318i Touring M40 camshaft replacement?

[Grepot]

Hi,

Since buying my 1.8 touring it's developed an issue where it intermittently struggles to rev past 3k. Up until the 3k point it feels smooth and brisk when driving, but up past 3k it slows down considerably to the point where it struggles to accelerate and begins churning and shaking. From skimming the wiki, I'm assuming this is due to camshaft wear. I can also hear a ticking sound which I'm also guessing is the tappets which deteriorate along with the camshaft?

I'm wondering if my assumption about the camshaft being the cause is correct and whether replacing of all of the relevant parts would be a job for me or my garage since I have no experience with doing this kind of work.

Cheers

[Brianmoooore]

What you're describing could well be the effects of a badly worn camshaft, but I'd hesitate to recommend replacing it without further investigation - at least a visual inspection of the cam lobes, and preferably a dial gauge on them to check their profile and lift.
The tapping noise is quite possibly failed hydraulic tappets, but that's not likely to be related to the possible camshaft failure. They fail on their own, but while they make a noise that attracts glances from passers by, they do not cause further significant damage, or have any great effect on performance.
None of us had "experience with doing this kind of work" at one time, and the only way to get experience is to get stuck in. There's nothing particularly difficult in doing the work you describe, and the Haynes Manual 1948 covers it all fairly well, as long as you mange to separate the intermingled M20 and M40 information.

[Grepot]

What you're describing could well be the effects of a badly worn camshaft, but I'd hesitate to recommend replacing it without further investigation - at least a visual inspection of the cam lobes, and preferably a dial gauge on them to check their profile and lift.
The tapping noise is quite possibly failed hydraulic tappets, but that's not likely to be related to the possible camshaft failure. They fail on their own, but while they make a noise that attracts glances from passers by, they do not cause further significant damage, or have any great effect on performance.
None of us had "experience with doing this kind of work" at one time, and the only way to get experience is to get stuck in. There's nothing particularly difficult in doing the work you describe, and the Haynes Manual 1948 covers it all fairly well, as long as you mange to separate the intermingled M20 and M40 information.

Cheers for the reply, I suppose the next steps would be setting a weekend aside where I can get in and have a look at what's wrong and then go about ordering replacements?

I'll also look at the Haynes manual, are there any more resources you'd reccomend before taking bits apart?

[Shutthatdoor]

Hi - if you want to get more confident see if you can get a top end from scrap
or cheap engine and do a trial of dismantle / inspection before you attempt the job in situ. Just pour over this site for info aside from manuals. As Brian said there is no substitute for getting hands on - good luck and enjoy learning and the sense of achievement.

[Grepot]

Hi - if you want to get more confident see if you can get a top end from scrap
or cheap engine and do a trial of dismantle / inspection before you attempt the job in situ. Just pour over this site for info aside from manuals. As Brian said there is no substitute for getting hands on - good luck and enjoy learning and the sense of achievement.

Using a scrap engine to practice on seems like a really solid idea- ideally this is what I'd do but I have no space to store it. Think it'll just have to be a matter of working slowly and methodically, thanks for the encouragement!

[fixedwheelnut]

As Brian said, check the cam lobes first, they tend to get an almost 's' shaped wear pattern that actually causes the valve to oscillate and at over 3K the pressure wave in the inlet tract can push the air flow meter flap backwards causing fuel starvation.

If you are lucky replacing the followers will work, but if you change the cam I would replace the followers as well

[Brianmoooore]

As Brian said, check the cam lobes first, they tend to get an almost 's' shaped wear pattern that actually causes the valve to oscillate and at over 3K the pressure wave in the inlet tract can push the air flow meter flap backwards causing fuel starvation.

Interesting explanation! I know that effect that cam wear on the M40 has, but I didn't know why.

[Grepot]

If it comes down to replacing any parts where would you reccomend? Cotswold?

[Shutthatdoor]

Have a look at autodoc, there will be a kit inc cam, lifters, spray bar etc etc.

As it’s just the top part of an engine you need to source to have a play, these can be done on a table top, needs little storage room and can be easily disguised by a towel if taken indoors

[Brianmoooore]

If it comes down to replacing any parts where would you reccomend? Cotswold?

For parts that are exclusive to BMW, then yes, but BMW buy in a lot of their parts from outside sources, so the trick is to identify those sources and buy direct from them. You get a different box, containing the same part, but without the BMW logo. Often the part will have marks on it where the BMW logo has been removed.

[Grepot]

Apologies if I'm asking for too much spoon-feeding, was wondering if anyone could help me with figuring out what to order.

As shutthatdoor mentioned, I've found a camshaft kit on autodoc but it seems quite steep for what it is- a camshaft with two rocker arms and two tappets. I was wondering if it would be better to buy pieces individually since it seems to be substantially cheaper (still from autodoc).

Would anyone be able to suggest a comprehensive list of parts I would need to replace the camshaft and any other pieces which would be worthwhile to replace while the camshaft is out?

Cheers

[Shutthatdoor]

If you have an explore on realoem.com you will find an exploded diagram of the engine and sub assembly parts thereof, that gives you an idea of the gubbins involved. Also, search for similar kits on eBay and then you can see the part range depending on how far you go
It’s an opened ended question really and one that is done to death but boils down to doing it properly or not at all.
For what it’s worth I’d pull the injector rail while you are thereabouts and either clean/service each injector yourself or buy recon ones. You’ll need gaskets for replacement of intake manifold etc too

[Shutthatdoor]

https://www.realoem.com/bmw/enUS/showpa ... Id=11_4323

[Brianmoooore]

It's all the parts other than the camshaft itself, that bumps up the price of the kit.
You could try just changing the cam, as long as the rocker, or drag levers, as BMW calls them, aren't worn too badly where they contact the cam.
The hydraulic tappets are the expensive part (or eight of them are), and they don't noticeably affect performance, even if faulty

[Brianmoooore]

As shutthatdoor mentioned, I've found a camshaft kit on autodoc but it seems quite steep for what it is- a camshaft with two rocker arms and two tappets.

I think you'll find that the kits include eight arms and tappets.

[Grepot]

https://www.realoem.com/bmw/enUS/showpa ... Id=11_4323

Cheers for this, had no idea stuff like this existed.

It's all the parts other than the camshaft itself, that bumps up the price of the kit.
You could try just changing the cam, as long as the rocker, or drag levers, as BMW calls them, aren't worn too badly where they contact the cam.
The hydraulic tappets are the expensive part (or eight of them are), and they don't noticeably affect performance, even if faulty

Yeah, looking at how deep you can go with replacing parts I might stick to what's necessary. I'm having it serviced in a week so I'll probably get the garage to have a look inside then and go from there.

[fixedwheelnut]

As Brian said, check the cam lobes first, they tend to get an almost 's' shaped wear pattern that actually causes the valve to oscillate and at over 3K the pressure wave in the inlet tract can push the air flow meter flap backwards causing fuel starvation.

Interesting explanation! I know that effect that cam wear on the M40 has, but I didn't know why.

There was a bulletin at the time, we had someone on the bonnet with the air filter box off to push the air flow meter forward and overcome the pressure to prove it, before health and safety days

[Grepot]

Just ordered a replacement camshaft, oil bar, followers, tappets and thrust pieces.

Was wondering if anyone has some advice for the actual camshaft installation. Is there any specific timing position that you want the engine in before installing the cam? Also what pattern are the bearing caps tightened in? I'm assuming outside in from each side but I've seen people fully tighten one cap and then go on to do each one evenly.

[Brianmoooore]

the Haynes Manual 1948 covers it all fairly well, as long as you mange to separate the intermingled M20 and M40 information.

[Grepot]

Hi,

After taking it to the garage I decided to have a look at the camshaft myself today to see how badly worn it is. Honestly don't know why I didn't do this sooner-- think I was afraid of destroying the gasket and waiting to have a new one delivered. Anyway, I had a look at the camshaft and took some pictures so I can get a second opinion.

I ran my fingernail across the lobes and couldn't feel any especially deep grooves, although from a visual inspection it seems clearly worn. Also, the spray bar is blocked on the leftmost port (looking into the engine from the driver's side).

Screenshot_20200905-153431.png

Screenshot_20200905-153447.png

(The mark across the lobe is from where I ran my finger over it)

Screenshot_20200905-153455.png

Is it still likely that the camshaft is the culprit for the problems with revving? I'm planning on going ahead with the refresh regardless.

[Brianmoooore]

Look back the thread at what fixedwheelnut says about the wear pattern. It's difficult to check cam wear by visual inspection alone - you need to get a dial gauge on the lobes to check for sure.
Be careful torquing down the cover bolts. They'll strip their threads in the head if you over tighten them.

[Grepot]

Look back the thread at what fixedwheelnut says about the wear pattern. It's difficult to check cam wear by visual inspection alone - you need to get a dial gauge on the lobes to check for sure.
Be careful torquing down the cover bolts. They'll strip their threads in the head if you over tighten them.

Yeah, just ordered a dial gauge so I can check them. Also inspected the exhaust and heard occasional popping sounds. Assuming this is also caused by worn lobes?

[BristolE30]

Good stuff mate, keeping cracking on. Everyone has to do it for a first

[Grepot]

Good stuff mate, keeping cracking on. Everyone has to do it for a first

Cheers. Changed the oil over yesterday and it's running a bit better now and the tappets are quieter.

While I was under the car I noticed there's a leak coming down the engine. Was worried the sump was coming off so I had a look inside but it looks fine. Assuming it's some other gasket higher up the block that's gone? Also noticed that the gearbox seems to be quite wet on the outside which doesn't look great.

Autodoc are dragging their feet a bit with the parts so I guess I'm not getting them until next week. Hopefully the camshaft sorts the running out. Cheers for the encouragement guys, glad I'm at least somewhat on track to be doing the work myself.

[Grepot]

Hi guys.

Just installed the new cam and other bits. I've closed everything back up but now the engine won't turn over by hand. It turns slightly and then completely stops. I haven't tried attaching a breaker or forcing it.

Don't know what could be causing this, any suggestions?

[Brianmoooore]

DO NOT FORCE IT!
The most likely thing stopping it, considering the work you've been doing, is valve to piston contact.
How sure are you that you've timed the cam correctly?

[Grepot]

DO NOT FORCE IT!
The most likely thing stopping it, considering the work you've been doing, is valve to piston contact.
How sure are you that you've timed the cam correctly?

Didn't force it thankfully.

Ended up taking everything apart and putting it back together checking that the crank and cam lined up with the tdc marks.

It rotates freely now, I've turned it over twice and the marks still line up to tdc, there's also no noises of anything contacting.

My only issue is that there's a hissing noise at points when turning it over and there are also points where there's no resistance while turning it. Would it be worth going forward with trying to start it?

[minesapint]

Did you/have you established beyond a shadow of doubt, why the engine wouldn’t turn over in the first place.

[Grepot]

Did you/have you established beyond a shadow of doubt, why the engine wouldn’t turn over in the first place.

No, like Brian said I'm assuming it's contact between internal components. What confuses me is that there was no sound at all and the timing didn't need much adjustment for it to begin to turn freely.

[minesapint]

I presume you’re following some written procedure here, from say the Wiki or Haynes etc.
If that’s the case, why do you think you got it wrong? And conversely, why do you now think it’s right?

[Grepot]

I presume you’re following some written procedure here, from say the Wiki or Haynes etc.
If that’s the case, why do you think you got it wrong? And conversely, why do you now think it’s right?

Truthfully, I have no idea how the timing had changed since I marked the belt and the sprocket before I removed them. I made sure to remove the cam at tdc (when the sprocket was at tdc) and reinstalled the cam at tdc (since it only connects to the sprocket at approximately tdc from what I understand). I didn't check the marks after since I was confident I hadn't changed anything through the process (clearly a mistake).

I've now ensured the crank and cam are located at tdc with the cam also being at it's tdc position locking into the cam sprocket. The engine turns freely and keeps timing after multiple rotations so as far as I understand that means it's installed correctly. My only reservation is the uneven resistance when turning.

[minesapint]

I presume you’re following some written procedure here, from say the Wiki or Haynes etc.
If that’s the case, why do you think you got it wrong? And conversely, why do you now think it’s right?

My only reservation is the uneven resistance when turning.

That’s normal. As the pistons come up to their compression stroke, you’ll feel an increase in the force needed to overcome that compression, then less force is needed until the next piston comes to the compression phase.

[minesapint]

But .....it’s going to be a brave man on here who’ll tell you to fire it up....and I’m afraid it’s not going to be me.

[Grepot]

Managed to get it up and running with the new cam this morning which is nice. Definitely runs better and actually revs freely now which is a bonus. However the engine still isn't running perfectly, esp at idle where it stumbles a lot.

Cheers for the encouragement guys, this isn't something I would've ever imagined I was capable of. Hopefully it actually stays running now

Also I hope my fingernails go back to their normal colour soon