Piston cleaning

[petemcr 10]

Anyone got any advise on piston cleaning, mine have got a fair bit of carbon build up and while the head is off I wouldn't mind cleaning them up,

 

I've been looking through a post on VW Vortex and the guy on it says to turn the bottom end over to bring up a fresh set of pistons to clean, but reading the Bentley manual it says don't adjust from TDC while cam sprockets are not attached as it may jump a tooth on the intermediate socket. Anyone carried this out? and what did you do, I was thinking about leaving some Redex on the pistons to soak in and then trying a microfibre to clean them up but if anyone has got any better ways it would be a big help.

 

Here's the link to the guide

 

http://forums.vwvortex.com/showthread.php?4054146

 

Cheers :thumbleft:

[vw rule 19]

Hello mate,

 

I normally use Brake Cleaner or Carb Cleaner as it's very similar to petrol,

and it really does help to dissolve the carbon and dirt off from pistons and most other engine parts.

Or yes you could use Redex it is ment to be really good as well.

 

It really depends on how much and how thick the carbon is,

I've also used WD40 as well but only when there's small traces of carbon,

and it's really easy to remove.

 

I wouldn't use a steel scraper as it could dig into the aluminum piston face.

 

You can use fine sandpaper and spray it with WD40 or brake cleaner,

but you'll have to be careful because if you use the sandpaper for too long,

it can produce a grindy past so you'll have to keep cleaning the surface off,

mainly by wiping the area and allowing the tissue or cloth to soak up the grindy past,

then using an air line and blow the area clean.

 

Or the other way I've done it when the carbon is on quite thick and rock hard,

is by using wire wool or a brillo pad,

as this helps to cut through the carbon and remove it,

this is quite soft on the pistons and won't damage them,

but you'll have to check for small wire pieces that have broken off from the wire wool / brillo pad.

 

Here is a video of someone using some wire wool and a small air compressor and an air drill,

with a small wire wheel fitted in the drill,

if you go for this only use it at a slow speed and don't stay in one area for too long,

or you'll wear the surface away unevenly.

 

 

 

I think it's a good idea what they've said in that VWVORTEX forum,

about using tape and attaching it over the oil and water ports to stop crap from getting in.

I would use duct tape as it's water prove and has a very strong bond,

so won't come off if it's spilt on with water, oil or brake cleaner.

 

 

You can turn the engine over by hand with the cylinder head removed,

but make sure you observe where TDC is,

as you'll need the engine to be timed up ready for the refit of the head.

Simply use your index and second finger on your right hand to hold up the timing chain slightly,

this will keep the chain tort and so it shouldn't jump, when you turn the engine over.

It helps as well to have some oil on your fingers.

 

This way you'll be able to have each piston in turn at TD to clean them.

 

 

The timing marks on the VR6 are normally on the side of the flywheel,

you can see them through the small window at the top of the bell housing,

plus there can be a mark on the crank shaft pulley.

Once engine is at TDC you should have pistons 1 and 6 up flush with the block.

 

 

Hope that helps.

 

 

Si

[G60_Marc 0]

As above.

 

I found that "wonder wheels" will take carbon off a treat using a green kitchen brillo pad and elbow grease. You must wear rubber gloves and eye protection.

 

Wonder wheels will slowly eat raw aluminium if you leave it for to long. I myself did not see any ill effects when i did my pistons/head/valves the other week as the exposure time was very small and when i had finished all traces of it were cleaned off.

 

With the pistons in situ, bring them to the top of the bores and clean them up, once cleaned up use an air compressor to blow the crud out from in the gap around the piston (or a can of compressed air pc keyboard cleaner from pc world etc), wipe up mess, hand crank the piston down the bore, wipe bore clean with rag or kitchen town and repeat many times until no crud is seen being wiped on the bore walls.

 

Also i found by experimenting that if you put your spark plugs to soak in wonder wheels overnight your plugs will look like new in the morning :)

 

 

I didn't get photos of the pistons, but here is the head and a spark plug.

 

Before:

 

After:

 

Edited October 22, 2013 by G60_Marc

[petemcr 10]

That's awesome, cheers guys, given me plenty to read and go off, how long did you leave Wonder Wheels on for Marc? as I recall the carbon wasn't too heavy as I managed to get some of it just using a microfibre so hopefully it shouldn't be too much of a battle.

 

I wanted to turn the engine over to see if piston 1 and 6 have any bore wear, I believe they're the two that experience it the most from what I've read on line, was just a bit worried about it jumping a tooth, but I'll give it a go, the crank pulley didn't have any TDC markings so I've used a small metal rod in spark cyl #1 hole till it lifted and then started to drop and made sure the cam lobe had more on the bottom to make sure it wasn't 180 degress out, so hopefully it shouldn't be an issue when timing it back to TDC

[G60_Marc 0]

I painted some on with a small brush, gave it 5 mins or so, scrubbed with green pad, wiped crud off and wonder wheels and repeated until i was happy then cleaned out the bores as above.

[science 0]

IMHO unless your going to strip the engine I wouldn't use scotch-brite, wire wool or a steel wire brush just in case bits break off and get missed with the compressed air. I have used a brass brush to good effect instead which is softer and easier to spot any bits that have broken off.

[Ray1965 10]

IMHO unless your going to strip the engine I wouldn't use scotch-brite, wire wool or a steel wire brush just in case bits break off and get missed with the compressed air. I have used a brass brush to good effect instead which is softer and easier to spot any bits that have broken off.

 

Agree this is the way to go.

[petemcr 10]

I need to start getting everything ready to put back together, got loads of other jobs to do though as well like replacing fuel lines

 

I'm gonna clean the pistons this weekend I think but I'm gonna check how heavy the carbon build up is, I assume of the engine has been serviced with good oil regular and hasn't been running rich it shouldn't be too heavy?

 

Been qouted £114 to have my head skimed, pressure tested and if it needs it the valves seating, £90 if no valve work needs doing

[petemcr 10]

 

 

Not the best pics, I'll get some more but the carbon build up doesn't seem too bad

[science 0]

I need to start getting everything ready to put back together, got loads of other jobs to do though as well like replacing fuel lines

 

I'm gonna clean the pistons this weekend I think but I'm gonna check how heavy the carbon build up is, I assume of the engine has been serviced with good oil regular and hasn't been running rich it shouldn't be too heavy?

 

Been qouted £114 to have my head skimed, pressure tested and if it needs it the valves seating, £90 if no valve work needs doing

 

That seems like a good price for the work, I would avoid having the head skimmed if you can though. The pistons look pretty normal to me. I would spend a good amount of time making sure the mating surface on the block is clean and flat, it's quite likely to need a metal blade scraper or Stanley blade to remove the residue and corrosion, just don't scratch it. I've used carplan "get your gasket off spray" from Euro Car Parts to help do this as it also removes carbon deposits but it seems expensive these days.

[petemcr 10]

Why no to the head skimming? I assume because if you get it skimmed it would lower the compression slightly? I was debating using one of the metal head gaskets from the MK4 US VR6's but they're quite costly, but being metal I would assume they will last a lot longer.

 

My job for this weekend is going to be cleaning up the bottom end ready for the new gasket if I decide to do it straight away, but I think I'm going to get the head work done first and leave the gasket set till I've had all my parts done and I've sorted out the engine bay a bit, it's crazy how much that inlet manifold hides. Also going to remove the old aircon pump which is no longer used to save a bit of weight.

 

Has anyone on here fitted the 1.8T intake temprature sensor? I believe the VR6 one is prone to heavy heat soak and this is a good option to to help eliminate that.

[Kevin Bacon 5]

Personally I would not touch the engine internals at all unless it's being rebuilt. Stuff can easily get down the sides of the pistons and set up home in the ring lands, ready to scuff the bores when you start it up.

 

Wonder wheels will slowly eat raw aluminium if you leave it for to long.

 

Does it not eat, or weaken, valve stem seals?

[Kevin Bacon 5]

Why no to the head skimming? I assume because if you get it skimmed it would lower the compression slightly?

 

Has anyone on here fitted the 1.8T intake temprature sensor? I believe the VR6 one is prone to heavy heat soak and this is a good option to to help eliminate that.

 

Not applicable on the VR6 as the combustion chamber is in the piston crown. If you're going to use an MLS head gasket, then it absolutely needs skimming. It *must* be as smooth and clean as possible. MLS gaskets do not tolerate surface imperfections like the old fibre gaskets could.

 

Consider the Cosworth style open bead sensor instead as I think it has the same thread as the VR6 one, so will screw into the intake. The 1.8T sensor is completely different and will requiring some machining work.

[petemcr 10]

Personally I would not touch the engine internals at all unless it's being rebuilt. Stuff can easily get down the sides of the pistons and set up home in the ring lands, ready to scuff the bores when you start it up.

 

 

 

Does it not eat, or weaken, valve stem seals?

 

So leave the carbon build up all together? What about when you're cleaning up the matting surface, surely you will get some debris in the chambers from doing this?

[science 0]

Why no to the head skimming? I assume because if you get it skimmed it would lower the compression slightly? I was debating using one of the metal head gaskets from the MK4 US VR6's but they're quite costly, but being metal I would assume they will last a lot longer.

 

My job for this weekend is going to be cleaning up the bottom end ready for the new gasket if I decide to do it straight away, but I think I'm going to get the head work done first and leave the gasket set till I've had all my parts done and I've sorted out the engine bay a bit, it's crazy how much that inlet manifold hides. Also going to remove the old aircon pump which is no longer used to save a bit of weight.

 

Has anyone on here fitted the 1.8T intake temprature sensor? I believe the VR6 one is prone to heavy heat soak and this is a good option to to help eliminate that.

 

I think the reason not to skim is that if to much material gets taken off if increases the risk valve piston collision if your timing is slightly out. There was a guy on eBay (doctor_car) selling the metal HG for around £26 you just have to search for the Elring part number (401.820) or you can get a Victor Reinz one delivered from the states for £47 for taxes. Some people relocate the the temperature sensor to the air box to run the 1.8T sensor.

Edited October 25, 2013 by science

[science 0]

There is a copper spray you can use to help seal MLS gaskets, some folks in the states swear but it but its rare to see over here.

[petemcr 10]

Am I best just sticking with the original factory head gasket? This looks to be the original head gasket and it has lasted up to the 185k mark so it seems like it's done its job well.

 

I had a look at the guide to fitting the 1.8T sensor to the VR6 inlet and it doesn't seem to be that much trouble to fit, just needs the original hole drilling out to be slightly bigger and a hole drilling/tapping to be able to fit a bolt.

[Kevin Bacon 5]

Permatex "Spray a Gasket". Yeah I used that on my VR6 turbo to help with seal some shonky surfaces, but I would steer clear of it personally. Just get the mating faces as flat and smooth as possible.

 

Regarding cleaning the block face and stuff getting down the sides of the pistons, I always turn the crank a bit (90 degs IIRC) so that none of the pistons are at TDC, then either smear grease on the bores to catch debris, or tape the bores off just below the deck. Remember to put it back to TDC before fitting the head!

 

There really is no harm leaving the carbon on the piston crowns. It's been there for 1000s of miles and not done any harm, and will come back again anyway. The valves would benefit from having carbon removed, along with new guides, seals and lapping in. They are after all what keep the compression in the cylinder.