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Location:
Brisbane
Registered:
July 2004
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7M Head gasket repair pics and advice
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Sat, 08 January 2005 20:08
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EDIT: What IS it with this forum, I use the same host for other forums without a problem, anyways hope the pics are working NOW!! JEEZ!  Could someone please let me know if they arent...
Sorry the pics are rather small, i've done this to save file size. I'd be happy to post bigger pics if anyones interested.
Man, only 2 months of painting my cam covers and they're already THIS dirty... 
Well heres a pic of my block- note carbon buildup on pistons 
Notice how generally dirty this 7M is? You can just make out the debris in the timing cover.
Heres a slightly better pic of that 'oily fluff'. This crap was found on all horizontal surfaces inside the timing case, presumably caused by oil leaking past the oil pump and foward crank seals (which ive since replaced), AND ....
THIS!!
My timing belt was doing a nice burnout against the lower (metal) timing cover. I'm not entirely sure why, either. Must have been like this for some time. Obviously I'm replacing it (only $44 AUD) so I'll keep an eye out that the one i install doesn't do this.
Heres a pic of my gasket- it wasnt blown. I looked carefully and saw carbon on either side of the metal rings in the gasket that seal the compression chambers, meaning gas had been leaking past them. It also has cooked some of the softer (looks like graphite) gasket material allowing exhaust gases and heat to get into my coolant system. At least i hope that this was causing the problem...
I originally intended to have the whole head stripped, crack and pressure tested and rebuilt but cost, time and whether the work is warranted was the key. The shop that looked at it said that it didn't look to be cracked anywhere- usually you can tell cos water gets into the compression chambers and 'cleans' everything of carbon.
Figure any place that talks me out of spending money there can't be all bad. So they're just going to skim the head a couple of thou to make sure it's straight. no more than $90. Besides the head was only rebuilt march last year and has done less than 20000kms so should be fine.
Anyway, I've just got a few questions:
-Whats the best way to clean the block down in preparation for the new gasket to stop debris from going into the oil, cooling system or getting inbetween the pistons and the bores?
-Is the amount of carbon buildup on the pistons anything to worry about??, should I clean it off now- if so, how?
I was going to attack the head with some carby cleaner and a toothbrush when it gets back from the head shop to remove the carbon buildup on the valves (they said they dont clean the heads up, just mill them)
-Has anyone else had a similar find with their timing belt?
Any help would be appreciated, Cheers.
[Updated on: Sat, 08 January 2005 22:33]
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Location:
W.A
Registered:
October 2004
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 Re: 7M Head gasket repair pics and advice
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Sun, 09 January 2005 09:51
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To the best of my knowledge carbon build up on the pistons is fine as long as its not a hughge amount, no carbon means oil is seeping through somewere and cleaning the piston heads (usually through the oil ring) i cleaned mine by sitting them in kero for a week and attaking them with a hard tooth brush, none of this gentle on gums shit, i dont think the pistons will mind that much, if your doing the rings scrape the grooves with a tiney screw driver, the grooves need to be spotless, just be carefull when u take the pistons out remeber witch bearings are for witch rods or u will need new ones and if u dont get them right your fucked.
hope this helps
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Location:
Brisbane
Registered:
February 2003
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Re: 7M Head gasket repair pics and advice
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Mon, 10 January 2005 00:18
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| Quote: |
-Whats the best way to clean the block down in preparation for the new gasket to stop debris from going into the oil, cooling system or getting inbetween the pistons and the bores?
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i'm doing this with my 5M...
-rotate engine around so no pistons are at top of bore (remember whch way you did this so you can return engine to correct TDC position)
-fill each bore with an oil-wet rag, or a paper towel wet in a heavy oil (or wet air filter oil if you have some)
-clean out oil drain holes, fill with a think taper made of rolled-up masking tape (cloth will tend to fall down into sump)
-clean out head-bolt holes with a cloth and narrow screw-driver, you will have to redo this after cleaning the deck
i got a wide metal paint scraper (aluminium would be safer), filed it down so the edge was knife like (they tend not ot be sharp.
gently scraped all gasket material off the block, trying where possible to avoid pushing rubbish into bores or down bolt holes
you'll probably do this in a number of goes, removing less and less as you go
after this, carefully remove the oily rags and masking tape plugs - cleanup using another oily rag (or even greasy) NOT something runny like machine oil or WD40 as it will let the gunk run down into the rings
you might find a vacuum cleaner will help remove loose debris
clean out bolt holes as per previous
clean head with light oil or spray stuff, give bores a light run with engine oil (or gear oil or trans fluid if it will be standing for some time) then carefully clean deck surface with lint-free cloth lightly wet with metho - you'll need that face free of any oil-n-shit otherwise the new gasket will have a short life
... follow rest of TSRM for other parts of head....
i'd not bother cleaning the carbon from the pistons - if you're concerned about the valves, use a mild wire (or brass) wire brush and clean up very carefully.
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Location:
Brisbane
Registered:
June 2003
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Re: 7M Head gasket repair pics and advice
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Mon, 10 January 2005 12:27
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thats a pretty sad looking block and bores....id really be pulling it out of the car and having it professionally cleaned/ honed bores etc...it makes sense bro trust me...
Thats what i did when i did my ma70's 7MGE...
The block probly needs to be surfaced as well...
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