118TSI Forged Piston Engine Rebuild

[rygreen93]

Some already know that my car suffered the dreaded 118TSI death. After 3 months with the car I was loving it. It had 65000km's on the clock and is a late 2011 built model (MY12). When I bought the car I was confident that being a later model I would have no issues with misfiring or cracked pistons. I was wrong!!!

Driving home from work one day and it started off with a rough idle at the lights. Then cruising down the highway and I felt it misfire and saw a puff of black smoke in my mirror. At first I didn't think much of it, but by the time I got home I could hear that nobody was home in 1 cylinder. I had it compression tested, and the fears were confirmed. No compression in cylinder 4.

Cylinder 4 had cracked the piston between the 2 lower rings and the ring had scratched the piston just enough that a nail caught. Couple pictures of the pistons after they were taken out.

Bore Scratch

Piston as it came out


After doing a lot of research I decided to steer away from the VW pistons. The advice from my mechanic at Eurotune Miami was that the area of the piston below the oil ring was way to thin. Even the VW replacement pistons showed exactly the same problem. With help from Blower and a few other forum members I went with Wossner pistons.

A couple of weeks and they had arrived from Germany.

Wossner Piston

Old vs New


The block will be in this week to be bored and 0.5mm larger to accomodate the new pistons. I am already running the Harding Performance stage 1 tune and was very happy with it before everything went bad. I have picked up a used S3 intercooler which will be fitted up to the car when the engine goes back in, which will allow me to go stage 2 once I am happy that everything has settled (downpipe required)

Feel free to follow my thread as my beloved car gets forged pistons and a few other upgrades to hopefully turn this engine into something extremely reliable.

[Rawcpoppa]

*subscribed*

[blower]

Subscribed too....hope it all goes well, the wossner's are work of art compared to the chocolate stock pistons.

They always fail in the same place, on the ring lands - has to be weakness in the design.

Just a bit of advice with the conrod bearing end caps - the bearing caps are of the 'cracked' variety, this means that the cap once removed from the conrod must go back the same way round and on the same conrod, you can't mix them up.

You will notice that the mating surfaces are rough and uneven, this is due to the way they get cracked apart during manufacture. When reassembling make sure they fit perfectly (if you haven't labelled them and marked orientation then you will need to trial and error each one by hand, ensuring the hairline crack on the sides where they mate is perfectly flush)

[The_Hawk]

Also subbed. Keen to see how it all goes back together, especially anything on the down pipe since that seems to be one of the harder parts of the puzzle to find.

I'm also driving a 118TSI, late 2011 (MY12) which has been running APR Stage 1 since near new. Mine has only covered 27k (but that includes a few track days ) and hasn't missed a beat so far (other than a couple of rouge misfires on cold recently which were solved with it's first major service and shiny new plugs).

I'm running a Forge intake and keep thinking about going the S3 intercooler (or maybe the forge front mount), stage 2 is also tempting but like I said the downpipe seems hard to get something good/useful and even then isn't a lot of gain. All in all it starts to make a GTI front cut look like a viable alternative as you consider pouring more money into the little twincharger. (Of course my decision is a little different with a Cabriolet since I don't have the option of just "buying a GTI" instead.

[Mk R]

Subscribed and excited for you mate! Bet you can't wait to get it back...

[ope126]

Well done, glad to hear it is all coming back together.
For the sake of the thread and for others out there that maybe faced with similar issues, what was you car again? (MK6 Golf Wagon???)

I have been following these threads quite closely, however does anyone actually know if a (2011 onwards) MK6 Jetta owner has ever had the same issues?

Are you also updating coil packs, spark plugs, N249 / N75 valves, fuel pump etc. to ensure smooth running moving forward.

Keen to see the outcome mate!!!

[rygreen93]

Also subbed. Keen to see how it all goes back together, especially anything on the down pipe since that seems to be one of the harder parts of the puzzle to find.

I'm also driving a 118TSI, late 2011 (MY12) which has been running APR Stage 1 since near new. Mine has only covered 27k (but that includes a few track days ) and hasn't missed a beat so far (other than a couple of rouge misfires on cold recently which were solved with it's first major service and shiny new plugs).

I'm running a Forge intake and keep thinking about going the S3 intercooler (or maybe the forge front mount), stage 2 is also tempting but like I said the downpipe seems hard to get something good/useful and even then isn't a lot of gain. All in all it starts to make a GTI front cut look like a viable alternative as you consider pouring more money into the little twincharger. (Of course my decision is a little different with a Cabriolet since I don't have the option of just "buying a GTI" instead.

Spoke to someone at the local exhaust shop and he told me that they could custom make on with a 200CEL cat. Then I would most likely get an exhaust blanket made up for it as they are extremely good at eliminating heat. Wraps aren't very good and can cause corrosion of the pipe. An exhaust blanket is much thicker and water resistant.

I probably won't get that done until I'm happy the engine is running well.

[rygreen93]

Well done, glad to hear it is all coming back together.
For the sake of the thread and for others out there that maybe faced with similar issues, what was you car again? (MK6 Golf Wagon???)

I have been following these threads quite closely, however does anyone actually know if a (2011 onwards) MK6 Jetta owner has ever had the same issues?

Are you also updating coil packs, spark plugs, N249 / N75 valves, fuel pump etc. to ensure smooth running moving forward.

Keen to see the outcome mate!!!

I am not sure if I have seen anyone with a Jetta have the same problem. Mine is a mk6 hatch not a wagon.

Being a late 2011 model I should have all the revised bits and pieces but the idea is to run the car with the new pistons for 1000kms and then take it back to the mechanic to have it scanned for any issues. I am getting the latest revision timing chain and tensioner assembly installed and will be putting a set of BKR7EIX spark plugs in. Coil packs all seemed fine. Funnily enough my car was not misfiring at all it just started to run rough and then obviously once the crack got bigger it started to misfire. But prior to that there were never any error codes.

Ill be sure to keep you guys up to date. Are you going to come to the meet at Lakeside on the 1st of October Ope126?

[Mk R]

Do you know if there's any weight difference is between the old and new pistons? Lighter pistons + rods might mean a higher possible rev limit in the new engine and the potential for a sweet custom map...

[Lucas_R]

Also subbed. Keen to see how it all goes back together, especially anything on the down pipe since that seems to be one of the harder parts of the puzzle to find.

For a fraction of the cost of a new aftermarket or custom downpipe, you could remove your stock one, knock out the 1st of the two catalytic converters to remove a layer of restriction and re-fit it to the car. If you wanted to go to the next level, get the 2nd cat removed and replaced with a 200 cel high flow item which might cost you $200-300 depending on the quality of cat converter you choose. I really don't think the little k03 on a 1.4L engine will flow enough air to benefit too much from an aftermarket downpipe, especially considering the pipe diameter on the stock exhaust is around 2.3" - 2.4" which is plenty big enough.

I did this with my Mk6 GTI and you get 80% of the benefit for about 10-20% of the cost of an aftermarket downpipe.