dieselkiki

Cylinder Head

142 posts in this topic

I'll do it soon, intend to open out engine and inspect the chain drives. Mine has only clocked just above 176,000 km but I think it is better to do the inspection now than suffer expensive repairs in the future. Then do periodic inspections perhaps every 25,000 km unless I renew both chains now. We will need more owners participating in the chain drive inspection scheme.

When I have pictures of mine I'll upload 'em. Oh, I have some info on torquing for the cylinder head, made up a drawing. Use of this is at your own risk, I assume no responsibility for damages through the use or misuse of the information.

UPDATE

I got another look at the info and the bolts are initially torqued to 30Nm, after which each is turned 90 degrees (using the same initial sequence) three more times (total 270 degrees), followed by one final turn of ten degrees each. Thanks to Tolsen for the heads-up.

UPDATE Aug 29 2012

Updated text on drawing to be more in-line with information in table form posted by Tolsen on Aug 28 2012.

post-2188-1346242018_thumb.jpg

Edited by sbungay

Share this post


Link to post
Share on other sites

I have thought for some time that a micro-light endoscope might be very helpful! Not to mention a cool toy!

I bought one like that a few weeks ago. Very useful. Liquid proof probe. The instructions have a warning not to shove the probe up your private parts since not approved for medical use.

Share this post


Link to post
Share on other sites

When I have pictures of mine I'll upload 'em. Oh, I have some info on torquing for the cylinder head, made up a drawing. Use of this is at your own risk, I assume no responsibility for damages through the use or misuse of the information.

I think you are right with the initial 30 Nm torque. This is followed by 3 x 90 degrees angle turn.http://outcat-cs.tecdoc.net/ows/en/D122819...&docId=1768

Share this post


Link to post
Share on other sites

I bought one like that a few weeks ago. Very useful. Liquid proof probe. The instructions have a warning not to shove the probe up your private parts since not approved for medical use.

Is there an output jack so you can view/record to a larger display? What make/model did you get? Inquiring minds want to know!Bil :sun:

Share this post


Link to post
Share on other sites

Is there an output jack so you can view/record to a larger display? What make/model did you get? Inquiring minds want to know!Bil :sun:

I bought mine in a Lidl supermarket. Same as this one but Lidl's own brand and a lot cheaper:http://www.ebuyer.com/283216-mini-handheld...medium=productsMine has no option for PC connection. Suggest you get one that at least has a memory card slot so you can take photos.

Share this post


Link to post
Share on other sites

Is there an output jack so you can view/record to a larger display? What make/model did you get? Inquiring minds want to know!Bil :sun:

Princess Auto has one that looks like it might do the job, and only $149.00.http://www.princessauto.com/pal/product/83...tion-VideoscopeLooks similar to the unit in Tolsen's link, a little more expensive though and a 16mm camera head. As of Aug 28 2012 79.99 GBP = $125.02 CAD. The Princess Auto unit does have USB and video out connections though.There is another one for $349, is has an 8mm camera head and 2x digital zoom, both units can focus to within 1 inch of their target. Edited by sbungay

Share this post


Link to post
Share on other sites

Is there a way to turn over the motor manually without taking it apart? So full length of the chain can be examined, for example...

Share this post


Link to post
Share on other sites

The chain damage should be visible through the oil filler hole, assuming that the rollers rotate freely on the chain as they do on most. Might be a good idea to have a close look through the hole!

The roller on chain dont rotate freely on the link. It's pressed on.And I dont think that a little camera could do the job. There is no space between the tentioner slider and the front cover. And dont forget that the oil pump sprocket are almost all in oil. Diesel oil is very dark. It will be maybe possible if you remove oil and if the head of your camera is very thin. :huh: Edited by dieselkiki

Share this post


Link to post
Share on other sites

The roller on chain dont rotate freely on the link. It's pressed on.

Yes, this is not roller chain (as used on a pushbike) but bush chain. The teeth of the chain wheel sprocket always contact the stationary bushes at the same point.IWIS states: "It is therefore important to provide excellent lubrication when using bush type chain drives."Lack of lubrication was my initial thought when I first read about these chain failures. Could be the case for the timing chain if the oil jet is clogged or somehow damaged. The failures are more of a problem to explain in the case of the oil pump chain. Engine would most likely seize if oil level did not reach this chain. So there is something more sinister behind these failures. Most likely batches of poor quality chain. Wrong heat treatment of bushes being the most likely cause. Someone at Smart or Mercedes will know but they will never admit for reasons of liabilities.Would be interesting to have the bushes checked for correct heat treatment. Are there any metalurgists on this forum that may offer their assistance?

Share this post


Link to post
Share on other sites

Posted Image

Roller and bush chain. Bush chain is essentially a roller chain stripped of its rollers. The rollers of a roller chain rotate, hence any roller wear will be spread out all around its cylindrical surface in way of contact with teeth of the sprockets. The bush is fixed and does not rotate. Any wear of the bushes of a bush chain is therefore always at the same points. I remember, in the olden days, we used to end for end bush chain to increase or double their service life.

Edited by tolsen

Share this post


Link to post
Share on other sites

When I have pictures of mine I'll upload 'em. Oh, I have some info on torquing for the cylinder head, made up a drawing. Use of this is at your own risk, I assume no responsibility for damages through the use or misuse of the information.

UPDATE

I got another look at the info and the bolts are initially torqued to 30Nm, after which each is turned 90 degrees (using the same initial sequence) three more times (total 270 degrees), followed by one final turn of ten degrees each. Thanks to Tolsen for the heads-up.

Position 9 & 10 are just short bolts (not M10) screwed into timing chain cover. These are tightened to a much lower torque and no angle turn, see torque specification for the petrol engines in table below.

The final 10 degree angle turn as often seen specified on our two main technical reference sites is a leftover from the early days of Smarts and nearly impossible to apply in practise. I would ignore the strange and often disputed 10 degree angle turn and just follow Elring, the cylinder head gasket manufacturer's recommendation.

Posted Image

Share this post


Link to post
Share on other sites

Lack of lubrication was my initial thought when I first read about these chain failures. Could be the case for the timing chain if the oil jet is clogged or somehow damaged. The failures are more of a problem to explain in the case of the oil pump chain. Engine would most likely seize if oil level did not reach this chain.

Tolsen, the timing chain are lubricate by a very little jet (a hole in the plastic casting) at the chain tentioner plounger housing. Mine was not clogged. Oil pump chain look to be lubricate by the free oil in the bottom of chain case. For the torque of 9-10 bolt, it true that I did not apply the same to these 2 bolts. If I remember, I think that I applyed 23nm on. That was the same size of turbo charger manifold stud and the torque for stud was 23nm too. So... no leak and no bolt failure at this time. But the real test will occure this weekend. I'll go down to NY city with the smart. It'will be the real test before west coast trip (California) in december. ;)

Share this post


Link to post
Share on other sites

A friend dropped by with his smart and we compared the upper timing chain sprockets of each car, based on what little we could see through the oil-filler cap. His upper sprocket has nice sharp pointy teeth, while I can clearly see that mine have rather broad flat tops and don't appear to come halfway up the diameter of a bush/roller. Would there be any advantage/disadvantages be to lowering the drive module as opposed to removing the engine?

Share this post


Link to post
Share on other sites

A friend dropped by with his smart and we compared the upper timing chain sprockets of each car, based on what little we could see through the oil-filler cap

Hmm... I must stick my finger down the hole and feel what mine are like!B :sun:

Share this post


Link to post
Share on other sites

I just had a peep at my timing chain:

Posted Image

Posted Image

Posted Image

There is no obvious wear of sprocket teeth. No sharp edges, no burrs.

Top of tooth sits exactly 4.0 mm below outer edge of chain, measured with a vernier calliper.

Share this post


Link to post
Share on other sites

Just measured mine with the verniers. 7.5mm below outer edge of the chain on one, 6.5 on another :( .That is a rather large difference.Tolsen your sprocket teeth do look more rounded compared to the other car I was looking at this afternoon. How many miles on her?

post-2188-1346279309_thumb.jpg

Edited by sbungay

Share this post


Link to post
Share on other sites

Cut open your oil filter, there should be some metal shavings in there. I think it's probably time to do a teardown.The weird thing is: the chains wear and the sprockets wear...I would have thought the chains would be harder and not show so much wear as Dom's.

Share this post


Link to post
Share on other sites

IWIS Head Office in Germany is on the trail! Will advise...Bil :sun:

Share this post


Link to post
Share on other sites

Cut open your oil filter, there should be some metal shavings in there. I think it's probably time to do a teardown.The weird thing is: the chains wear and the sprockets wear...I would have thought the chains would be harder and not show so much wear as Dom's.

Indeed. I plan on having the engine out and on an engine stand by the end of the week. Of course the best laid plans and all that still apply so it might take a little longer.

Share this post


Link to post
Share on other sites

My oil filter and the oil pan had some metal shaving inside. A good inspection of the oil filter when you doing your oil change is a good mean to know if you have a worn sprocket or chain. ;)

Share this post


Link to post
Share on other sites

Would there be any advantage/disadvantages be to lowering the drive module as opposed to removing the engine?

Engine in the hole:-Head bolts removing and torquing are more easy-Dont have to unplug alt., starter, coulant hoses, A/C compressor, etc...-Dont have to hurt your back to move the engine out-Less wasting time to do the jobEngine out:-More room to inspect and work around the engine-More ergonomical position of working (you can work in standing position and not lying on floor).

Share this post


Link to post
Share on other sites

Engine in the hole:-Head bolts removing and torquing are more easy-Dont have to unplug alt., starter, coulant hoses, A/C compressor, etc...-Dont have to hurt your back to move the engine out-Less wasting time to do the jobEngine out:-More room to inspect and work around the engine-More ergonomical position of working (you can work in standing position and not lying on floor).

Thanks Dom. I think I'll remove the engine and put it on a stand to work on it. There's quite a bit of rust in the engine bay and having it empty (or pretty near empty anyway) should make cleaning it up and repainting it much simpler. Its been a long time since I did anything like this and oddly enough I find myself looking forward to it... (That'll all go out the window when the knuckle busting starts LOL).

Share this post


Link to post
Share on other sites

Just measured mine with the verniers. 7.5mm below outer edge of the chain on one, 6.5 on another :( .That is a rather large difference.Tolsen your sprocket teeth do look more rounded compared to the other car I was looking at this afternoon. How many miles on her?

Mine is a low mileage Smart first registered in 2002. Have only clocked 176,000 km so far.As regards doing the job in situ or with engine out, I certainly would go for the latter. You remove the whole power train complete with subframe, deDion tube and wheels etc in 30 minutes. Then place engine on an engine stand for ease of access and less strain on your back. Clean and paint deDion tube and engine subframe whilst it is all out. Also, touch up chassis as required before it is too late.This I intend to do before the winter comes. Mine is looking rather rusty from below so something has to be done before the rust goes too deep making Swiss cheese and iron ore out of my Smart.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now

    Chatbox
    You don't have permission to chat.
    Load More