Setting Cam Timing with Unkown Crank Orientation

[bigbird94]

To make a long story short I have a 1992 Talon TSI that just had the head rebuilt and upon first start up a large oil leak was coming from the exhaust cam (thanks to the shop for not installing cam seals in my head). I decided to remove the belt and cam gears to clean all of the oil from these components and put it in the new cam seals etc. I proceeded to brake both cam gear bolts free and remove the cam gears/ and timing belt.

The problem is that my stupid ass never lined up the timing marks on the engine before pulling the timing belt off.

So now my cam dowels are in opposite directions and my relative crank position unknown. I am afraid to turn anything right now in fear of valve to piston contact. I know for sure I can take the head off and turn both the cam gears and crank by hand and put it back together that way but Id rather leave the head on ( and cams ) in place if possible.


Can I just remove the cams, line my crank up with the timing mark, and reinstall my cams with the dowel pins at the proper, 12 o'clock position, and then install the timing belt?



*Balance shafts have been removed and are not a factor*

 

[19Eclipse90]

Can I just remove the cams, line my crank up with the timing mark, and reinstall my cams with the dowel pins at the proper, 12 o'clock position, and then install the timing belt?

Yes.

 

[BogusSVO]

yes you can.

 

[ed1380]

Its 16 valleys on the timing belt from dowel pin to dowel pin.

From timing mark to timing mark

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[bigbird94]

Okay then, that is what I will do. Thanks for all of the quick responses guys. I really appreciate it. Gotta love this site.

 

[pauleyman]

why on earth would you remove the cams? Put the pistons where they are in the middle, put the dowels up top, line the crank up and install the belt.

 

[DSM1G90]

Or, pull No. 1 spark plug and put a long shaft screwdriver down the hole and roll the crank til the screwdriver stops at its highest point when it's being pushed up by the piston.

Then check with the timing marks on the timing cover and pulley. Then you can get the cams where they need to be prior to belt install.


But, you're still gonna have to do the autoaduster and pulley alignments though....so that belt cover HAS to come off anywho...so off comes the crank pulley.

 

[EclipticalGS]

why on earth would you remove the cams? Put the pistons where they are in the middle, put the dowels up top, line the crank up and install the belt.

Uhh..because if he took his belt off, any rotation of the cams or crank without the belt would ultimately bend valves if spun independently. Taking the cams out allows all your valves to depress back into their seats thus allowing rotation of the crank without bending valves.

Come on this is common knowledge a 4g63 is an interference motor...

Or, pull No. 1 spark plug and put a long shaft screwdriver down the hole and roll the crank til the screwdriver stops at its highest point when it's being pushed up by the piston.

Then check with the timing marks on the timing cover and pulley. Then you can get the cams where they need to be prior to belt install.


But, you're still gonna have to do the autoaduster and pulley alignments though....so that belt cover HAS to come off anywho...so off comes the crank pulley.

Read above, you cannot spin these cam pulleys or the crank independently with cams installed and no timing belt!! You wouldn't even be able to spin the crank pulley more than 45* before your piston would be touching a valve.

The OP has got himself into a situation because he didn't use the timing belt tool that holds your hydraulic adjuster. Now all the accessory belts, crank pulley, lower timing cover, and cams have to come out.

 

[romeen]

Uhh..because if he took his belt off, any rotation of the cams or crank without the belt would ultimately bend valves if spun independently. Taking the cams out allows all your valves to depress back into their seats thus allowing rotation of the crank without bending valves.

Come on this is common knowledge a 4g63 is an interference motor...



Read above, you cannot spin these cam pulleys or the crank independently with cams installed and no timing belt!! You wouldn't even be able to spin the crank pulley more than 45* before your piston would be touching a valve.

Everything you've said is correct except the part about not being able to turn the crank independently of the cams. With a screwdriver, dowel, etc. on top of the piston for reference you just need to determine which way to spin the crank so that all pistons are moving towards the middle of their stroke. When the belt is off there is no reason that you can't spin the crank counterclockwise.

 

[EclipticalGS]

To make a long story short I have a 1992 Talon TSI that just had the head rebuilt and upon first start up a large oil leak was coming from the exhaust cam (thanks to the shop for not installing cam seals in my head). I decided to remove the belt and cam gears to clean all of the oil from these components and put it in the new cam seals etc. I proceeded to brake both cam gear bolts free and remove the cam gears/ and timing belt.

The problem is that my stupid ass never lined up the timing marks on the engine before pulling the timing belt off.

So now my cam dowels are in opposite directions and my relative crank position unknown. I am afraid to turn anything right now in fear of valve to piston contact. I know for sure I can take the head off and turn both the cam gears and crank by hand and put it back together that way but Id rather leave the head on ( and cams ) in place if possible.


Can I just remove the cams, line my crank up with the timing mark, and reinstall my cams with the dowel pins at the proper, 12 o'clock position, and then install the timing belt?



*Balance shafts have been removed and are not a factor*

Read above.

 

[Tyeler18]

Uhh..because if he took his belt off, any rotation of the cams or crank without the belt would ultimately bend valves if spun independently. Taking the cams out allows all your valves to depress back into their seats thus allowing rotation of the crank without bending valves.

Come on this is common knowledge a 4g63 is an interference motor...



Read above, you cannot spin these cam pulleys or the crank independently with cams installed and no timing belt!! You wouldn't even be able to spin the crank pulley more than 45* before your piston would be touching a valve.

The OP has got himself into a situation because he didn't use the timing belt tool that holds your hydraulic adjuster. Now all the accessory belts, crank pulley, lower timing cover, and cams have to come out.

Uh, wrong. Like stated, as long as all 4 pistons are 1/2 down their bore you can spin the cams all day long. I've done it on plenty of motors and I'm sure plenty of others have as well.

 

[EclipticalGS]

Everything you've said is correct except the part about not being able to turn the crank independently of the cams. With a screwdriver, dowel, etc. on top of the piston for reference you just need to determine which way to spin the crank so that all pistons are moving towards the middle of their stroke. When the belt is off there is no reason that you can't spin the crank counterclockwise.

This is true, you can get the pistons to the middle, then rotate cams into position. Then return crank to TDC. But doing this still doesn't negate the fact that everything needs to come off except for the cams, that is if he wants to do the scenario you mentioned.

 

[turbo98eclipse]

Agreed with the middle position piston theory!

 

[EclipticalGS]

Uh, wrong. Like stated, as long as all 4 pistons are 1/2 down their bore you can spin the cams all day long. I've done it on plenty of motors and I'm sure plenty of others have as well.

You are correct I misread pauleymans intentions as I thought he stated the same info as DSM1G90. Either way to correctly ensure timing and tension, everything but the cams will come out.

 

[pauleyman]

Of course it's a full timing belt job but there is no reason to pull the cams out. You will have to pull the gears off of course. It's no more or less difficult that any other tbelt job.

 

[EclipticalGS]

I agree, if there's anything new needed; hydraulic tensioner, idler pulley, water pump, it'd be best to knock it out now with it all apart.

 

[DSM1G90]

When the belt is off there is no reason that you can't spin the crank counterclockwise.

For, usually with the dowels up at 12:00 position, aren't ALL the valves closed anywhos due to the spring tension pushing up on the lifters on the cam lobes to rotate the cams in the relaxed position and actually get your mark where it needs to be?

If not, I usually roll the cams to where they are in the relaxed position before I mess with the crank...and get the sparkplugs out so not fighting compression.

This really makes it easy to do belt timings.

Known this one for a few moons...

-DSM

 

[romeen]

For, usually with the dowels up at 12:00 position, aren't ALL the valves closed anywhos due to the spring tension pushing up on the lifters on the cam lobes to rotate the cams in the relaxed position and actually get your mark where it needs to be?
-DSM

I think that's only true for cylinder #1 which is at TDC.

 

[steve]

For, usually with the dowels up at 12:00 position, aren't ALL the valves closed

I think that's only true for cylinder #1 which is at TDC.

Right, Cylinder 1 has both sets of valves closed at TDC because normally the spark plug would have just fired and we are starting the power stroke but cylinder 4 has both sets valves open in overlap.

So no, the valves aren't all closed with the cam dowels up at 12:00 position.

 

[bigbird94]

If there is one thing that any future reader should take away from this thread it is that you should make sure all timing marks are lined up before attempting to remove the timing belt.



BTW I just re-did this engine with all new OEM timing components, oil pump, rebuilt head, etc... A massive oil leak upon startup caused was the reason for tearing it back down. The shop that rebuilt my head never installed any cam seals, or maybe they were leaving that part up to me? Idk what the typical procedure is there but I considering they put in my cams..... Just thought I'd mention.

 

[DSM1G90]

The shop that rebuilt my head never installed any cam seals, or maybe they were leaving that part up to me?

Was that in the rebuild quote? Did you take the head back and showed them that no seals were installed?

 

[bigbird94]

Was that in the rebuild quote? Did you take the head back and showed them that no seals were installed?

Cam seals were never mentioned on the quote, reciept, or in any of the multiple phone calls I had with the shop's owner. They installed the cams on the head before shipping it out to me, to install the cams properly, wouldnt they have HAD to use seals?

 

[romeen]

Cam seals were never mentioned on the quote, reciept, or in any of the multiple phone calls I had with the shop's owner. They installed the cams on the head before shipping it out to me, to install the cams properly, wouldnt they have HAD to use seals?

Not necessarily. The seals don't have to be in place in order to install the cams. But since the cam caps were already off it would have been very easy to put the seals in place and then install the cam cap that goes over it (what I would have done). The seals can also be pressed in if not removing the cams or the respective cam cap. Either way, the shop really should have discussed this with you.

Out of curiosity, who reinstalled the cam gears?

 

[steve]

Out of curiosity, who reinstalled the cam gears?

That to me seems like a key point.

 

[DSM1G90]

But since the cam caps were already off it would have been very easy to put the seals in place and then install the cam cap that goes over it (what I would have done).

And been there and done that with 1.8L motors with leaky cam seals: take the sprocket off, remove the cap, do a seal in a quick and put it all back together within an hour.

No more leaks.

But still, it'd be like not installing the main seals when a short block is rebuilt - just something that definitely needs to be there.

Something is definitely not right.