Already put a couple of related posts up, but I thought I would record the (slow) progress of this job for the benefit of others.

 

Wow look at that valve!

How bad are the guides?

They look ok and certainly dont look oval, but the workshop manual allows for a max lateral movement at the base of the valve of 0.1mm and I was getting 0.7mm+ with the exhausts, but better with the inlets. I'm just replacing the exhaust valves and guides, but doing all the stem seals - which are a PITA to get off.

 

I was worried about removing the sleeves, but 2 pulled out quite easily and one needed a tap with a drift.

They look ok and certainly dont look oval, but the workshop manual allows for a max lateral movement at the base of the valve of 0.1mm and I was getting 0.7mm+ with the exhausts, but better with the inlets. I'm just replacing the exhaust valves and guides, but doing all the stem seals - which are a PITA to get off.

 

I was worried about removing the sleeves, but 2 pulled out quite easily and one needed a tap with a drift.

 

You sir are doing it right.

Great post Gareth. The photos are very interesting. I have a question please : When you write :

 

 "I was worried about removing the sleeves, but 2 pulled out quite easily and one needed a tap with a drift."

 

What are the "sleeves"? If they are the valve guides then it's interesting to learn that they came out without the use of a press. Can new guides be fitted by tapping them with a drift?

Cheers.

Great post Gareth. The photos are very interesting. I have a question please : When you write :

 

 "I was worried about removing the sleeves, but 2 pulled out quite easily and one needed a tap with a drift."

 

What are the "sleeves"? If they are the valve guides then it's interesting to learn that they came out without the use of a press. Can new guides be fitted by tapping them with a drift?

Cheers.

Yes, for sleeves, read guides. This is the first time I've done it - was inspired by a chap on yt doing the small job on on air cooled vdub. The threads stripped on the first bolt I was using to pull the guides after 2 guides - its only M6 stuff, so I didnt think that was too bad. So long as you dont go mad with the hammer I think its ok to drift them out when the pulling method fails. I just gave it couple of taps and then used the pulling bolt again. I'm hoping the new ones go in ok!

Warming up the head should help with fitting the new guides, maybe to about 70C, lowest setting on your oven? Not hot enough to burn you badly, but should expand the holes a bit.

 

If you get a chance, have a look at this thread and consider trying to inspect/clean the oil feed holes in the roller/rocker fingers (right hand side of first picture in post #10).  Your head photos suggest that oil changes haven't been super-frequent in the engine's history, so possible that these vital lube holes are a bit clogged. Only tricky bit is finding something small enough to poke through there without snapping off in the hole.

And leave the new guides in the freezer before trying to fit them as well.

And do the new guides have to be reamed after they have been fitted to the head, to suit the valve stems?

And do the new guides have to be reamed after they have been fitted to the head, to suit the valve stems?

 

Always, because the fitting process crushes them slightly unless they're cast iron instead of bronze in which case they must be honed as necessary.

Can the honing be done by hand by a competent DIYer (with the right tools) or is it a job for a machine shop?

 

Where can the information on what bore size to hone to be found or is it a matter of honing until the valve stems feel a good fit in the guides?

 

Thanks again.

 

(sorry about the questions guys, but I've often wondered if this was a job I could tackle myself when my turn comes on my high mileage Fab). 

Test fit the valves after the guides are fully inserted, if they seem to move freely I'd say job done.

 

I borrowed a (hand, tapered) reamer - same nominal size as valve stems - when I did this job on my Mk2 Golf, seemed to work fine, but TBH, I think the fit was fine before I reamed.  If anything, I think they were better before. It worked alright, but the engine hasn't done many miles in the subsequent couple of years, so hard to know how good/bad my work was.

 

Nothing in the official literature about guide replacement/reaming on these 1.2s, I think they assume head replacement is the way to solve this problem. If you can find somewhere what 'normal' clearance between valve guide and stem should be, you could calculate the reamer size based on your (exhaust) valve stem dimension that is supposed to be 5.96mm.

 

There was a Scandinavian chap (Torbo?) on here who not so long ago ripped his AWY into the smallest possible bits and rebuilt it, can't remember whether he replaced guides though. 

Edited 11 November, 20169 yr by Wino

 

 

There was a Scandinavian chap (Torbo?) on here who not so long ago ripped his AWY into the smallest possible bits and rebuilt it, can't remember whether he replaced guides though. 

 

 

This post?

 

http://www.briskoda.net/forums/topic/391355-oil-consumption/

Can the honing be done by hand by a competent DIYer (with the right tools) or is it a job for a machine shop?

 

Where can the information on what bore size to hone to be found or is it a matter of honing until the valve stems feel a good fit in the guides?

 

Thanks again.

 

(sorry about the questions guys, but I've often wondered if this was a job I could tackle myself when my turn comes on my high mileage Fab). 

 

Absolutely, it's a hand finishing process like reaming, just buy the correct sized flex-hone (looks like a small bottle brush) and work it until you have the fit and finish necessary, you can use a cordless drill at low speed to save time but careful not to overdo it.

All the guides are in - I did all 6 in the end as I managed to damage an inlet one taking the seal off. As for honing, I dont think I'm going to need to do any - I matched each guide up with a valve in order to get the best fit and only one seemed a little sticky and even it seems ok now. Ground the valves in yesterday and going to do the springs later today. Pics to follow.

Now that the rain has stopped, so I'm gonna try and get some bits back on today. My elsawin wont tell me the tightening sequence for the camshaft housing - or the torque (which I think I've read as 6Nm + 90 deg).

 

Can anyone enlighten me? - I'll have to blag it otherwise!

Gimme half an hour...

The torque you mention is same as what Haynes says, tightening order is shown as this:

 

 

Will check elsewhere to confirm in a minute.  Yep, confirmed.

Edited 19 November, 20169 yr by Wino

thats brilliant thanks, just got to try and do 6Nm now!

 

 

 

Sorry, some pics of my oven crept in there!

 

There seems to have been some stretching of the chain and quite a bit of wear on the crank sprocket. The reduction in the tensioner extension from 25 to 15mm also point to stretching.

 

Engine is all timed up now, timing cover is back on, manifolds and ancillaries next!

:thumbup:

Good work and great photos. Must admit, I was struggling to work out where that heating element had come from!

Brilliant post I saw the heating element and thought the same ? looks like a cooker heater element ?