Engine reassembly

I

Ichidragon

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I've gotten my hands on a 5Vz-FE V6 from a 1997 4Runner that was disassembled for a head gasket replacement. The guy that took it apart didn't set the engine to TDC and didn't mark the cam positions when we removed them. This is my first Toyota V6 repair and I would like information on how to tell when I have the motor in TDC COMPRESSION. I've got the crank pully set to TDC, but without a distributor or cams in place, how can I make sure I'm in the compression stroke?
 
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If the pulley is at tdc. It is already at the compression stroke.

The position of the camshafts sets which cycle the compression stroke is.



Set you tdc, align the timing belt marks with your cams shafts and you should be all set to go.
 
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but his problem is that the belt was already taken off. where are the marks on the cams and where should they align?
 
The cams have marks on the gears when they're installed. You line up those marks. Then you bolt on the cam pulley, rotate them and you're good. The pulley only goes on one way.

Same with the crank pulley, when you have the mark aligned you're at TDC. Doesn't matter that the cams were removed.
 
Singtoe said:
If the pulley is at tdc. It is already at the compression stroke.

The position of the camshafts sets which cycle the compression stroke is.



Set you tdc, align the timing belt marks with your cams shafts and you should be all set to go.
Click to expand...

Well...at TDC , can it be the exhaust stroke as well?
Isn't the piston comes to the top twice (compression and exhaust) in a one full 4 stroke cycle (720 degrees)? His question is how to find out the compression stroke.

TDC can be easy to find in an engine with a distributor.
 
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agloukhoff said:
Refer to this for the location and position of timing marks - pictures and everything: Toyota Maintenance: 3.4L V6 Timing Belt Replacement
Click to expand...

bingo.
your crank gear is keyed, each 360 degree rotation brings you back to tdc on cyl #1. so as long as the mark on your crank pulley gear is pointing up/aligned with the mark. your at tdc.

0996b43f8020854a.jpg
 
nissanh said:
Well...at TDC , can it be the exhaust stroke as well?
Isn't the piston comes to the top twice (compression and exhaust) in a one full 4 stroke cycle (720 degrees)? His question is how to find out the compression stroke.

TDC can be easy to find in an engine with a distributor.
Click to expand...

I don't believe the mark would line up when it's on the exhaust stroke though.
 
The only timing to be done is lining up all the appropriate marks when youre ready to put the TB on. This is after your heads, cams, and pulleys are all reinstalled. Spin them all independently as much as you like, it makes no difference.
 
nissanh said:
Well...at TDC , can it be the exhaust stroke as well?
Isn't the piston comes to the top twice (compression and exhaust) in a one full 4 stroke cycle (720 degrees)? His question is how to find out the compression stroke.

TDC can be easy to find in an engine with a distributor.
Click to expand...

Yes, if it is on TDC, It could also be on the exhaust stroke. But with the TB off, there is no exhaust stroke because the valves aren't opening up.

The nice thing about the yota is that there is no distributor. so nothing to line up or parts to wear out.


FWIW. If your motor was on the exhaust stroke at TDC, not rotating the Crank, you can slip the timing belt off, spin your cam shafts 180 degrees, re-install the timing belt and vola, your motor is on the compression stroke.
 
nissanh said:
Well...at TDC , can it be the exhaust stroke as well?
Isn't the piston comes to the top twice (compression and exhaust) in a one full 4 stroke cycle (720 degrees)? His question is how to find out the compression stroke.

TDC can be easy to find in an engine with a distributor.
Click to expand...

Whether TDC (on cylinder 1) is compression or exhaust is determined by the position of the cams (TDC on the crank is TDC on either stroke). That is why you line up the crank to TDC and then install the cams with the marks at the right spot. It is a little tricky/confusing on these motors, so do follow the manual or how-to link (which I used).

FWIW. If your motor was on the exhaust stroke at TDC, not rotating the Crank, you can slip the timing belt off, spin your cam shafts 180 degrees, re-install the timing belt and vola, your motor is on the compression stroke.
Click to expand...

Once it's all assembled, the crank will be at TDC in compression AND exhaust stroke (irrelevant really). The cams determine if it's compression or exhaust, and, as noted, since these don't have a distributor, you just turn the crank to TDC, set the cam positions and go. Don't overthink this!
 
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Singtoe said:
Yes, if it is on TDC, It could also be on the exhaust stroke. But with the TB off, there is no exhaust stroke because the valves aren't opening up.

The nice thing about the yota is that there is no distributor. so nothing to line up or parts to wear out.


FWIW. If your motor was on the exhaust stroke at TDC, not rotating the Crank, you can slip the timing belt off, spin your cam shafts 180 degrees, re-install the timing belt and vola, your motor is on the compression stroke.
Click to expand...

Yeah...make sense to me now. Thank you so much for the clarification.
Thanks Pal...

So bring it to TDC and put the belts on. Easy...

nissanh
 
98OzarksRunner said:
Whether TDC (on cylinder 1) is compression or exhaust is determined by the position of the cams (TDC on the crank is TDC on either stroke). That is why you line up the crank to TDC and then install the cams with the marks at the right spot. It is a little tricky/confusing on these motors, so do follow the manual or how-to link (which I used).



Once it's all assembled, the crank will be at TDC in compression AND exhaust stroke (irrelevant really). The cams determine if it's compression or exhaust, and, as noted, since these don't have a distributor, you just turn the crank to TDC, set the cam positions and go. Don't overthink this!
Click to expand...


Very nice explanation as well. Man these engines are easy to work than 4afe.

Thanks!!1
 
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