Replacing Valve Stem Oil Seals - Help!

[silent_running 0]

My mate just bought a 1.6 GTi ('89) that we're about to service, but it definitely needs the valve stem oil seals replacing. At the same time we're going to do all the fluids, belts, filters, electrics etc. Basically a full service in our own slow way. We're not mechanics by the way, just part time bodgers who want to have a go at keeping this GTi on the road.

 

So, the question is, is taking the head off to fix the valve stem oil seals going to be a pig of a job? To give you an idea of where I'm at skills-wise, I just rebuilt a pair of 4-pot brake calipers on my Subaru, replaced all the suspension and dismantled and replaced the clutch hydraulics. Not to say that I enjoyed doing those jobs, but I enjoyed not having to pay someone else to do it, if you see what I mean. I've never really delved into the engine any further than the rocker cover.

 

Having looked in the Haynes with all this talk of not disturbing the wet liners, and shimming the valves etc I'm beginning to think it might be better to try and replace the valve stem seals in some magical way that doesn't involve removing the head. We've already got the special pliers. Changing service items and generally repairing worn out components I can handle. Taking half the engine apart just to change a set of oil seals seems a hell of a lot of work and hassle and knowing my luck, will end up causing more problems than it solves?

 

Opinions would be really helpful. And yes, I have done a search on this topic already and need more input. Cheers!

Edited November 22, 2006 by silent_running

[christopher 5 1 Cars]

This has been discussed many times...

 

Taking the head off has many benefits, like being able to port the head or regrind the valves or change teh cam belt to name a few.

 

It can be done without taking the head off and there has been many a discussion about if this is possible or not. I would reckon most think it is not.

 

One method suggested on here here is with compressed air down the plug hole.

 

I know it can be done with a piece of string down the plug hole instead. It took an experienced peugeot mechanic about two hours. I watched with my own eyes...

[boombang 2]

I've done it before on an Mi! - was absolutely terrible to do and would never do it again.

 

Risk of liner movement isn't that bad so long as you are careful, and if the stem seals are creamed chances are the head gasket isn't great anyhow!

 

Why not just do it all in one hit, plus you get a chance to check condition of the bores.

 

You won't have to re-shim either, but you might as well check clearances whilst the rocker cover is off.

[newdean0 0]

It would be back-breaking work with the head still on as the valves are tilted away from you. Trying to hold the valve spring down whilst assembling the tiny parts is hard enough on a workbench in good light.

 

Taking the head off is quite easy and since the inlet manifold will have to come off you might as well get the injectors cleaned. It's worth grinding the valves in too as the seats will probably be a bit pitted and the bits you need to do it are so cheap (tool to hold the valve + grinding paste).

[welshpug 1,622]

and for the cost of the seals on the bottom of the liners you may as well replace them for peace of mind too!

 

rebuild time

[silent_running 0]

Thanks for all the replies. Lots of talk of it being an easy job, but what are we talking about here? A day's work to get it off, a day's work to look over the head and fix what needs fixing and then a day's work to put it back?

 

What I really need to know is whether it's a '4 spanner' job because it's difficult and fiddly, or because it's time-consuming and has to be done in the right order?

 

The other problem is all these 'might as well' jobs - e.g. getting the injectors cleaned. I just had mine done on my Subaru but then that's my own motor and needs to run over 300bhp reliably. Hence I can justify spending £60 on a proper injector servicing. On my mate's £375 GTi, a £60 injector service is 1/5 of the car's entire value!

 

Bear in mind I have never done anything requiring removal of the head so the whole job will be brand new to me. The thing about grinding in the valves...what's that all about? Using one of those twiddle stick things to get the seats smoothed out if they're rough? Then presumably the valves will sit further out of the chamber and the shims will need to be adjusted or something to counter this?

[GLPoomobile 958]

It is an easy job. I did it recently and I'm a muppet!! My biggest worry was snapping a head bolt, but I just took major precautions by soaking them in Plusgas for days and easing them off gently. You don't need to do that per se, just that I was really paranoid!

 

ONe thing I would say from experience, is that if I was to do it all again, instead of fannying around trying to clean up the head and valves etc, I would pay a professional (circa £80) to clean the head, skim it if necessary, check the valves etc.

 

I took it slow and did the job over a few weeks as I don;t use the car daily, so I can't say how long it 'should' take if you haven;t done it before.

[silent_running 0]

Well yes the thing is there's no particular hurry to have it done. It's off the road at the moment and won't really need to be up and running until next year. Looks like we'll give it a go then.

 

Never thought about snapping a head bolt though. Presumably it's worth whacking some form of penetrating lubricant on each one then.

[Guest rick03054]

Definitely, and clean up the threads that stick out at the bottom. And don't worry about disturbing the liners, I was worried about that, but when it came to removing the liners I had to beat the crap out of the bottom of them just to loosen them!

[silent_running 0]

LOL ok thanks for the advice.

 

Just out of interest, what does a head gasket set come with? I'm thinking gaskets/seals for the rocker cover, head and manifolds. Anything else?

[Guest ep82chris]

head set comes with head gasket and all other seals and gaskets that gos on the head all so worth fitting new head bolts too there cheap as chips

[silent_running 0]

Cheers for that. I think we're going to change the cambelt tensioner as well while we're there. How will I know if the water pump needs replacing? Do they ever need replacing?

[steve@cornwall 100]

Cheers for that. I think we're going to change the cambelt tensioner as well while we're there. How will I know if the water pump needs replacing? Do they ever need replacing?

 

Why not rebuild a known good s/h head? then its just one off-quick belt (w/pump?) change and one back on while your memory's fresh!

[madvalver 0]

If the valve stem seals are worn then chances are the valve guides are the cause of the problem. Exhaust valve guides wear quick on the xu engine so remember to check, or have them checked at the same time. An easy way of doing this is to try and wobble a good valve in the guide and feel for excissive movement. They need to be a very close fit. A worn guide will also affect the seating of the valve causing low compression and loss of power.

[silent_running 0]

Why not rebuild a known good s/h head? then its just one off-quick belt (w/pump?) change and one back on while your memory's fresh!

Trying to keep cost down, hence why we're tackling it ourselves and rebuilding rather than doing a swap. Although I know what you mean, it would be easier to do it as an off and then on job.

 

It's just been for a compression test and they came out as (offside to nearside) 190, 220, 180, 190. So one seems noticeably higher than the other three, but all in all, no low compressions there, so kind of rules out any bottom end problems e.g with the rings?

 

If valve guides do need doing, what sort of a job is this to do? And will we need a valve spring compressor for the overhaul or can we bodge it with a G-cramp off the market?

[madvalver 0]

Trying to keep cost down, hence why we're tackling it ourselves and rebuilding rather than doing a swap. Although I know what you mean, it would be easier to do it as an off and then on job.

 

It's just been for a compression test and they came out as (offside to nearside) 190, 220, 180, 190. So one seems noticeably higher than the other three, but all in all, no low compressions there, so kind of rules out any bottom end problems e.g with the rings?

 

If valve guides do need doing, what sort of a job is this to do? And will we need a valve spring compressor for the overhaul or can we bodge it with a G-cramp off the market?

 

G-clamp might work thougt you will need a deep socket or bit of tube with a slot cut in it to remove the collets from the spring retainer.

 

Valve guides can start getting pricey as really need to be put in with liquid nitrogen and reemed out afterwards. Though its possible to press um out and new ones in, if you careful and forget about the about the reeming. just make sure the valves arnt tight afterwards.

 

Guides are about a tenner each as there bronze and soft with it so take care if you try to fit um yourself

 

220 psi is high. 180-190 is more normal. Might have had some oil sat on the piston causing the high reading which will also give you the blue smoke on start up.

[28CRAIG 2]

And dont forget to put the extra spacer on the back left head bolt when the head go's back on or you will get a bolt breaking into the water ways in the block.