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Discussion Starter #1
Hello all,

I can not wrap my head around why my engine seems not to be damaged..

I had noisy hydraulic lifters. Well one for sure. noisy ticking sound that disappears after 1 minute or so.. Opened cam cover, set timing to zero by turning crank. Everything lines up nicely. Removed camshaft wheels, removed cams, removed lifters. Checked for obvious damage, none to be found. Went to a shop for new lifters.

New lifters were 24mm long instead of 26mm long. Did not like that (even though the difference is in skirt lenght only. Length of piston between valve and cam and maximum lift of piston are the same), decided to put old lifters back because I need the car and get back to this few weeks later.

After putting everything back (torque wrench was used of course and timing was back on zero I am sure), tried to start engine. It had some issues with closing the valves at first, but then it ran with some noise and eventually died after 20 seconds or so.

Did not like that, opened cover again, zeroed the crank and very disturbingly, found the inlet cam to be on zero, but exhaust cam to be somewhere around +90 degrees. However, cam wheel was on correct angle. Took exhaust cam wheel away - screw was suspiciously easy to remove - and the locking pin inside was broken and it was allowed to spin relatively freely on cam. I am not even interested in how this happened (am sure I tightened it correctly, but I expect I might have overlooked some dirt under the screw or in the thread that allowed me to reach the torque but not tighten the wheel properly)

Big question is - why are my exhaust valves not bent? Got new cam wheel, new lifters, put it back together (meticulously cleaned and checked million times), measured compression, 11 bar (160 psi) on every cylinder, tried to run the engine. Runs as smooth as silk, quiet, lambda is ok, fuel economy is ok, power is ok.

Oh.. before I put it back together, checked the piston heads with boroscope camera. No marking from valves whatsoever.. I was already prepared to pull head.. and.. nothing? not needed? wtf?
 

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by the sounds of it you've been lucky,all modern 16v engine(regardless of marque) are interference engines..never come across a 16v which isn't..
 

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Discussion Starter #3
Yeah, I am sure that it is an interference engine.. Only possibility I see is that exhaust valves are a bit smaller. Maybe this combined with empty lifters after they have been taken out saved me.
 

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Sounds like you had interference and it sheared the pin. Had it been a 15mm steel key it would have been a different story.
 

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Be grateful for small mercies
I think you should be interested (in the circumstances) concerning 'the screw was suspiciously easy to remove' particularly if that was p[art of your oen work. Shear-pins and plates don't shear particularly readily but are designed to
protect a fault from becoming serious...as you would know...

It is wise to turn engine by hand after timing repairs and before cranking disconnect ignition if the hand turning seems free. "Interference' means they can hit pistons or each other ...not that they cannot hit. As you suggest the lifters may not have charged with oil,,, sometimes this has to be done manually before fitting them.

In any event if the pin shared through contact and not through your own work or was already sheared I'd give compression check to feel confident no shaft is bent. You seem happy with the outcome you have so..
lead on mcDuff!.
 
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