Timing chain replacement went wrong

[WezP]

Hi guys, I recently replaced the timing chain on my 05 yaris 1.0 vvti 16v. I'm a fairly experienced DIY and as far as I'm aware I did everything correctly however unfortunately when started the car valve piston collision occurred in cyl 3 between prison and intake valves. I can now only spin the crank 180°.

Before I repair the damaged valves I am trying to figure out exactly what went wrong and I am hoping some of you guys might have more experience with this engine and might be able to help me. 

Before fitting the new chain I made sure the cams were in TDC compression stroke for cyl 1 and that the crank was at TDC for cyl 1. I lined all the timing marks up on the sprocket with the corresponding teeth on the new chain. I rotated the engine 4 or 5 times to make sure everything moved freely. When reassembling, before putting the valve cover on I again rotated the engine so the TDC mark on the pulley lined up with the 0 mark on the timing cover. Checking the cams corresponded with TDC compression stroke. 

Things I think might have gone wrong:

When I took the crankshaft position sensor plate off I didn't make a note of how it was aligned, but when refitting it I know usually the F would be at the front and the missing teeth if you like would be left of the crank. Mine didn't have an f but had a Y so I assumed same difference and fitted it with the Y at the front, the missing teeth were at the left side. Maybe this was incorrect... 

When I removed the timing cover I noticed it was in pretty bad condition (covered in oil) and had a crack in one corner. So I got a second hand replacement online. It came with a crankshaft position sensor from the previous vehicle still attached which looked in better condition than the old one so I just left it in. 

Did I put the sensor plate on backwards or could the crankshaft position sensor have been faulty and could this have messed up the vvti and caused the piston valve collision on the intake (vvti) side. 

Any help would be really appreciated. Thanks in advance 

 

 

[flash22]

did you use any locking tools ?

[WezP]

As far as I'm aware there are no locking tools for this engine. My understanding is if the gold links on the chain are aligned with marks on the sprocket you're all good. As per haynes

[HS78]

Firstly, how do you know that there has been valve/piston contact in cylinder 3? It normally becomes apparent which valves have been damaged when you remove the cylinder head and perform a leak test. 

It is more suggestive of an error of crank/cam timing. The crank is easily rotated unless locked during chain replacement. Is it possible that the crankshaft is a complete revolution out to the camshafts? 

[WezP]

When I try to rotate the crank now it will only move 180°. When the rotation comes to a stop and I feel resistance the intake cam moves slightly so I know it is an intake valve the piston is hitting. At this point cyl 1 and 4 are at BDC and cyl 2 should be in exhaust stroke. 

There was a point when I was trying to remove the crank pulley bolt to replace the timing cover that the woodruff key fell out, allowing the crank to be rotated independently from the cams however I'm not aware of this happening to a full revolution but it is possible. My understanding was that the individual rotation of the crankshaft didn't matter as the pistons and crankshaft are in the same position during compression and exhaust stroke for a given cylinder and thus only the cams determine if its compression or exhaust stroke. I thought as long as the cams were TDC compression for cyl 1 and the piston in cyl 1 was TDC all was okay.

Is this not the case for this engine? Whoops

[HS78]

1 complete revolution of a camshaft pulley = 2 complete revolutions of the crankshaft pulley. i.e. when the crankshaft rotates twice, the camshaft(s) only rotates once. 

As flash22 mentioned locking tools, locking the crankshaft is important if possible, to avoid accidental rotation. 

[WezP]

Thanks for the help. Much appreciated. This must be what has happened. Is there any way I can verify that the crankshaft is on the correct rotation when I replace the damaged valves and reassemble, such as a mark on the flywheel etc. 

I have noticed that there is a hole where the flywheel can be viewed near the oil sump. Perhaps there is a timing mark? 

[Stivino]

The marks are on the chain and the pulleys, you showed the pictures.

[HS78]

After you remove the cylinder head you will be able to see the exact position of the pistons which will help. At this point I would try and locate a hole on the engine block (if there is one) where a locking pin can be inserted to stop the crankshaft rotating. 

[WezP]

Ah okay so I take it the piston will come up ever so slightly more to TDC on the compression stroke than the exhaust stroke as to not hit the exhaust valve. And when I observe this I can then lock it in place? Very frustrating, I wish I knew this engine was designed in such a way. 

I got this car as a project and to practice on so I'm not too bothered, more practice I suppose. 

Thanks for the help. I really appreciate you helping me get this sorted 

[HS78]

I hope you manage to sort it. If you need any help there is plenty of help on this forum. 

[Stivino]

13 minutes ago, WezP said:

Ah okay so I take it the piston will come up ever so slightly more to TDC on the compression stroke than the exhaust stroke as to not hit the exhaust valve

The piston stops at the same point no matter what stroke it is on.

[WezP]

That is what I thought originally, that essentially the piston and camshaft are in the exact same position twice during the four stroke cycle. So the crankshaft cannot be 360°. This doesn't make sense though because the timing marks were definitely lined up perfectly. I checked it so many times 

[WezP]

360° out*

[WezP]

If the pistons and crankshaft are in the exact same position twice during one revolution of the cams. How can the crankshaft be a whole revolution out from the cams. It would be irrelevant if it were in the same position anyway. That's what I'm struggling to understand. 

[flash22]

ah its the 4 cylinder 1szfe you still need to hold the crank

the cam's are in time but the crank is out by 90-180º

also did you pull the pin on the tensioner

[WezP]

Yes it is the 1sz-fe. So I'm right in thinking this is only an issue due to the particular design of this engine? 

[WezP]

Yes I did pull the pin haha 

[bathtub tom]

It doesn't matter about the exhaust and compression stroke on re-build, as long as you get TDC and camshaft correct.

I once crossed over exhaust and inlet valves on a re-build - it did several thousand before the inlet (in the exhaust) burnt out.

I suggest you go back and carefully check everything.