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S/V/C VVT Question

itlksez

Member
Joined
Oct 6, 2009
Location
Post Falls, ID
I?m swapping an RN engine into my 850. I have limited experience with VVT. Are these timing marks ?close enough? or is the intake off a tooth? I?ll be installing a new timing belt, and I?m curious if it needs adjustment. Crank is dead center on the TDC mark.

Exhaust:
KwuEGk3.jpg


Intake:
bXE4v4M.jpg
 
I?m swapping an RN engine into my 850. I have limited experience with VVT. Are these timing marks ?close enough? or is the intake off a tooth? I?ll be installing a new timing belt, and I?m curious if it needs adjustment. Crank is dead center on the TDC

The crank should be on the timing mark which is not TDC of the #1 cylinder.
It's close, but not the same.
 
best bet is to undo everything and relock it all with the tools. Thats the best way to reset it all.

How are you going to control VVT in your 850?
 
Not yet. I’m asking this first before I pull the belt. I don’t want to lock it in place if where it’s at is wrong.

If you use the locking tool that goes at the back of the cams, the camshafts will be set to the correct position.
 
Was the engine running prior to removal?

If yes, as long as the crank is aligned, then yes, those marks are fine as long as they remain in the same position when you put the new belt on. If the cam spins when you had have it apart, you can spin the gear back into alignment without issue.

If you're unsure if the engine was running, you should lock the cams and reset the VVT and exhaust cam gear.

To be honest though, I've installed a bunch of JY engines over the years, and as long as the marks are lined up, I've never had a problem.

Also, I should note, you've taken the belt off, locked the cams, adjusted properly, the lines often don't line up perfectly afterwards. It isn't a problem.

Jordan
 
From what I?ve researched, they?re fine if you do nothing.

the car will drive from point A to point B but the power curve is horrible and the car looses most of its torque.

We did the same thing on our race car and I have regrets everytime I hit the gas pedal.
 
She?s a runner!

https://youtube.com/shorts/eUUszJ54FiQ?feature=share

the car will drive from point A to point B but the power curve is horrible and the car looses most of its torque.

We did the same thing on our race car and I have regrets everytime I hit the gas pedal.

That?s interesting. I?ve put about 50 miles on this so far, and the torque is markedly improved. It pulls hard off idle. I?m actually concerned it might roast my transmission now.

The only issue I have so far is the rear exhaust cam seal I pulled out of the old head and re-used is leaking. Dang, I?ll have to spend the $5 on a new one. Other than that, all is well. Keeping the beater with a heater going. Total cost was $40 for a new timing belt and $20 for an oil change.

Thanks for your input everyone.
 
What was the engine out of? (I see it's NA). On the whiteblocks, it's been seen that only the single VVT turbo cars (exhaust) are fine if left blocked/unplugged, as the cam events are pretty close to the N versions. The info found over on VS is primarily turbo-related, but there are a couple bits of NA info (from '01 NA RN motors).

The #'s for the N NA cams
Intake:250dr duration 8,45mm lift
Exhaust:252,6dr duration 8,45mm lift

I don't see values for the duration of the '01 cams, but the lift on them varies from 8.60mm to 8.95mm, so you're probably seeing some "gain" from that.
 
There may be some differences in the cam timing events, but it's hard to say without digging more. If you set it up properly when changing the timing belt, things should be in the stock "zero" location.

We have an '01 LPT motor in my wife's '97 GLT that has the exhaust VVT. We ran it for a couple years with the solenoid disconnected, as besides the lift changes, the cam timing events were very close to the N motor. We now have it functioning with some code from VAST. Once the weather warms up I plan on playing with it more than the basic "safe" map I have on it currently.

I know you're just keeping the beater running, but it's still interesting stuff.
 
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