Smart engine - It LIVES!!!

[Crazymanneil]

Hey, just an update on my build. (really should sort my website for these!)

Got the Smart engine wired up and running but unfortunately it appears to be getting oil into the cylinders from somewhere and running on that too. Took a while to figure out why it would rev quite high after started (and occasionally sounded like it was running very advanced). Filled the neighbourhood with thick black/grey smoke in the process too (at least the neighbours will know who I am now!). The giveaway was when I switched it off (killing injection and fuel lift pump) and she ran on.

Anyhoo, the turbo and oil breather are disconnected from the inlet manifold and always have been since before I got the engine (I didn't get the intercooler with it) so can't be getting in there. Although when the engine was transported to me it was lying on its back so perhaps she has oil in from before. The plastic inlet manifold is a bit gunky looking too so will give that a clean. Only other options are oil getting past the rings or past the valve stem seals which don't excite me too much. Any other ideas?

Next step will be clean the inlet manifold, try turning it over with the glowplugs out (to see if anything comes out of there) and try starting it again but thottle the air with my hand to stop it revving much above idle. It did start pretty easily though which was encouraging...

Neil

[oilburner]

I'd say you are on the right track. I had a 1979 VW diesel Rabbit run away due to freezeover of the air filter which sucked oil from the base via the crankcase breather. I stopped it by stalling in 5th gear. I removed the air filter, mopped up the engine oil, turned the engine over by the crank pulley to be sure it wasn't hydraulic locked. It smoked for perhaps ten miles or so before finally settling down.

FWIW

[andrewaust]

Looks like your covering all ground quite well. If you have had this occur the once I'd say oil has got into the cylinders from having the engine lying over. That's the go = screwing the glow plugs out and turning the engine over. Might be a good idea to hold a rag or towel along the glow plug ports as muck could go everywhere.

I've never seen a diesel run on by excessive oil from rings or valve guides - I have seen engines run on from blown turbos and sump pressure caused by bad rings that force oil up into the breather and into the inlet manifold. You have these disconnected so I guess your engine might be all good, just a little oiled up.

Did you try turning the engine over by hand first? One thing you don't want is a fluid lock, it will do all sorts of damage.


Cheers


Andrew

[Crazymanneil]

Thanks for the input guys. I investigated further and I think it is faulty injector(s) now. I think this because the engine will run with the injectors disconnected but stops as soon as the common rail is disconnected. It seems as though an injector is stuck open and constantly spraying fuel in. This is probably also washing oil off the bore which can't help matters. Oil level has also increased which leads me to suspect that some of the diesel has found its way past the rings.

I've run the engine for a while now and it shows no signs of clearing up so I don't think its oil in it from lying over. I'm going to take the exhaust manifold off today to see if it is localised to one cylinder. If so I will swap injectors round to see if the problem moves with it. I am also going to disconnect the spill lines and turn the engine over as there should be no leakage in that condition.

I also tried taking glow plugs out as suggested (by yourself and also a friend), but 2 of these broke off in the head . Luckily they seem to be gastight still but are a cause for concern for long term reliability. I'm going to concentrate on getting the engine to run for now and then building the frame around it. While thats happening I'll keep an eye out for another engine.

Never easy...

[Crazymanneil]

Ok, so an update for anyone watching out there.

Took spill lines off all injectors and started engine (with injectors disconnected electrically). Result was no spill from the injectors, but engine running (and smoking) as usual so far. This indicates that the relief valve bit of the injectors is ok but not conclusive.

So took exhaust manifold off and started engine to discover the smoke was coming from cylinder 3. Took injector out of cylinder 3 and swapped with cylinder 2. I noted that no3 injector did not have a seating washer like no2 did and that it had leaked out of the cylinder head slightly as a result. Also noted that the part number printed on the top of no3 injector looked slightly different (like it was part of a different batch).

Started engine again which resulted in the smoke moving to cylinder 2. The conclusion I draw from this is that someone has pinched an injector from my engine (at the breakers or before) and bunged the dodgy one in (without seating washer or anything). Scumbags.

Next move is to get another injector. Though this would leave me with an engine which has the aforementioned 2x sheared off glowplugs. I don't really want to get into a rebuild to get them out of there although the potential reliability issue of a plug that may break/fall into the cylinder is not lost on me. Anyone any opinions on likelyhood of this happening on me? The plugs are sheared off at the point they enter the head so still have full threaded body length bit.

At least I know it wasn't something I've done that was the problem although would like to get the thing running nicely now to get on with the frame build...

Neil

[oilburner]

Geez, in the long run it might be better to buy another engine and keep this one for parts. From what I've read on a Smart car forum posting (April 25/08 ), injectors are $800CDN a pop

[Crazymanneil]

I'm thinking the same thing - keep it for parts. The likes of the turbo and high pressure pump are bound to be worth something at least. I'm trying to get injectors at the minute anyway.

Also found this which you guys may find interesting -

http://alan.mcreynolds.googlepages.com/ ... cedesom606

There is also an interesting youtube video here -

http://uk.youtube.com/watch?v=koghDoROFko

Might try this on mine - nothing to loose really if I'm getting another engine anyway...

N

[Crazymanneil]

Injector bench tested at local diesel place today and leaking like a good un (without even power connected). He's gonna take it apart and let me know if its gonna be expensive or not. Just trying to get in touch with a german ebay guy at the mo which would save me a fortune (for a full brand new set!) because he does not mention post to UK...

Neil

[Darren]

Neil,

Shame to have all these problems.

For the glow plugs it might be worth looking at

http://www.uniteddiesel.co.uk/diesel_en ... oducts/13/

I guess that these kits do a similar job to what was in the page you linked above? Just a bit more costly and look like they should have a higher success rate.

Best

Darren

(edit) Just watched the you tube vid - looks like a similar kit

[Crazymanneil]

Darren,

Yep I came across those guys first which is what got me searching. Unfortunately it looks like their kits are not geared towards the OM660 which is the engine I have so it would have to be a generic route for me. Am going to ask a friend who is a diesel technician (works on lorries) to see if there is any local companies that do it.

Ta,

Neil

[Darren]

Are you sure none of the kits they stock/hire are suitable?

They have a kit for M12x1.25 Merc CDI and another for M10x1 Mercedes CDI

[Crazymanneil]

Darren,

Thats a good point and I was wondering that myself. I bet the glowplugs from my engine would fit some other merc engine too. However, I looked at the kit and part of the tooling is a drill holder that keeps it straight. I don't think my plugs are gonna be also at the same angle as the other engines or that i'd even have the same places on the engine to bolt the jig onto.

That said it does not rule out carefully drilling the plug out by hand and using the same method to extract it (they appear to be M10 plugs with a fine thread of some sort (1.25 or 1mm). However, I'm not going to try it until I get another engine because hitting the threads would hold up the project whereas the plugs are not leaking (that I know of) at the moment.

Priority at the moment is trying to get hold of an injector at a sensible price and test that the engine runs as expected. Still no replies from the guys selling them in Germany. Anyone know someone in Germany that would be happy to forward them to me? I'd add a comission on top of the postage of course.

Neil

[Dan J]

Neil - no chance GSF can help (http://www.gsfcarparts.com/)? They've always been great for all manner of BMW (car) parts for me...

[Crazymanneil]

Cheers Dan. I've used GSF and also Euro car parts before and agree they are great for most things, but not this engine unfortunately. Thats what I get for choosing an engine which is rarer here. Gonna give it a week and if I can't get the cheaper ones then I'll go back to the local diesel guy (who wanted something like £240 for one injector!).

Neil

[Crazymanneil]

Right,

Lots of progress - kinda long post so sorry in advance if its not interesting! Got me 3x decent looking (used) injectors for a sensible price from Germany. I may still buy some new ones now although I will try to get the engine running first.

Started the engine again and as expected a fair bit of smoke and knocking til she cleared herself out of the diesel left in the cylinder from before and settled down a bit. However, now have a new issue somewhere...

With throttle set to idle the engine starts and runs for a few seconds and then dies.

With throttle set to around 30% (and left there) the engine starts and revs up and then dies off. However, before loosing much speed she cuts in again and revs up and repeats this hunting process. The cut-in is pretty sudden as though the electrics were suddenly restored (which led me to running separate wires to the battery to ensure no voltage drops).

At the moment I am thinking that my fuel lift pump may not be up to the job. It is a 2.5 bar at 160 l/min job by Bosch (brand new). However I suspect that this is not enough to supply the engine and this is the reason why it cuts out. My theory is that the high pressure pump is starved of fuel and gradually dies off until it is no longer high enough pressure to continue running the engine.

I think that the problem is less prevalant at higher rpm because the relief valve will be closed on the high pressure rail and thus there will be less flow back to the tank resulting in lower fuel demand from the lift pump. The high pressure pump would also be spinning faster and thus able to pump faster (if its getting fuel).

The high pressure pump in the engine includes a safety valve that cuts in around 1.5 bar. This valve ensures that the pump will only get fuel provided that the fuel lift side is higher than this pressure (otherwise fuel only goes through a lubrication and cooling circuit). I think the pressure may be dropping below this hence the cutoff.

Another thing I tried was to put a voltmeter on the high pressure sensor on the fuel rail. I know this should be around 1.4~1.5 volts at idle. When starting at idle the voltage goes up from 0.5 to around 1.1 whereupon the engine fires and then on up to 1.5~1.6. Then it appears to die down to about 1.1 or 1 volt whererupon the engine dies so this seems in line with my suspicions about insufficient fuel rail pressure. Must try to find an analogue meter as this would be easier to watch the rise and fall on.

Does this make sense or is there something else I need to check? I've checked over connections etc and everything is soldered.

Anyhoo, the neighbours are loving the smoke and noise

Neil

[andrewaust]

Hi Neil



Looks like you are covering all bases, just check for a relief valve sticking and aerated fuel.

I'm not an expert on common rail ECU diesels, more from the old mechanical type units , without seeing the setup first hand it's hard to tell.

Maybe someone with common rail knowledge will notice the post and give some input on a solution.

The ECU Diesels can be a handful, but they do run great once you sort them out.

[Crazymanneil]

Cheers for the supportive words guys. I'm determined to get this thing to run, even if I later end up getting another engine. (a bit concerned about this one now that its had very advanced fuelling from the leaking injector - the knocking noise was tremendous!).

This week will be getting the lend of a pressure guage to test the fuel lift pump with engine running. Should know better if thats the issue then though I think it is.

Sticking relief valve could well be an issue if it is sticking open. If its not the fuel lift pump then it could well be this. I may be able to borrow a logging oscilliscope to check this too. I wish I had the diagnostics for the ECU although they are ££££ apparently.

You are right that the electronics add complexity although they do make a powerful, light and economic engine when running properly. Electronics are where I myself feel relatively comfortable as opposed to the mechanical side strangely although I do hate having to troubleshoot. Intermittent problems like dodgy connections are especially painful which is why everything is soldered even for testing.

I do think common rail is the way forwards. I've read a fair bit about it now and its very flexible in being able to do multiple fueling events for a single ignition stroke and other things. For our purposes it would be nice to have an open source/affordable ECU like MegaSquirt has done for the petrol engines. Perhaps if I had more time to play with these things...

Neil

[Darren]

I've not played with a common rail but it sounds like you may be on the right track.

Do you have any information about the supply pumps used in the Smart? Can you find out what others have used when fitting these engines in boats, bikes etc.

Shame about the after market ECU diagnostics situation.

I guess your ECU has it's own diagnostics protocol?

[Crazymanneil]

Good points Darren. I've some basic info about the smart lift pumps but ideally need the Bosch part number. From what I have read about common rail in general I may need a 6 Bar pump but that is not specific info to this model of engine so its a shot in the dark. I've emailed a few people who use this engine so will see if they have any info.

Tolsen over at the onsmart forums was very kind enough to measure the fuel lift pressure so I have got something to compare with -

http://www.onsmart.co.uk/phpBB2/viewtop ... f=3&t=2566

The ECU uses CAN bus but runs propriatary software over this to set ECU parameters etc. I've not tried plugging anything into this to see if it gives out standard fault codes yet though. There is also an ECU lamp which gives blink codes although its not giving me any blink codes at the moment so its maybe not a failure mode that the ECU caters for.

Hopefully this pressure guage should give some interesting results. Fingers crossed thats the issue cos I have no other ideas at the minute.

I've just put a blog on my site (under projects at the right hand side). This has RSS if anyone wants to keep tabs on it. Not much on there yet but I've some photos etc to get on there soon.

Neil

[Crazymanneil]

Right time for an update on the Smart engine methinks.

So I got the fuel pressure guage. Stuck it inline between filter and engine to see what the high pressure pump is getting. To my shock/amazement it goes up to around 7 bar with the lift pump on before starting engine! This is more than enough for the high pressure pump so should be no worries there. I also noticed the plastic fuel filter I am using bulges at this pressure (unsurprisingly) so I am lucky it has not broken and sprayed me with diesel yet...

Anyway. Some more investigations. At first the engine started up fine and kept running at idle speed which was another surprise. I scratched my head for a while and revved it a bit and all seemed ok until the revs started to rise beyond the throttle setting again. Dagnabbit. Got the engine stopped.

Tried to restart to see what the craic was and discovered it was back to its usual "start-run-die" failure mode. Started another couple of times with various throttle settings and was getting more or less the same thing. At this point ruled out the lift pump as that seems ok.

So thought about this for a while and wondered what the engine does if the oil pressure does not come up as there is an oil pressure switch but obviously no oil light anywhere for the user. I put the multimeter across the switch and discovered it is closed with engine off (low pressure = closed). So for sake of a trial run I disconnected the thing and left the multimeter on it.

Engine started good this time and ran ok although after a while she started to smoke a bit (I think there was some blue in there with the grey) and rev out as usual but this time did not die til I killed it myself. Oil pressure switch never went open, indicating that the oil pressure did not come up as expected.

Now what I have noted before is that the oil level rose in the sump after the problematic injector incident so I can assume there is some diesel in there now too. My current theory is that this diesel has thinned the oil hence the low oil pressure causing the engine to cut out. This diesel would also probably make it past the piston rings in a small but sufficient quantity for the engine to burn when ignited by the normal fuel charge of the injector (engine stops when injection is cut off).

I think the engine ran fine first time because it was standing for a while and the diesel in the oil would have separated out to the top a bit. Since the oil pickup would be at the bottom of the sump pan she would have got mostly oil (bringing pressure up and not causing undesired combustion) at the start til the stuff got churned up again. At least this is what I am talking myself into at the moment.

So fair enough you'd say, change the oil and see what it does. Except that the Smart engine has no drain plug. Spent a fair bit of time today trying to get the tool to suck the oil out the dipstick tube only its £70 for something I'd maybe use a couple of times. I did have a cheaper one for the car though it seems to not work anymore (maybe because its cheap eh?).

So plan at the moment is to get the oil (/diesel?) outta there somehow. Tempted to turn it upside down since it is in the engine stand although not sure what might happen if I do or if everything would come out. Or maybe a small drill hole in the sump and weld it up after?

If all this is right its nice to know the injection system etc seems to be working ok although I'm a bit suspicious about if the engine will turn out to be reliable or not now. I'm still on the lookout for another engine at the right price as a result, though preferably one with a good story behind it this time!

It was also encouraging that when the engine was running in the stand it was quite smooth - not really any worse than say a twin petrol engine might be so would hopefully be a good job in the bike.

Thanks for the support, I'm sure I'll get this thing going yet!

Neil

[Darren]

Rig something up to suck out the dipstick.

I've got a little 12 volt gear pump I use that does the job nicely.

My brother just made up a tool to bleed the brakes on his car. His vacuum cleaner gaffa taped to a hole in a pot. Then another hole with a hose that went to the bleed nipple. The suction of the hoover is enough to pull up the brake fluid.

I use a length of nylon pipe to push down the dipstick hole. Guess you old knackered suction device should have all the bits you need - just need to make something up to allow a vacuum cleaner to suck out of the reservoir.

Fingers crossed changing the oil will cure the erratic running.

[oldbmw]

If I were you I would install another oil pressure switch first.

I have a big metal syringe affair for putting oil in my BMW motorcycle, as most of teh oil filler holes are either inaccessable or horizontal. It will suck as well as pump. Cost 20 euros froma tractor garage.

[Crazymanneil]

Cheers for that Darren.

hmm vacuum cleaner and some sort of resevoir...

I've compressed air available too, was wondering if there was something I could do with that too. We'll find out tomorrow!

Neil

[taildraggin]

Marine supply shops (chandlers, but no one calls them that anymore) also sell small hand pumps that go down dipsticks. Best way to get the oil out of a big diesel sitting down in the bilge.

[Diesel Dave]

Looks like you are going to need a solution to changing the oil anyway so here's my 2c worth.

Fridge pumps are capable of raising quite a vacuum and easily obtained (notwithstanding the new reg's on fridge disposal & CFC gasses), connect this to an airtight resevoir and from this a pipe into the dipstick hole and turn on.

Also useful for bleeding brakes.

Many moons ago we had a similar setup of a fridge pump conncted to a small homebuilt airtight box with plexiglass door (even had a light inside). any mixes of paint or fibreglass resin would be popped in for a minute and the vac raised. All the trapped air bubbles would pop to the surface making the mix a lot easier to work with - really useful for Gell coats and great for brush paint too.

The inevitable happened one day when someone switched it on and walked off to make a cuppa - the box imploded. We really missed it after that.

Ultra cheepo version - get a cheap plastic bicycle pump and reverse the pump washer inside, chop the connector off the flexi pipe and attach a piece of brake pipe to stick down the dipstick hole. Back in the 1930's many trials riders would use their bicycle pump to draw off oil fom the engine tank to apply to the chain before riding home after a muddy event.

Dave

[taildraggin]

OT - sounds like a good motor for vacuum bagging (fiberglas layups)...

[Crazymanneil]

Cheers guys,

Managed to get the oil out. Used a 25 litre drum and connected hose to dipstick. Put this hose and a vacuum cleaner hose through the hole at the top and sealed roughly round it with my hand. Worked a treat. Got the last bit out of the engine by turning it upside down on the engine stand.

Changed oil and started again. Got some oil pressure (pressure switch went open) and then after a short while the same thing happened again. Engine revved away, blue smoke, no oil pressure (switch closed again).

I am thinking it is new engine time now. Only other thing I can think of is that I've not plumbed up a coolant circuit. My thinking was that this would be ok for a quick test run although perhaps the engine is not heating up evenly as a result? Its not been run for long or hard and there is no load on it. Engine is not overly warm to touch either.

I've no other ideas except that engine was dead on arrival

N

[Diesel Dave]

Ooooops.

quote

Only other thing I can think of is that I've not plumbed up a coolant circuit.

That may well have buggered the thing! can't run a water cooled motor for almost any time before distortion occurs.

It might have a blown head gasket and be weeping oil into the cylinder.

Dave

[Crazymanneil]

Cheers Diesel Dave. Not the best news but I'd rather have the truth i guess

Will try it with some sort of coolant circuit tomorrow to see how it goes but does not sound good. Though the engine has not been run for more than a minute in any one run. It is an alloy head though

n

[Nanko]

Ran , for fun , a wornout peugeot diesel without oil and cooling liquid for 10 minutes on idle , nothing happened.
Only after several minutes on ~3000 rmp the engine seized with a lot of white smoke .
The pug. had alloy head so sometimes these engines can handle a lot of abuse.