126 560 smoke

[squealinneil]

Today I went for a test drive in a '91 560SEC. Under HARD acceleration, from about 4000+ rpm, with the pedal planted, there was a lot of blue smoke coming out the rear. No smoke under normal driving.
What's wrong? Is it fixable reasonably cheaply or is it a walk away problem? If I am to negotiate hw much should I try to knock off because of this?
Any advice/thoughts welcomed
TIA.

 

[pascal]

I was always thought to walk away from blue smoke.
An indication of engine wear (burning oil) I was told.

I suppose if you get enough off the price to cover an engine re-build or
replacement and don't mind the bother.

 

[talbir]

Blue smoke indicates engine is burning oil.

Usually due to worn valve seals and possibly valve guides.

The seals are cheap - it's the labour/time involved in fitting the new seals. Some out there do a quick fix but it really ought to be a top end overhaul.

What's the mileage ? If it's approaching 100k or over, then ask for documantation on timing chain and tensioner renewal. If it hasn't be done, this SHOULD be done as a precautionary measure at approx 100k miles on the M117 engine in the 560SEC. Those that don't bother with the chain risk it jumping - and when that happens it's usually goodbye to the whole lump.

Given that you need to replace valve seals, you may as well do timing chain + tensioner at the same time.

Put aside between £500 - £1000 for the valve seals + guides + timing chain and tensioner. It's not the cost of parts - it's the labour and time that makes it costly.


BTW, check for rust under the rear window, inside the boot - if bulkhead is rusted, put aside another 500 squidders.

talbir

 

[paulcallender]

Just out of interest, what is the approximate cost of the parts (seals, timing chain and tensioner) and any other parts you need (gaskets etc) while taking off the head? The reason I ask, I have a 1975 280CE (with a M110 engine, D-jetronic FI) and its displaying similar symptoms.

Luckily, I have the time to do the job, since its a 2nd car for me. I assume its not too much of a problem to correctly set the camshafts' timing (do you need special tools for this?).

Also, the previous owner told me to use additive in lieu of leaded petrol. While the head is off, is it worth the extra money to have an unleaded conversion done? And if so, I guess thats a shop job?

 

[squealinneil]

Thanks everyone,
talbir, are you by any chance a mechanic?
EDIT: Silly question. I just read your profile.
Can you recommend a mechanic in London?

 

[guydewdney]

blue smoke under hard acceleration is usually piston rings - blue smoke on the over - run is usually guides / seals.

HOWEVER - if the car has hardly ever been pushed, it might just be oil in the inlet (from the breather) being sucked in. if this was the case, a few miles of thrashing it would clear it... but i bet the seller wouldnt be happy for you to do that!

You could get a compression test done (very cheap and easy)..

I'd walk - there are enough of these around - unless the bodywork is supurb... perfect bodywork is difficult to find.

 

[squealinneil]

Guy,

I've been told that if it was the rings it would be smoking all the time, not just under hard acceleration. I'm neither mechanically gifted nor wise so does this make sense or sound right to anyone?

If anybody knows of a very good 500 or 560 SEC for sale pls. let me know. I've looked at loads & apart from this one they've all had the rust under parcel shelf problem. This particular one has 109K, pearl grey with a couple of blotches but no rust I could see/black, loaded, good SH & enthusiast owner who said he'd never noticed the smoke! Asking £8K!

Looked at 2 yesterday. The first, a 93 500SEC with 129K was nice looking & drove well but the rust was bad under the rear window, the boot was damp going on wet, the rear window appeared to be letting water in (parcel shelf damp) & it had had 6 owners. The bloke wanted £7,000, which I thought was taking the p1ss.

 

[mjtray]

Sounds like there are some seriously deluded SEC sellers out there at the moment with prices like that +rusting rear bulkheads and ponds in the boot!

Re the engine, and just to add my two penneth....blocked breather pipe or valve stem seals sounds likely to me. If the valve stem seals are on their way out oil will drip into the combustion chamber and under hard acceleration will get burnt off. As Guy says you will also see this if you accelerate hard and long and then come off the accelerator and let it coast for a bit, then jump back on the accelerator....should see a puff of smoke or you will see plumes of the stuff as you coast.

Rings normally produce smoke all the time, and if you dab the accelerator at idle you will normally see little puffs of the stuff.

The M117 engines do suffer from blocked breathers by the way.

I would also be surprised if its rings at 109k, as that is very low mileage for a M117 engine but as has been stated you could get a compression check done if you want to err on the side of caution.

It does sound as if you have looked at loads, with this in mind if the pearl grey one is in good nick with none of the classic rust issues I would look to chip the owner down a couple of grand +, ie its over priced in the first place and needs @ £1000 to get oil, chain, tensioners replaced etc.

I would also expect to see some pretty good service history for the price.

 

[squealinneil]

Just finished talking to the owner.

I told him that in light of the smoke & pig in a poke nature of the problem I thought his asking price was too high & suggested he reduce it to a more realistic £6,500.

He's not budging. His mechanic said the car is nigh on perfect & he's never noticed the smoke before. Judging from his reaction when it looked like the boot was on fire I think he's telling fibs. He didn't even bother to turn around to look, let alone say anything. If it had been my car smoking like that for the first time I would have had a much stronger reaction, or at least A reaction.

Also, he & his mechanic had discussed the timing chain renewal & decided as the old one was fine they'd leave well enough alone!!!!

Next.

Anybody know of one pls. let me know.

Thanks for all your help & comments.

 

[mjtray]

Run away as fast as you can......hopefully something better will turn up.

It does amaze me sometimes what people think they can try and get away with.

As an aside, I recently had a look at a 560 SEC which was advertised on e-bay...some of you may have seen it. It was reportedly owned by James Hunt (I don't doubt this) and in the description it stated that the car had had a light crunch on the front....the photo's showed distortion to the bonnet etc.

Deciding that I would go and have a look at the car I was confronted with a car with no front panels....ie slam plate and cross members had all been taken off, no radiator etc.

The offside chassis member was distorted and would need to have been put on a jig...out by 1.5inches. The engine block was wet with oil. The boot was sopping wet with real bad rust under the window. Big rust blisters were coming out of the C pillars. Interior was filthy.

The amazing thing was that it reached something like £2600 which was great for the owner, but I just wonder whether the winning bidder had bothered to go and have a look at the car or whether they had just gone off the photos and basic write-up....big shock if they did just go off the description and photo's

Anyway good luck with the ongoing hunt and let us know what you find in the end.

 

[guydewdney]

'93 500 SEC W126?? doesnt exist...

126s were made up to 91 - then they made 140s - ok the first 140s were called sec as well - and changed to CL in 1996.

if this is the best one you have found - take it round to a SEC specialist - such as www.sec-shop.co.uk (or com) in sw london ish... and ask them their opinion.

200k for a 117 lump is nothing - as mjtray says - and i was surprised at the smoke thing - so i'd be inclined to look at the breather (or ask the guy at sec-shop...

Guy

edit - its sec-shop.com


they have:-

1984 500 SEC Rebuilt engine and gearbox, Service history, Previous MOTs Very nice car!

ONLY £2,800 ovno Personal Plate extra,

 

[talbir]

'200k for a 117 lump is nothing'

The above statement assumes that the car has a FULL service history - and that history MUST show a timing chain + tensioner replacement at least once. Even 100k is plenty for any MB engine if it has not been maintained correctly.

Changing oils and filters etc. at regular intervals is NOT enough - you need to take of those valve covers once in a while and see what's going on underneath w.r.t all the crucial components.

Also, it IS possible to have a '92 W126 SEC - the year on the V5 logbook refers to year of registration NOT year of manufacture. Although the last W126 coupes rolled off the production line late 91, there are plenty that were not sold until late 92.

And NEVER rely on service history - plenty of false ones with false back-ups. Assess the condition of the car w.r.t engine, tranny, interior, bodywork, suspension. Don't base your judgement of a vehicle on stamps in a book. Just because someone has handed the car to their dealership for a few hours every 12 months and paid 500 squidders, does not make it a good car. It's how the car has been treated in between and that will be portrayed by the condition of the car.

And always check that a 560 is actually a 560 and not a 500 being badged as a 560. Two quick ways to tell - firstly chassis number on a 560 will always start WDB 126 045....whereas 500SEC's are WDB 126.044. Secondly, speedo markings on a 500 end at 160mph, on a 560SEC although the final number is 160mph, the markings extend to 170mph. The 560's have self-levelling suspension and are only built post 85.


talbir

 

[stwat]

'200k for a 117 lump is nothing'

The above statement assumes that the car has a FULL service history - and that history MUST show a timing chain + tensioner replacement at least once. Even 100k is plenty for any MB engine if it has not been maintained correctly.

Changing oils and filters etc. at regular intervals is NOT enough - you need to take of those valve covers once in a while and see what's going on underneath w.r.t all the crucial components.

Also, it IS possible to have a '92 W126 SEC - the year on the V5 logbook refers to year of registration NOT year of manufacture. Although the last W126 coupes rolled off the production line late 91, there are plenty that were not sold until late 92.

And NEVER rely on service history - plenty of false ones with false back-ups. Assess the condition of the car w.r.t engine, tranny, interior, bodywork, suspension. Don't base your judgement of a vehicle on stamps in a book. Just because someone has handed the car to their dealership for a few hours every 12 months and paid 500 squidders, does not make it a good car. It's how the car has been treated in between and that will be portrayed by the condition of the car.

And always check that a 560 is actually a 560 and not a 500 being badged as a 560. Two quick ways to tell - firstly chassis number on a 560 will always start WDB 126 045....whereas 500SEC's are WDB 126.044. Secondly, speedo markings on a 500 end at 160mph, on a 560SEC although the final number is 160mph, the markings extend to 170mph. The 560's have self-levelling suspension and are only built post 85.


talbir

Top man Some honest, spot on info there :lol: Nice

Stu

 

[guydewdney]

talbir - yup - 92 is possible - but not 93... or at least unlikely...


squeel:-
go talk to sec shop if i were u...