It will most likely have a shattered piston or two because the owner was using 95RON fuel so all the time it was running on the edge of knock, the revised piston has thicker lands

 

I put some liquid in each cylinders, 2 of them went down

 

New pistons then...

 

I pulled of the sump and removed the pistons
First picture is cylinder 2 and the other one is cylinder 4

 

Yes, we have seen a few of these, on one we had in at the beginning of lockdown caused me so much distress that I ended up fitting a genuine VAG exchange engine just to get it done and gone.

 

I can understand why those engines are such a pain to work on, too many parts to remove, I just hope I remember where everything goes 😅

 

I used Nural pistons and I am convinced they were the cause of my problems (I checked them against a genuine control part, perfect match) but after gutting the engine to nothing (bare acid dipped block) and building back up with all new parts except the crank (checked independently and perfect) and rods (no joking, new genuine head and cam carrier), it still sounded awful and presented poor oil pressure even with a genuine new VAG oil pump. It drove me to the edge after 5 strip downs and rebuilds with three chain kits and lifters/followers. I have been building VW engines for forty years and I could not fix it and I had to admit defeat after throwing £20k of parts and labour at it and still think it was the chain cover but have feeble evidence to back it up.

 

Wow 20k worth of parts, horrible engine design, may I ask why do you believe it may be the chain cover, im getting worried now when I come to build mine I hope I don't run into any issues

 

It was around £5k of parts, the labour lost we could only guesstimate, convinced that 3 Bar @2k rpm was inadequate oil pressure (I like 5 Bar) I tried to find a schematic of the oil system but couldn’t so with the bare block on the bench I plotted the system and it is daft! A whole post in explanation of it’s oddity. Also I rebuilt the engine meticulously using RedLine assembly lube, top quality bearings and every part micrometer checked and bearing clearances checked with Plasiguage and the clearances painted on the block, this is the same attention to detail I have used in my engine builds for 35 years, I am a fanatic! When built up on the frame stand I built oil pressure before it went in the car and at 300 rpm it showed 3.5 Bar on Millers 10w/40 running in oil. I also pressure smoke tested the engine parts step by steep and the finished overall engine to check for internal leaks, nothing. At one point I became convinced it was dynamic piston to valve contact as the oil pressure was always 1 Bar above minimum spec so I bought a genuine VW piston, took the Nural ones out of the engine (again!) and meticulously measured with a dial indicator and micrometer the VW (also Nural) against the aftermarket Nural and to 0.01mm I could not detect even the slightest difference. I considered doing a dynamic contact check on the stand but the time involved put me off and the head was now new genuine anyway. The final build only reused the block (meticulously checked, honed and deck skimmed by an outside engineer), sump, chain cover, rods and crank (again outside checked by my engineers and polished) and when in and started, after 30 seconds I turned it off as I could not cope with the noise. In defeat I bought a genuine VW exchange engine (£5k) and this came quite obviously by their finishes (you can just tell by experience) a brand new block (no idea of the internals), a reconditioned head, a brand new cam carrier and an obviously brand new timing chain cover… the engine sounded lovely and I got shot of the car, the poor lad was travelling buy bus during lockdown. Now the timing chain cover is a none wearing part, all you need to do is dip it clean and reuse, so WHY did the genuine VW exchange engine come with a new (£500 retail) timing chain cover?

 

Wow that's very strange you've done everything by the book or maybe even better but still had issues, those engine's are such a pain in the back side.

 

Once I rebuild the engine how many miles do I need to run it in and do I have to use 10w40 to run the engine in

 

I insist on running in oil and the thinnest I can find is 10w/40, after 500 miles of gentle running in I change to 10w/40 pure mineral and only when I am sure the rings have settled will I use synthetic.

 

So after 500 miles you use 10w40 pure mineral oil and when can I use normal 5w30

 

When you are happy there is little or no oil consumption

 

On the genuine exchange engine I used LongLife 3 straight away as that is what they insist on, if it burned oil it is VAG’s problem as it now it has a two year dealer backed parts and labour warranty. It is what I had campaigned for from the initial broken piston discovery but I was brow beaten back by the desire to save money and generate workshop time… then lockdown 1 hit and I was left on my own to deal with the fallout and I was so stubborn I refused to give in and dug myself an expensive hole. Life lesson number 77034 (ish), mind you many have been learned thrice times or more… will I ever learn, doubt it.

 

Hi I was wondering would you know the part number for the camshaft sprocket holding tool

 

T10171B, if you ask your local VW dealer nicely they can order it for you IF they want to, the aftermarket versions I have tried are awful

 

Hi sorry I meant the counterhold tool when undoing the cam sprocket and vvt

 

T10172 the VAG version is terrible and the Laser version perfect. the other way around to the other tool. You will also need 3415 to remove and install the centre bolt. If the engine is original the crank centre bolt is 18mm 12 point but replacements are 21mm 12 point, the bolt, sea and diamond washers MUST be replaced; even then the timing can slip and wreck your new chain sprocket.

 

I think mine has 21mm bolt do you have any part numbers for the bolts and washers

 

Hi there, I'm a brand new member to this group and interested in joining your discussion. If the rings have gone would you expect to see excessive exhaust smoke?

 

Hi mate, you would see excessive smoke if the piston rings are gone, I bought my 1.4 tsi golf as a project and it was puffing out a lot of blue smoke, cylinder 2 had low compression so I decided to strip the engine and noticed piston 1 and 2 had a crack

 

Surely 80 psi isn't enough, from what I read they're meant to be about 180psi per cylinder, correct me if I'm wrong, maybe the piston rings are bad, maybe valve issue, could be piston issue

 

From my limited experience 150psi should be about right, but I would be happy to have 140psi across all 4 at the moment.
I too would be thinking pistons and or rings, especially from what Crasher said about the need to use the more expensive high octane fuels, I can guarantee that the previous owners would have been reluctant to spend the extra. However if it was the piston or rings, I would have expected to see blue smoke from this, at the moment all I get is the usual white puff on cold start up.
Anyway I will carry out some more checks, drop a camera inside and run some oil on top of the pistons to see if any disappears back past the pistons, I'll let you know how it goes.

 

Thanks mate, I didn't want to hear that but half expected it.
Is that an engine out job or can the piston and rings be replaced in situ, also I'm guessing its best to replace all 4, but what else should I replace while I'm at it?
I Really appreciate your time and feedback.

 

The pistons can be removed with the engine still in, make this a professional job you should also replace and do the following;

Have the head professionally rebuilt with new exhaust guides and valves plus a very light skim.
New cam compensation elements (lifters) and rocker arms
Check the cam carrier bores with an inside micrometer and the cam journals with an external micrometer and a visual check of the cam lobes for wear/damage
Full quality chain kit with VVT hub (aftermarket) which include the sprocket bolts, remember the VVT hub bolt is left hand thread
Oil pump (modified) and drive kit (aftermarket)
Top end gasket set and sump and chain cover sealants which are importantly different
Lots of new VW bolts
Remove piston cooling jets, hone bores (VITAL) and fit new updated piston jets (genuine only)
Con rod (big end) bearings and bolts, these MUST be replaced or the bolts will snap and shove a rod out sideways which isn’t good!
Fit new pistons, the Nural ones I used were a “suspect” in the problems I had but unproved
Running in oil and new oil filter
Front crank bolt (upgraded 21mm 12 point) and bush plus O ring seal and Diamond washers, all genuine only
A pile of specialist tools inc Digital Dial Gauge plus crank and cam locking tools.

That is until (like me) you strip the whole thing down again engine, bare block on the bench and examined in minute detail to the absolute bare bores and the block and crank sent away for independent checking only to rebuild again with many of the above parts bought for the third time with a brand new genuine head, exhaust cam, cam carrier and genuine oil pump only for the resulting lump to sound like “a skeleton wanking in a biscuit tin”. I have been building VW engines for 40 years and never been in this situation because even after stripping it down again I could find nothing wrong. I gave up and bought a genuine VW exchange engine to get the car out, roughly £20k down the drain.

 

Hi crasher, I haven't finished building the engine yet but I was wondering how do i prime the engine before starting it to prevent a dry start up, I've used assembly lube on every component I touched

 

Unless you have a primer system that pumps through the oil pressure switch hole, then it is cranking with the plugs out. If you have filled the oil pump with assembly lube and poured oil down the oil filter pressure feed, pressure should come up in a few seconds but you need a gauge to see it as the dash won’t tell you.