bhunter

iTrader: (3)

Ok, after my long trip in the max (2600+ miles) my vtc's are worse. I have put 9,000 miles on the car in the 7 months I've owned it, went to the Toyota filter, changed the oil about every 2,000 miles. I changed the oil and tranny fluid right before I left on the trip. The vtc's would always shut up after the car was totally warmed up. Now since I got back I've noticed they clack most of the time. What's up with that?

Cliff Clavin

iTrader: (11)

I am having the same problem. I got a JDM motor last fall (installed by Jeff) and it was fine then. Now mine sounds like a diesel practically full time. I guess when it's their time to go, it's inevitable.

I have put in the same filters (Toyota), changed the oil twice (less than 1k miles each) and babied the car.

subs1000w

im in the same boat but im not easy on the car nor do i change the oil that much about every 5k with yota filter

they started ticking this winter when i had about 20k on my JDM

i guess im going to rebiuld them this summer

92SE_Dave

Try grounding them for like a month then take off the grounding.. this made mine get a bit better.

Jeff92se

iTrader: (82)

Sorry to hear that Chris. Considering how clean that engine looked, I would have thought this engine's vtcs should have been quiet for many thousands of miles.

Mine clack a bit now when I start the car warm (but sitting for a few hours). I just lug the engine in 2nd or 3rd gear and the noise goes away. Little trick from 5 years ago hehe.

Jeff92se

iTrader: (82)

The noise just comes back.

eric93SE

iTrader: (1)

wow that sucks, that means that jdm engines have a heck of a lot more miles on them. I can't remember but I think my vtc's clacked around 90k miles.

If my engine or tranny ever failed I'd rebuild it, no jdm for me.

Jeff92se

iTrader: (82)

Hard to really say eric. The engine I received for Chris was absolutely spotless inside. Water jackets were spotless. It had less varnish than my replacement engine that was run on semi-synthetic all of it's 60k life when I got it. Unless someone in Japan took extremely good care of it. Typically japanese engines don't have much mileage on them

eric93SE

iTrader: (1)

I don't know jeff, sounds like engine importers are full of b.s., there are two jdm people with relatively low mileage having failures.

Low mileage jdm engine = old wives tale ???

Jeff92se

iTrader: (82)

Eric. I was the one that looked at this engine. I took the valve cover off and did the KS replacement as well. This was one of the cleanest VE engines I've seen. And I've seen more than a few.

I can't saw how many miles they really have as I can't see the od reading. But in Japan, it's almost impossible to run the car for very long as the taxes for older cars are very expensive. (hence the jdm engine market in the first place)

This engine ran STRONG when I did the swap also. It had the fidanza, intake and Y pipe. If he had my JWT ecu, it might have run stronger than my car.

Either way, the miles on these JDM motors are ALOT less than what you can typically find here in the USA. If you want to rebuild your own engine, that's fine. But that's alot of time and expense for that also. I got Chris's car up and running in 2 days after I did the studs/ks/gaskets/wp/seals etc...

I might rebuild my extra VE though. #5 cylinder is low on compression. Probably a broken piston ring.

eric93SE

iTrader: (1)

I'm still not convinced jeff,


I had 130k miles when I took my valve covers off to do the vtc job, and it looked pretty immaculate in there.

Jeff92se

iTrader: (82)

Here is what Keelan's looked like. Chris' looked like this also.

Until you can give some information that most Japanese people can afford to drive their car for any significant amount of time before it being too expensive to own vs buying new again in 1992-1994, I'll stick to my guns

eric93SE

iTrader: (1)

okay jeff, I'll let you off the hook for now.

ChrisCheezer

does anyone know if idea of, cloged VTC oil galleys, was A cause for VTC ticking?
- My JDM motor has ticking during warm up, for about 2min. i plan an extencive (but safe) engine flush this weekend, and hoping for good results.

92SE_Dave

Of course it will come back. The noise eventually comes back on rebuilt vtc's too.. all a matter of time.

I ran valve tune, w/vtc's grounded for 2k miles, changed oil, and ungrounded the vtc's and they are way better, it's been a week, and whenevr they start to get bad again then I'll re-ground and/or install dash contact for grounding.

Jeff92se

iTrader: (82)

Not really a valid comparison but maybe you can detail why grounding would make any difference at all in the reduction of the noise. I've wondered about this. My rebuilt one lasted over 30k and it was still going..

Cliff Clavin

iTrader: (11)

My engine is very strong and I am happy with everything that Jeff did. I am beginning to think the VTCs going out aren't always an indicator of the mileage on the vehicle or maybe even how well they are maintained.

I have been talking with my brother and I am starting to wonder if it has to do with the number of times you turn the engine on and off. When you stop the engine, the oil drains to the bottom and takes a while to get moved up to the top. If you keep the engine running, especially above idle, it will keep the pressure going and send oil to the VTCs. This is all just a theory and I can't really prove it.

My first VE 5-speed I drove past 160k and the VTCs didn't tick at all. I drove about 10 miles on a highway (no stop signs or lights) to work each day and I spent hours at a time on the freeway. I never replaced the brakes or the clutch, even.

The first engine in my current car, my brother drove a lot on the freeway (commuted to college about 35 miles round trip) but started commuting to a job that was only a few miles in bad traffic. It never ticked until a few years after he started this job, when the car had a little over 100k.

My current JDM engine did not have much tick at all when I got it. However, I only live two miles from work and I will go for a week or more without running the car for longer than maybe 10-15 minutes at a time. This engine ticks pretty bad now, even though I have done everything possible to prevent it.

I am thinking that in Japan, being as most things are pretty close together, a lot of engines don't rack up many miles, but get run for short periods at low rpm and stop and go traffic. My engine is super clean and like Jeff said, there is no way it had lots of miles on it. However, it is possible that it was driven to work for a couple of years by a guy who only lived a few miles away, where the VTCs wouldn't get the oil they needed.

Anyway, this is just a theory. I have a rebuilt set of VTCs that have never been installed, but I don't even want to think about working on the engine. Maybe next year.

bhunter

iTrader: (3)

That is sort of the point of my thread. I would have thought that a long drive that really got the fresh oil flowing up there would have made it better somehow, not worse.

92SE_Dave

Well.. from what I have gathered (and may be wrong)... VTC uses advanced timing from ~2000 to ~4000 rpm give or take, and above or below that range it defaults to non-advanced timing. The mechanism uses a spring (springs to advanced timing), and oil pressure buildup that works against the spring to bring it to 'normal' cam position.

So... I believe that most of the ticking is caused by the VTC not being in the correct position for the rpm it is at. That's why you often get ticking at startup even on with 'ok' vtc's, becuase it has to build oil pressure for a few seconds to get to 'normal' cam position.

Bad vtc are caused by a few things one of which is dirty, clogged oil galleys, that cause the spring to not have as much force to advance timing, and cause oil pressure buildup to take longer.

By grounding the vtc solenoids, they always run in normal position, ie have oil flowing into actuator working against the spring. So by having them grounded you get more oil flow, hence get cleaning, which is amplified by having oil treatment and grounded vtc's. Long drives won't necessarily help with ungrounded vtc's since they will have cam in advanced position on highway and not get as much oil flow...

Theres my theory... might be off.. I don't know.

Jeff92se

iTrader: (82)

Hmm interesting.

alpicone

When I did a JDM swap the motor that I replaced had 190K miles. The valvetrain looked just as clean. I still have the motor and I will take some pics later.

Jeff92se

iTrader: (82)

Ugh. I give up. That wasn't the only low miler indicator. You guys can believe what you will.

eric93SE

iTrader: (1)

Most of what you said is correct. But the spring is only a return spring, meaning it brings the cam back to the non advanced state when the oil pressure is turned off. When oil press is applied the spring is compressed and timming is then advanced.

Yes, a clogged oil galley can lead to failure, but this is due to the fact that oil as we know acts not only as a lubricant but as a means of dissipating heat, so if oil cannot flow freely to the vtc mechanism it will then run hot, which is whats ruining the spring steel, thereby loosing some of its properties (permanently) and the mechanism can no longer fully bring the timming back to the non advanced state. So the rebuild kit, with the stiffer spring is nissans answer to the problem, but as we all now know is not the full solution since the clogged oil galley will ruin the spring once again.

92SE_Dave

Are you sure it springs to non-advanced ??

The whole idea of having the anti-flow back oil filter is to maintain pressure when the car is off, so that it can immediatly get oil to actuate the cam to normal position at idle... I thought...

MrGone

iTrader: (30)

from off idle

Has nothing to do with cam position.

No, there is always oil flowing through the VTC. When they are grounded a solenoid blocks the exit gally making pressure build up which is what activates the VTC's).

Actually as long as he is driving normally, the VTC's most likely stayed in their "free" position. In theory, because the spring doing all the work the entire time it could have "weakened" it. The only problem with this is now people will say VE's only make good city cars which is not true. I know of alot of high highway mile VE's who's VTC's are just fine.



The only real reason I can come up with as to why they make noise is that the spring becomes fatigued and cannot provide enough pressure to keep the cam from 'twisting' within the VTC assembly, so it slightly retards until the VTC spring pressure is enough to counter the valvesprings pressure (if you have ever tried to turn a cam by hand you will find it is not as easy as you think it would be). From there the 'whipping back' or 'pressure release' or what have you makes the noise. I would think it is the center part of the VTC hit the outter housing. However I have taken a few apart and the only real wear marks come from where the springs are, so logic says it is probably the springs making the noise, but it's just hard to imagine that type of noise could come from the spring. (maybe the cam moves back into its normal (non grounded) timing faster than the spring can push it back.


The other part to that would be how some VTC's are ' notrebuildable'. The spring wears a groove into the base. the extra distance makes it so the spring cannot put out as much pressure as it was designed to resulting in "failure". (which could explain Aarons thing, plus he has had a few cross country trips which can confirm part of what I said above).

I guess the smart thing to do would be to start a bidding war on Mizeree_X's new vtc assemblies

(I might have missed some things, It's time for lunch)

92SE_Dave

Ok, that mostly makes sense.

So grounding them has cam always advanced ? Shouldn't that mess up the idle a bit ? And shouldn't that mean that grounded vtc car has same peak power as working vtc ??

DMad8724

iTrader: (4)

Not a big engine or VTC guy, but now that I have a VE with some (rather annoying) VTCs I'd thought I'd chime in..

Does anyone have a picture of the 'oil gallies' that supposedly get clogged? Why not when rebuilding VTCs try to make these gallies bigger? Is this possible?

Mizeree_X

iTrader: (9)

The VTC TSB tells you how to do exactly that. It requires pulling the heads.

eric93SE

iTrader: (1)

MrGone, I looked it up to check, look at page "EF & EC-174". Timming is advanced (intake valve opens sooner) when the vtc solenoid is on.


92SE_Dave, yes grounding them leaves them advanced, and many people do have a rougher idle. And no, a grounded vtc will not have the same peak power, since the vtc is supposed to turn off at high rpm (>4000) for the cars natural torque peak.

James92SE

iTrader: (31)

Mileage certainly isnt an indicator of VTC failure

Case in point: When my mom bought the blue VE auto (my old Skyblue one), back in 96-97 or so.. it had about 65k miles on it. A week after we got it it started clacking. That right there proves VTC's can fail relatively soon. Luckily we had a warranty on it so they got replaced (I've still got the invoice)

Then they started clacking again at about 130k right when I sold the car.. so the brand new VTC's started to fail after 65k miles.. and my dad kept meticulous care of the car so I know it wasnt due to neglect

MrGone

iTrader: (30)

sort of, technically the cams are never really advanced.
Grounded = solenoids activated = advanced cam = off idle to I think its 4700rpm (someone will confirm with the FSM). So if anything you will notice a lower idle.

Another thing that is stange is how VTC's will clack when they are grounded (however as far as I know, they will stop while you are lugging the engine).


Dmad:
http://s92599732.onlinehome.us/image...Oil%20Gallies/

Jeff92se

iTrader: (82)

http://s92599732.onlinehome.us/image...20assembly.jpg

Shawn. Isn't that the oil feed for the cam? The VTC oil feed is the hole near the left cam tower bolt? The hole near the solenoid?

eric93SE

iTrader: (1)

And just to point out to everyone, that when the VTC is turned on, there is 20 degrees of intake valve timming advace.

eric93SE

iTrader: (1)

Shawn, I think we posted at the same time, check my post at the end of pg.1.

92SE_Dave

I noticed no difference in idle, except that it SEEMED smoother because the clakety clacking is less intense, and gone after some revving (btw Mr Gone, this would make sense about clacking at low rpm , then stopping while lugging because oil pressure goes up, maybe clacking is a two way thing, spring & oil pressure can't do job properly under certain conditions...).

Ok I wasn't sure about the exact RPM that it turns off.. but I just assumed it was after the power peak.

MrGone

iTrader: (30)

Yeah.

I have the FSM pages posted on the site I linked to. I got confused, sorry, for some reason I was thinking advanced = after TDC. I'm going to go edit my posts.


Also for the oil galley thing

eric93SE

iTrader: (1)

Appology accepted

MrGone

iTrader: (30)

My idle goes to crap when they are grounded, not as bad as it used to be though. I also have taken a good ammount of the rotational mass of the engine off it though.



Eric, I'm having a brain fart right now. From what I remember the general rule of thumb was when you advance the cam, the powerband moves up.

MrGone

iTrader: (30)

dont worry, it'll happen again in 3-6 months

92SE_Dave

But is it advancing the intake or exhaust valves ???

Nevermind just read the other post...