A 2nd A2 for me - project FSI

No problem with the hijacking! I’ll put it back on thread every time I do anything vaguely worth writing down.

I wonder if anyone has considered whether later VAG 1.6fsi lower intakes from other models are compatible, or could be machined to be. I know gaskets are common across several applications so this set me thinking. As an example, if search eBay for GK00266 then you get manifolds that look similar but are much cheaper used. The flap actuator and arm are differently positioned, the injector spacer tubes look to be integrated. Obviously it may be literally playing with fire to go messing with the high pressure fuel circuit sealing design but if it bolts together and works...? Anyone?


Sent from my iPhone using Tapatalk
 
Progress report:
All back together bar the fresh air inlet duct thing for the aircon/heater. Filled up with coolant.
Won’t start. Giving camshaft position sensor error. Wiring measures 1.09megaOhms back to controller so that isn’t open circuit. I have ordered a new sensor, to be delivered tomorrow.
The battery was a bit flat before I charged it and I did notice one compression stroke a lot quicker than the others so I suspect there is something to be discovered with a compression test after I get it running again. Also the throttle body is failing the basic settings adaption and sounds awful, might have to strip that down tonight while awaiting the sensor.
Matt


Sent from my iPhone using Tapatalk
 
I have just found that it is possible to fit a vacuum actuator without removing the inlet manifold. However, I was only able to do it once I had sliced off the two small retaining pegs on the cylinder at the end of the actuator arm. These two little pegs (see BiggDogg's photos 2, 3 & 6 above) have corresponding slots (see BiggDogg's photo 7) in the flap rotation lever but the lever does not rotate far enough to be able to line up the pegs and slots because the cam cover gets in the way of where you want to place the new actuator. With the locating pegs removed the actuator arm can be inserted in the lever arm with some manipulation and fiddling. This isn't a clear description but have a look a BiggDogg's excellent photos above and it'll make sense. Having assembled it I noticed that the end of the actuator arm is under slight torsion all the time, which makes the fact that this design flaw was never rectified by Audi all the more annoying.
 
Nye, thanks for finishing off this theory, that’s great work.
My progress tonight was that have replaced the G40 camshaft sensor, project FSI is a runner.
I topped up the coolant and ran it up to temperature, reading 90degC on the gauge and 108 to 112degC in VCDS. No leaks. Having recharged the battery, throttle body adaption (block 060) worked fine. Block 142 is also saying ADP OK which I think means it is happy with the flaps.
However: the idle is not very smooth. Lambda is swinging from -5 to +5 and the ignition timing is all over the place.
I decided to take the spark plugs out to do a compression test and fit the new set I’d bought. The old plugs were all extremely sooty. Also they are a few mm shorter than the new ones. I checked the new spark plug part number at three different websites and they were correct. I compared the old plugs with an old set from my son’s BBY-engined Polo and they are the exact same length so U think a previous mechanic has fitted plugs meant for a 1.4.
So all the compression test told me was that my gauge is FUBAR. I fitted the new plugs and it runs just the same. I also got a fault code immediately after a hot start for misfire on cylinder 3.
I’m going to borrow a mates compression gauge and test it again. I think maybe the lambda sensor is shot - would that cause this?
Oh, and I ham-fistedly snapped the little white plastic elbow where the oil filler on top of the cam cover has a breather feed to the intake. I’ve joined back and it’s not leaking, but needs replacement.
Old and new plugs (tiny Iridium centre electrode on old one):
f9cb2ff2fb39d2e6631d0fbb98f7bc89.jpg

Old plug and Polo BBY plug:
c2d1918e2c6abf152a97ba3289e21962.jpg



Sent from my iPhone using Tapatalk
 
On a bit of a downer with this project. Here's why:
Compression test results with a mate's compression gauge are puzzling me, but have confirmed that there is a problem with cylinder 3:
Cylinder 1: 250psi
Cylinder 2: 260psi
Cylinder 3: 105psi (turned over noticeably faster)
Cylinder 4: 280psi (flywheel end)
These were taken with all plugs removed, the engine having run for about 1 minute from cold just before removing the plugs.
The accelerator position during cranking made no difference.
Now, these seem ridiculously high, except for cylinder 3 which is worryingly low. I haven't done anything to disable the injectors - could that explain the high pressure - is it being increased by the high pressure petrol being injected? It is possible that my mate's gauge is knackered too.

I'm also getting a DTC for cylinder 3 misfire but not all the time, though this car is SORNED and I can only drive it on the private land out the back of my house so it's not like I can take it out for a proper thrash up the motorway.

My logic goes as follows:

1. The head gasket may be blown between cylinders - but there would be 2 cylinders down on pressure.
2. The head gasket may be blown to a waterway - but there didn't appear to be the slightest oil in the coolant when I let it out when doing the death pipe, I still have that coolant in a bucket. The expansion tank looks clean.
3. The head gasket may be blown to an oilway, but there's no "mayonnaise" on the dipstick nor under the cam cover oil filler cap, nor the oil filler cap behind the service flap.
4. The head gasket could be blowing direct to outside - I reckon I'd hear it though, and I don't.
5. The head could be cracked.
6. There could be a problem with cylinder 3's piston rings or a scored bore.
7. The piston in cylinder 3 could be holed (pressure probably to high for that though, and would run worse than this)
8. A valve may be leaking.
9. The new teflon injector combustion seal may be leaking, but it went in easily enough in one go so I'd hope it's ok.

Leaving aside the high compression readings on 3 cylinders it seems the head has to come off.
I'm unsure whether to bother re-doing the compression test with a 3rd gauge and also do a wet test with oil in the bores. Possibly the oil won't even get to the sides of the piston if it sits in the profile in the top of the piston though, so might not tell me anything about the piston ring seal.

I've yet to search for other posts on the subject, and I known B4Andra is going through something similar, but does anyone have any advice?
Fix this engine or get an engine from a breaker?
Anything else to look out for?

The lesson for me is to establish the true condition of an engine as best you can before diving in and putting right what is more easily diagnosed.

All the best,

Matt
 
B4Andra posted his compression readings here . His next post includes a workshop reference table for comparision. No idea if his procedure matched yours, you would have to ask. Academic really as cylinder 3 is obviously bad.

Regret to say most people would scrap the engine at this point.

Andy
 
I would try the oil in cylinder test in all cylinder, inject the oil via an oil can and aim it at the cylinder wall not straight down at the piston crown
If No 3 is not improved then you are most likely looking at bad valves on No 3 most likely exhaust valves
best to try to establish this before removing the head as it would be a pain if you did the valves and head gasket then found out it was the rings on cylinder 3
 
Thanks both. Paul, the spark plug hole is is about 25mm across and 180mm deep so there’s no chance of squirting oil at the walls even with a flexible spout oil can. I’ll have to rig up a tube with an elbow at the end and try that. Will let you know how I get on.
I am contemplating removing the head and looking at pricing for a gasket set £75+ and a bolt set at £15+. I have a valve spring compressor tool already so wouldn’t need that. Also contemplating replacing my fubar Gunson HiGauge with a £30 leak-down test set off Amazon (got a compressor already).
I’m also contemplating a used engine but that will be just as much of an unknown as this was. There’s one on eBay in Coventry for £165 that sounds too good to be true. Is it from anyone here?

Cheers,

Matt


Sent from my iPhone using Tapatalk
 
Only a bit of progress in the last month. I made a tube to squirt oil sideways at the cylinder bores. Cylinder 3 compression dry 105psi and with oil 130psi. Seemed to show a difference but I was expecting it to go right up if the rings or bores were shot. I tried to convince myself I had put too much oil in and probably reduced the compressed volume. (1 cylinder = 400cc, compressed volume about 40cc, if I added 10ml of non-compressible oil... 33% higher maybe....?). I tried using my £10 USB bore-o-scope and the cylinder walls looked fine, all I could see was the reflection of the mucky piston top.
I toyed some more with the idea of a replacement 2nd hand engine and came down the side of stripping this one down which at least wouldn't cost me anything even if it came to nothing (which it still may).
So, after spending only a few hours across a couple of weekends stripping down it was time to take the head off.
Along the way I noticed that some of the Allen head bolts in the cam housing had been rounded off before - so someone has been in here before, assuming they didn't routinely round off the bolt heads at the factory...
I was slightly heartened to see the camshafts, roller followers etc without the slightest sign of wear, no sludge and everything shiny.
The exhaust manifold flange onto the starter catalytic converter bolts came off easily and so did the bracket onto the back of the bell-housing, though it was a wriggle to get it free.
The head itself came off quite easily after loosening the bolts in the order specified in the workshop manual. No bore has any wear ridge at the top.
All the bores show scuffing rather than scoring on the rear side (which takes the sideways part of the reaction to thrust load on the power stroke after ignition). The worst is on cylinder 3, the one with the low compression. The scuffing consists of really fine vertical lines. I can't feel them with my finger tip but they are perceptible with a fingernail, they don't drag with a fingernail so I wouldn't call them scoring.

I decided to turn the crankshaft to equalise the cylinder top levels and poured about 100cc of paraffin into each one. Cylinder 3 took about 45 minutes for the paraffin to drain into the sump. I got bored (so nearly a pun) waiting for cylinders 1, 2 and 4 to drain and went to bed but they were a long way behind.

What about the head? I've not removed any valves yet but the combustion chamber tops of cylinders 1, 2 and 4 are sooty whereas 3 has less soot but is wet with condensation... so maybe the head gasket was leaking a little too. The gasket itself is metal with solidified black goop on both sides and I have a job to do now scraping the remnants off the head and the deck before I can use a straight edge and feeler gauge to see if they need skimming flat.

Really I don't know yet whether the block is scrap. Over-size pistons aren't available so far as I'm aware so a re-bore is out of the question. I'm going to get my trusted mechanic neighbour to take a look and see if he thinks anything can be done with a very light re-bore or honing and new rings. I don't think sleeving the would be economic. Anyone got any other ideas? Anyone got a complete block and bottom end in great condition they'd like to flog to me for something less than the LOL prices on eBay?

So, what caused this bore scuffing the first place? I can think of some possibilities:
1) Pipe of death bust and it got really close to seizing.
2) Improperly filtered air. I have never liked K&N and I like them less now.
3) Wrong oil, oil starvation or filter failed - but the camshafts etc are lovely and the oil pressure lamp hasn't come on.

Enjoy the photos below and all the best.

Matt

IMG_4964.JPG
IMG_4963.JPG
IMG_4962.JPG
 

Attachments

  • IMG_4972.JPG
    IMG_4972.JPG
    3 MB · Views: 279
The cam cover bolts are stretch so should be replaced also and have a torque sequece like a head, don't forget the little oring filter on the oilway.
Good luck with the rebild, I wouldnt be surprised if the death pipe had gone and the engine overheated in the past, you could check the date stamp on it maybe?
 
Thanks Nige, the old death pipe was date coded 2010 (vaguely recall mentioning that earlier in the thread but maybe not). I'm following the workshop manual (my Elsawin or the on-line version, sometimes both at the same time - they seem to differ subtly). Hence I am familiar with just how often Audi use "always renew" parts. The cam housing and cylinder head bolts will be new if it ever goes back together.
My mechanic chum has said he reckons that the scuffing should respond to honing with a tool he can loan me. I am holding off buying any bits for the time being.
The sump will need to come off and the pistons will need to come out. It's not 100% clear to me yet whether they'll slide out of the top of the bores or whether it's block out, crank out.
I am minded to drop the remaining bits of engine and gearbox out anyway because it is currently sat with the sump on a trolley jack and the gearbox mount holding the other end. As a bonus I'll be able to easily replace the clutch and get the block on the bench. If I opted to take the sump off in-situ then would need to make up something to hang the block on at the pulley end akin to the workshop manual recommended equipment. Also I know if I don't drop it all out then as soon as everything is back together and running sweet then I'll discover the clutch is fubar :rolleyes:
Matt
 
Hi Matt
Back in the 90's, I had a VW Polo. I once had to remove the head because of a loss of power, coolant and white smoke at the tail. I found one cylinder very clean and the 3 others somewhat sooty. The head gasket had broken between a waterway and the cylinder.
I will follow closely your post as I have a FSI in need of proper TLC.
Cheers
 
Has it broken a cambelt at idle in a previous life, someone removed the head thinking the valves were damaged & just looking at them, thought they then weren't so refitted the head.
However sometimes if a valve it impacted just in the right place, it bends the stem but the valve head looks to have remained in more or less full contact with the seat, especially with light valves, low speed impact. Remove the valves & fit new unless you have access to a valve concentricity gauge, https://goodson.com/products/valve-concentricity-gauge, very rare in the UK.
 
have you checked the valves in cylinder 3 yet, if not then do so before you start to pull the bottom end of the engine apart

I suspect the bore wear is minimal and you will find burned valves are to blame for the lack of compression

change or lap the valves in and go from there. if the valves are in good order then I suspect a blown head gasket was to blame

if you do want to do the bottom end then a light honning and new rings would be in order

cheers,
Paul
 
Nye said:
I have just found that it is possible to fit a vacuum actuator without removing the inlet manifold. However, I was only able to do it once I had sliced off the two small retaining pegs on the cylinder at the end of the actuator arm. These two little pegs (see BiggDogg's photos 2, 3 & 6 above) have corresponding slots (see BiggDogg's photo 7) in the flap rotation lever but the lever does not rotate far enough to be able to line up the pegs and slots because the cam cover gets in the way of where you want to place the new actuator. With the locating pegs removed the actuator arm can be inserted in the lever arm with some manipulation and fiddling. This isn't a clear description but have a look a BiggDogg's excellent photos above and it'll make sense. Having assembled it I noticed that the end of the actuator arm is under slight torsion all the time, which makes the fact that this design flaw was never rectified by Audi all the more annoying.
Click to expand...
It is also possible to remove the potentiometer (P.N. 036907385C) without taking off the whole intake but part of a plastic shroud has to be cut away. This gives access (just) to the lower retaining screw holding on the potentiometer. See the before and after photos below.
Shroud over pot.JPG
Shroud cut showing pot.JPG
 
Captain059 said:
Hi Matt
Back in the 90's, I had a VW Polo. I once had to remove the head because of a loss of power, coolant and white smoke at the tail. I found one cylinder very clean and the 3 others somewhat sooty. The head gasket had broken between a waterway and the cylinder.
I will follow closely your post as I have a FSI in need of proper TLC.
Cheers
Click to expand...
Thanks, a colleague at work said he'd seen a cylinder with a blown HG "steam cleaned" like you say.
 
Thanks for the advice Bruno and Paul. About the valves on cylinder 3: I have the head upside down on my bench now with the mating face horizontal. The spark plugs and injectors are still fitted. Last night I filled cylinder 3 combustion chamber with paraffin right up to the "top". (I double checked it is the correct cylinder - it all looks backwards now of course). Tonight the level has dropped about 0.5mm - hardly at all really in 24h. I am inclined to think the valves are alright.
  • Does anyone disagree?
I'll take all 4 valves out since I have a valve spring compressor tool and it is fairly trivial, and take a look at the seats too. If they are deteriorated at all then I'll lapp them in and also check the others too and repeat the paraffin leak test. I expect the inlet ports could do with a clean. I'll see if it is possible to measure the valve guide wear and decide whether to do the oil seals or not. Probably false economy not to. I'll keep the valves separate and identified so that they can go back in the same position.

I've put a straight edge on the head and used a 0.05mm feeler blade to check for warping having got all the remnants of the old head gasket sealant off with a plastic scraper - I used a few of those otherwise-useless plastic iPhone screen opening tools that come free with a replacement screen. Basically it is as flat as a really flat thing. I'll check the flatness of the deck of the block too once it is clean, but I'll be surprised if that's like a banana when the head is true.

All the best,

Matt
 
Hi Matt
I think the valves are OK, but a reseating won't do any harm. I had to do the reseating of valves on a V6 Renault, by hand! Very tedious and boring.
I hope you'll succeed! Good luck!
 
Another update.

I took all the valves out, cleaned and reground them. The inlet valves and ports were extremely thick with hard carbon crud. It can't have been able to breathe properly. Photos below. Before and after.
My mechanic chum has taken a look at the bore scuffing and reckons it will come up ok with a hone, he has lent me a honing tool.
Obviously I have to take the pistons out first, so that means the sump has to come off. My mate reckons that if I'm careful then I can avoid getting any swarf or carborundum stuck in the bottom end, and hence avoid having to take the crankshaft out.

I've found a way to support the engine with a block of wood on a trolley jack under the bell housing. The mass of the engine block and remaining ancillaries is cantilevered off the bell housing but seems fine like this. I've also had a change of heart on taking out the remainder of the engine because of this. I had begun to think there was a danger of me never the getting the car back together and on the road if I did it that way. If it turns out the clutch is knackered then I'll just have to tackle that when it arises.

Today I tried to take the sump off with the engine still in situ. The two large bolts that go into the bell housing came out easily, but 7 of the 18 smaller bolts which hold the sump to the block and to the oil pump housing decided they didn't want to budge until the 5.5mm Allen-head rounded off, even though I was using a new Wurth bit that I had inserted properly. I tried hammering in a broken-off T30 torx bit which has a nice taper to it, but that didn't work on any of the screws (it's worked a treat in other situations). For 3 or 4 of them I can get to them with an angle grinder and cut a 1mm slot in the top that will take a flat blade screwdriver. I think for the others I am going to have to get my drill out. This will be a right PITA. I expect I'll have to weld nuts onto the remnants of the bolts to get them out. Quite why Audi used sump screws made from metal that is about as hard as cheddar is beyond me. I will be using proper external-hex-head bolts to replace them, and guess what, I WON'T be buying them from Audi.

All the best,

Matt

valves closeup.jpg
valves before.jpg
IMG_5170.JPG
 
You must log in or register to reply here.
Back
Top