AndyGT
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| posted on 23/2/17 at 08:53 PM |
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What happened to my engine?
As title, would like to know general thoughts on what may have happened to my engine to fail.
The engine is an Opel 20XE 16 valver.
Bought it about 18 months ago and turned over with some compression.
Stored the engine for future project.
After 2 or 3 months I couldn't turn over the engine easily so poured oil down the bores and left it.
3 or 4 days later the engine was less stuck and freed up with a bit of gentle persuasion.
15 months after this (now) I took off sump to fit a different sump.
Old oil when dropped was chocolate brown with some signs of mayonnaise (15-18 months after last running??)
Overheating seems to have taken place as gungy deposits on engine (especially around the head area) smells of burnt oil.
While in bits decided to whip off the GM head (porous?)
Everything was coked up like bad running and/or compression.
Took out the pistons to find 6 from 8 compression rings well stuck to the pistons and rusty too.
Brand new looking head gasket. Lovely golden coloured metal rings and green gasket like new.
Head surface like new and perfectly flat.
heavy stubborn soot in combustion pocket of head but soft and easy to remove soot on flat surface of head that also makes up the combustion
chambre.
(I think the head has been redone by inadequate mechanics.)
SO? What do you guys (and galls) think has happened?
Why chocolate coloured oil? Is the burnt smell normal?
Why all the mayonnaise yet a head job looks like it has been done recently?
Is the head likely to be porous? Will lining one of the head's oil gallleries with roughly 8mm alluminium tubing cure porosity?
Engine getting re-ringed, new rear oil crankshaft seal fitted and having new shells fitted this weekend but is there anything else to be changed
whilst stripped?
Thanks for any pointers and advice...
nothing is impossible
everything is possible
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r1_pete
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| posted on 23/2/17 at 09:34 PM |
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You need to hone or have the bores honed so the new rings will bed in.
Sounds like the engine has previously been running too cool, i.e. Not hot enough to burn the deposits away.
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Slimy38
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| posted on 24/2/17 at 07:38 AM |
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quote:
Originally posted by AndyGT
Is the head likely to be porous? Will lining one of the head's oil gallleries with roughly 8mm alluminium tubing cure porosity?
This is the standard fix for the porous head, plenty of pages describing how;
http://www.migweb.co.uk/forums/engines-transmission/340906-thought-id-have-go-porous-cracked-head-modification.html
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FuryRebuild
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| posted on 24/2/17 at 09:21 AM |
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"mayonnaise" is generally a sign that the head gasket has failed, and finding a shiny new gasket in there may back this up. Having the
engine full of crap and nasty oil also implies it may not have been all that loved in the past.
The best way to check the head is to take it to a reputable motor engineer who can get the dial guages on it and check for flatness, as well as crack
test it. I'm not sure about testing for porosity - I don't know anything about that.
For me, a strip, cracktest of the head, decking of head and block, new oil pump, rebuild (inc hone and new rings) would be the way to go to get
reliability, especially if you're intending to give it the beans on a regular basis. I'd also consider having it balanced it you're
intending to push it. It only cost a couple of hundred to have my duratec balanced.
Saying that, this engine may be the equivalent of the grandma someone has who's 90 years old and only gets her nutrition from the 40 woodbines a
day she smokes.
I'm not sure where you are geographically, but I used Drakes in Bradford for a lot of engine work, and they're very good. Excellent
establishment, very clean - lots of good staff on hand to talk to, and I felt excellent value for money.
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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bonzoronnie
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| posted on 24/2/17 at 10:10 AM |
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quote:
Originally posted by FuryRebuild
Saying that, this engine may be the equivalent of the grandma someone has who's 90 years old and only gets her nutrition from the 40 woodbines a
day she smokes.
That genuinely made me LOL
Sums up my late mother perfectly, even to the brand of ciggies. 
To OP
Definitely signs of head gasket failure at some point.
Also the possibility of the dreaded head porosity that these GM/Opel engines were prone to.
Not saying that this is the case with your engine, just something not to be overlooked.
Depending on your budget & what you want from this engine.
I would be on the lookout for a Coscast head to replace the GM/Opel one.
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AndyGT
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| posted on 24/2/17 at 10:32 AM |
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quote:
Originally posted by bonzoronnie
I would be on the lookout for a Coscast head to replace the GM/Opel one.
Yes, never really thought about that as I just envisaged repairing what I had.
Easy to forget to stand back and look at the bigger picture!
Thanks
nothing is impossible
everything is possible
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SPYDER
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| posted on 24/2/17 at 02:32 PM |
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Whatever you do, put a new water pump on it whilst you have the opportunity.
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chillis
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| posted on 24/2/17 at 06:08 PM |
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sounds like poor servicing with infrequent or absent oil changes. Vauxhalls are prone to thermostat failures as well resulting in a cool running
engine.
Never under estimate the ingenuity of an idiot!
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