Excessive valve wear (Not for the faint hearted)

Moto Bins and Motoren Israel have both supplied Intervalves for years , and I cant imagine them doing so if the had ever had problems with them.

I've had them in several bikes over the years and have never had a problem.

The valve seats in Rich's 90 were replaced with unleaded during the original work. We lapped them in the other night and they looked perfect, no sign of regression or any wear at all.

As Rich mentioned in his post the bike incredibly quiet and smooth with the new valves in.
 
Hopefully it's just a one off. The main thing is that there was no megabucks damage and the bike is mobile again. Should have the bits back and mine reassembled next week, hopefully it is as smooth as Rich's -certainly will be quieter than it was after the judicious application of a handful of shims :D
 
I did mean seat inserts that were further into the head , not the actual sealing area recessed into the insert, which is no good.

The series of articles by thye Piper cams guy that someone posted a link to covered the situation, but I cant remember where the link was posted----.
 
I've had them in several bikes over the years and have never had a problem.
The valve seats in Rich's 90 were replaced with unleaded during the original work. We lapped them in the other night and they looked perfect, no sign of regression or any wear at all.
As Rich mentioned in his post the bike incredibly quiet and smooth with the new valves in.

So if its a 'one-off' , all the more reason to chase a refund on a rogue part :thumb2
 
So if its a 'one-off' , all the more reason to chase a refund on a rogue part :thumb2

Sadly I think this will be fruitless. It's a long story and I ended up with the bike because one of Robs mates passed away. The upshot is we dont even have the receipt for the work carried out by the Cylinder Head Shop who werent the supplier of the valves in any case.

I'm not much intersted in chasing a refund on £60 worth of valves. From my point of view I'm happy it's now sorted and a more expensive disaster has been averted.

Understanding the causes would be very interesting though. Anyone know anyone who works in a metallurgy lab who can examine the valves? A mate of mines parents had to commission a report on a crankshaft once in the 1980's when it had failed on a new car. British Leyland as it was then refused the claim saying lack of oil was to blame. The metallurgical report proved other wise.
 
Looks like valve bounce to me. Have you checked spring condition and fitted length?
 
That is the link - a lot of good stuff there.

The first couple of paragraphs of chapter 4 cover the position of the exhaust valve seat in the head.
 
I'm bumping this old thread, since I've seen something similar, which may or may not be useful to someone.

Seven years ago I got myself new valves for my then new-to-me R80/7, primarily for peace of mind (dropped valve syndrome) since I got no info on previous head work on the then 70 kMi bike.

Bought new BMW "original" valves myself, but ended up sending the heads to one of the most recommended independent BMW boxer experts, to get the guides replaced.

Since then, on a few occasions when setting the valve-rocker gaps, I noticed closing up gaps. Despite use of lead replacement additives, I thought the heads were suffering from valve seat recession, and prepared myself for getting unleaded seats fitted.

When I recently took off and dismantled the heads, I couldn't get the exhaust valves to slide out. It turned out the cotter grooves had mushroomed:

413368549.jpg
= RIGHT valve stem
413411231.jpg
= LEFT valve stem

The seats were fine, indicating that the closing up gaps I had noticed were stretching of the tip of the valve stems.

As opposed to the valves Rob Farmer posted about, the top of my exhaust valves wasn't damaged to the extent that the manufacturer's markings wasn't visible: they were AE valves.

So either I got sent the wrong valves from my supplier (I found the receipt, which clearly specifies the "BMW original" valves, both in terms of part no. and price), or the independent expert who did the head work (the invoice states "labour to cut seat and lap: 4") had them mixed up.

I've since then had a few pairs of Intervalve exhaust valves fitted, but so far without sufficient mileage on them to be able to check for stem/cotter groove damage. Hopefully they are OK. Considering the time of purchase, my new valves & the ones reported on by Rob also in 2010, it could be a bad batch from AE? In any case, I'll double check that the "original BMW" valves I will replace the AE ones with indeed are TRW ones!
 


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