[Serf27]

2013 n20.
I bought it a few months ago, crashed, but full of good service history.
I was fixing it up and the engine sounded fine this whole time.
I changed the engine mounts today and I went to move it from the drive way and the timing chain started slapping and making noise/rough idle. I turned it off and back on and same deal. I turned it off and the chain felt loose.

I poured 1/2-3/4 of a qt of oil directly on the chain for instant lubrication and started it.

It made noise for a second then got quiet. Idle is now smooth with no noise and codes.

I bought this to be a daily driver to keep miles off my e90.

I’m not sure if it’s worth doing the timing chain job now.
It’s a base model with 130k miles and no options. I think the only good option it has is comfort access. If this was a well optioned car or m sport, I’d do it no questions asked.

Reading repair DIYs, I saw someone mention to replace the tensioner first before doing the whole Timing chain. What I can see of the guides through the oil fill cap looks fine. I know they can break or crack down under but I can’t see that.

Here is a video of the noise.
The video is broken up into 3 pieces. 1 part is the loose chain, second is the noise, third is a quiet engine at idle.
I didn’t record this, but the chain felt tight and normal after I shut it off when the noise went away.

https://youtube.com/shorts/jQwI-Mxg_...gxXGoRCMtob4ez

I’m at a crossroads where ideally, I’d like to get 10k miles out of it as is.

If I can drive it until I get consistent chain slap noise or error codes and then do the repairs or sell with a bad engine, cool.
If a new chain tensioner may fix it, ok.
If it’s going to grenade in the first 100 miles I drive it, then idk if to do the job or not.

Any help/advice is appreciated.
Thanks.

[Billfitz]

Change the tensioner, it's easy and inexpensive. You don't want to open the changing the chain can of worms unless it's absolutely necessary.

[Serf27]

Originally Posted by Billfitz

Change the tensioner, it's easy and inexpensive. You don't want to open the changing the chain can of worms unless it's absolutely necessary.

Is changing the tensioner as easy as it sounds?
I saw someone mention the possibility of the timing chain skipping a tooth once the old tensioner was removed. I will do some more research on just replacing the tensioner.

Thanks.

[Billfitz]

It's as easy as it sounds. I used a pressure clamp inserted through the filler cap to hold the chain tight to the sprocket so it couldn't jump, but that's not necessary according to TIS and others who've done it. The hard part is putting pressure on the tensioner while screwing it in. I made that easy with a ratcheting open end wrench, they're inexpensive at AliExpress.

[Serf27]

This is the new revised tensioner?
https://www.fcpeuro.com/products/bmw...8i-11317567680

Here, someone lost timing while doing the tensioner alone.
https://x3.xbimmers.com/forums/showthread.php?t=1960447

Do you have a photo of how you held the chain to the sprocket or a link to the TIS?

I am guessing you used the open end wrench so you could put pressure on the timing bolt with one hand and thread it in with the other hand with the wrench?

[alohasurftoad]

i did my tensioner on my 28i recently, without holding the chain. as soon as i removed the tensioner and the chain slacked, i was panicking that it would move.

as Billfitz already noted, the most difficult part is fighting against the spring to engage the threads of the replacement tensioner. i recall the pain in my fingertips from pushing and turning the bolt at the same time, idk around 10x tries and a lot of cussing. i wish i read how Billfitz did his before doing mine, lol.

although my install went fine, i recommend locking the chain by some means, for peace of mind.
.

[gameson]

I replaced my tensioner but I didn’t have any difficulties. How do i know if i lose the timing? Tensioner was done over a year ago.

[Serf27]

Originally Posted by alohasurftoad

i did my tensioner on my 28i recently, without holding the chain. as soon as i removed the tensioner and the chain slacked, i was panicking that it would move.

as Billfitz already noted, the most difficult part is fighting against the spring to engage the threads of the replacement tensioner. i recall the pain in my fingertips from pushing and turning the bolt at the same time, idk around 10x tries and a lot of cussing. i wish i read how Billfitz did his before doing mine, lol.

although my install went fine, i recommend locking the chain by some means, for peace of mind.
.

Why did you and billfitz change the tensioner?
To prevent the life of the chain/guides? Or were there timing chain issues and a new tensioner corrected it?

Losing slack and running into potentially slipping a tooth is what I am worried about.

I am trying to figure out how billfitz held the chain in place.
Without removing the valve cover, all I can think of it someone using a big flat head through the oil cap and putting their weight on the flathead while I try to swap the tensioner quickly.


Can someone confirm the tensioner I linked is the revised one please.
Thanks.

[Billfitz]

Originally Posted by Serf27

Why did you and billfitz change the tensioner?

Because I can add one plus one to arrive at two. The N55 and N20 used the same chain, the same guide, different tensioners. The N55 didn't have timing chain problems. BMW revised the tensioner in 2016. They don't fix something that isn't broken.

[Serf27]

Didn’t the n55 release before the n20?
Did BMW just decide they needed a different tensioner for the smaller 4cyl engine?

I’ve got the new tensioner, the one I linked above. I am still unsure of what you used to hold your chain in place, @billfitz.
Do you have a photo or link of the pressure clamp?
Different things pop up when I search it.


The only idea I’ve come up with is to put a pipe in through the oil fill cap and put it on the chain.
Then use a ratchet strap hooked some on the engine bay to put pressure on the pipe.

[fajitatone]

Originally Posted by Billfitz

Because I can add one plus one to arrive at two. The N55 and N20 used the same chain, the same guide, different tensioners. The N55 didn't have timing chain problems. BMW revised the tensioner in 2016. They don't fix something that isn't broken.

I have a 2016. How can I tell if I have the updated tensioner? I just crossed 100K miles. Do I need to do the chain/guides?

[Billfitz]

The new tensioner went into service in August 2016. Your car build date is displayed on the sticker that's attached to the driver side door jamb. It's a 4 digit number mm/yy. The revised chain went into service early 2015, so you may not need a revised tensioner. But I'd err on the side of caution.

[Serf27]

When the tensioner is removed, the timing chain wants to skip teeth in a clockwise direction over the exhaust cam, right?

So keeping pressure on the chain over the exhaust cam will not allow the chain to skip gear teeth/timing, correct?