Scenic 1.5 dCi Engine Rebuild.

[Hell Razor5543]

Yupe, hydrogen and oxygen are produced during the electrolysis process, hence the need for good ventilation. My first job was for a company who made PCBs, and that involved electrolysis (and there were signs up in that area clearly indicating there was to be no smoking due to the risk of explosion).

[lexi]

Just wondered if this was on backburner ATM?

[steelcityuk]

Hi Lexi,

Not intentionally, I'm in the middle of selling and buying a home so that's taking a chunk of my time up but there was stage when I was struggling to find the parts I needed at a price I could afford. Anyhow here's an update.

After the electrolysis and a good wire brushing I ended up with this.


The parts were then treated with rust cure.


Then given a couple of coats of high temperature Aluminium paint.


I'd bought some Hammerite type paint from Screwfix a few years ago but found it a bit thin but I thought I'd try dipping small items to see if it worked better. After blasting and dipping they look like this.


A good clean up of the turbo and EGR parts using oven cleaner. I polished the EGR valve for something to do.


Taking the turbo apart required the destruction of the nozzle retaining ring so a new one was bought.


Rebuilding the turbo allowed progress to continue on the rebuild.




Following this there was a lull of several weeks because I realised that I hadn't checked the valve clearances before mounting the head or even fitting the timing belt, serious mistake! The valve clearances were so far out I had to buy a 32 blade feeler gauge so that I could measure what the actual clearances were. Following this it took a while to find the tappets that I needed. Now on a tight budget it was going to have to be second hand parts. I order 4x 7.55mm tappets from the Midlands Renault Parts in Birmingham B11 1JS. The 2 day delivery turned into over a week and the parcel contained one short fat piece of pipe worth about 10p - some kind of spacer that isn't even a precision part. They still haven't refunded my money!

[steelcityuk]

So after fitting the tappets, timing belt and other bits and bobs the engine was refitted. Bolting it back into place didn't take too long.


Connecting up all the bits and pieces dragged on a bit, stuts, driveshafts, hubs, brakes, etc. Bleeding the clutch and brakes was straightforward.


I've been on cat sitting duty too so I had to break off to go and take care of Lola so it took all weekend to fit the engine and connect everything up. Filled the cooling system, engine and transmission with new fluid - no leaks!


Connecting up the loom took some time because it was so long since I'd disconnected it. Got it all connected up and fired up the Clip. Only one fault - refrigeration sensor, this is because there's no pressure in the system.


Now I'm at the stage of trying to get the car running. It doesn't. Looking at the parameters in Clip it appears to be because there's no fuel rail pressure. I thought this one over for a day and did some research, the pump on a common rail diesel (at least this one) is very simple - think Lucas Epic stripped of electronics and sync'd multiple outputs. I initially thought it's possibly an internal air lock in the pump but after rigging up a temporary diesel supply I doubt it is. After cranking the engine over I very carefully cracked an injector pipe, fuel began to ooze out so I now suspect that the fuel rail pressure sensor is faulty. Just got to track one down now.

Steve.

[lexi]

Hopefully that will be it with sensor.
ATB with house business.........stressfull.

[demag]

Steve is it possible to change valve shims with the camshaft in place or does it have to come out?

[steelcityuk]

Hi Dave,

I doubt it is, the shim is under the bucket well out of the way. I'll get around to finishing this car one day. Currently the XM is off the road because it's been run into whilst parked. Looks like a write off.

Steve.

[demag]

Bad news on the Xm Steve lets hope it can be saved.

[steelcityuk]

Thanks Dave, very unfortunate. I don't normally park in the spot where it was hit but because a bunch of students were waiting next to where I normally park I decided to give them room to spread out and parked two spaces further back. Anyhow we'll see how I feel about it, at the moment I've pulled out the rear wing so that I can continue to run it.

Steve.

[steelcityuk]

Hi All.

Time for an update about the Scenic.

Not being entirely sure of the cause of the non starting I decided that the first thing would be a compression check, I tested the compressions and found they all read around 150 psi. That I would think was well down on what a dCi should achieve. This lead me to think that my compression tester wasn't working correctly so I tested the XM, it gave much higher readings but the XM was tested using a dummy injector wheras the Scenic was tested using a dummy glowplug. I noticed that the dummy injector had a one way valve fitted but the dummy injector I bought (it wasn't in the Snap On set I had) didn't. I bought a hose that had a one way valve in it, still the same reading but I noticed that slowly the pressure leaked away so I assumed that the valve in the hose could be leaking away the 'real' pressure before it could build up. In the end I bought a Sealey set and tested again, same result 150 psi. So now I had to work out why the pressure was so low, was it because I had made a mistake with the valve clearances? If so I made the same mistake with them all, so that seemed unlikely. The next thought was that the piston rings weren't right but I'd been very careful about fitting them and making sure the gaps were offset according to recommendations. I was convinced the cylinder bores were OK, there wasn't any damage to the walls and no significant wear despite the high mileage. I'd rehoned the bores and used the correct tools to fit the pistons rings and then fit the pistons, plenty of engine build lube was used to prevent scuffing. In the end I thought the low compressions must be because the engine was cold, it wasn't run in (so the rings weren't bedded in) and the lube could have long drained away (the engine was rebuilt about a year ago). Adding oil to the cylinders could be a non starter because the pistons have combustion chambers in their tops, the oil would just sit in the top of the pistons. So I bent a piece of Citroen 3.5mm hydraulic pipe into a gentle curve and fed this through the injector port after making sure the piston was at the bottom of it's stroke, I could tell if the pipe was in the 'cup' or on the head of the piston according to how far in it went, I injected a few drops of oil and tested the compression again - 150 psi... OK I thought it's because it's cold and not run in.

Well there's nothing I could do to up the compression so I decided that a squirt of Easy Start would get the engine to fire and the heat and speed of the pistons would allow the engine to run. It didn't work, it fired a little but was nowhere near running. Must be a lack of fuel I thought so I connected up the Can Clip and looked at the readings for rail pressure, at cranking the ECU want 400 bar the fuel pump was delivering 398 - 402 bar so that's a relief. Must be the injectors, these are infamous for failing at the slightest provocation. Out came the injectors to be dismantled and cleaned in my ultrasonic bath, in every one the control valve was stuck and in one the injector pintle was stuck in it's nozzle. After a thorough but gentle cleaning they were rebuilt and refitted to the engine. I made up a leak back kit using water bottles and pipe bought at B&Q. Cranking the engine showed one injector was leaking back more then the other three but it wasn't terrible. The Can Clip was showing good pressure. The engine now seemed on the edge of running, firing readily but sort of bogging down after several revolutions. I connected up another battery with jump leads but it seemed barely any better even with a quick squirt of Easy Start. As a final shot of getting it to start I pushed it to the end of the drive so I could get the XM next to it and use that to boost it. I rigged up a lead to the starter solenoid so that I could crank the engine and give it a squirt at the same time. It came very close to starting but seemed to bog down again, I've never been happy about the positive battery connector on the Scenic (too much plastic in the way to get a good clamp) so I pushed the clamp hard down on the largest bit of metal I could get to and tried again, it worked. I expected it to splutter to a halt by the time I'd removed the jump leads but it kept going. After about 5 minutes I revved it a bit, it seemed very sluggish so I thought I'll leave it to warm up and see how it goes.

After 10 minutes I was sitting in the drivers seat checking if the various gauges worked when a loud pop from under the bonnet brought me back down to earth, then I thought it'll just be the leakback back hose from my DIY kit that had come off, it wasn't, the fuel primer bulb had burst and was leaking a serious amount of diesel onto the recently cleaned block paving. I had no choice but to turn off the engine and shove a litter tray underneath to catch what leakage I could. I had intended letting it run for an hour if possible. Still it had started and ticked over with a steady beat so it was a big improvement over previous attempts.

Steve.

[xantia_v6]

Could be the low compression pressure is due to valve timing being slightly out?

[lexi]

Lots of work there Steve and a good read, although commiserations on your hassle.

Many times in the past I have started the old diesel Land Rovers with a tow when all else failed. Towing can be very effective on diesels just to get running.
Just need to go over it all again and timing is a possible. Look forward to next episode.

[steelcityuk]

I considered timing being a possibilty due to the compressions being all the 'same' and that would have been next but as you know with the layout and timing procedure of the K9K checking the timing wouldn't be as easy as what I did. I was very careful when originally timing the engine up using the proper tools and making sure the fuel pump is timed up. Great care was taken with the crankshaft pulley bolt for obvious reasons.

As a temporary fix I cut out the blown priming pump and fitted a inline fuel filter because it fitted the pipework. The engine started easily, whether that was because it was hot or that the rings has settled in better after a bit of compression on them I couldn't tell but I allowed me to leave the engine running for about an hour. I connected up my little Scangage II so that I could check actual oil and water temperatures and such things. It was during this time I found the alternator wasn't charging. Over the next few days I started it up once a day after allowing it to go cold overnight, the engine always starts very easily which is a relief. The new clutch and slave cylinder must be working OK, it's smooth and light with no trace of judder, revving the engine is spinning up the turbo but until I get it out for a run I'll not know for sure if it works as it should. I managed to pickup a secondhand Valeo alternator and a engine mount (the existing one was faulty), fitting the alternator was best done by stripping off the front end and whilst it was in bits I replaced the burst primer pump. Before starting the engine I remembered to reprogram the UPC for the change of alternator, the car took a bit of starting after having messed around with the fuel system but that's to be expected. The alternator is showing a health 14V according to the Scangage II so that's another step towards the MOT. Today a droplink has arrived so that can be fitted later.

Steve.

[lexi]

That's great news Steve You are getting the reward now for your painstaking work.
That will be a great little tool when fully functioning.

I know they are trouble, yet I still have a hankering for one. Probably too much Delphi running gear on them? That stuff seems to give the problems?

[steelcityuk]

After replacing the droplink, I put the Scenic in for a MOT. It passed without even an advisory. However it still isn't right, probably the injectors but I'm too busy to deal with it.

Steve.