noisy tappets

[AdamB]

I own a late 1995 E36 320i coupe. With the M52 engine. The car is excellent in every way. It's in perfect condition. The engine's done 177,000km and is still super smooth and powerful, totally linear and a smooth idle, never overheats and never fails to start. BUT......it does have a problem with the tappets! They're noisy as hell. By my reckoning at least a couple of the hydraulic lifters are lazy, causing the tick,tick,tick......It's been that way for at least 50,000km now, I've tried everything to solve it but no luck. And it has gotten slightly worse as time's gone by, now there also sometimes being a slightly louder knock which could well be the cams wearing.
Every BMW mechanic and plenty of decent independents I've spoken to have said not to worry, as it's just annoying sound wise, and the engine is actually fine. Which I'm sure is right 'cause the engine drives perfectly.
But I've had enough of it. So I want to either fix it; don't know if I should just replace the tappets or have a whole top end rebuild.
Or, I was thinking about swapping in an M52B25 from a 323i.

So I would love your opinion; does it make more sense to sort out the tappets on my 2 liter? How much do you think it'd cost? Or would it cost only a little bit more to swap a more powerful B25 engine? If so, is it a straight swap for my B20? Or do I need to know about anything else?

Thanks for your help.

[David Bevan]

Hi, before i rebuilt my M50 2.5 i had noisy tappits, i'm glad to say that they can be cleaned! to do this you must remove them. unfortunatly this is not straight forward. you have to lock the crank and cam shafts with suitably fabricated tools. remove the 2 cams using the method detailed on this site removes the need to buy the very expensive BMW special cam removal tool. Remove the bearing ledges that hold the hydraulic tappits in place to do this you will need to take care and observe which tappits fall from which bore, ideally they should go back where they came from.
To clean the tappits you'll need to fill a grease guy with engine oil, and make a die for the tappit to slide into with a grease nipple tapped into the side. the aim of this is to apply high pressure oil into the small hole on the side of the tappit and hydraulically pop out the central actuator once this button is ejected the inside of the tappit can be thouroughly cleaned with parrafin.
You will be amazed at the amount of sludge comes out, it seems these hydraulic lifters are prone to the crud in the oil sedimenting there and jamming the workings. On assembly fill with oil and keep submerged in oil until install. I pre bled mine by pumping the central button while under oil until all the bubbles stopped emerging. you will find that cleaning these alone will improve performance, economy, driveability and put your Bimmer back the way it should be. if you need help with the fabrication of tools or methods, let me know and i'll provide pictures and dimensions.
Best of luck

[AdamB]

Thanks for that David.

I would indeed be very interested in some pictures and a write up if you don't mind.

[David Bevan]

Noisy hydraulic lifters and the cleaning procedure BMW M50 Engines (All)

To remove the hydraulic lifters in an M50 engine you have to prepare to not have your car for about 2 days and have either a garage or an area undercover so you can work un- interrupted if the weather breaks.
The process must be kept very clean it amazing what a grain of sand can do in this complex an engine.
During re assembly coat everything with fresh clean motor oil of the same brand and viscosity as you normally use in the engine.
Never skimp on gaskets, oils or time, preparation is paramount.
If you are not confident with your mechanical skills do not attempt to do this it is not simple like a cam belt!
Read this through and understand it fully before attempting the procedure.
When dismantling a complex engine treat everything as step by step store everything logically in sectioned storage writing on the lid where they came from, and if necessary take photos make notes because you will get distracted and take tea breaks.

The following are essential:
A full set of Combination spanners from 8 to 19 mm,
A full ¼, 3/8, ½ inch socket sets, quality set like Teng/Snap-on is advisable,
A ½” drive solid breaker bar at least 600mm long,
A torque wrench,
A set of TX/Star sockets,
Screwdrivers,
A Crank locking pin (drawings provided),
A Cam locking tool (drawings provided),
A VANOS Spanner (drawings provided, req’d if you have VANOS with plate spring),
A piece of steel wire 1.5-2mm diameter or a 1.5-2mm Allen key will do,
An adjustable spanner 25mm opening,
Engine degreaser/Paraffin or similar,
2 medium sized plastic boxes for cleaning parts in, one for dirty one for clean,
A selection of clean paint brushes for cleaning parts,
GT85 preferred or WD40 will do,
Motor oil of your choice but should be the same as your usual brand/type,
Plastic zip ties 4x300mm strong type essential,
Wire cutters,
A clean uncluttered workbench,

Recommended:
Large plastic storage boxes about 400x300x300mm to keep all the big bits in,
Storage trays with dividers to keep all the smaller bits you take off organised,
A fine permanent pen to write on the containers,
A digital camera,
A magnetic pickup tool,
A 3 arm bearing/seal puller,
A new rocker cover gasket,
RTV sealant,
New VANOS / front cover gasket,
2 pieces of wooden dowel one 300mm long the other about 120mm 10mm diameter,
A length of broom handle, 12 round magnets and some glue

Removal process:
Remove the following:
Top plastic covers from the engine.
Windscreen wipers, 13mm socket plenty of lube allow to soak as req’d.
The rubber Scuttle seal.
The plastic scuttle panel.
The air intake for the heater fan 8mm bolts into the bulkhead.
The connector from the coils packs, and tuck the cables out of the way.
The rocker cover breather pipe.
The rocker cover can be accessed easily now to remove the numerous 10mm nuts.
The coil pack grounding strap is an 8mm nut that is easy to round off,
Remove the rocker cover with care as you may want to reuse the gasket, not a good idea.
The spark plugs,

You should now be faced with a plastic cover over the intake cam, using a 6mm flat screwdriver unclip it by inserting the blade into the slots either side.

Next step ensure the car is out of gear and nothing is obstructing the engine from turning!
It is always a good safety precaution to disconnect the battery during this kind of work

Find the number one TDC (top dead centre) by using a 300mm piece of dowel inserted through the number 1 sparkplug hole touching the piston crown. Turn the engine with a spanner on the crank hub bolt, (this is where the adjustable comes in) turn the engine over by hand so that the dowel is at its highest point and the indents on the back end of the cams are facing upwards perpendicular to the top face of the head.

Lock the crank with the locking pin inserted into the locking port on the back of the block just under the starter motor.
The cams with the cam locking tool this should slide over the flats of the cams and prevent any rotation, the 2 rear rocker studs will need to be removed for it to sit in properly.

If you have VANOS you’ll have to remove the 2 access plugs on the front of the VANOS unit to gain access to the 2 bolts on the exhaust cam sprocket. If you don’t have VANOS then remove all 4. This needs to be done now so that you don’t put too much stress on the studs that hold the VANOS unit or front cover on.
Slacken off the 4 bolts holding the exhaust sprocket on ½ turn is sufficient.

Remove the 10mm nuts around the VANOS unit/front cover and the engine lifting eye 13mm bolt.
Press down on the secondary chain tensioner and lock down with the wire/Allen key through the hole to the rear of the tensioner.
Pull the VANOS unit away from the cams on early models with VANOS the inlet sprocket should rotate anticlockwise a few degrees with light hand pressure.
On later models from ’95 on or any engine with the upgrade will require the assistance provided by the VANOS spanner.

Remove the primary chain tensioner from the side of the engine be prepared for the spring and some oil spillage.

Remove the 4 bolts and thrust plate washer from the exhaust camshafts, take care not to drop anything down inside the timing case if you do and you can’t retrieve it you are stuffed and will have to remove the engine to get it back! I recommend stuffing a clean rag into the hole to prevent this.
Remove the exhaust sprockets and secondary chain to a safe location.
Tie up the primary chain with a zip tie to prevent the chain dropping down inside the timing cover.
continued......>>>>>>

[David Bevan]

Now comes the fun bit, removing the cams:

Remove the crank locking pin and turn the crank hub bolt 30 degrees clockwise, this ensures that no pistons are at top dead centre and no valves will touch the pistons.
Now rotate the intake cam so that one pair of cam lobes is fully acting on one pair of hydraulic lifters, there are spanner flats between cylinders 5 and 6 for this purpose.
Get an assistant to hold the cam still with the spanner while you remove all the bolts except the 2 on the bearing cap between the lobes that are fully acting on the lifters.
The idea behind this is isolating the stress to the one bearing cap and removing the last 2 nuts slowly 1/4 turn at a time this method stops any potential cam snapping forces.
Once all the caps are off the cam can be removed, I used this idea successfully and I’m pleased to say it works a treat thanks to Wayne at pelicanparts.com.

Repeat for the exhaust cam.

Remove the bearing ledge one at a time they will require a pull and a wiggle upwards, the hydraulic lifters will fall free of the bearing ledge.
Once the ledge is free of the head place the lifters back in their bores that they came from and use these to transport to the workbench.

Service the lifters one at a time and place back into their home bores.

The lifters are cleaned by popping out the centre actuator under hydraulic pressure and cleaning all of the dismantled parts with the cleaning fluid. Do a pre clean and a clean-clean using your 2 buckets you want to do this right as it’s a lot of work to go to for a half arsed job.
Ensure the lifters are free of cleaning fluid before re assembly.
The cleaned lifters require priming before re fitting as at the moment they are empty of oil and will rattle like hell for ages if you don’t prime them first.
Submerge the lifter in motor oil with the small hole at the top pump the central button until no more bubbles emerge, then these are pre bled lifters ready for installation. Back into the bearing ledges.

To refit the ledges back into the head is a bit tricky without a special tool this can be made by cutting a length of broom handle the same length as the cam and gluing small magnets to it where the lifters are in relation to the bearing surfaces. The magnets hold the lifters in the ledge while you turn it right side up and fit back onto the head studs.

The re fitting of the bearing ledges is quite straightforward with the above tool and is well worth making.

Once the bearing ledged are back in the head lay the cams in the bearings and put cap number one on and tighten the 2 nuts had tight to take up the slack. Rotate the cam to load up bearing cap 1 and tighten ¼ turn at a time the rest of the cam should be laying in its bearing with no load on it the rest of the cam can be tightened down to the specified torque.
Once the cam is in place and all the bearings are torqued then rotate the cam so that the 2 indents on the rear of the cam are once again facing perpendicular to the head repeat this with the second cam and lock in place with the cam locking tool.

With the cams locked in the correct position for No 1TDC the crank will need to be locked again at 1 TDC, for this you will need an assistant to very slowly rotate the crank by the hub bolt while you press the locking pin into the flywheel you will feel the pin slot into place.

The primary chain exhaust sprocket now needs to be re-fitted to the cam with the chain in place the 2 arrows on the sprocket should be vertical to the block i.e. perpendicular to the top surface of the head, any slack in the chain should be on the left hand side the right side should be straight and relatively taught.
The secondary chain is now fitted back onto the intake cam sprocket if you have VANOS or if you don’t then just ensure the arrows on the exhaust side line up with the exhaust sprocket and the arrows on the intake are also pointing vertical.

Remove the secondary chain tensioner locking pin!

With the VANOS unit refitting is a little involved for the first time and requires the secondary chain to be turned fully clockwise, so that the bolts on the exhaust sprocket are at the left hand side of the slots.
Push the splined cup fully home back into the VANOS unit, offer up the VANOS unit to the intake cam and ensure the first spline engages. The secondary chain is then rotated anticlockwise while applying reasonable pressure onto the VANOS unit pushing in towards the cam. The splines will engage and the unit will slide fully home.

Tighten up the VANOS cover screws to the specified torque.

Cut a length of dowel to push into the primary tensioner hole to act upon the tensioner piston just long enough that the cap can be screwed on and allow a couple of threads to be tightened to apply 1.3Nm to the primary tensioner rail.
With the tensioner rail torqued to 1.3Nm, the bolts on the exhaust sprocket can be torqued back up.
Once the chain has been tensioned the primary chain tensioner can be re-assembled by reinserting the spring and tightening the cap back up.

Remove the Crank and cam locking tools and rotate the engine by the crank hub bolt you should have no unusual noises suddenly coming to a stop where the piston hit the valves etc, if it does then you have not lined the sprockets up correctly.
Apply RTV sealant to the joint where the VANOS unit meets the head and cam cover and the half moon cut outs at the back of the cam cover.

If all is well then re assembly is the reverse process.

Before you get carried away and start the engine, make sure you have accounted for all the tools and parts i.e. no spare parts, tidy up your work area before you reconnect the battery.

Start the engine and listen for any unusual noises depending on how long it took to re assemble the engine the lifters may rattle for up to 10 seconds but if all has gone to plan that’s the last you’ll hear from them for 100k Miles.
Notice now how smooth idle is, you should be able to balance a coin on the rocker cover!

How do I prevent this from happening again?
Regular oil changes, I change mine before the last green light goes out.
Never use any kind of oil flush, all it does is mobilise the crap in the sump and deposit it in the head where it can do the most damage.
Never run the engine without anti freeze this magical stuff reduces the surface tension of the water and stops hot spots in the head and block, hot spots = oil breakdown and production of particulates i.e. crud! It also stops corrosion in the engine which leads to head gasket failure, head, radiator failure, heater matrix, and water pump failure.

Good luck and happy motoring.

Adam let me know if you have any questions, i will sort the pictures and drawings for you tomorrow evening when i get a chance.

[David Bevan]

Adam can i send a .doc file to you in an e-mail i can't figure out how to insert it into this forum thingy!

[AdamB]

thanks for the write up David. Much appreciated. Of course you can send me .doc file. My email is adambowden@gmail.com