993 Valve guides .. whats the story!?

[Ballcock]

I've noticed our American friends seem to spend an inordinate amount of energy on their Porsche forums complianing of worn valve guides , and the resultant high oil consumption , with eventual top end overhaul .. ££££ Kerching!
Yet there's very little about these issues this side of the globe ... What gives (to quote Western vernacular!!)

[ACEparts_com]

My limited understanding of the matter is that the guides are actually made from butter but it doesn't cause a 'failure' as such except in the US cars as they have i believe extra smog equipment that gets blocked up if / when the guides wear a bit.

[Pickled Piper]

Ballcock,

you are obviously spending too much time on Rennlist. The worn valve guides don't ever appear to be a problem outside the USA. It may be down to smog equipment/ fuel type etc.

pp

[Ballcock]

Yeah PP , I'm a bit addicted to RL at the mo ... Sooo much techie info!!

I'm just trying to understand why valve guides don't affect us.. I know that the smog checkers on US 993's mean they won't pass their MOT's but is this the only problem associated with worn guides? .. Someone suggested that worn guides MAY result in a dropped valve .

Don't get me wrong , I'm not worried bout this happening , I just want to understand the concept of worn guides and their effects..

[phelix]

You'll get the same worn guides but no check engine light due to an SAI failure because ROW NA 993 don't have OBD-II. Those worn guides will result in a small compression loss and increased oil consumption and in time a top-end rebuild will be the only cure. Problem seems most prevelant in cars that are used in stop and go traffic where they don't get as much airflow across the engine as when used on the open road.

[Ballcock]

Thanks a mil that's the info I was looking for..
So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

It was posted elsewhere that bringing the engine up to full revs once the engine is warm can at least delay guide wear ... Not that I need an excuse , but , great excuse!

[phelix]

Ballcock said:

So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

It really depends on what use it's seen over its whole life. My 993tt had worn exhaust valve guides at 60k miles (about 1mm lateral play in the valve heads when fully open and 10-12% leakdown numbers); it spent the first 4-5 years of its life in Paris so that's probably how it got started.

[Ballcock]

phelix said:

Ballcock said:

So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

It really depends on what use it's seen over its whole life. My 993tt had worn exhaust valve guides at 60k miles (about 1mm lateral play in the valve heads when fully open and 10-12% leakdown numbers); it spent the first 4-5 years of its life in Paris so that's probably how it got started.

So does that mean anything to you in terms of needing to get it remedied or is it an issue longterm?
What's your oil consumption like.. Or is this something that's associated with worn guides?

Thanks for the info Btw , I've not seen much about this on PH already..

[ProAna]

Have you read about removing the engine tray yet? Another Rennlist obsession.

This one really excites them with owners measuring the temperatures at various points with and without the tray fitted.

Sometimes I understand it and at others, I’m damned if I can see what the fuss is all about.

Verysideways, please what is it all about?

[phelix]

Ballcock said:

phelix said:

Ballcock said:

So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

It really depends on what use it's seen over its whole life. My 993tt had worn exhaust valve guides at 60k miles (about 1mm lateral play in the valve heads when fully open and 10-12% leakdown numbers); it spent the first 4-5 years of its life in Paris so that's probably how it got started.

So does that mean anything to you in terms of needing to get it remedied or is it an issue longterm?
What's your oil consumption like.. Or is this something that's associated with worn guides?

Thanks for the info Btw , I've not seen much about this on PH already..

Top end rebuild done and dusted. Oil consumption wasn't bad, maybe a litre every 1500 miles. It's now nil.

[Ballcock]

Okay .. Spill the beans .. How much should I be looking forward to parting with when it comes to top end time ?

[Wetwipe]

Ballcock said:

Don't get me wrong , I'm not worried bout this happening , I just want to understand the concept of worn guides and their effects..

and then

ballcock said:

Thanks a mil that's the info I was looking for..
So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

make up yer mind laddie!!

either your worried or your not!!

you beardy types - never happy unless you're unhappy

Edited by Wetwipe on Wednesday 12th December 20:44

Edited by Wetwipe on Wednesday 12th December 20:44

[Ballcock]

Wetwipe said:

Ballcock said:

Don't get me wrong , I'm not worried bout this happening , I just want to understand the concept of worn guides and their effects..

and then

ballcock said:

Thanks a mil that's the info I was looking for..
So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

make up yer mind laddie!!

either your worried or your not!!

you beardy types - never happy unless you're unhappy

Wot took you so long ole fruit!!?
How the ell are ya anyway!

[Irish]

Ballcock said:

Wetwipe said:

Ballcock said:

Don't get me wrong , I'm not worried bout this happening , I just want to understand the concept of worn guides and their effects..

and then

ballcock said:

Thanks a mil that's the info I was looking for..
So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

make up yer mind laddie!!

either your worried or your not!!

you beardy types - never happy unless you're unhappy

Wot took you so long ole fruit!!?
How the ell are ya anyway!

Ah, the oul RMS was far easier to understand............

[Ballcock]

Irish said:

Ballcock said:

Wetwipe said:

Ballcock said:

Don't get me wrong , I'm not worried bout this happening , I just want to understand the concept of worn guides and their effects..

and then

ballcock said:

Thanks a mil that's the info I was looking for..
So if I'm not doing much town driving then in theory this shouldn't be an issue , right?

make up yer mind laddie!!

either your worried or your not!!

you beardy types - never happy unless you're unhappy

Wot took you so long ole fruit!!?
How the ell are ya anyway!

Ah, the oul RMS was far easier to understand............

..

Feck of ye feckin feckers

[phelix]

Ballcock said:

Okay .. Spill the beans .. How much should I be looking forward to parting with when it comes to top end time ?

It depends... standard top-end rebuild on a NA 993 will be about £4-5K. It depends what else is found and what other preventative maintenance is done. It's a good time to preventatively replace things like lifters, lower valve covers, timing chain tensioners, clutch, LSD rebuild, etc. But that adds to the cost.

If the car's not using excessive oil, runs well and isn't down on power leave well enough alone!

[Agent Orange]

As a guide to cost, was suffering IRO 52%/ 32% leaks on 5 and 6 , result ....i ve just had new valve guides , seats, general clean up on heads ,happened to need a rocker arm and a camshaft incurred from earlier incident..........did nt need new valves ,rings also ok ............really more like a couple of grand ................happened to uprate and thoroughly check out everything while the opportunity was there, engine low mileage but most of it on track days ..................

[TRPLBLK]

Conventional wisdom on RL seems to be that had Porsche spend slightly more money on the quality of the material in the guides to begin with, this situation would never have happened. Understand the guides have gone through four or five revisions by Porsche since the mid-90's.

[Pickled Piper]

Agent Orange said:

As a guide to cost, was suffering IRO 52%/ 32% leaks on 5 and 6 , result ....i ve just had new valve guides , seats, general clean up on heads ,happened to need a rocker arm and a camshaft incurred from earlier incident..........did nt need new valves ,rings also ok ............really more like a couple of grand ................happened to uprate and thoroughly check out everything while the opportunity was there, engine low mileage but most of it on track days ..................

Can I ask where you had the work done. Sounds like a good price.

pp

[Agent Orange]

Fearnsport ,Silverstone ..............frankly impressed with their attention to detail , the whole things been in bits and everything measured etc ; receiving spread sheet for Crank,barrels and pistons showing ABSOLUTELY nil wear on original .I get pictures as each stage goes through and the rebuild has been fascinating........Cats and turbos have recently been done as has LSD .............NOT FOR £2000