Timing chain...if it needs to be changed...is that

[Speedmaster]

indicative of an impending motor rebuild?

I have the chance to buy an M5 locally that the owner claims will need a timing chain in 20-30K miles.

Am I as close to a rebuild? I have not done a leak-down test or any other test for that matter. Miles are north of 200K.

Ideas, thoughts?

[gkrea1]

A compression check and leak down test will tell you a great deal about the health of the motor. You will find out if the rings, intake and exhaust valves seal well or not. If the tests are good, and you aren't using too much oil between changes, than I'd say it doesn't need a rebuild.

The chain and guides' R&R is a preventative measure that should be done on this motor right away if it's never been done before. The danger there is a loose chain will allow a cam gear to loose coordination and let valves smash into pistons. But you probably already knew that.

[bojangles]

my understanding is that the plastic guide is suspect to get brittle and crack and drop down to the lower sprocket. This will jam the chain, causing a big smash up inside the engine.

The Jury is out on the Proof of all this, once all smashed up it is kinda hard to find out what really failed first.

Most of us got scared and decided to change that part. there is a long list of "while you are in there" parts and most end up doing chain, guide, rails, maybe tensionner, maybe sprockets.

I did mine at home, the plastic part was not really so bad. seems flexible still.

Biggest challenge of the job is to get the crank hub nut off,,, and most importantly ON with the correct torque.

[bmwdave]

For reference, I recently completed the timing chain/guide rail repairs. My engine had excellent compression and leak down #'s at 152k miles.

Upon disassembly, I found the drivers side guide rail cracked and loose at the mounting pins. I feel I was a couple runs away from disaster! The tensioner rails were also deeply grooved, a good sign that a redo is necessary.

[Tucker]

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

[Rich Euro M5]

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

My Euro M5 suffered a timing chain failure at a little over 100K miles. Fortunately it happened at low RPM about a 1/4 mile from the house. Physical damage was limited to 6 bent valves and dents in the top of pistons. Damage to the bank account was much greater.

Scottie Sharpe had a guide failure in his S38 engine while entering the freeway. Cams jumped time and jammed things up enough to bust the cam box and basically grenaded the engine. Scottie bought a good used M88/3 which replaced the S38B35 in his M5.

FWIW: If the plastic guide on the left side of the engine goes away and doesn't jam anything it probably won't cause a problem, as that's the descending side and the chain is under constant tension. All I can say is your customer was very lucky.

Since you've stated on a public forum that you believe the timing chain / guide issue is over hyped. Are you going to step up and make someone whole again if they take your word on the guides being a non-issue and suffer from this failure?

Just my $.02.

Rich

[Tucker]

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

My Euro M5 suffered a timing chain failure at a little over 100K miles. Fortunately it happened at low RPM about a 1/4 mile from the house. Physical damage was limited to 6 bent valves and dents in the top of pistons. Damage to the bank account was much greater.

Scottie Sharpe had a guide failure in his S38 engine while entering the freeway. Cams jumped time and jammed things up enough to bust the cam box and basically grenaded the engine. Scottie bought a good used M88/3 which replaced the S38B35 in his M5.

FWIW: If the plastic guide on the left side of the engine goes away and doesn't jam anything it probably won't cause a problem, as that's the descending side and the chain is under constant tension. All I can say is your customer was very lucky.

Since you've stated on a public forum that you believe the timing chain / guide issue is over hyped. Are you going to step up and make someone whole again if they take your word on the guides being a non-issue and suffer from this failure?

Just my $.02.

Rich

I didn't say it was a non-issue, and would never tell someone that. I recommended that this customer at least inspect, if not replace the chain and guides when he first got the car, the first time I saw it, since there was no record of their replacement in it's history, and the mileage is on the high side. But it's not an inexpensive job so he didn't get right to it. All I'm saying is that the conventional internet wisdom is that they're all going to fail massively if you look at them sideways, which isn't the case. Everyone who has had them fail makes a lot of noise about it (and justifiably), and everyone else takes it as gospel that it's this massive issue with every car. I can count the number of guys that I've read about actually having catastrophic failures on one hand. Of course there's more than that, but out of a production of thousands of cars you can't say the percentage is high. I'm not saying it's wrong to talk about it and make the possibility of failure apparent, and it's certainly among the most important things to check for if considering one of these cars, but I think there's a bit of a misconception about it, especially among guys who don't even own or work on the cars, but read stuff on the internet and share it as absolute fact, as so often happens. Of course it's good preventative maintenance to at least inspect it, and on a car I've never seen before with no record of replacement, the first thing I'll do is recommend pulling the cam cover and having a look, but I've taken care of a number of S38 & M88 cars over the years and this is the first I've seen at the edge of severe engine damage. That doesn't make me any authority on it, any more than any of you guys, but based on my personal experience with the engines I think it's misrepresented. My M5 went 160k before it was done as part of a head job though all was in good order, and my friend's M5 here went through 220k of abuse (not even a valve adjustment in the records) before he got it, with the OEM chain and guides. It's a known problem, but they're wear items, and like any other should be checked regularly. It just seems a little blown out of proportion, that's all.

[turbodan]

So you have a car thats missing the guide rail completely and you're saying you dont believe this is a real issue?

Isn't the fact that the guide rail is in fact missing indicative of a problem? He's lucky none of the little bits and pieces made it into the cam chain/gears. Thats what kills the motor.

I wouldn't say there's any fear mongering about the timing components. There are several documented failures and people trying to keep that kind of thing from happening. Its obvious they aren't blowing up left and right, but it is a potential issue. Its similar to the clutch pack failures in 4HP22's, just not quite as common. There are lots and lots of cars out there on the original timing components, most of them will be fine. The issue is in the small but significant portion of those engines that will be destroyed because of this.

[Tucker]

So you have a car thats missing the guide rail completely and you're saying you dont believe this is a real issue?

.

Did you even read my last post? Jeez. Of course it's an issue, it's just not as prevalent as the internet has most people believing.

[turbodan]

So you have a car thats missing the guide rail completely and you're saying you dont believe this is a real issue?

.

Did you even read my last post? Jeez. Of course it's an issue, it's just not as prevalent as the internet has most people believing.

This one?

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

Yeah.

[Tucker]

This one?

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

Yeah.

No, this one, after Rich misinterpreted me too:

I didn't say it was a non-issue, and would never tell someone that. I recommended that this customer at least inspect, if not replace the chain and guides when he first got the car, the first time I saw it, since there was no record of their replacement in it's history, and the mileage is on the high side. But it's not an inexpensive job so he didn't get right to it. All I'm saying is that the conventional internet wisdom is that they're all going to fail massively if you look at them sideways, which isn't the case. Everyone who has had them fail makes a lot of noise about it (and justifiably), and everyone else takes it as gospel that it's this massive issue with every car. I can count the number of guys that I've read about actually having catastrophic failures on one hand. Of course there's more than that, but out of a production of thousands of cars you can't say the percentage is high. I'm not saying it's wrong to talk about it and make the possibility of failure apparent, and it's certainly among the most important things to check for if considering one of these cars, but I think there's a bit of a misconception about it, especially among guys who don't even own or work on the cars, but read stuff on the internet and share it as absolute fact, as so often happens. Of course it's good preventative maintenance to at least inspect it, and on a car I've never seen before with no record of replacement, the first thing I'll do is recommend pulling the cam cover and having a look, but I've taken care of a number of S38 & M88 cars over the years and this is the first I've seen at the edge of severe engine damage. That doesn't make me any authority on it, any more than any of you guys, but based on my personal experience with the engines I think it's misrepresented. My M5 went 160k before it was done as part of a head job though all was in good order, and my friend's M5 here went through 220k of abuse (not even a valve adjustment in the records) before he got it, with the OEM chain and guides. It's a known problem, but they're wear items, and like any other should be checked regularly. It just seems a little blown out of proportion, that's all.

Pay attention before you jump on someone Dan, it's not the first time.

Sorry your thread's been hijacked, Speedmaster, and to answer your question, no a worn timing chain or broken guides are not necessarily indicitave of an impending engine rebuild. The results of a compression and leakdown test will give you that answer, though if the compression numbers are low or leakdown percentages high, make sure you figure out if it's in the top or bottom of the engine.

[Rich Euro M5]

I didn't say it was a non-issue, and would never tell someone that.

Your original post implies that you don't believe it's such a big deal.

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

No, this one, after Rich misinterpreted me too:

I didn't misrepresent what you said, You replied to the OP who was asking about whether he should consider servicing the timing components.

No where in your response did you offer a proper response to the OP, nor did you elaborate on what you think he should do.

I said you shouldn't make such comments on a public forum. This is particularly true if you make your living as a professional mechanic. Consider this, what if a new M5 owner read your response and decided not to have his timing chain serviced based on your post, then has his engine grenade because of that decision. That's the issue I see, and why I challenged your response.

You need to grow thicker skin.

Rich

[Tucker]

I didn't say it was a non-issue, and would never tell someone that.

Your original post implies that you don't believe it's such a big deal.

I don't buy the huge omigod hype about timing chain failures on S38 & M88 cars based on actual experience, but they do go after awhile. I have some great pics of an M635 M88 in the shop now on which the main guide rail (left side) is completely gone, not even there. And the guy has been driving it for a bit that way.

No, this one, after Rich misinterpreted me too:

I didn't misrepresent what you said, You replied to the OP who was asking about whether he should consider servicing the timing components.

No where in your response did you offer a proper response to the OP, nor did you elaborate on what you think he should do.

I said you shouldn't make such comments on a public forum. This is particularly true if you make your living as a professional mechanic. Consider this, what if a new M5 owner read your response and decided not to have his timing chain serviced based on your post, then has his engine grenade because of that decision. That's the issue I see, and why I challenged your response.

You need to grow thicker skin.

Rich

Look... I could have been clearer in my original post, you're right. I could see why you misunderstood me at first, and just wanted to clear up what I was trying to say with my second post, not argue with anyone. My skin is plenty thick, I just don't want to be misunderstood and don't believe in ninja post edits to hide behind. When Dan came after me without doing his homework in the thread, as he's done before, I had to snap back. Sorry, but I won't take shit like that.
In my first post I said they do go after awhile, then described a car in my care right now with this exact problem, so how could I possibly believe it's not an issue as I was accused of? If I was a noobie M5 owner I can't see interpreting that as saying it's not a problem, especially with the huge amount of info available to anyone who knows how to use the search function. End of discussion as far as I'm concerned, sorry for the waste of bandwidth.

[JayM]

The OP wasn't asking if he should do the timing chain, he was asking whether the need to do the chain also meant a major overhaul. I think the answer, no, has been made.

I understand Tucker's point - I also agree with him that the issue is overstated, and there is really no reliable "mileage" figure where it must be done. IIRC BMW have never issued a service bulletin on it (unlike Mercedes with their 3.8L V8) and has no recommended service interval for the chain components (I think there is an interval for the tensioner, but I'm not 100% sure).

The point that should be emphasiszed is that these cars are at least 20 years old. The timing chain guides are plastic. If you subject plastic to the stresses and contaminants of an engine for 20+ years it's going to go through some chemical changes, and you risk failure. Given the cost of such a failure, any E24 or E28 M-car MUST be regarded as a candidate for timing chain component R&R if there is no record of one it it's history (or no history period). This applies regardless of the number of rows of the chain (M88/3 or S38).

And on that note: does anyone have the upper chain guide (the "slide rail" p/n 11 31 1 306 603) for an M88? They are listed as available on a number of sites, but seem to be special order, and my dealer shows no stock in Germany, so there is a 6-8 week wait to get a new one (they make it to order, apparently).

[Tucker]

And on that note: does anyone have the upper chain guide (the "slide rail" p/n 11 31 1 306 603) for an M88? They are listed as available on a number of sites, but seem to be special order, and my dealer shows no stock in Germany, so there is a 6-8 week wait to get a new one (they make it to order, apparently).

I just got one for the M635 in the shop, overnight from SSF Imported Autoparts in San Francisco. They're an industry supplier so I don't know about individual sales, but you might give them a shot.

[alpinab10biturbo]

And on that note: does anyone have the upper chain guide (the "slide rail" p/n 11 31 1 306 603) for an M88? They are listed as available on a number of sites, but seem to be special order, and my dealer shows no stock in Germany, so there is a 6-8 week wait to get a new one (they make it to order, apparently).

According to my EPC (version 1/2006), the correct part number is 11 31 1 317 335. I ordered one for my M88/3 at the end of June and it was deliverd on 7 July this year.

[Double02]

Does changing the upper chain guide/slide rail require going into the camshaft carrier? Is changing this recommended as part of the timing components changeout discussed at length above?

Thanks.

[Tucker]

Does changing the upper chain guide/slide rail require going into the camshaft carrier? Is changing this recommended as part of the timing components changeout discussed at length above?

Thanks.

Nope, you don't have to touch the cams to replace the top slide rail. Two 6mm Allen bolts and it will slide out from behind the chain. It's also not totally necessary to replace with the rest of the guides if it's in good shape.

[JayM]

And on that note: does anyone have the upper chain guide (the "slide rail" p/n 11 31 1 306 603) for an M88? They are listed as available on a number of sites, but seem to be special order, and my dealer shows no stock in Germany, so there is a 6-8 week wait to get a new one (they make it to order, apparently).

According to my EPC (version 1/2006), the correct part number is 11 31 1 317 335. I ordered one for my M88/3 at the end of June and it was deliverd on 7 July this year.

Not the same part. If you look up the part number I gave you'll see it's different. The "slide rail" is right at the top of the chain path.

Incidentally, a couple of parts sources told me that the M88 part had been superseded by the S38 part. I had my doubts because the dual-row chain box is larger at the top - from what guys have said about the dual row conversion they had to do some machining to get everything to fit. In any case, I ordered it from Maximilian (they showed it as a part supersession) since it was only $68 compared to nearly $400 for the M88 one. Sure enough, it didn't fit. At least, as Tucker says, it's the easiest part to swap out - just remove the valve cover, unscrew it and put the new one in.

If anyone needs the upper slide rail I'll send it to you anywhere in Canada or the US for $60(US) shipped.