07 Crappy valve guides
 

Hello S2k community. I have a question for you.
I own 2007 TPW S2k with 38K . Great condition, very few mods. Love the car. But I don't work on it myself. I'm a computer guy, not mechanic. I found a local s2K shop and everything OK so far. But from day one my mechanic warned me of following
He said that on 2006 and above he sees many cars with crappy valve guides and they wear out fast. So he recommends to do periodic compression and leak down test. If any start to fail he recommends to replace valve guides and do racing valve springs and retainers. In the process he says he will have to rebuild cylinder head. And he says he had to do many on fairly low mileage.

so to all of 06 and above owners, is that true? Or is this the case where owners were not adjusting the valves regularly?

If this is true, should I just do this as preventative maintenance?

Thank you in advance for your responses.

'06 plus are known for developing tight valves on the exhaust. Not read of the proactive replacement valve guides with racing springs and retainers.

Your mechanic sounds like a dentist that wants to drill every tooth for supposed "cavities".

The DBW models tend to run lean which causes the exhaust valve clearances to tighten faster. I learned about it a little late and did a valve adjustment; found tight exhaust valves. I was getting knock counts on cylinder #2 before and after the adjustment (probably the valve smacking something inside) and a compression test showed that it was low on that cylinder compared to the rest. So I'm sure by then a few of my exhaust valves were torched and probably some of the valve guides were bad so I was just going to replace the whole valvetrain. . Unfortunately I had to replace my cylinder head too because it also developed a crack between the valve seat/spark plug hole. Your car is still pretty low in mileage and if it's still stock, probably didn't run as lean as a car with some bolt-on mods (mine had intake/hfc/exhaust). Check your valve clearances and if they're still within spec or just a little tight, adjust them and just do the valve adjustments more frequently than the factory recommendation. More info in Billman's DBW warning thread. I doubt at your mileage that anything is damaged to that point where you need all that work your mechanic recommended right now. Just make sure to check your valves more frequently.

Here's a photo of my old cylinder head/valve faces
https://cimg2.ibsrv.net/gimg/www.s2k...8467311269.jpg

Valve adjustment is tedious, numbing two hours on a Saturday morning. (Engine needs to be cold, below 100°F.) Adjust them for MAXimum specs, not minimum as they tighten in use. Billman "spec" for the exhaust is "a thousandths over" or 0.012" and I trust him completely. (Thread linked in the message above.)

$20 worth of tools and another $20 for gaskets. Might as well fit new spark plugs while you're in there.

-- Chuck

Do not, under any circumstances, replace the springs and retainers with aftermarket 'racing' parts. That is a recipe for disaster.

Besides, what would crappy valve guides have to do with springs and retainers?

Yes, dbw, '06+ cars run lean, and subsequently have issues with exhaust valves getting tight too soon. But there is no issue with valve guides. The solution to the issue of getting to tight too soon is twofold.

1. Adjust them more often
2. Adjust them a little looser (use billman specs)

A third solution would be to get Flashpro, and a tune that addresses the lean condition nthat is the root cause.

Have you EVER had a f20/f22 engine apart or spec'd a head? Every used f20 head in my shop right now has worn out exhaust guides. It's a well documented problem.

This is the second time I've heard that its a well documented problem, and the last time it was refuted by many in the know on this forum, and the one asserting the claim could not point to any such documented cases of it being a common issue. I have not personally heard of anyone having this issue.

But I am here to learn (and to spread what I learn when it can help others). So if I'm wrong or uninformed, I want to be corrected. So please give me more details on this issue.

Point me to threads where other have had the problem. Tell me which engines are affected. Any details on why it occurs, and if there is any way to prevent it. I'll take any details you have.

Found exhaust valves leaking on #2 cylinder, removed head and guides for the exhaust valves were the issue. 2002 - F20C - 160k miles - no modifications. Currently re-assembling the engine. Hope it all works out!

Same 01 F20c 166k miles all stock. misfires and low compression on #2 head pulled all exhaust guides were loose #2 guides were clearly trash. Still waiting to get the head back from the machine shop right now