Hi,

This project actually happened last year but thought it makes a pretty interesting read (I think) HA!

Basically we had a little 2009 Polo 1.2 and I got sick of driving this around (was the only car we had at the time so no G40 at this point). Anyway having owned a few Golfs we love them so found this one for sale for £2000!!

£2000 for a 2007 MK5 ? I hear you say, well the catch was it had a slipped timing chain with unknown engine damage, this basically means write the engine off. Having done my homework and having owned a couple in my time I knew that a running version of this car with such low mileage (60,000 miles) they are worth about £5000 and with the extra's we have about £6000 :-)

This is the engine that is in the car:

Its the 1.4 Twin Charged TSI 140 Sport. So basically the same as the Golf GT 170 engine but has a different MAP. Anyway this engine is the BMY engine code and my research started. I basically had a limit of £2000 to get the car running so my first trick was to strip the engine down and see what I could use.

The story I was told by the garage I bought it from was that the owner had been using the car daily and during a service interval (the second one was due on a long service interval) a warning light illuminated. The garage informed the driver not to use the car as the warning was that there was excess movement in the timing chain thus sending the timing out very slightly, this was the sign that the chain had stretched and needed changing. So on ignoring the garage's advice the previous owner drove the car the next day with no issues stopped after work again with no apparent issues, the next morning the car would not turn over at all. Deciding that the cold had ruined the battery the owner bought a new one and fitted thinking this would be a simple fix, not the case as the engine was still not turning over. When the garage got hold of it they discovered the engine was not turning by hand and was seized. Being a genuine VW dealer they decided the engine was a write off and would need replacing quoting around £4000 to do the work!

This is where I came in and bought it.

So I was hoping that I could strip the engine and with the knowledge that it apparently didn't run with a slipped chain but rather just turned once and jammed I thought this should be a simple piston and valve change. read on to see how wrong I was!

So the engine started to come out.

I love the newer cars, once the bumper and front end is out of the way the engine is so easy to get to!

One thing is that there is things like Aircon to deal with which is a little boring as I had to pay a guy to come out and empty the system for me, easy to do but you need to get rid of the contents properly and it's dangerous stuff so didn't want to mess around with it.

Anyway home made engine crane built and the engine was prepped to take out. Every engine i pretty much the same, unbolt and take out! the great think about this engine is there is not two loom connector the same, they are all different so didn't need to mark anything up, but man there are so many sensors and things. Very complex system this twin charged thing.

So after a bit of fettling the engine came out.

Note the oil coming out, the garage had taken the timing chain cover off to prove this was the issue and hadn't put it back together so when I took the engine out oil came out all over the place

So the next stage was to get the box off and engine stripped down to get it onto the engine stand. I was pretty keen to find out the damage as I was going away with work the next morning which gave me the opportunity to order the parts required for my return. I had found another 1.4 TSI engine (the turbo only version) which I was going to use to donate pistons etc, this only cost me £600 and had a mere 2000 miles on it so from a brand new car. It took me a lot of reading to find out the specs of these engines to determine what parts were the same across the range and luckily for me VW kept the design of the blocks and head pretty much the same across the range (regardless of what VW garages will tell you). There are many differences as I found out and certainly tripped me up along the way.

So on with the engine strip and the first opportunity to get it on the stand. The first move was to drop the oil out. No a lot of bits came out and a few small specks of metal dropped out, not good! then I spun the engine over on the engine stand and a horrible noise followed. it sounded like a had turned over a piggy bank with about 20 2 pence pieces in! it was then I knew I was dealing with a badly damaged engine.

So off with the head! and I was greeted with this

So the pistons are ruined but I knew this would be the case.

Sat on top of the pistons were 6 Exhaust valves

But where is the other exhaust valves? Well one didn't snap off but the other had and then been jammed back into the head, so thats the head written off then!

So having seen the damage I thought I'd strip the block and make sure I could still use the block itself. Here is the remains of the internals once removed

as you can see Piston 3 has shattered into so many pieces they can't be counted, this is where the shards of metal came from when emptying the oil then! One piston was still intact although the crown is destroyed and the other two pistons where only held together with the piston rings! Rods were fine and so was the crank.

So I started to clean up the block and inspect it before taking it to get it properly checked out but on closer inspection I notices that cylinder 2 had a crack straight through the cylinder and liner!

Gutted is one word as that meant the whole engine was a write off! such a shame as well as the block looked pretty good otherwise.

So now the engine I had on it's way was really no use as I had no block to put the new bits into, hmm I wonder if the new block is the same? could they have kept them the same? more research required, but basically I found out that they were identical internally and had all the same stats as each other. So the new engine I had was from a MK6 TSI 122BHP engine. Of course the one thing I was fully aware of is that this model engine had just a turbo and not the supercharger! so did they change the mounting points?

Looking at pictures of this block they looked identical.

Here is the new engine, put it up onto the engine stand and my nightmare had been realised as the supercharger mounting points were still part of the cast however they were not threaded to take any bolts! ah crap!

Next update will include the solution and how i got the engine back up and running, it wasn't as simple as I thought and includes yet another engine strip down! update to follow soon :-)

Edited 5 June, 201412 yr by Paulg40

So thought I'd write another part of the tale.

So bought another engine for £600, this engine is a CAXA code and the engine that was in the car is a BMY, anyone who knows golf engine codes will know that the BMY and BLG codes are the twin charged engines (both the same just the map is different to give different power). The CAXA is from the late MK5 and MK6 turbo'd TSI, these came with a water charge cooler on the back of the engine in the place of the supercharger.

Anyway I bought the engine following some research, all BMY and BLG engine prices where around £2000 so I thought that it's very unlikely that VW rebuilt the entire engine other than just the ancillaries. Looking at the stats of each they are identical I even checked up on the part numbers inside the block and head, turns out the only thing that was different was the exhaust valves. They were sodium filled valves in the original engine. So I phoned to order some valves only to find they had discontinued the old valves in replacement for the parts in the new engine! Brilliant, this means I only have one possible problem, the mounting points of the supercharger might not be on the block which would be an issue.

The engine, the great thing is it came out of a 2011 car with only 2000 miles on it.

One look at the block and my fear was realised, the lobes where the supercharger mounts on the block were not threaded, but at least they were there.

So I drilled the block and then threaded the holes! crapping myself was an understatement, oil ways were not far in all directions :-)

Note, one of the holes looks off centre but this is where it needs to be for the supercharger to line up :-)

Next issue I had to overcome was the fact that they had moved the oil feed pipe outlet from the head to the side casing on this engine, along with changing the breather pipe outlet. So I bolted the turbo on and sized up the pipe work, using the original feed and drain pipes I managed to fit them in nicely.

Added the ancillaries etc

So time to bolt the supercharger onto the new mounts and see if they fit! and fit the belts, took a while to work out the route it took as I didn't take this one off, it was the garage who took the belt off when originally trying to work out the damage.

So bit of a jump here when it comes to pictures!

Basically it didn't take long to bolt everything on and get it back in the car. One thing I did have to do was buy a new High pressure Fuel pump which sits ontop of the engine and feeds the fuel rail a constant 150 BAR... Yep thats right 150 bar (about 2100 PSI!!!). basically this was something else they changed so I had to buy a new item at about £130

So engine in and I got everything back together and was looking forward to start it up and finally drive the car for the first time.

So pretty good going or so I thought!

The engine fired up and ran but it was hunting for revs and would not rev over 3000 RPM which suggested it was in LIMP MODE. So I got a VAGCOM cable and ran a diagnostics and setup the throttle servo's but still nothing. The fault codes showed a couple of items which pointed to faulty sensors, easy fix, but not what would cause the engine to run so erratically. I checked the fuel pressures in the rails and it seemed they weren't correct, so I eventually worked out that the only thing that the engine was not running that was original was the new style fuel pump that I bought, which meant in order to fit the old style pump the cam cover must come off to swapped for the other. Having taken the other one off I knew this is a cam shaft removal job, which means the timing chain has to come off, to do that half the engine has to be removed! not a joke....I have the engineers manual and they say to drop the subframe down with the engine to do this job!

So for me it meant:

Engine back out less than 2 days since I put it in.

Before long I had the engine stripped and ready to get the timing chain fitted again.

You can see what I mean by half the engine has to come apart just to get the cam cover off! as to take the cover off everything has to be removed out the way. Ok some bits could have stayed but I just got it out the way.

Note in the net few pics how clean the engine is! the other thing about new engines is the timing tools, no timing marks on these engines as you must have the correct tools to time them up, so yet another £120 later I now own a timing kit for golf TSI engines. pretty snazzy kit as well.

Check out the difference between the oil stained cam cover (original) and the 2000 mile cover (top). Unfortunatley I had to fit the old item in order to fit the correct fuel pump, now thinking about it the cams are probably different as well so probably best.

Timing chain fitted with guides in time. Note the slack in the chain, this is correct believe it or not. The tensioner reacts fast and tightens the chain...well the tensioner is actually oil driven so works from the oil pressure built up from the engine turning over so this design is always going to be flawed in that there is a split second when the engine turns that the chain is not under tension, it is this tensioner that failed and is reason I am having to change this engine at such a low mileage. Anyway....

So back on with all ancillaries etc

and back into the car! again didn't take long so not many photo's of this stage plus it was the second time I had done this in the same week so just wanted to get it done. Only took 2 hours from having the engine timed.

Classic complete engine pic :-)

battery needed a charge and at 10PM I wanted to see if I had fixed the issue so I started the engine and.....

IT WORKED!

I did have a few teething issues like a couple of sensors needing changed, two coil packs failing and an intermittent hesitation when hot. All fixed apart from the hesitation.

I have yet to prove this but I have narrowed the issue down to one overlooked issue.

Basically the inlet manifold and fuel rail has built in vacuum flaps which make the inlet ports smaller for low revs and larger for high revs, this helps smooth the transition of the supercharger and turbo charger and also helps give a very torquey bottom end of the rev range whilst maintaining good power top end. This is vacuum operated so as the boost builds the flaps open up, as the flaps open they switch a micro switch which I can only assume switches the ECU into max fuelling MAP (or something like that), anyway the new engines did not come with these flaps due to the removal of the supercharger, so when I looked at the ports on the Cylinder head I realised they didn't have the cut outs for the flaps to sit into.

So basically I need to grind down the edges of the flaps so that they don't get stuck on the sides of the ports which stops the micro switches from stopping and giving full air at top end revs.

Basically I have adjusted it slightly but they still don't open fully, the ECU has even put a fault code in saying they are jammed. so I now need to get the dremel out and grind a little off the flaps to stop them sticking.

Anyway Hope you enjoyed the read.

Edited 8 August, 201412 yr by Paulg40

Awsome recovery and detail man. Love it.

yeah i wouldnt have even known where to start with that one.... hahah

kudos for taking the job on dude! nice work and an awesome write up!

Cheers guys!

It was a bit of a nightmare to find anything out, and these engines are just so complicated when they develop a fault its hard to work out what it is even with VAGCOM. Infact even the garages will sometimes write an engine off simply because they can't work out a fault! which is crazy.

I took it to VW for a full diagnostics last year to try and find the reason for the hesitation and after I told them about the engine change they just said its the wrong engine! even though they had no idea what was actually going on. Have totally lost my faith in garage engineers, if the computer can't tell them whats wrong then its a write off. My report actually said "it could be one of a 1000 things"

The sad truth is this car would have ended up in a scrap yard if I or someone like me didn't take it on, which is crazy considering what a great car it is.

We have put 20,000 miles on the car since the rebuild and about 16 months has gone by, as I mention only a couple of bits need sorting, the hesitation and a small coolant leak. Not bad going for under 3K.

Ah right, i think its spot on man. Good engine and car for under 3k sounds perfect haha.

Great write up...