From digest.v7.n73 Fri Aug 8 04:11:51 1997
From: "Carl Buckland" <buckland_at_xmission.com>
Date: Fri, 8 Aug 1997 00:29:06 +0000
Subject: Productive Group Focus--Valve Failure(Long)

As most of you know, I downshifted from 3rd to 2nd this weekend, while in competition, and hit high rpm's, causing valve train failure. I am fully accepting responsibility for this racing error, but have opened a thread on the issue "Valve Train Failure in the E36 M3, Diagnosis and Solutions."

this was typical of the letters that I got.....

I am extremely sorry to hear about your misadventure with your valve train. I fear that it is almost certainly more than just a top end problem. Thanks for posting your experience to help and warn others. Your advice about valve stem retainers is good, for 325, as well as M3 owners.

or this....

> I'm truly sorry to hear of your misfortune. I cannot imagine what
> an aweful feeling it must be to have this happen.
>
> As I recall, Dan Martinez (now an Mr. Active Autowerkes Turbo stud)
> has a *LOT* of info on valve spring retainers and the like. He had
> BMW replace his under warranty. I followed his directions, and his
> plan of attack to the letter but I got laughed at by BMW. Maybe if
> we all make a big enough stink we can get this issue fixed as a
> recall or TSB. Doesn't help you at all, but maybe others in the
> future.
>

>

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Friends on the digest,
(re: my recent valve failure, leading to M3 engine demise)

thanks for the"condolensce" notes. I am taking this more as a "that's racing" than anything else. However, I do think that it has helped us, as a group, to focus on the weak link in our power trains, the valves. I think that we should work on a solution, but not necessarily pinpointing BMW NA as the culprit. I do think that NA should see, corporately, that this is a major issue, and that they have a moral obligation to share their superior engineering insights. We don't necessarily need for them to take the full brunt of the valve train defect ( they knew, at least by 9/95, that the weak retainers needed to be upgraded, and did so on subsequent production), but they should share their knowledge.

This is a direct quote from a very internal NA memo: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx For your information, the change is, indeed, as of 10/95. To quote a BMW Engineering Document (anonymously mailed to me, and forwarded to you in the same spirit) -

"COMPLAINT DETAIL: Exceeding the rev. limits of engines leads to widening of the center hole in the valve spring retainers on both the intake and exhaust sides of to the point where the keepers are 'pulled through' the retainers. At the same time the retainers are getting bent; there are no cases of retainer breakage. The damage to the engines is not limited to those areas where the valve(s) hit the piston(s)."

...<skipped>

"ANALYSIS:

1)Damage to the retainers is explainable through the excessive acceleration forces acting during an overrev condition. In all cases of engine damage where the engine or components were inspected by BMW personnel, overrev was the root cause."

2)Damage could be limited if the hardening depth of the retainers was increased.

...<skipped>

"COUNTERACTIONS:
...<skipped>

"PRODUCTION CHANGE: approximately 10/95 - upper valve spring retainers were carbonitrided to insure a hardening depth of at least 10 microns. "

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This is my opinion, not my legal advise:

If the M3 owner's engine is a pre 10/95 production, I think that the owner should notify BMW NA that they are aware of the deficiency, and ask for, in the very least, concrete information about the problem and the solution. A factory recall is not at all out of line. In the event that the owner has sustained a catostrophic valve train failure, after having asked NA for information and solution assistance, then the owner may have redress against BMW NA for failure to disclose a product defect.

That said, I have, for the moment, sucked it in, and bought a new engine. BMW offers a new long block for $6600 retail, including shipping. Wholesale is, I believe, about $5850. The factory engines are officially "remanufactered engines, with 12/12 warranties." They are said to have the valve update already done. I have chosen instead, to buy an engine from TC Kline Racing. TC took the engine out of his nearly new CSL, disasembled it, blue printed it, put in a Gp N cam, and reassembled it, designating it for endurance racing. He soon opted to go with a European 3.2 instead, and I am the lucky owner of his hand-me-down. It is being reinstalled by Slipstream of Boulder, Colorado. My already maximized intakes and exhaust will be reinstalled. Reports to come.

I have not yet decided what I want to do with respect to the valve train. For now, I will be very careful with my downshifts, especially in light of the fact that I am employing an 8 1/2 lb flywheel and a 3:38 rear end. In time, I will install a very modified valve train, using the metals that will give me reliable, sustainable high revolution engine life. At this point, my inclination would be to stay away from titanium components, until I am convinced that there is a way that they can be used in long duration engines. This was a post of note:

One general thought about titanium parts. Although this metal is very light and has high tensile strength, its surface hardness is rather low, not as low as aluminum but way less than steel. Unless surface-treated, titanium is unsuitable for any application where it may rub. This may not be a problem with a race engine that is regularly disassembled and inspected, but could be with a road car expected to rack up miles. Although I'm familiar with engine innards in general, I've never viewed the M3 valvegear, so can't say whether this is a potential issue for us or not. May be worth a discussion with Korman though. Titanium that has been carbide (dark grey colour) or nitride (gold) treated is however very hard indeed.

I think that we should keep the pressure on BMW NA for help with this very serious product defect, but I also think that we should take responsiblity for our high performance use of the product, and use our own insights and common sense to find a solution that is both high performance and long lived.

Thank you, all , for your heartfelt letters , but I think that , in the group sense, this is a positive thing, that can help avoid future catostrophic valve train failures, caused in part by faulty valve retainers. I, personally, look forward to running a newly rebuilt engine that is looking at the start of 52k instead of the final hours.

Keep the pedal down,

Carl

Carl Buckland
Salt Lake City, Utah
E36 M3, #27, CSP