emwmarine
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| posted on 22/4/13 at 08:00 PM |
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How delicate are zetec valves.
This week seems to be my stupid period.
having put the zetec back together completely forgot there was no campbelt on the engine. Don't ask I know it's pretty obvious.
Anyway, spinning a camshaft around with a socket and the torx I suddenly felt some resistance. Instead of thinking - ah that must be the valves
touching the pistons I applied a bit more force to see why it wasn't moving. (at least I didn't hit it with a hammer).
Am I likely to have bent/damaged the valves, or are they tougher than that being made by Mr. Ford? I don't really want to take the head off.
[Edited on 22/4/13 by emwmarine]
Building a Dax Rush.
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austin man
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| posted on 22/4/13 at 08:05 PM |
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personally I doubt it they usually bend due to the opposing forces ie vals coming down piston coming up
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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emwmarine
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| posted on 22/4/13 at 08:21 PM |
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quote:
Originally posted by austin man
personally I doubt it they usually bend due to the opposing forces ie vals coming down piston coming up
Which would be a bigger bang than me pulling on a socket.
Building a Dax Rush.
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britishtrident
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| posted on 22/4/13 at 08:25 PM |
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Cylinder Leak Down test is the only way to check with out lifting the head.
Valve against valve rather than valve against piston is the usual killer.
[Edited on 22/4/13 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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r1_pete
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| posted on 22/4/13 at 08:29 PM |
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I'm pretty sure it will have pushed the piston down a little before bending the valve.
One way to re assure yourself is to mod a spark plyg so you can connect it to a compressor, spray lube down the ports so the valve seats are
'wet' and down the bores, insert the plug, pressurise to say 25 psi, then time how long it takes to de pressurise, repeat for each pot, if
the results are similar, you're OK.
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Theshed
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| posted on 23/4/13 at 07:35 AM |
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If your valves are shimmed then measuring the clearances should give you an idea of whether you did any harm. If the valves are bent the clearances
will have opened up considerably.Not quite as good as a compression test but easier.
On the downside....I once did the same thing on a Jaguar engine turning the crank by hand on the fanbelt with the cam chain off - very bent valve!
They are very flimsy. Fingers crossed.
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MikeRJ
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| posted on 23/4/13 at 10:42 AM |
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Valves in 16v engine have rather thin stems and they are not difficult to bend. You need to get a compression test or (better still) a leak down test
performed.
quote:
Originally posted by r1_pete
I'm pretty sure it will have pushed the piston down a little before bending the valve.
Not if it was at TDC.
[Edited on 23/4/13 by MikeRJ]
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dave_424
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| posted on 23/4/13 at 12:15 PM |
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quote:
Originally posted by MikeRJ
Valves in 16v engine have rather thin stems and they are not difficult to bend. You need to get a compression test or (better still) a leak down test
performed.
quote:
Originally posted by r1_pete
I'm pretty sure it will have pushed the piston down a little before bending the valve.
Not if it was at TDC.
[Edited on 23/4/13 by MikeRJ]
Or even within 20ish degrees around TDC, Why would it be such a pain to remove the head?
Dave
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