need a hand from experienced mk3 grease monkeys

Tahrey1043 · Post by **Tahrey1043** » Sun May 29, 2005 12:35 pm

Heya guys, i wouldn't normally crosspost like this, but i need to find someone who's taken the sump off with engine in-situ before, on a 1990/91 1-litre. I think I've run across something Haynes oh-so helpfully glosses over, and anyone who's worked on a benched engine won't have realised about...

http://www.tigerstyle.co.uk/poloforum/v ... c&start=15
(the post at the very bottom of the page)

Cheers

Gareth_GT_Hatch · Post by **Gareth_GT_Hatch** » Sun May 29, 2005 5:41 pm

taking sump off an early mk3 engine with engine in car:

drain oil

remove driveshaft guard

unbolt driveshaft from gearbox and place out of the way. (I found this was all i needed to do, i didnt need to remove the driveshaft completely)

remove the flywheel coverplate from the gearbox (one 11mm bolt right at the bottom of the bell housing.

rotate the engine until the two cut-outs in the flywheel are in a position to enable you to remove the two sump bolts that it would otherwise be obstructing.

unbolt the 20 or so bolts that hold the thing on. you will need a small ratchet; 1/4" square drive with 6" extension to get at some of the more awkward ones. a 10mm spanner may help too.

you may also have to move the alternator wire out of the way, but you shouldnt have to take off the exhaust downpipe. I didnt have to anyway when I did mine.

Tahrey1043 · Post by **Tahrey1043** » Sun May 29, 2005 7:52 pm

lol thanks... you just described in eight lines all the things i discovered the past couple weeks. Nice to have it summarised for the next guy, i guess!
The two most crucial ones being those discovered in the last 6 hours - removing the cover plate (and lining the holes up) and an unwritten one --------- remove THOSE two bolts first! (and presumably put them in last).

Of course i've undone the other 18-odd before even realising they were there. Yay for retarded designs!

Just finished getting the sump off and having my dinner

And indeed I was able to do both with the driveshaft and downpipe still half connected as you describe

It's wierd how bendy the exhaust actually is! (i'm not sure how well held up it is at the moment either - got a feeling the rear rubber hangers are the only things keeping it off the floor)

Next part of the overblown saga: getting the important obsructive bits of the oil pump out of the way, measuring clearances etc (if ive got the feeler guages i may as well use them) and unbolting the pistons from the crank. After that..... who knows?
(all depends on whether Car Spares can rustle up the rings from their special order catalogue, or if they get a big DENIED! on the computer screen)

Tahrey1043 · Post by **Tahrey1043** » Sun Jun 05, 2005 11:10 pm

BUMP --- need another bit of brain syphonage

Is it easy to tell if rings are knackered by looking at them? ... got a horrible feeling ive wasted my time. After an epic battle (tahrey1043 vs VW-SEAT engineers all stars away team 1990), all the pistons are out...

Now, the top of the block was pure sh*te, spent probably an hour removing stuff off it with a little plastic ice scraper and a 40-pack of toilet-nuking wet wipes (highly effective!)... the top bit of the bores similarly covered in carbon and gunge, removed the same way (with a nice ridge on pot 1 which is either permanent (rebore time..) or needing wire wool)... and the tops of the pistons / top outer faces of the sides looking kind of grody. But the rings are shiny and whole. All eight scrapers, and, as far as i can tell, all 4 compression ones too (invert words if wrong).

Hrm.

Photos round here somewhere (cant remember where i set the digicam down)

Cheers

PS should there be variable amounts of play between the conrods/bearings and the crank? each piston was different, from 0.075mm (pot 4 - tight as a nuns purse) up to a full mil (wibbly wobbly pot 2)!!
(1: a bit under 0.2mm... 3: about 0.3mm)

GroovyCarrot · Post by **GroovyCarrot** » Mon Jun 06, 2005 12:01 am

Eight compression rings, four scrapers

No, there's no easy way to tell. The amount of wear in components like piston rings is microscopic, and if one had physically broken then you'd have more symptoms than slightly heavy oil useage.

If there is any play in the big ends whatsoever, change the bearings. I believe GSF charge about Â£20 a set, and "Your big end's gone, mate" is the kind of classic line that you really don't want to hear..

Tahrey1043 · Post by **Tahrey1043** » Mon Jun 06, 2005 10:53 pm

Does seem to be a fair bit of cack down the side of that one now i look back at the pics - more than the others anyway... unless its just spatter from the sump.
Yeah i was hoping to be "catching it early"... if they're actually good then it doesnt explain how the compression was off but dropping oil in fixed it (there's also the matter of the lighter coloured encrustings on the valve chamber compared to the other pots). Maybe they've worn away so they're not quite sealing right any more but still look ok.. If it were seriously shagged out when i began this, well, i wouldnt have begun it. As it was, could still have got away with selling it off to someone and just hoping that they wouldn't remember my address after another 5000 miles.

When you say big end wear ... um, you'll have to explain it a bit more precisely. I haven't really a clue which end that might mean. You mean side-to-side (along the crank), or up & down (smacking one side then the other against the crank on each combustion) ?? And by "any" - hehe - how much is that? I could understand a millimetre being too much (it came off easiest of all), but if piston 4 had too much play then i'll give up right now as i'll never get it back together properly without putting my shoulder out.
I could only measure it using my third thinnest feeler and it took a lot of stress to get the thing off, ending up with me thinking "f*ck it" and not so much tapping as battering the underside of the crown to get the piston out of the top of the block whilst the shell was still stuck to the bottom of the conrod (and then finally fell free once that happened - luckily i scribed the orientation on it FIRST). 0.075mm is TIGHT when nasty old oil is involved - and even when dry, i suspect.

GroovyCarrot · Post by **GroovyCarrot** » Mon Jun 06, 2005 11:08 pm

Righto, big ends and little ends refer to each end of the con rod - big ends being the end which attaches to the crank, little ends attach to the pistons. By any play in the big ends, quite simply if you can feel any kind of movement against the crankshaft then you ought really to be changing the bearings, if a bearing wears badly and the big end starts knocking then you'll start having problems. Check the bearings for visible wear as well. Certainly if one big end feels looser than the others I'd suggest you change the bearings just as a matter of course. They're easy to do anyway, they just snap into the shells, can't really get them wrong.

Btw, easiest way to free the bearing shells is to remove the nuts, then tap the bolts upwards with a rubber / wooden mallet. The bolts are usually firmly enough stuck into the con rods that this will release the bearing shell and push the piston up the bore. Obviously also make sure the crank is aligned so that you are pushing the piston as close to straight up the bore as you can, just to make life easier.

Light colouring on the head above one of the cylinders compared to the others to me suggests a water leak, eg failed head gasket.. but obviously you'll be changing that when you reassemble it, so that'll be alright.

Tahrey1043 · Post by **Tahrey1043** » Mon Jun 06, 2005 11:29 pm

Blast, you mean i might have gone through all the BS of this stage just for a head gasket?

Suppose I should have investigated a bit closer after getting it off... there was an *awful* lot of cack taken off when i got busy with the scraper, and it was definately leaking oil that's for certain - the cam cover gasket wasnt in great shape but theres no way it could have leaked the amount that was soaking round the belt end of the block.
However i dont think i was losing any coolant or suffering contamination either way. No darkening of the antifreeze, no mayo in the oil or on the filler.

Should the bearing... er... "thingies" (races? the smaller thin silver bits) spontaneously fall out of their shells without being subject to a chiselling campaign? A couple of them came free but i'd have to de-bag the pistons to check which (or maybe just scrutinise the photos REAAAL close) --- bet if i do, it'll be no.2 and no.3? They looked good from where i was, but that was getting quite late at night.. wasnt leaving til they were all out!

Didnt even consider the screw bits of the bolt/nut arrangement could be taken out of the conrods - thought they were a solid mass! Did give them a concerted bit of hammering, with a rubber mallet.. but to no avail. Instead put the mallet handle up the bore (thin - none of the other hammers would fit) and wailed on the rubber head with a "real" hammer until i felt movement, checked how far it had all moved, separated etc, and then repeated.

GroovyCarrot · Post by **GroovyCarrot** » Mon Jun 06, 2005 11:42 pm

Yeah, the bearings should pull out of their shells pretty easily. Usually they don't just fall out, but certainly it's just a case of giving them a pull.

Strange that you couldn't get the shells seperated by knocking up on the bolts, I always found that was the only way to do it, but it worked very nicely. Just line the crank up so I was pushing straight up the bore, then a couple of taps and the shells would be free and the piston would push up easily.

I may well be wrong about the discolouration, it could just be that the other three cylinders were losing more oil and so becoming more heavily carbonised by the burning oil, could be anything really. Either way, it's all being changed so it shouldn't be a problem

Tahrey1043 · Post by **Tahrey1043** » Mon Jun 06, 2005 11:48 pm

dont get me wrong mate, i wasnt bezerking away like that on all of 'em

pots 2 and 3 came out so easy i was laughing and thought "i'll be out of here in no time". ha. fat chance. number one was a bit more tricky but responded to some careful big end wiggling and bopping - wonder if there's anything in the way it didnt come out properly or stay there until the third time it seemed to pop upwards from the block?

number 4 was the only real nightmare, and it did all seem to correspond to the clearance as measured by the feelers, if i measured the right thing and did it properly of course. like i said - tighter than a nuns purse

Tahrey1043 · Post by **Tahrey1043** » Tue Jun 07, 2005 8:22 pm

hm, seems like DMX, if you cant get it on your own then GSF gon' deliver to ya.

LogIK · Post by **LogIK** » Tue Jun 07, 2005 9:47 pm

Pistons 1 and 4 were a little tighter in the bores than pistons 2 and 3 when I removed mine, as well. I wonder why this is?

GC's way of seperating the big end shells was exactly the way I did it, and it works a treat. Just a light tap on the bolts and it seperates them nice and evenly.