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  #16  
Old 25th June 2008, 11:00 PM
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Default Re: Valve Grind & De-coke on 6.9

Ah, that's why I didn't get it before - here in South Africa they are 10"
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'80 W116 280SE euro - the ride
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'78 W116 6.9 euro - the AMG
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'82 W126 500SEL euro - full hydraulics - the limo
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  #17  
Old 25th June 2008, 11:27 PM
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Default Re: Valve Grind & De-coke on 6.9

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Originally Posted by Mercules View Post
It is a time honoured tradition for a mechanic to send the dopey apprentice/work experience kid off the the parts shop for a left-handed screwdriver, a box of blue grinding sparks and a 9" population tool - hahahaaaa

So what is a population tool? I think it bears some resemblance to the trouser snake or the lamb cannon
Dont forget the metric shifter and striped paint.
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  #18  
Old 26th June 2008, 12:13 AM
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Default Re: Valve Grind & De-coke on 6.9

Ah, now I see the photos. Well done guys. it looks like the heads must have been really close up against the firewall.
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'80 W116 280SE euro - the ride
'76 W116 6.9 euro - trusty rusty
'78 W116 6.9 euro - the AMG
'74 W116 350SE euro - the stand-in ride
'82 W126 500SEL euro - full hydraulics - the limo
'83 FORD XR3 - the beast

0 benzes on stands, 5 RUNNING
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  #19  
Old 26th June 2008, 03:52 AM
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Default Re: Valve Grind & De-coke on 6.9

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Originally Posted by Michel View Post
I understand now why you have been so quiet lately (in my neck of the woods)...

Glad to see you had some serious help ...

Looks forward to seeing you 'mobile' in the GB again...
...only ever a phone call away.....Regards Styria
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  #20  
Old 26th June 2008, 04:36 AM
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Default Re: Valve Grind & De-coke on 6.9

Just some further observations and other tasks carried out.

Luckily enough, or at least from what I can ascertain so far, no internal engine damage has been occasioned by the mixture of oil and water. I fully expected the complete engine to be covered in that creamy, gooey mess, but such was not the case. Whilst I have not yet examined nor dismantled the heads removed, it was certainly the gasket steel re-inforcing ring on No. 4 cylinder that caused the water leakage problem.

Camshafts and camshaft bearings are still in good condition after some 370k. kilometers, and there is no discernable lip in the cylinder bores.

However, as can be seen from one of my photographs, I already have two reconditioned heads on hand, with new exhaust valve guides and obviously new valve stem seals. They have been skimmed and leak tested, and it only remains for me to check the deck height to ensure that not too much material has been removed from the heads. The "Reconditioner" of the heads when I quizzed him on minimum deck height had no idea what I was talking about - and that was a bit of a worry !

These heads had only done 220k. kilometers, and I will also be using the camshafts and bearings from the same engine. Incidentally, there is absolutely no difference in the high and low compression engines headwise except for a threaded machined boss on the right hand unit to accept the emission pipe for the anti smog pump. Both heads for both types of engines have a channel machined into the head surface which is a potential weak spot as far as head gasket leaks are concerned - cylinders 1 and 2 can suffer from low compression readings, as can 5 and 6. I will, in due course, put up photos to illustrate what I am talking about. Presently, I am considering filling those channels - from memory, both heads have that channel but will double check.

I have also removed the water pump housing in order to gain access to the pins that locate the lower chain guides and rails, particularly the one on the right hand side which is activated by the chain tensioner. They're expensive (at least $A700.00 - ridiculous) but I have a good second hand unit from the other engine. Talking prices, I have ascertained that the sixteen locknuts for the exhaust manifold retail for $4.00 each - I know what I won't be buying.

So, that's just a bit of an update. Will provide further information as the "beautifying process" continues. Regards Styria
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  #21  
Old 26th June 2008, 04:50 AM
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Default Re: Valve Grind & De-coke on 6.9

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Originally Posted by Styria View Post
Camshafts and camshaft bearings are still in good condition after some 370k. kilometers, and there is no discernable lip in the cylinder bores.
That is certainly encouraging to hear. I have heard similar stories about lack of bore wear from other sources. I am hoping my luck holds out in this respect with trusty rusty.
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'80 W116 280SE euro - the ride
'76 W116 6.9 euro - trusty rusty
'78 W116 6.9 euro - the AMG
'74 W116 350SE euro - the stand-in ride
'82 W126 500SEL euro - full hydraulics - the limo
'83 FORD XR3 - the beast

0 benzes on stands, 5 RUNNING
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  #22  
Old 26th June 2008, 06:00 AM
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Default Re: Valve Grind & De-coke on 6.9

Hi S-Class, whilst it is encouraging that there is no discernable lip in the bores, it may not be the "be all and end all" as far as engine condition is concerned. A fellow 6.9 owner in Sydney has a spare engine with no wear in the bores, yet the rings were totally unserviceable.

We priced a set of rings the other day - close enough to $A2000.00 - "get that up you Charlie" - at least, that's how I feel one would be addressed when ascertaining some prices, including the 6.9 rings from Mercedes Benz- and that is not the OZ price I might add.

Whilst I do not expect anyone to rush me, we have worked out a way of overcoming the price slug by Daimler Benz. So, anyone that wants to fit new rings to a standard size bore, Styria should be able to supply the goods. However, you will need to have the Benz pistons machined. Anyway, this is just toying with ideas and finding ways of overcoming MB spare parts prices. Regards Styria
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  #23  
Old 26th June 2008, 07:31 AM
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Default Re: Valve Grind & De-coke on 6.9

Stop complaining Stryia.
Try $30,000 for a Phantom head.
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  #24  
Old 26th June 2008, 07:55 AM
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Default Re: Valve Grind & De-coke on 6.9

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Originally Posted by s class View Post
Ah, that's why I didn't get it before - here in South Africa they are 10"
Priceless !!!
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  #25  
Old 26th June 2008, 10:30 AM
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Default Re: Valve Grind & De-coke on 6.9

Without wishing to be a Glass of cold water at a pissup what are your bearings like.

I know with Porsche experience that if a watercooled Porsche mixes water and oil you are expected to change the big-end bearings.

They make no mention of the mains because it is a much bigger job and in a 6.9 it would really need engine removal for both mains and bigends so it is not really likely to happen.

It is a reason to get the car fixed at the first sign of water in the oil.

Bill
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  #26  
Old 26th June 2008, 07:34 PM
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Default Re: Valve Grind & De-coke on 6.9

A much bigger job on a 6.9 than I realised - and I am staggered at the time you needed to get each head off, a big difference!. If you need another pair of hands to help speed up the job give me a call.
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  #27  
Old 27th June 2008, 02:05 AM
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Default Re: Valve Grind & De-coke on 6.9

Quote:
Originally Posted by Styria View Post
Hi S-Class, whilst it is encouraging that there is no discernable lip in the bores, it may not be the "be all and end all" as far as engine condition is concerned. A fellow 6.9 owner in Sydney has a spare engine with no wear in the bores, yet the rings were totally unserviceable.
Rings may be very expensive, but ring wear is still preferable to bore wear in my books. This may indeed be trusty rusty's case. I have not had the heads off to see the tops of the bores, but from the bottom (sump off) it all looks very good. Compression is weak and uneven across cylinders though. Wet compression tests suggest that valves are main culprits for the weak compression.
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'80 W116 280SE euro - the ride
'76 W116 6.9 euro - trusty rusty
'78 W116 6.9 euro - the AMG
'74 W116 350SE euro - the stand-in ride
'82 W126 500SEL euro - full hydraulics - the limo
'83 FORD XR3 - the beast

0 benzes on stands, 5 RUNNING
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  #28  
Old 27th June 2008, 02:59 AM
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Default Re: Valve Grind & De-coke on 6.9

WGB - I know where you're coming from as far as engine damage is concerned when relating to the quality of the oil, or lack thereof. I guess I am the perpetual optimist who looks at things on the bright side and hopes for the best by trusting his judgement.

As some of you may know, the oil pressure gauge on 'Gleaming Beauty' has been inoperative from the time I purchased her thirteen years ago this coming August. Once or twice I have had the opportunity to fit another oil line, but it always seemed to be the last job, and by that time I seemed to have enough and just wanted to finish the job - removal of the dash comes to mind. One could also say that maybe, just maybe, I did not really want to know about a working gauge - it may have been too much of a shock.

Anyway, this time I am going to bite the bullet and get the gauge working. Keep fingers crossed. Regards Styria
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  #29  
Old 27th June 2008, 03:28 AM
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Default Re: Valve Grind & De-coke on 6.9

Hi S-Class, I was under the impression that 'trusty rusty' was the star performer in your fleet, although I seem to recall that your red AMG model has been really transformed since you sorted out the valve timing. It seems at odds that you should experience such uneven running characteristics.

The strange part with 'Gleaming Beauty' is the fact that performance wise one would have thought that there were absolutely no problems. The puff-puff on No. 6 seemed to virtually disappear as soon as the revs built up, and even economy wasn't all that bad. It will indeed be interesting to see what improvements, if any (!) will be evident once this job is completed.

I have also previously mentioned that the timing chain had been changed some three years ago and referred to the fact that there seemed to be no difference performance wise, and this had been a small source of disappointment at the time. When dismantling the top end, we looked in vain for a connecting link to split the chain so I wonder...(?) I had also asked that valve stem seals should be changed but this mechanic was of the opinion that they did not need doing..if anyone in Sydney would like to know who I am referring to, I would be pleased to give him a reference.....

Hi JohnS - thanks heaps for the offer. Look, most of the onerous and dirt tasks have been completed. Presently, the heads are being set up with the correct adjustment shims for the valve lash compensating elements on a spare 6.9 engine block and I am waiting for a new, good quality timing chain plus some other parts. Regards Styria
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  #30  
Old 27th June 2008, 06:08 AM
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Default Re: Valve Grind & De-coke on 6.9

Hi styria,

you are correct that my red AMG has improved a lot with the new timing chain. Trusty rusty has always had a very different character though, and subjectively performed better than the AMG, though the gap may have been closed since the AMG's new chain. (I haven't driven trusty rusty in some 4 months so comparisons are difficult). Anyway, the point is that trusty rusty has always pulled solidly, seemingly at odds with the compression results. Trusty rusty idles pretty well all things considered, but there is some exhaust smoke under acceleration, which to me means rings/bore issues - though the compression tests suggest valves are the biggest issues.

OK I have some ignorant questions for you :

1) you talk of another Sydney engine having good bores, but unserviceable rings - what about them makes them unserviceable - wear? loss of temper?

2) you talk of setting up your new heads with shims to correct the valve lash - I'm unfamiliar with this - what is involved, and what is the goal?

Thanks for all your insights in this most interesting thread.
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'80 W116 280SE euro - the ride
'76 W116 6.9 euro - trusty rusty
'78 W116 6.9 euro - the AMG
'74 W116 350SE euro - the stand-in ride
'82 W126 500SEL euro - full hydraulics - the limo
'83 FORD XR3 - the beast

0 benzes on stands, 5 RUNNING
Reply With Quote
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