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Posted: Thu Jun 07, 2012 5:05 am |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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1st engine (180gti+cat 256 cam)
apparantly they said the spark plug hit the piston, but why would that happen?
2nd engine (gti+ cat 4901608+ piper hydraulic lifter+valve spring)
Piston disappeared for this one, but why?
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Posted: Thu Jun 07, 2012 5:14 am |
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Joined: Apr 13, 2011 Posts: 37
Trade Rating: +1
Location: Lancs
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Was it the same bottom end on both engines, or was it a complete replacement?
Same piston each time?
The spark plug cannot 'hit the piston'.....it is definitely always the piston that hits the spark plug
Main reason would be the crank IMO - if it's out of alignment, then it could push the conrod too high (particularly at high revs), hence the piston/plug interface
Have you had the head skimmed at all? - something has happened to create too little 'space' between the crown of the piston and the spark plug
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Posted: Thu Jun 07, 2012 5:23 am |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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zoomer wrote: |
Was it the same bottom end on both engines, or was it a complete replacement?
Same piston each time?
The spark plug cannot 'hit the piston'.....it is definitely always the piston that hits the spark plug
Main reason would be the crank IMO - if it's out of alignment, then it could push the conrod too high (particularly at high revs), hence the piston/plug interface
Have you had the head skimmed at all? - something has happened to create too little 'space' between the crown of the piston and the spark plug |
not my engine but was interesting to know what is the cause.
they are different engine, so different head and bottom; the top one is 180gti and the bottom is just gti. And i think both of them blown up under high rev.
Not 100% sure about head skimming but i though you can get different thickness of gasket from dealer?
And yes, you are right, both engine blown up from the same cyclinder...
they said is because of doggy spark plug (the spark plug claim to have auto adjusted heat range, magic!); but i seriously doubt the spark plug could do that damage.
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Posted: Thu Jun 07, 2012 9:17 am |
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Joined: Nov 27, 2010 Posts: 11520
Trade Rating: +10
Location: What's it to you? ? ?
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Using the wrong heat range of spark plugs can melt the top of the piston.
Just because a spark plug fits in the hole doesnt means its the correct one for the engine, you have to get the right heat range of plug, at best it will run badly & at worse it will ruin the engine.
Either these engines have been poorly assembled OR really badly abused.
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| Toyota C-HR GR Sport 2.0 Hybrid with JBL & Alcantara packs. | |
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Posted: Thu Jun 07, 2012 9:20 am |
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Joined: Feb 03, 2012 Posts: 87
Trade Rating: 0
Location: newark
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Had a friend with an mr2 turbo and he blew his engine having the wrong heat grade of plug. Plugs are such an important part often overlooked.
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Posted: Thu Jun 07, 2012 9:21 am |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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but you would have though if the plug is bad, other cylinder would suffer as well?
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Posted: Thu Jun 07, 2012 9:27 am |
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Joined: Nov 27, 2010 Posts: 11520
Trade Rating: +10
Location: What's it to you? ? ?
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Seabook wrote: |
but you would have though if the plug is bad, other cylinder would suffer as well? |
Depends on the engine cooling system & if there are any hot / weak spots in the heads cooling.
Ive seen a 1.9 PSA turbo diesel lump where the aluminium in the cylinder head has melted in to the combustion chamber due to a cooling system failure & the driver ignoring the warning lights & guage.
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| Toyota C-HR GR Sport 2.0 Hybrid with JBL & Alcantara packs. | |
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Posted: Thu Jun 07, 2012 11:01 am |
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Joined: Aug 01, 2011 Posts: 390
Trade Rating: 0
Location: Bath UK
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Where's the missing valve?
It looks as if the valve has disintegrated and then parts of that has caught between the piston head and the cylinder head denting the other valves and the spark plug
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Posted: Thu Jun 07, 2012 3:06 pm |
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Joined: Feb 07, 2010 Posts: 2949
Trade Rating: +6
Location: Athens, Greece
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MrBSI wrote: |
Using the wrong heat range of spark plugs can melt the top of the piston.
Just because a spark plug fits in the hole doesnt means its the correct one for the engine, you have to get the right heat range of plug, at best it will run badly & at worse it will ruin the engine.
Either these engines have been poorly assembled OR really badly abused. |
Yep, and other factors too.
100% agreed.
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| 1.4i, 2001, 3-door, China Blue
Repair safely - Drive safely | |
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Posted: Thu Jun 07, 2012 3:08 pm |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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so you think is the problem of the cylinder head then?
it kind of make sense to me as i would have though is either the valve spring or lifter failed under high revs, then valve kissing piston then boom!
as i have said before both engine has modified camshaft, esp. the bottom one which runs long duration high lifting camshaft.....
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Posted: Thu Jun 07, 2012 3:11 pm |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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V9977 wrote: |
MrBSI wrote: |
Using the wrong heat range of spark plugs can melt the top of the piston.
Just because a spark plug fits in the hole doesnt means its the correct one for the engine, you have to get the right heat range of plug, at best it will run badly & at worse it will ruin the engine.
Either these engines have been poorly assembled OR really badly abused. |
Yep, and other factors too.
100% agreed. |
no matter how many times i told them, nobody believe....
bosch oem plug is the only way forward....
they always like something special; magic spark plug which can auto adjust heat range; spark magnifier, those induction fan....etc
i never understand that
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Posted: Thu Jun 07, 2012 3:40 pm |
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Joined: Feb 07, 2010 Posts: 13077
Trade Rating: +65
Location: England
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Timing out?
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Posted: Thu Jun 07, 2012 4:14 pm |
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Joined: Feb 07, 2010 Posts: 2248
Trade Rating: +18
Location: Leicester
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Both cammed up aswell. Id say its timing thats at fault.
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Posted: Thu Jun 07, 2012 4:24 pm |
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Joined: Apr 08, 2012 Posts: 512
Trade Rating: +2
Location: Scunthorpe
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mattievrs wrote: |
Both cammed up aswell. Id say its timing thats at fault. |
Must have something to do with it, bit of a coinsidence isn't it
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Posted: Thu Jun 07, 2012 4:27 pm |
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Joined: Feb 08, 2010 Posts: 10151
Trade Rating: +12
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could be that...
but you would have though if the timing is out, it would be fairly easy to spot when doing the remap?
as the gti engine survive after the remap (after fitting the camshaft, apparently 2 tank of fuel was used during the remap so i assume it has done quite a bit dyno mileage lol)
not sure about the 180gti as what i have heard is after he fit the magic spark plug then the engine blown up within short period of time.
==
These things seems so odd to me. we got plenty of cammed gti exmaples on info and i have yet to see these things happen....
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