M30 Timing chain & guide replacement write up

**shogun** · 12-29-2009, 07:35 AM

wriiten by Greg Rea
1985 M639 arctic blue shark II
1989 E32/M30 white whale

"I replaced the timing chain and guide on my M635 and found that the process would be very similar on the M30. About 95% of this write up will apply to the M30 motor."
http://forums.roadfly.com/forums/bmw...8642567&page=3
part II
http://forums.roadfly.com/forums/bmw...8677213&page=1

**Heysus** · 04-09-2010, 01:10 PM

noob here.....

just got my first e30, and it's m30 swapped. guy said the front timing cover has a small oil leak. any tips ? any crazy shit I should watch out for? like some random spring that'll pop out as soon as i remove the cover?

**shogun** · 04-09-2010, 01:13 PM

small leak: go to my website below: left side DIY links>private DIY links>Jon Evans has the write up

**Heysus** · 04-09-2010, 01:33 PM

thanks!

you guys are quick!

**tooter302** · 04-09-2010, 03:27 PM

Welcome to the house of Shogun...Answers are swift and accurate!

**shogun** · 12-16-2011, 09:34 AM

**shogun** · 10-30-2014, 09:36 AM

REPLACING THE TIMING CHAIN TENSIONER ON AN M30 ENGINE
If you need to remove your timing chain tensioner piston, I recommend replacing it. The reason for replacement is that if they have any wear they are less efficient, and can create noise from the timing chain.

On the big 6 cylinder engines, there is a small reservoir of oil in the upper right portion of the lower timing cover, where the tensioner piston enters, which is used to ensure the tensioner does not bleed down. The first thing to check when having tensioner problems is for leaks in this immediate area. If you find oil leaks in the area of the timing covers, repair these first.

Allow the car to sit overnight before replacing the tensioner piston. There are two reasons for this, one is to allow the engine to cool, the second is to check the integrity of the aforementioned oil reservoir. You are going to have to remove the valve cover, so now is a great time to adjust your valves, a benefit of having the engine dead cold is better accuracy of the adjustment.

After removing the valve cover, place a rag over the A/C compressor and remove the 19mm cap over the tensioner piston. When you remove this, and slide the piston out, you should get about a table spoon full of oil flow out of the opening. If no oil comes out, you will need to replace your lower timing cover gaskets, or risk shortening the life of the tensioner dramatically. Once the old piston is out, install a new seal on the cap, insert the piston into the hole, followed by the spring, the narrow end of the spring faces out to the cap. The spring is quite long and takes a little dexterity to get it into place and the cap done up. Be gently with the cap, do not use a tool on it until you have screwed it in by had for at least a quarter of the way, to prevent cross threading it.

Now comes the tricky part. you need to bleed the piston before it will work. This is why you have removed the valve cover. Pour some oil down the right side of the engine directly above the tensioner piston, this will fill the reservoir in the top of the lower cover. Once the reservoir is full, use a long screwdriver to move the tensioner rail back and forth, this will expel the air from behind the tensioner piston, replacing it with oil. If you can see the reservoir, you will see the bubbles coming out. You may need to top off the oil once or twice during this procedure. You are finished when you can no longer move the rail in either direction. It should take less than a minute to achieve this.
Do not attempt to skip this procedure, it may take minutes of engine running to bleed this piston, during which, severe damage to chain and rails could occur.
Replace the valve cover gasket and install the valve cover.
Source: http://www.koalamotorsport.com/tech/...ntensioner.asp

BMW M20 & M30 Engine Timing
http://www.exx.se/techinfo/timing/

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