We somehow started the discussion in a classified ad about causes and effects that leads to valve failure. In my limited experience of working on cylinder heads back in the school days, I observed the valve guide seals, especially the exhaust one, harden like hard plastic instead of rubber like pliable when new. I'd seen this in as low mileage as 40k miles or so. I am thinking about replacing them in my 45k miles Mini, as a preventive maintenance. No problemo with my Mini. Okey dokey.

Valve guide seals meter the right amount of oil to lubricate the stem and guide. Too much oil leads to rapid carbon buildup, and too little leads to premature wear of guides, followed by valve face and seat pitting, and ...

I however, recognize material advanced considerably since my experience. Do the ones in the Mini lasts considerably longer before hardening?

Who has first hand experience seeing the condition of the seal at < 50k miles? I am a bit gun shy to "just do it", as I have a few recent incidences of replacing out perfectly working parts in my other vehicles.

Here is a skinny by Fel-pro.

 

they should be fine

 

Ditto what Jan said, even with 125k+ and burnt valves due to heat stress on my earlier head, my valve seals were still just fine.

 

I just did one and the OE seals were brittle. The car had 59K miles. I've got 2 more engines to do. I'll let you know how those go. One has 123K and the other has 59K. I've got the head off, the seals come with the gasket set that I buy, I really don't see a reason not to do it, and I'm a cheap bastard. These were/are N14 engines. My 2 w11s are running very well.

 

Thanks all for chiming in. The problem is I am getting conflicting information from you. BlwnAway - Are you saying the valve seals are still flexible at 125k miles? RUPNOK's experience is at 59k they are brittle, which is what I am concern. Once they turn brittle, the can meter too little, or too much oil into the guides. Either is not good.

RUPNOK - are the brittle seals @59k off the Prince engine and not the Tritec?

 

Yes this was on a N14. I'm not the only one.
https://www.northamericanmotoring.co...ml#post4362370
https://www.northamericanmotoring.co...ml#post4363647

 

pnwR53S is a W11 tritec not a N14...............lol

 

No ****. I noted this in an earlier post in this thread. I'm sure that the companies that make the seals only make w11 or n14 seals specifically, with totally different compounds.

If the OP has no problems then I would not go looking for trouble, but if you've got the head off then it is a no brainer.

 

I've torn down and built more W11 engines than probably most shops combined. The valve stem seals are the least of the problems we see with heads. If you have high oil consumption you might take a look at them and the guides, but he says his engine is ok........Not here to argue just offer my experience on this engine as I have pushed it farther than any of the Chrysler engineers could have imagined. Look for us to breach the 900whp mark on another project

 

I appreciate you share your extensive experience. This is the kind of information I set out to find out with this thread. My Mini consumes next to no oil. He does has heavy drinking problem with fuel.

RUPNOK. Thanks for clarifying and the links. The reason I noted your 45k report was on the Prince engine is to make it clear it is not one the Tritec engine. While I don’t have a gen 2 Mini, I heard all about the common carbon problem with the valves. Those photos of the valves are some of the worst I have seen. I look forward to hear what you find out with the Tritec engines.