4runnerlife

hello guys,
i am getting to more problems as i go....
in my 99 4runner v6 i have two cam pulleys, one on right side and one on left side (inside timing belt cover) when looking at the engine the one on the left is turning nice and smooth, the one on the right is turning as if he is stuck compare to the other one, does both do the same job? or does one control the valves and the the other one the pistons? sorry for the dumb question i have no clue how this works, so i don't know if it suppose to go so hard?
thanks

James Woods

iTrader: (1)

No they both control valves, it could be that one cam is unloaded and the other is loaded.

4runnerlife

Can you please explain what is loaded or not,
Thanks

Kiroshu

Valve spring(s) pressure

4runnerlife

What does it meets valve spring pressure?
I have no clue what to make of it...
Please be more specific
Rhanks

Kiroshu

Rule of thumb normally when replacing the timing belt to never turn the crankshaft or the camshaft(s) once the timing belt and or chain have been removed. Because piston to valve contact can and may occur. However this is normally not a problem in the "3.4 liter 5VZE" as it is a non-interference engine meaning piston to valve contact cannot occur(normally). If you lined up the engine to TDC(Top Dead Center)#1 piston compression you should not be needing to move the camshaft or the crank. Unless you are performing some other kind of repair? If your not familiar with how and engine works internally(don't mean to be rude) but one should not be "muking about" inside the engine.

Camshafts will have resitance to them as they are doing "work" and that work is operating the valves open. The cam lobe pushes down on the "bucket" or "shim" located on (3.4 engine)top of valve and valve spring and thus pushes down on the valve and allows it open. The valve springs have alot of pressure some around 90-150+- lbs of pressure so when the valve is opened by the lobe on the cam shaft and finishes opening the valve has to close correct? When the lobe has finished the valve action what actually closes the valve is the valve spring pressure "pulling" the valve back or "springing" it back closed. "Poppet valves" <--- all automobile engines have them.

4runnerlife

Thanks for that, 2 questions to you...
First, all the utube videos show to line the cam pulley with the cover marks, is it not needed?
Second, does the cam being hard to turn is normal? Or maybe that's the reason the belt got broken... Maybe it's stuck

James Woods

iTrader: (1)

Is the cam hard to turn 360 degrees or does it just have some resistance and then free up suddenly? If it is the latter, that is how cams work normally, if it is hard to turn all the way then you have a problem.

4runnerlife

Yes it's hard to turn all the way.
Should I open the valve cover to see what's causing it?

Kiroshu

If the belt "broke" then i would suspect the engine to be "out of time?" Even though alot of engines are "non-interference" engines there are still a few times where piston and valves esp. while trying to fix timing can contact and once this happens the crank and or the cam will appear to get "stuck" while moving the camshaft where it seems to get stuck and try moving the crank "counter clockwise" slightly to let the valves open all the way and the cam shaft turn.

Follow Factory Service manual for timing marks. Yes there should be timing marks on the covers(rear covers) for the cam sprockets. And one on the oil pump for the crank.

Team420

It should also be noted that you should not use a wrench, or socket/ratchet to turn the cams via the bolts, that can lead to a loose cam pulley which will cause further carnage in the future.
My opinion... If u dont know how the engine works, u shouldnt be messing with it! Although... that may b the only way to learn, it can b an expensive method. I'd get a buddy that does know something about engines, buy him/her a 12 pack of their favorite beer, and watch them, so u KNOW what to do next time.
Good luck to ya !