bmwmilos

450 CDI disassembly and overhaul ( some help needed )

30 posts in this topic

Greetings to all!

 

As I already wrote in my presentation topic I had to, unfortunately, drop the engine from my recently bought Smart 450 CDI to diagnose the noise from the engine.

I brought it to my work as I have tools and space there. I found that the lifters were gone and damaged rockers and valve stem tops. Fortunately the camshaft is as good as new. Since I had to remove the head I then decided to disassemble the engine completely and rebuild it renewing everything necessary. I had a lot of trouble removing lifters from the head. It seems that the pounding from camshaft pressed them inside ( here in my opinion there is also a design flaw with lifters because they expand immediately at the bottom and the conical transition on lifter makes an imprint on the head and the two cones then grip ). After trying many different things and producing many different "tools" to extract the lifters,and almost abandoning the head and going to search for a replacement, at hte end I did manage to make a tool strong enough to force the lifters out. The rest of the engine was relatively easy to disassemble. 

The timing chain has absolutely no signs of damage ( 2002. 0.8 CDI with 160000 kms on the clock ). The sprockets are god as new with only a little signs of "work" at the bottom of the teeth. The sides of the teeth are intact. Cylinders are near perfect with honing still visible and almost no wear ( I measured but do not remember the number ).The pistong rings are a little bit worn,the oil scraper's inner spring has lost its strength but this was expected. Valve guides for exhaust valves need to be changed but I cannot seem to find the part number or any of the reference anywhere online. Oil pump is perfect, so is the chain and sprocket. The oil pump sprocket in my opinion has very low teeth profile,however by the signs of wear ( or lack of to be exact ) it seems that the desing is ok. I read a lot about problems with sprockets and chains here on forum.

The EGR valve was full of c..p,and I was surprised to see what was coming out of intake manifold when I washed it with pressure washer. I washed it 7 times and it still has some dirt inside, I do not understand how this engine could breathe...

My friend and I already have some testing going on for a while for EGR related problems ( carbon buildup in intake manifold,.... ). It was his idea and after explaining it to me it sounded reasonable so we are testing this on both of our cars ( his Audi A8 4.2 TDI and my BMW 530d ) and so far it seems that his logic was right. But this is something to be discussed in another topic.

Also I found that clutch actuator was almost going through clutch fork ( off course no grease anywhere not even in traces ).

Now I am acquiring all the parts I need to reassemble the engine. I already ordered piston rings set, lifters, rocker arms, valves, head gasket set, crankshaft seals front and rear, oil sump with plug, timing chain kit with guides and tensioner, oil chain only, head screws,both rear engine mounts ( front is new ), new turbine cartridge, oil, filters,clutch fork with release bearing,water pump, shaft seals on gearbox.

I am having problems finding valve guides ( no info anywhere on the web ) and also conrod big end bearings. Crankshaft main bearings are like new and I will put them back in. The conrod big end bearings are also like new and I am tempted to reinstall them back.

So if anyone has some info on valve guides and conrod bearings that would help me a lot. Also I think that the gearbox splined shaft seal was leaking a bit ( but I am not sure since the gearbx breather is inside the bell housing and the entire housing was "lightly coated" in oil ) so if anyone has the dimensions and type of seal that would be of great help also.

The tightening torques for the engine are also a mystery, very little info. I also read that MB changed the torque values over the years so I am not sure anymore what are the correct torque values for all of the bolts ( especially main bearings and side screws, conrod bearing screws, sprockets,crank pulley,....)

I need all the help I can get and I am willing to help others if they come across any problems or decide to work on their car/engine.

 

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Now that the work is finished I can update this thread. I did spend more time than planned looking for parts. In particular there were problems with big end bearings and valve guides. At the end we discovered that the guides are the same as some models of Sprinter 3.0 CDI and also some models of Jeep Cherokee. So while I waited for all of the parts to arrive I cleaned everything and even painted some parts.

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I started to reassemble the engine block after cleaning and all the parts present and immediately encountered another problem. Two of the crankshaft bolts stretched excessively when tightening to 55Nm,one almost to a point of breaking as you can see in photo. I thought ok,I will order new bolts. And here is the problem, MB does not list these bolts anywhere and you cannot buy them as a spare part! Moreover the bolts are M9 thread so no easy substitute. Fortunately in a town Zagreb ( 150kms from Rijeka ) there is a big Smart service center ( not MB official but very good ) and they have a lot of old engines laying around so the guy dismounted and sent me 4 bolts. A the end I replaced 4 bolts because they were longer ( stretched ) more than others! I use analogue torque wrench ( with needle pointer ) for this work because I can see on the needle how the bolt reacts to tightening ( apart from feeling it in my hand ).

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Posted (edited) · Report post

Next day I cleaned the pistons,put new rings and installed pistons in engine block. When tightening conrod bolts I also felt they were stretching excessively so I immediately ordered new conrod bolts from local MB dealer ( 0.50€/piece ). I also assembled other items on engine block ( oil cooler,oil return pipe,... ). A couple of bolts snapped during dissassembly ( oil cooler and water pump housing ) so I bored the screws and managed to get them out without damaging the threads. I also passed all of the threads on engine block with taps to clean them and I used copper anti seize on all the bolts mounted externally on block. You have to be careful when using anti seize beacuse it significantly reduces friction and it's much easier to overtighten the bolts and ruin the threads. I tightened all of the small bolts "by feel", not by torque wrench. I picked up the head from a local workshop redone with new valves,guides,reworked seats and stem seals.FormatFactoryIMG_20180706_065911.jpgFormatFactoryIMG_20180706_065924.jpgFormatFactoryIMG_20180706_065932.jpgFormatFactoryIMG_20180707_100937.jpg

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Edited by bmwmilos
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The next day I replaced the turbo cartridge ( both exhaust manifold and intake part were in excellent condition), the exhaust manifold was completely cleaned and painted in heat resistant paint.I installed a new water pump on the housing. I acquired a new timing and oil chain kit but the kit did not include oil chain tensioner. Well,the old one was in good condition so I wanted to install it. However after washing it and drying with compressed air there were 3 hairline cracks on the plastic part. I then rang again the MB dealer and found out that oil chain tensioner is about 3€ ( plastic part ) and another 2 or 3€ the spring. So I had to wait 2 days for this and conrod bolts to arrive. I also bought a new oil pan with drain plug ( 22€ ).

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Posted (edited) · Report post

Excellent thread with much great information, imho. Thank you.
Now the bigger question, when do you start your own rebuilding business...lol...there must be a demand for top quality rebuilt Smart Engines.....lol.   You are doing exactly what I wanted to do.....have a brand new engine ready to go just incase so to speak. I bought a second spare car just to get a running engine to rebuild.  Dare i ask the cost of doing this...? Machine work is a standard but buying the parts is what interests me....so to speak.  You were very lucky with that stretched bolt and it didn't snap!  Very close....lol.
Again great thread...enjoyed reading it. With good pictures also.

Just a question, will you leave it totally stock or play with the different systems to try and make it a better engine? EGR etc etc..?

Is it possible for you to list each new part you ordered and it's part number and what it cost, where you managed to get it from...?  Thanks

 

Edited by Willys

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After the tensioner arrived I assembled oil chain, prepared timing chain with new tensioner in place and installed cylinder head with new bolts.

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Posted (edited) · Report post

I will supply the complete list of parts with codes and prices at the end. I was surprised because at the end the prices are not as big as I expected them to be ( since Smart is expensive car to buy new ,at least for my taste :-) )

As far as I looked there are maybe 2 people that would do this kind of work in a circle of 70-100kms from me. I guess I am the 3rd now,he,he ! Apart from that, I doubt in knowledge and patience of local mechanics, especially on these engines. Now after all the work is done I can say that it is like a model engine ( well the entire car is like a model car ),and like with every model toy you have to be very delicate and patient,you cannot do things in a hurry. That's why I prefer to do everything by myself. Apart from learning experience, I am sure that what I did I did correct,what I cleaned I cleaned properly and what I payed for new I installed new.

 

Now the system does not allow more photos,so I have to upload them somewhere and then paste the links here!

 

Edited by bmwmilos
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After installing the head I installed new hydraulic lifters, new rocker arms and camshaft. I did not find the torque value for camshaft bearing caps so I phoned my friend who has all the data and if I remember correctly the torque is 12Nm. Also the three camshaft sprocket bolts are 8Nm torque. My friend advised me to use Loctite 243 blue medium thread locker on sprocket bolts and to tighten them "by feel" which I did.

Oh,one thing,before installing cylinder head I installed the chain ,tensioner and timing chain cover since the head bolts to chain cover. The tensioner has a pin in it which I extracted only after installing head,camshaft,sprocket and aligned the chain with guides. The chain guides have two pins inside the cylinder head that hold them. I extracted them using long M6 bolt,nut,large washer and a piece of pipe to use as a spacer. To install them I coated lightly with Loctite hydraulic sealant,screwed in a short M6 bolt and using a hammer I pressed them inside the head,after aligning the guides with the hole. To time the engine you have to mount the pulley on crankshaft, it has a notch to indicate correct position when aligned with a mark on timing chain cover. At this point the camshaft sprockets two lines should be aligned with cylinder head top surface.

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I then installed exhaust manifold with new turbine cartridge. I chose to install the intake housing afterwards on the engine, but it was a little bit more difficult due to the fact that you have to press the Oring for the intake housing with one hand and install the big circlip with the other so it slides into place in intake housing. The circlip is strong and also conically made so it keeps the tension on the intake housing. But after a couple of tries I managed to do it!

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Afterwards I installed the back plate for clutch. I found this to be very hard to do. First of all,blocking the crankshaft is not easy beacuse the engine block is aluminum and there is very little space for inserting wood piece to block it. You have to be careful where the force is going to apply to engine block. I managed to make two pieces of hard wood to insert in block between cranskaft counterweight and block. This way the force is distributed not only on bottom housing ( which has thin aluminum strips close to counterweights ),but also on the upper part of the engine block. The next problem was to hold the engine while tightening the bolts,but one of the colleagues from work was there to assist. I used a 3/4" fixed bar with reduction to 1/2" socket wrench 17mm. I used the same setup to tighten the crankshaft sprocket only with E18 socket wrench.

I finished the day installing other bits to block and head.

 

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Here are some more photos at the end of the day :

 

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The next day I changed input shaft seal,both output shaft seals and clutch bearing and fork on gearbox. The gearbox was oily below seals,and the clutch actuator almost went through the old fork. The clutch itself was in good condition. I lubricated the actuator inside with white lithium grease spray abbundantly. I reworked the actuator rod a little bit making it more round and smooth. I applied Shell Gadus high performance grease on fork and actuator rod,and also a small amount on clutch bearing face and slider.

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I also disassembled EGR body, cleaned it well, removed the deflector plate inside so it is a clear opening. I cut both flanges from EGR pipe. I produced a stainless steel washer to put below flange on exhaust manifold and used exhaust mounting paste and screwed it in. I also made a gasket without hole to close the exhaust gas inlet in EGR. And finally I turned the valve element inside 180 degrees so there is no way exhaust gasses can enter in intake anymore. I decided to do it like this,because the EGR solenoid stays in place and no errors should be logged. If necessary I will do EGR delete from software.

I am waiting for KWP2000Plus adapter to arrive so I can start playing around with software mods on engine. I already found some info on this forum and I will see how the engine reacts. I have found there were files for download but now I do not remember where :-(

 

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I transported the engine back to my father's garage and after assemblying engine and gearbox, installing new rear mounts ( front mount was already replaced and in excellent condition ) and other thingies this was the result.

 

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I took the injectors to pressure testing and one of them had excessive overflow so I had them replace that element. Other two injectors were ok. This alone was around 130€.

I installed the injectors ( did not find the correct tightening torque so I also tightened them by feel ),assembled rear hatch,exhaust,cross-member,poured in new oil ( Mobil 1 5W-50 ),poured new oil in gearbox ( Mobil ATF 220 ).I was surprised that in engine goes more than 3 litres of oil ( I think it was 3,6 lt ). I thought it was less than 3lt. I poured water inside cooling system for initial testing. If everything goes ok I will flush the system and fill with antifreeze. Oh, the three wires that go from engine harness to floor tray and then somewhere versus front of the car I didn't want to remove the undertrays, so I cut them in front of the engine when dismounting and now I installed 3-way waterproof connector so for the next time it's easier.

I connected the battery, turned to ignition a couple of times to fill the rail with fuel and then tried to start. In a few seconds the engine was running at idle,smoothly, no smoke,no knocking,very nice.

 

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I also removed rear side windows and changed the seals as they were leaking in rain. Overall the car power has increased significantly,specially in low revs. The engine is silent, the only thing is that when going in low rpms there is a sound like the engine is "knocking", similar to petrol engines with bad petrol or ignition adjusted early ( autocombustion,detonation ). I do not know if this is normal in these engines.After passing 2000rpm that sound vanishes and the engine is running very silent.

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Don't own a cdi but that is some excellent work.  Thanks for the tutorial. :)

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Thanks for sharing. Great information for the rest of us.

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I am more than willing to assist anyone when doing similar work or with any other problem. Most of the tutorials I saw for engine removal say to drop the entire subframe. I found it easier to do removing only engine and gearbox using hydraulic jack and the car remains mobile ( you can push it around ).

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Oh and I could have taken better photos,but most of the photos were taken with my hands half dirty and I didn't hold the cell properly so some are a little bit out of focus.

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As I said before, absolutely excellent work and thank you...this needs to be saved for future refference...just saying...

 

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Posted (edited) · Report post

On 7/16/2018 at 11:26 AM, bmwmilos said:

I also removed rear side windows and changed the seals as they were leaking in rain. Overall the car power has increased significantly,specially in low revs. The engine is silent, the only thing is that when going in low rpms there is a sound like the engine is "knocking", similar to petrol engines with bad petrol or ignition adjusted early ( autocombustion,detonation ). I do not know if this is normal in these engines.After passing 2000rpm that sound vanishes and the engine is running very silent.

Could it be piston slap?

Edited by Thio

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Well done. I get the same knocking at low rpm with high load. 

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I also went to see my friend and tried two other smart cdis and they alsp have the same sound, I guess the sound is normal, it's just weird to me...having no experience with Smart.

I started to notice some weird sound from timong chain case. It is noticeable on idle and it sounds like a bad tensioner,like chain is slapping around occasionally. I installed the entire timing chain kit ( sprockets,guides,tensioner ) from FAI/LUCAS and I cannot see anything wrong looking down oil filler cap hole. I guess I will have to drop the engine again and change the tensioner. I have read that there were some similar experiences and that remounting old tensioner solved the problem. 

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