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BMW 3-Series and 4-Series Forum (F30 / F32) | F30POST > Technical Forums > N20, N26, B46, B48 Turbo Engine / Drivetrain / Exhaust Modifications > N20 Timing Chain at Home
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      06-23-2021, 10:16 PM   #1
mattwong92
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N20 Timing Chain at Home

Posted here before dealing with the slack on my chain, techs at BMW dealerships telling me its normal with cam lobes rotating back.

My car is a 02/2012 F30 328i N20 engine with 75k miles.

Its been a couple years since then and the slack has increased from 1-2 fingers fitting between the guide and chain (occasionally rest of the time its tight). For background info been apart of the discussions here. I dont use start/stop (coded off), oil changes with BMW oil every 4-5k miles depending on how much I drive which is very little. Put on around 6k miles a year.

Heres my old videos:
Not tight

Tight


Just hit 75k miles and thought might as well knock it out in a weekend (I was impatient and started before the weekend). I didn't see a point to make a full in depth video besides just showing how I did it at home in my garage without a lift since the FCP Euro video is excellent.

Note that I looked around doing it at independent shops and with parts (unknown if updated) its around $2800. I thought I'd just spend the $800 from FCP Euro and try it myself.

I ordered my kit off FCP Euro. Theres cheaper kits on eBay but I don't trust the sellers to sell me an updated kit with the newer oil drive chain + crankshaft sprocket.

Kit arrived after being delayed and lost by FedEx for a couple extra days.


Bought all the necessary tools from Harbor Freight. The timing tools I bought off Amazon so I can return afterwards. I chose to go with CTA instead of eBay/ cheaper ones off Amazon due to reviews saying some people couldn't get timing correct due to imperfections in manufacturing of cheaper timing kits.


Started disassembly of panels + drained the oil. Screws are all bagged (yes in doggy poop bags cuz I pay for HOA), tagged and taped to panels they belong on. Bunch of panels now in my garage.


Thats where I'm at for now. Waiting on an E20 from Amazon and no one nearby has one.


Will continue posting on the progress

Heres a picture of the new GTS style V1 lights installed last week until updates come:
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Last edited by mattwong92; 06-23-2021 at 11:12 PM.. Reason: images
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      06-23-2021, 10:54 PM   #2
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You are brave to take on the task of replacing the timing chain. When I saw my mechanic having to use a blow torch to heat the oil pump bolt to get the oil pump pulley out I was glad he was doing it and not me. And he took the engine out for the job too. Good luck. The good thing about changing the timing chain on my car, the diesel engine sound is much less now. Not sure if it has to do with the replacement.
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      06-23-2021, 11:58 PM   #3
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That's very impressive. It's a tough job and takes a lot of commitment. Tons of steps, parts etc.

I've been thinking of doing it as well. Glad to hear others have been having good success with the DIY.

Mine is an Xdrive. To add on to the job, I'd also need to remove the front differential.
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      06-24-2021, 02:56 AM   #4
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You might want to consider removing the front bumper and radiator to easily work on the oil pump pulley. Would make the job much easier to access the front of the engine. While you are at it, change the turbo feedline with the updated ones to prevent blue smoke.
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      06-24-2021, 07:43 AM   #5
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For anyone considering this first change the chain tensioner, then see how it affects the chain stretch. The N55 uses the same chain and slide rail, but different tensioners. The N20/26 tensioner was superseded in 2016, while the N55 tensioner has been the same since 2009. Everything I've seen points to the tensioner being the root problem, not the chain.
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      06-24-2021, 10:27 AM   #6
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Quote:
Originally Posted by Billfitz View Post
For anyone considering this first change the chain tensioner, then see how it affects the chain stretch. The N55 uses the same chain and slide rail, but different tensioners. The N20/26 tensioner was superseded in 2016, while the N55 tensioner has been the same since 2009. Everything I've seen points to the tensioner being the root problem, not the chain.
I had mine replaced as a precaution. When the chain and guide were taken out, there were no signs of stress, crack whatsoever, but I feel and drive easier knowing the timing chain issue is averted. Its all in my head at the end of the day but was darn stressful driving the car thinking it may explode on me anytime. Lol!
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      06-25-2021, 01:13 AM   #7
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Thanks for all the support guys.

Just for note alex0607 had my Turbo + lines + manifold replaced under warranty for blown turbo about 20k miles ago.

and Billfitz couldn't agree more having worked on the n54 a couple weeks ago and the chain + guides are identical. Having now played with the engine without the valve cover I can confirm that yes when the lobes are vertical it does rotate back slightly and create a lot of slack on the chain. I did several full rotations and the chain is tight in sections but others are stretched. On top of that the guides are clearly cracked.

Ok so part 2:

Found out it was an E18 not E20 FCP euro listed in their video... (theres actual several sizes they list that are completely wrong)

Got the bracing off:

Got the wiring harness out of the way. The plastics were far more brittle than I had anticipated, all the heat cycles were too much and a couple broke but they still hold the wires in place. The n54 I worked on a couple weeks ago was from 2006 and I expected it to be brittle.



Next were the fuel lines and high pressure fuel pump. Super easy to get out in this car. Make sure you have rags to soak up the fuel as it drips out.



The vacuum pump was a pain... I couldn't find a stubby T40 socket so I had to use a T40 bit with a 1/4 wrench and hold both by hand and slow turn 10 degrees each rotation.

Next was the valve cover, a lot easier to remove then the N54 valve cover. All the bolts were super easy to get to and access with all the room in the engine bay. I gave it some light taps with the back of my screw driver then used a trim tool to break it free from the head from the front of the car. Yes I cleaned the mating surfaces before taking these shots.



Here's a picture of an n54 motor I had with the valve cover off just for comparison. You can see the upper guide + chain are identical.


Now the timing chain + guides in all its glory. Rotated it several times and played with the guides. You can clearly see it's cracked here.



Now just waiting for my thin walled spark plug socket to come in the mail. I can't seem to find mine.
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      07-02-2021, 02:14 AM   #8
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Testing out the CTA timing tools:


got the crankshaft pulley off.


had to use a breaker bar + the bar to my jack to break the crankshaft bolt



got it off


had to unbolt the engine from the mounts. Raise engine by the transmission and passenger engine mount.

[IMG]https://f30.bimmerpost.com/forums/attachment.php?
attachmentid=2639785&stc=1&d=1625208109[/IMG]

still couldn't get enough room to get the oil pan off even with the engine off the mounts so I started working on taking out the upper timing chain assembly.



Noticed that the pins holding the guides in were worn so much they were polished. My guess is the guides must have been vibrating on the pins.



Got the crankshaft snout thing out


It can be quite tight so this is how I pulled it off. I used my wrench and threaded in 4 of the bolts and pulled.


Heres the old lower gear

Heres the new gear that came with the FCP Euro kit with the laser engraving


Heres my old guides notice the portions that cracked off


table is starting to get full


finally got the pan out had to raise the engine a lot. I placed a jack fully extended right under the transmission and another one on the passenger motor mount. I had to remove the driver side mount


The parts of my timing chain were in the oil pan


Heres what's behind the oil pan. Had to literally raise the engine + drop the subframe. Just unbolt all the subframe bolts and pry at the rear portion against the car to lower.




removed the oil chain drive unit was pretty simple.
Heres the new guides + chain assembled ready to go


The lower chain drive was easy to install
upper portion installed




got this seal remover which made it a lot easier to remove the front seal

pulled the old seal out super easy


new seal going in



Reattaching the cam adjusters and preparing for the timing tool




Preparing the chain tensioner tool


putting the oil pan in was a pain. You need to drop the subframe for this there was no other way.


got the crankshaft pulley back on


Got the valve cover back on


Didn't take any photos but the vacuum pump in the rear was annoying to line up.
fueling system reattached


high pressure fuel pump reinstalled. Note you should install the front wiring harness (to the injectors + coils) before bolting down the fuel pump


air box + cover reinstalled


cranked the car without coils + fuel injectors plugged in 3x. Then plugged them in and car started right up
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      07-02-2021, 03:00 PM   #9
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Looks awesome, Ive been following along. I give you a ton of credit for tackling this at home. Thanks for posting all of the pics, huge help to the community.

Regarding your comment "Having now played with the engine without the valve cover I can confirm that yes when the lobes are vertical it does rotate back slightly and create a lot of slack on the chain."

...I am wondering what your thoughts are on changing the timing chain tensioner alone (from outside of the engine). Do you think there is enough slack with what you described above to have the chain jump a tooth while the tensioner is removed briefly during replacement?

I have been wondering this for a while and suppose it definitely is a risk just not sure how big of one... depending on how much slack is created when/if lobes roll back without tension on chain. Since you just went through it, figured you may have insight.

Last edited by sspade; 07-02-2021 at 03:15 PM..
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      07-02-2021, 03:27 PM   #10
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Im talking about #5 below. This can be changed from outside of the engine rather simply but Im wondering about how much slack will be on the chain when removed. And then if that amount of slack will allow chain to jump time.
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      07-02-2021, 06:40 PM   #11
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sspade
So my chain didn't look stretched. The guides were shattered at one connection point but besides that it looked fine no deep groves or anything.

The oil chain drive I believe is what was whining the most.

Comparing my old tensioner to the new one, the new one is almost impossible to compress for me with a single hand vs the old one I can. Like Billfitz said above and with this knowledge I would probably switch it out every 30-40k miles.
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      07-02-2021, 08:19 PM   #12
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Mine went in my F30 N20, got the full replacement kit from Bimmerworld and it was about $1,500 for the shop to do the work.
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      07-03-2021, 08:00 AM   #13
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following. hats up for you for doing this at home.

to OP: was the guides shattered on the bottom and the car was still running fine?
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      07-03-2021, 01:36 PM   #14
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Guides were shattered where the upper guide mates with the lower guide
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      07-03-2021, 07:44 PM   #15
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Quote:
Originally Posted by mattwong92 View Post
Guides were shattered where the upper guide mates with the lower guide
Did you have any symptoms of it being failed or was this just a good catch before it Killed itself?
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      07-03-2021, 09:33 PM   #16
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This is where things get interesting. The guides are the same as those in the N55, and those don't have an unusual failure rate. The chain is the same as the N55, where it doesn't have an unusual failure rate. The tensioner is different, and the OP has confirmed that the new tensioner is stiffer. IMO the original tensioner either loses it's ability to put sufficient pressure on the chain over time, or it was inadequate from day one. Insufficient tension allows the chain to flap about far enough to damage the guides, which then allows the chain to flap even more, which probably further damages the guides, and eventually the damaged guides, stretched chain and inadequate tension on the chain combine to allow the chain enough slop to jump the sprockets. BMW has never confirmed this scenario, but the fact that they changed then tensioner after the 'improved' chain went into service speaks volumes.
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      07-04-2021, 03:36 PM   #17
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I forgot to mention the oil chain drive unit was shattered where it mounts to the engine. The chain unit was also updated and different compared to the design in the n54 and n55 so I think there might be a chance the vibrations from the oil chain drive unit also caused the upper guides to crack.

With that knowledge I think I am still going to change the tensioner probably every 35k miles.
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      07-04-2021, 07:16 PM   #18
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Rockinryan2424

There was slight whining from lower portion of engine where oil drive chain was but no significant whining from timing unit.

I did a side by side comparison of the old chain to the new chain and there was no stretch at all.
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      01-08-2024, 02:44 PM   #19
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Did you get any pictures of the jacking points when lifting the engine up to remove the oil pan?
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      02-04-2024, 01:36 AM   #20
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Hello,
My wife has a 2013 X3 x28i F25 with N20 engine. I hear a whining sound that gets higher in pitch with increase in RPM. I've been poking around and see that it could be a timing chain issue? How is the FCPEuro kit holding up? What's the status on your car?
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      02-04-2024, 08:22 AM   #21
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It's probably the timing chain ready to let go. Get it looked at yesterday, if not the day before. Or dump the car. The cost to fix the chain may not be worth keeping the car.
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