mediabloke
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| posted on 10/5/08 at 03:59 PM |
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Oil at wrong end of cylinder...
Hi all,
Quality site. I've spent ages reading loads of helpful posts. I couldn't see one for this, though... [ waits to be corrected  ]
I bought an MK Indy a few months ago with a X16XEL (ecotec) engine in it. Since I got it, I've been doing some basic stuff to get it running as
I want it - fitting a Megajolt ignition kit, sorting out the bike carbs that are on it, etc.
Just before a trackday a few weeks ago, I changed the oil & filter, putting 5w40 instead of the 10w40 specced by Vauxhall (figuring this might
give a bit more stop/start protection whilst I'm fettling).
Immediately afterwards, it started to misfire on #1 cylinder. A plug-check confirmed some oil fouling on #1 plug, and a torch inspection showed a
shiny pool of oil on top of #1 piston. Rsss...
As a test, I dropped the 5w40, replaced it with 15w40 and fitted a new filter, in case it was cold-start oil getting past the valve guides / stem
seals. It was better, but still blowing from the exhaust at cold-idle and dampening the top of the piston. The plug-fouling burns off on a long
drive, but returns after a restart.
[EDIT:
I've had the cylinder pressure-tested. No air leaks from water, sump, rocker cover, exhaust or inlet. Surprisingly, it even passed on MOT
emissions a couple of days after it started. Amazing!]
I guess the most likely cause is either my stupidity or worn guides / stem seals, but wondered if anyone could give me a clue as the best way to
confirm it?
I'd prefer to be confident before I have my (cylinder) head recon'd, rather than still have the problem afterwards, y'know?
Thanks in advance - MB
[Edited on 10/5/08 by mediabloke]
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theconrodkid
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| posted on 10/5/08 at 04:09 PM |
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sounds like valve stem seals or the guides,if the engine has been standing for some months it may be the seals have gone hard,give it some miles,if it
still smokes rip the head off
who cares who wins
pass the pork pies
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Pants On Fire
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| posted on 10/5/08 at 04:13 PM |
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Sounds similar to my recent XE woes.
Turned out the inlet valve spring on pot 3 had split into 3 parts, knackered the guides and seals.
Just finished rebuilding it last weekend and now the kin alternator has packed up, so much for locost motoring.
Yes, I am an agent of Satan, but my duties are largely ceremonial.
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mookaloid
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| posted on 10/5/08 at 04:28 PM |
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If the compression pressures are all ok then I would say valve stem seals too.
Welcome to the site by the way
Cheers
Mark
"That thing you're thinking - it wont be that."
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rusty nuts
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| posted on 10/5/08 at 04:40 PM |
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When you say you had the cylinder pressure tested do you mean a compression test or a cylinder leakage test? If it was a compression test was a wet
test carried out after a dry test? A large improvement on compression pressure points to worn pistons/rings or bores . Is the crankcase vented
properly with no blockages? Does the inlet get oil ed up? Does the carb for the affected cylinder flood or cause that cylinder to run rich ? If no
then it could be valve guides /stems worn but it would pay to check the above
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mediabloke
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| posted on 11/5/08 at 01:13 AM |
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Thanks for the welcome & prompt responses - I'm still impressed. And sorry to hear that you've had similar probs.
quote:
Originally posted by rusty nuts
When you say you had the cylinder pressure tested do you mean a compression test or a cylinder leakage test? If it was a compression test was a wet
test carried out after a dry test? A large improvement on compression pressure points to worn pistons/rings or bores . Is the crankcase vented
properly with no blockages? Does the inlet get oil ed up? Does the carb for the affected cylinder flood or cause that cylinder to run rich
?
It was a leakage test, rather than a compression test. I'm shopping around at the mo for a compression gauge that I can get down the plug
recess, but I'll do the dry & wet tests when I get hold of one. Wierd that it was just this cylinder though - if it was due to worn rings,
I was expecting some other plugs to be fouled, but there's none.
I'm about to remove the inlet manifold to check more closely for oil there. Because of the misfire from the plug fouling though, I expected the
affected cylinder to be richer than the other 3. Or do you think this might indicate something else in itself?
I've not had any of the breather hoses off yet. Judging by the state of the oil that I originally dropped though, I wouldn't be surprised
if one were blocked / narrowed.
[Edited on 11/5/08 by mediabloke]
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thomas4age
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| posted on 11/5/08 at 06:56 AM |
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it's the same on 4age's
my first one had been on 10W40 semi synth for all it's life, i stupidly decided that 10w40 full synth would be nice. 7km's on,
"rattle rattle huff huff" bey bey big-ends.
also going from 10W40 to 5W40 after a long period seems to be a defenate NO GO,
grtz Thomas
[Edited on 11/5/08 by thomas4age]
If Lucas made guns, Wars wouldn't start either.
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mediabloke
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| posted on 11/5/08 at 10:08 AM |
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quote:
Originally posted by thomas4age
my first one had been on 10W40 semi synth for all it's life, i stupidly decided that 10w40 full synth would be nice. 7km's on,
"rattle rattle huff huff" bey bey big-ends.
Hmm... I recognise the "rattle rattle" bit - just toward the end of lap 3 on the trackday... I'm not noticing any bearing rumble
though. The XE seems to be relatively quiet, apart from the tappet buckets being noiser than usual for a few seconds longer. Might be a good idea if
I use the trusty screwdriver stethoscope.
Looking on the bright side, I'm learning a lot!
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britishtrident
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| posted on 11/5/08 at 02:35 PM |
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Piston Ring --- most likely broken or seized oil control ring. This won't show up on a cylinder leak down or compression test.
Oil getting past the valve guides gives clouds of white/grey smoke if the engine has been allowed to idle for a minute or and is then driven ie as at
leaving the traffic lights.
[Edited on 11/5/08 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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mediabloke
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| posted on 11/5/08 at 09:17 PM |
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quote:
Originally posted by britishtrident
Oil getting past the valve guides gives clouds of white/grey smoke if the engine has been allowed to idle for a minute or and is then driven ie as at
leaving the traffic lights.
Yep - that's the one. Not so much smoke with 15w40 in, but with the original 5w40? Loads! Quote from a mate: "Some interesting smoke
going on, there"
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mediabloke
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| posted on 20/5/08 at 12:08 AM |
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Just got the compression-test results after some swearing over a faulty tester:
1 ~ 198psi
2 ~ 198psi
3 ~ 190psi
4 ~ 190psi
These are nicely in the middle of the acceptable 174-218psi range. So it leaves me with either stem seals, guides or a broken ring. The inlet
manifold and exhaust mid-section are coming off for other jobs, anyway, so I'll get jiggy with the head work at the same time.
20 quid for seals + a small amount for bolts = Locost!
The Plan:
- Get some stem seals
- Drain carbs (new float bowl o-ring to fit) & remove inlet manifold.
- Remove exhaust manifold - exhaust hanger needs adjusting with "minor adjustment tool" (strangely hammer-shaped...)
- Rip off the head and get busy with a spring compressor & same "minor adjustment tool"...
Thanks all - will update this as I go, if it's of use to anyone. 
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