14 times per day which like I said I think stresses the cam more, mostly because of having 2 jobs 7 days/week and some other stuff on the weekends.

I guess making sure oil is at the recommended limit will reduce risk too. Maybe even adding slightly more but it will drain back regardless because the cam is high in the engine.

Point is though that it should not be happening.

faiz23

bullet proof my A*S. The cost to do anything is too high at this point considering swaps or parting out unless you like taking losses. I would slap a camshaft in there and if you are extremely paranoid then throw in a amsoil pre oiler. Just drive the vehicle and wait for the next thing to break. My recommendation....keep the vehicle stock and rag the sh*t out of it daily without having to worry about $$$$ or sh*t breaking constantly...l8r


http://accusump.com/accusump_units.html

http://g35driver.com/forums/g35-seda...t-forever.html

https://my350z.com/forum/forced-indu...s-saviour.html

Andrei

iTrader: (7)

I agree. Wish I would have known about this problem before, I've never seen it mentioned until now. I'm going to have to stick with it until next year at tax time to sell it. I wont have it ready for sale this tax season.

Neimad

How many miles did you run without a thermostat?

Andrei

iTrader: (7)

Had the motor in the car Feb and put tstat back in August maybe, for winter. Anyway I fixed it and the cam I needed from the set I bought here was trash so I had to go to Z1 and buy a single cam for $150 used. So over $600 total with the rental I had to get and 4 days of my ****ing time gone. Also had limited time to work on it.

I was in a hurry to get this done so I did not follow FSM entirely. I did it quicker and I left all accessories in the car and just loosened the PS and Alt and left them in the bay, AC can stay bolted, PS has many bolts 5. I only removed the sprockets for intake and exh on the side that was broken, bank 2. I did not remove the rear timing cover. I did not open up the intake sprocket since there is no reason. I wrapped secondary tensioner bank 2 with a zip tie and cut if off after it was back on. I stuck a paper clip in the pin hole for the primary tensioner and that worked great. There is no reason to take off the covers for water pump or primary tensioner or VTC sprocket covers. I did not take off the starter to block the flywheel, I just used the clutch and hand brake to keep motor from turning. I did not replace any o rings. I did not replace the front oil seal. I also loosened the crank pulley bolt with the handle of a floor jack on a ratchet. I used Lucas as assembly lube and filled intake camshaft bank 2 with it as a precaution. I got the primary timing chain on by putting it on the intake sprockets, around the water pump and onto the crank sprocket and then used a 22mm wrench to turn the bank 2 intake cam a little to allow me to get the crank sprocket to match the crank key. I did not remove the guide on the rear timing cover towards bank 1. I removed only the top guide and put it back on after primary chain was on. I removed crank pulley by hand shifting from the side to side and pulling. Also left AC belt tensioner bolted to the upper oil pan and only remove the bolts in the F timing case.

Rob Z1 also said that on a stock VQ35DE they will rev it to 7300 stock and they never seen a broken cam. I also noticed that only the first 2 caps have oil vains while the last 2 have only have oil orifices from the cams. Cost cutting or bad design, it's **** either way.

NismoZ123

iTrader: (2)

Clearly there was something going on with your engine that was extreme enough to cause that to occur just after startup. Just be careful with it, no one wants to see you having to post more horror stories about your engine. I would also agree that the parts Are of The Finest Japanese Craftsmanship, user error notwithstanding.

Andrei

iTrader: (7)

No, there was nothing going on with this engine other than it being a piece of **** from inception because it was "new" when I got it with 210 compression which it still has, and it's from a lease car that was automatic.

**** that breaks that is NOT suppose to break can break on someone else time and money that likes faulty ****. I have neither time or money, I work day and night for ******** scraps, I don't need this ****. I am done. But if I did have money I would let FPSRussia unload on it and post it on youtube.

At least it happened now and not later because I would of shipped a piece of scrap metal to EU for $3k and that would of been a monumental **** up.