Tips to align pistons w/o timing belt on?

[coclimber]

My 2.5L "interference" engine has no timing belt on it and the timing components are NOT aligned with the tick marks on the engine.  How do I make sure the pistons are set up properly and the tick marks align without ruining any valves when I put the new timing belt on?  

 

TIA,

Jason

[MilesFox]

the keyway on the crank snout will be 6 o'clock. the hash mark on the timing sprocket will align to the dot on the crank sensor.

[Fairtax4me]

First you need to set the pistons at half stroke.

Rotate the crank keyway toward either 12 or 6 o'clock, whichever is closest.

 

Now you can use a wrench to turn the camshafts to their timing marks. The big deal with the DOHC heads is there can be valve to valve interference, so rotate slowly, and if you feel the cam stop hard at any point back off. It's usually best to remove the valve covers so you can see which valves are open.

If all four valves on one cylinder are open at the same time, there is a high chance of interference. Turn one cam 90° so one set of valves closes before turning the other cam to its timing mark. Once there, turn the other cam back 90° to its original position

[1-3-2-4]

Oh and to add make sure you turn the cams the correct way as well

[johnceggleston]

SOHC or DOHC?

 

the double cam is a little more dangerous.

 

the good news is that the spring loaded valves tend to slam closed,

removing them from action.

this is especially true on the single cam ej engines.

on the double cams, the cams move independently of each other.

so one could slam shut while the other is sitting still.

this COULD cause valve damage.

 

but with the the engine off, and the belt missing,

unless you force something,

more often than not, there will not be any damage.

ESPECIALLY if the crank is in any position except 3 o'clock or 9 o'clock.

 

only at 3 and 9 are there any pistons at the top of the stroke.

 

but as mentioned, at 6 or 12 all pistons are at mid stroke.

[coclimber]

Here's a photo of the engine. Evidently, it is the hugest engine photo ever taken!  I hope people can see it OK.

 

2.5L 

SOHC   (it is NOT DOHC)

 

 

I still have to take the intake manifold and coolant manifold off for the project I'm doing.  However, I'd love to not have to remove valve covers to see in there.  Would pulling the spark plugs help at all to release compression when moving the cams around or help to somehow see what is going on?

[johnceggleston]

no.

 

the piston position is absolutely determined by the crank shaft position.

 

look at the crank shaft ,

find the slot for the keey.

turn the crank the shortest distance, either direction, so the slot lines up pointing down or up.

DO NOT turn it so the keyway (slot) passes 9 or 3 o'clock.

you should be turning it less than 90 degrees.

this will make it safe to turn the cam shafts.

 

you are going to need a crank bolt to do it from the front.

but you may be able to do it from the rear using a flywheel bolt.

 

turn it slowly.

if you feel or hear it hit something ,

STOP.

but if you turn it less than 90 and it lines up either up or down,

you will not feel it hit anything.

 

once the crank is in the right position,

you can turn the cams to their correct position.

[Fairtax4me]

SOHC is über easy. Looks like your crank key is at 9. Turn the crank counter-clockwise to 6 o'clock. Then you can turn the cams over to their marks.

 

Line up the dash on the outer edge of the sprocket straight up with the seam in the head.

The little arrows will be at 45°.

 

You probably want to put new valve cover gaskets on it while its out.

 

Did you take all of the bolts out of the water pump?

Edited December 22, 2013 by Fairtax4me

[Gloyale]

 Looks like your crank key is at 9. Turn the crank counter-clockwise to 6 o'clock. Then you can turn the cams over to their marks.

 

 

If there is oil in it.....DO NOT rotate it counter clockwise.  Drain the oil, and remove the oil filter if you must rotate it backwards.

 

Oil pumps are "positive displacement"  which means if it turns, it WILL move oil.

 

Rotating backwards sucks in on the O-rings in the block, the backflow preventer in the oil filter, and worstly, the pressure relief/bypass valve in the pump itself can be destryed by rotating the enigne backward with oil in it.

 

Now 1/4 turn probably won't hurt anything......I just though it good to point out that rotating an oil filled engine backwards is a No-No.

[Fairtax4me]

If there is oil in it.....DO NOT rotate it counter clockwise. Drain the oil, and remove the oil filter if you must rotate it backwards.

 

Oil pumps are "positive displacement" which means if it turns, it WILL move oil.

 

Rotating backwards sucks in on the O-rings in the block, the backflow preventer in the oil filter, and worstly, the pressure relief/bypass valve in the pump itself can be destryed by rotating the enigne backward with oil in it.

 

Now 1/4 turn probably won't hurt anything......I just though it good to point out that rotating an oil filled engine backwards is a No-No.

Good point. It still takes 2-3 seconds of cranking to make the 3-4 psi that makes the oil pressure light turn off, so a 1/4 turn by hand won't hurt anything, but don't free spin it over and over again. Set the crank and leave it there.

[coclimber]

Hi all!

 

Yesterday, I successfully installed my first timing belt kit and water pump ever.  Thanks to everyone for your help on this thread.  Very satisfying to do this on my own.  Photo of "minorly" successful install here.... Read on!     

 

So, I get the timing belt on, ensure its lined, up and pull the pin only to see that I forgot the rear timing cover that goes behind the last idler pulley.  DOH!!!  I got the pin back in, luckily.  Then, removed that last idler pulley and put the timing cover on. Done.  

 

[1-3-2-4]

damn I wish I had a open space like that to work!