2006 Z4MR at 40K miles - VANOS, timing chain guide, RB?

[Lucky1]

So my Z4MR is at 40K miles. Really wondering if putting off VANOS rebuild, timing chain guide and rod bearings is going to come back to bite me. Whats the consensus on when to proactively tackle these grenades?

[XMetal]

At 40k miles, I wouldn't worry too much about VANOS rebuild. But I would certainly get it taken care of when it gets opened up for the Upper Timing Chain Guide replacement. My Upper Timing Chain Guide was about to snap when it got replaced at about 46k miles, which I also did all the Beisan stuffs on the VANOS at that time. I think the Upper Timing Chain Guide should be a 50k-mile maintenance item, unless you get the Beisan guide.

[KevinC]

Plenty of S54's out there with 3x your mileage with none of that stuff done to them. Rod bearings? Yeah at some point, but I'd watch Blackstone analysis for clues as to when it's needed, as well as your own use case - is the car tracked, driven hard, taken to redline frequently? Or is it a weekend cruiser?

[Coi]

40,000 miles is pretty low so you probably don't need to worry about any of those things imminently. I would second the suggestions for oil testing.

I would check the vanos for irregular noises from time to time though. The vanos exhaust hub tabs can crack or break off, so if you get the vanos done before that happens you can keep the stock hub and just get the disk with undersized holes. That saves a few hundred bucks. Since you have an 2006 you may have the old vanos hub bolts which can back out. The new design of the bolts supposedly fixes this but they should still be installed with threadlocker.

I bought my car with a pretty audible vanos rattle so got everything done with Beisan Systems parts as soon as possible. My hub tabs were fine so just got their disk. For peace of mind I got rebuilt solenoids and everything. I got an upgraded upper timing chain guide since that's simple for the mechanic to do when doing vanos and that was prudent since the original was about to snap in half at 75k miles. The entire vanos rebuild and chain guide cost me less than $2k so it makes more sense to just do proactively than rod bearings which are more expensive. Also costs a little less if you have a valve adjustment done at the same time.

[XMetal]

Originally Posted by Coi

40,000 miles is pretty low so you probably don't need to worry about any of those things imminently. I would second the suggestions for oil testing.

I would check the vanos for irregular noises from time to time though. The vanos exhaust hub tabs can crack or break off, so if you get the vanos done before that happens you can keep the stock hub and just get the disk with undersized holes. That saves a few hundred bucks. Since you have an 2006 you may have the old vanos hub bolts which can back out. The new design of the bolts supposedly fixes this but they should still be installed with threadlocker.

I bought my car with a pretty audible vanos rattle so got everything done with Beisan Systems parts as soon as possible. My hub tabs were fine so just got their disk. For peace of mind I got rebuilt solenoids and everything. I got an upgraded upper timing chain guide since that's simple for the mechanic to do when doing vanos and that was prudent since the original was about to snap in half at 75k miles. The entire vanos rebuild and chain guide cost me less than $2k so it makes more sense to just do proactively than rod bearings which are more expensive. Also costs a little less if you have a valve adjustment done at the same time.

If you can accept your vanos rebuild for $2k, then rod bearings is in the same ball park. It cost me under $2k all in at a reputable shop using WPC treated OE bearings. Should be less if using ACL. But that was almost 4 years ago. Prices have gone up on everything recently.

[elerner61]

At 40K miles, I'd put checking and addressing the exhaust hub tab at the top of the list. Come to think of it, if the cooling system hasn't been addressed (over 10 years old) that's also a ticking time bomb I'd put at a close second. Coolant reservoir, hose from reservoir to block, upper and lower radiator hoses.

If either the exhaust hub tab or one of the cooling system pieces fails you'll need to have luck on your side.

[Lucky1]

Originally Posted by elerner61

At 40K miles, I'd put checking and addressing the exhaust hub tab at the top of the list. Come to think of it, if the cooling system hasn't been addressed (over 10 years old) that's also a ticking time bomb I'd put at a close second. Coolant reservoir, hose from reservoir to block, upper and lower radiator hoses.

If either the exhaust hub tab or one of the cooling system pieces fails you'll need to have luck on your side.

Never heard of either problem brought up before. What happens if they fail? Being stranded vs grenading your engine or car are in two different categories for me. If its a tow + fix + back on the road no harm no foul situation I'm less inclined to be proactive about it unless there's a major cost avoidance to be had.

[chickdr]

Originally Posted by Lucky1

Never heard of either problem brought up before. What happens if they fail? Being stranded vs grenading your engine or car are in two different categories for me. If its a tow + fix + back on the road no harm no foul situation I'm less inclined to be proactive about it unless there's a major cost avoidance to be had.

You haven't heard of the exhaust tab issue? You should look it up. I too have an 06 (with 20k miles) and think about replacing the hub from time to time. No way to know if mine will be fine, or not. There is also the issue with the screws holding the hub in place coming loose on earlier cars.

[kaybat]

I did Dr Vanos hub @30k(06MR) fwiw, my stock hub looked perfect when we switched it out.

[elerner61]

Originally Posted by kaybat

I did Dr Vanos hub @30k(06MR) fwiw, my stock hub looked perfect when we switched it out.

Breaking an exhaust hub tab can grenade your engine, it's all a matter of luck (depends where the broken tab travels to).

[Lucky1]

So how many total known grenades on this engine are we up to now?

[kaybat]

Originally Posted by Lucky1

So how many total known grenades on this engine are we up to now?

[Emmrbee]

Originally Posted by Lucky1

So how many total known grenades on this engine are we up to now?

4, name them if you can.
2 are in the VANOS

[elerner61]

Vanos: Hub bolts and Exhaust hub tab
Timing chain guide?
Fourth one?

[Lucky1]

Originally Posted by elerner61

Vanos: Hub bolts and Exhaust hub tab
Timing chain guide?
Fourth one?

Rod bearings!

[Emmrbee]

That's all four folks

[Coi]

I'd throw in oil pump nut and cooling system too for a total of six.

[Emmrbee]

Originally Posted by Coi

I'd throw in oil pump nut and cooling system too for a total of six.

The oil pump nut problem was associated with the M54 engine and not known to be a problem with the S54. The lose of cooling system would not cause catastrophic failure if the engine was shut down in time.

Just saying, back to 4 potential causes of catastrophic failure of the E85/E86 S54 engine.

[elerner61]

Originally Posted by Lucky1

Rod bearings!

Arrrggh! Forgot that one (even though I had mine done). Getting older sux (turned 60 this year).

[Lucky1]

Originally Posted by elerner61

Arrrggh! Forgot that one (even though I had mine done). Getting older sux (turned 60 this year).

At least you can still remember how to drive a stick

[Sergio19]

The tabs tend to remain in the disc hole when they break. The cam hub bolts have no where to to go once they loosen - only an issue if all of them get sheared off. The engine will sound terrible before that happens. Rod bearings...forget about it.

At your mileage just drive it and pay attention to any new noises/rattles from the engine.

[beaniegti]

I had the beisan seals, redrilled pump disc and timing chain guide done on mine around 55k I think. Guide was perfect with virtually no wear. Disc and hub tabs also fine with minimal marking to the disc and it also had the later bolts already installed (my07 10/06 production)

The seals made a bit of a difference in response when freshly installed but after a while that improvement subsided. I don’t know if that was related to the seals bedding in or adaptations of some sort, softening things.

At 40k, I’d just leave it. Although mine is now better set for the future I wouldn’t do it again at that mileage knowing what I know now. Unfortunately to get to that opinion you need to have it all apart, at which point you might as well change it all!