2000 740i M62 Head Gasket Replacement / Camshaft Removal Questions

[Flyingboy2014]

Hello all, long time BMW owner here. After a few E36's and an E46, bought my first E38 recently. Always loved the look and was lucky to find a good deal on a black 2000 sporty shorty. Being a seasoned shadetree mechanic, I'm undertaking the work myself. Timing guides were fine, but Vanos units rattling, so I'm having them rebuilt. in the meantime, I've decided to do a head gasket replacement since I'm replacing all the other gaskets. Thankfully there is a lot of info on timing guide replacement/ Vanos, but not much on head gasket replacement for the M62. After searching around the forums, i didn't see any comprehensive guides on head gasket replacement, So here are my questions.

1. What are the cam bearing cap bolts loosening/ tightening sequence?
2. Cam removal need a special tool like the inline 6's to prevent breakage?
3. I will be using new head bolts, do the cam bearing cap studs/ flange nuts need replacing too?
4. Head bolt loosening/ tightening sequence? Standard inside to outside bolt alternating method?

Any tips/ advice from those having done an M62 head gasket replacement is helpful, thanks!

[bmwdirtracer]

Hi Flyboy, and welcome to the forum.

1) Torquing down BMW camshafts is an extremely fragile procedure, unless you have the correct tools. The cams are hollow, and they are easily broken. The special tool grabs the camshaft across it's entire length, and holds it down uniformly, while you tighten and torque the nuts. Therefore, there is no "sequence", officially.

Now, I'll share "unofficially" with you. It is a procedure which has served me faithfully, for many engines, over many years. Knock on wood, I've never broken a cam this way. I have known of other techs and owners to break cams, but I haven't ever watched their procedures. But all risk is your own -- EVERY BIT OF THIS IS INCORRECT, AND DANGEROUS. I hereby absolve myself of "professional's liability", because I'm telling you that none of this is "safe".

Unofficially:

TRY to set the cam so that no lobes will experience maximum loading, straight down.
Watch the nuts; they are your sign for how far each stud, each lobe, is actually parallel to the neighboring ones. (The object is to keep the cam straight)
Bring the cam down slowly and evenly..first snug up all the nuts, fingertight, and visualize the tensions, by comparing the distance the nuts have to travel, to the angles of the cam lobes.
Then bring the cam down evenly and smoothly, turning each nut, on average, 1/2 turn at a time.

Before beginning all this cam manipulation, you need to back the crankshaft off, from TDC, about 15 or 20 degrees. This keeps the pistons down far enough that the valves can't hit them, while you're setting the cams.

2) See above. A V8 cam is safer, but still, take all the precautions I mentioned, and give praise to your favored deity, for good measure.

3) No, they are not "torque to yield", and are not specified as replacement items. That said, nuts are cheap.

4) See picture.

If you have the heads machined, machine the timing covers an equal amount. A valve job is a good idea, if the heads are off.

If you have an appropriate wire wheel on an air tool, you'll be excited over how good you can make the timing covers and heads look.

The most common oil leakspot on this engine is the joint between lower timing cover, upper timing cover, head, and block. Use a top-quality sealant there: Victor Reinz Anthracite, Permatex Ultra Grey, or Toyotabond.

Make sure you carefully inspect the small tensioner rails. Personally, I'd have to replace the rails and tensioners, if I had the heads off, and if it were my own engine. ....because I'm there, and this is a big damned job, and I really hate having to tear stuff apart again, a month later, because "that looked okay".

Make really sure that you use factory directions and proper locking tools and procedure, multimeter etc., when setting timing, and make sure all slack is on the main tensioner side of the chain, when you set the cams and crank.

Chris

[Flyingboy2014]

Thank you for that indepth and comprehensive reply, good info. Thankfullly the heads can be removed with the cams still in there, so that's what I did. I'm going to take the heads/ cams installed to a machine shop for resurfacing. There is also some of that white, hard, "barnacled" looking crud on 4 of the valves, so a valve job is in order too. What causes that white crud? I've heard fuel additives, but on only 4 valves in different cylinders?

- - - Updated - - -

Oh and when you say use Ultra Grey RTV on the upper/ lower timing case covers, you mean in addition to the Victor Reinz rubber gaskets? Are the thick washers on the head bolts reusable?

[bmwdirtracer]

I personally add the excellent RTV (Victor Reinz Anthracite, or Ultra Grey) to the corners where Timing covers, block, and heads meet. This is the "special" oil leak point of this engine.

You should be aware that the M62, while a truly magnificent motor, is the leakiest sumbich BMW has ever made. It leaks air, oil, coolant, from orifices you didn't know even existed.

Make sure you replace every single gasket and seal while the engine is apart. A "Top End Gasket Set" is the minimum.

Yes, the thick washers are reusable.

[ThomasMurray]

Hi Flyboy, and welcome to the forum.

1) Torquing down BMW camshafts is an extremely fragile procedure, unless you have the correct tools. The cams are hollow, and they are easily broken. The special tool grabs the camshaft across it's entire length, and holds it down uniformly, while you tighten and torque the nuts. Therefore, there is no "sequence", officially.

Now, I'll share "unofficially" with you. It is a procedure which has served me faithfully, for many engines, over many years. Knock on wood, I've never broken a cam this way. I have known of other techs and owners to break cams, but I haven't ever watched their procedures. But all risk is your own -- EVERY BIT OF THIS IS INCORRECT, AND DANGEROUS. I hereby absolve myself of "professional's liability", because I'm telling you that none of this is "safe".

Unofficially:

TRY to set the cam so that no lobes will experience maximum loading, straight down.
Watch the nuts; they are your sign for how far each stud, each lobe, is actually parallel to the neighboring ones. (The object is to keep the cam straight)
Bring the cam down slowly and evenly..first snug up all the nuts, fingertight, and visualize the tensions, by comparing the distance the nuts have to travel, to the angles of the cam lobes.
Then bring the cam down evenly and smoothly, turning each nut, on average, 1/2 turn at a time.

Before beginning all this cam manipulation, you need to back the crankshaft off, from TDC, about 15 or 20 degrees. This keeps the pistons down far enough that the valves can't hit them, while you're setting the cams.

2) See above. A V8 cam is safer, but still, take all the precautions I mentioned, and give praise to your favored deity, for good measure.

3) No, they are not "torque to yield", and are not specified as replacement items. That said, nuts are cheap.

4) See picture.

If you have the heads machined, machine the timing covers an equal amount. A valve job is a good idea, if the heads are off.

If you have an appropriate wire wheel on an air tool, you'll be excited over how good you can make the timing covers and heads look.

The most common oil leakspot on this engine is the joint between lower timing cover, upper timing cover, head, and block. Use a top-quality sealant there: Victor Reinz Anthracite, Permatex Ultra Grey, or Toyotabond.

Make sure you carefully inspect the small tensioner rails. Personally, I'd have to replace the rails and tensioners, if I had the heads off, and if it were my own engine. ....because I'm there, and this is a big damned job, and I really hate having to tear stuff apart again, a month later, because "that looked okay".

Make really sure that you use factory directions and proper locking tools and procedure, multimeter etc., when setting timing, and make sure all slack is on the main tensioner side of the chain, when you set the cams and crank.

Chris

Hey! I'm new to the forum. I just saw this post and wanted to clarify something for future reference.
I'm starting right at the official BMW guide for removing camshafts and there is no mention of a special tool. There is, in fact, a tightening and loosening sequence.
With the chain to your left on the left, driver's side head, counting the bolts on the bearing caps from top to bottom, left to right, the loosening sequence goes:
1, 10, 2, 9, 3, 8, 4, 7, 5, 6

Tighten them only 1/2 turn at a time!
The tightening sequence goes:
5, 6, 7, 4, 8, 3, 9, 2, 10, 1

Once again, not my words, this was taken straight from the official BMW guide for the m62 engine.
If anyone wants me to scan it, let me know!

[bmwdirtracer]

Oops - you're correct, no special tool for holding down the cams on the M62, as on all the sixes. As I mentioned, the V8 is safer, because the cams are shorter. However, it is absolutely crucial that the cams are in the correct position as you begin loosening or tightening.

Cylinder 5-8, the intake cam must have the lobes of the cam for cylinder 8 upwards. Exhaust cam must have the lobes of cylinder 6 upwards.
Bank 1, cylinders 1-4, must have the lobes of the intake cam cylinder 1 upwards, the exhaust cam lobes of cylinder 2 upwards.

These positions put the cams in the unloaded positions mentioned in the earlier post.

And of course, the cam bearing caps MUST be installed in exactly the same position and orientation on exactly the same cam lobe. Don't mix caps from one bank to the other, either.

Thanks, Thomas, for correcting that point.

[Dolsey056]

I personally add the excellent RTV (Victor Reinz Anthracite, or Ultra Grey) to the corners where Timing covers, block, and heads meet. This is the "special" oil leak point of this engine.

You should be aware that the M62, while a truly magnificent motor, is the leakiest sumbich BMW has ever made. It leaks air, oil, coolant, from orifices you didn't know even existed.

Make sure you replace every single gasket and seal while the engine is apart. A "Top End Gasket Set" is the minimum.

Yes, the thick washers are reusable.

Chris, how far from Durham are you? I bought a 98 540i with the M62 non vanos and am planning on pulling the heads soon to rebuild. Everyone seems afraid of the 4.4 especially when setting the timing. Im wondering if I would pay you to help me when I start putting it back together. Right now Im estimating costs and deciding what to replace while i have it opened up. So far I figure the waterpump,thermostat, hoses, water pipes under intake and the part they go into on the back of the block. I figure I will have the heads tanked,pressure tested, surface checked, and seals done. I was thinking of looking for an M60 intake while its apart as well.

[bmwdirtracer]

Sorry, Dolsey, but I'm ~4+ hours away, and I don't do "side-work", much less travel all the way across the state to do it.

Bimmer Performance Center is in Raleigh.....they have a beautiful track E30 with an S62 M5 engine in it....I promise, they're not scared of an M62.....