Little back round i have a vq35 swap in/

So i was messing around today and i reved to 7k and all of a sudden it started missing. Well i got back home and checked out the plug and the electrode was smashed!!!

I regapped it and started it up and now i have some tapping sound that i didnt have before




The perfomance seems unaffected though. Hopefully i will be doing a compression check later on this week to see. But im thinking that i might of bent a valve. But one would think that my perfomance would be affected.

Any insight that anyone would have would be much appricated

 

Uh oh!

Where'd you get the motor from? Is it warrantied?

I thought 3.5s were good to at least 7k.

Good luck man

 

damn that doesnt sound good at all>.>

good luck!

 

sounds like one of your rod are bent and that sounds like your engine doesnt have much life left in it, my fried 01 started making a sound similar to that just a bit louder and the car died in 6 days.

 

well least i know i can get a 3.5 for cheap

 

I feel your pain...

 

Yeah, that's not a high pitched clack like a valve that sounds like rod knock from a spun bearing.

That could also explain the electrode since I know sometimes the bearings double up on the top or bottom of the rod journal causing the extra stroke to hit the plug

 

Damn, you sure it was only 7k? Motor wont last much longer.

 

**** dude!!!! that sucks!!!! if your getting a new motor at least keep this one and maybe even rebuild it if the block isnt f'd.

 

yes that deff does sound like your motor is FUBAR.

 

I drove it some today.

For some reason it only does this cold..

It didnt seem as bad when it was warmed up.

Im scared to look at my oil though

Oh yeah for sure. Least some head work

 

Well i check the oil. And plugs

It black but no shavings???

But the plugs have a green shade to them..... Probley from me advancing the timing to much

If it were a rod knock or a bad bearing wouldnt i get the knock all the time?? And if it were a bearing wouldnt i get some kind of metal shavings???

Here are some of the facts of this noise

1. No performance loss
2. it happens from idle to about 3k then it goes away.
3. after it is at operational temp it is very faint.
4. No metal shavings


Should i try and throw in some lucas or some marvels???

 

is it pinging? knocking? is your ig timing advanced still or did the KS actually do its job for once and retard it? any codes?

 

when you put back your spark plugs are any of them sitting inside very loosely? reason i ask is becuz your plug might be damaged or maybe you need a helicoil to hold your spark plug in place.

 

My friend has the exact same noise in a Saab Aero, sad to say it was rod knock.

 

well ive been driving this lately with the knock.

Well today i was beating on it a little bit and now

cylinder #3 had a smashed spark plug....

So my assumption would be a bad main bearing or my crank is bent

and or both now

 

I'm sorry but one question : why do you rev to 7k ?? don't you feel responsible for this problem ?

 

Umm yeah thank you mr.obvious

Why dont you go criticize someone else now.........

 

well, lesson learned at least. sorry dude.

 

exactly, thank you for the healthy criticism

Really i do appreciate it

 

been there, done that. live and learn, at least you know what not to do next time.

 

Thats rod knock for sure, (rod fatigue) commom problem on the vq35 if your going to get another 3.5 i would build it over for a piece of mind, nissan took short cuts on the 3.5 they rushed it into production my brother just took one back to the junk yard got a refund, motor was no good.Or you can get a 3.0dek motor and put in 350z rev up cams. Im currently rebuilding a dek with 3.0 stock pistons, rings and 350z cams acl race bearings waiting for parts to come in just finished tearing it down,the rods on the 3.0's are forged very strong and reliable. Good luck i hope you get your car back in shape.

 

further evidence the 3.0 is stronger than the 3.5...

 

Yeah i pretty much have came to the conclusion the motor is going to go. It sucks but what can you do???

Once i get my winter beater(probably a Honda) I will start pulling her out.

I know what your saying i beat the **** out of my old 3.0 and it took every 7.5k rev(daily)

 

Damn! Sorry to hear about the 3.5! I am curious what went wrong in that the plug got tapped, then the problem went away completely, then happened again and smashed the sparkplug. Had to have been the rod bearing spinning, doubling up, then later sorting itself out, and then failing again?


Do you still have your old 3.0 to throw back in there?

 

Im not sure what actually happened. I havent done a tear down yet to actually see what happened. I drove it around with it knocking for a while till i started getting some smoke out of the VC.

Yeah i actually still have a couple of 3.0's. But when tax season comes ill be throwing in another 3.5 But this time around i will keep the stock rev limiter

 

Damn, that is a bummer the 3.5 isn't as beefy as the 3.0. Being able to rev to 7500 reliably right out of the box on 3.5's would be absolutely awesome.

Do you think the 3.5 limited to 6500 is still faster than your 00vied 3.0 at 7500?

EDIT: BTW, off topic, but I saw you picked up a B12 as a winter beater. Great cars. I had an 89 B12 XE sport coupe. Fun car.