cylinder #3 has water, hydro locked..HELP!!

[waehrik]

Quoted for awesomeness! I would like to clarify the torque process of the head bolts. You initially torque it to the specified rating, then you turn it 90 degrees, plus another 90 degrees regardless of torque value. Am I understanding correctly?

Yep, you're understanding that right.

It's very disconcerting doing those two additional 90 degree torque steps because you have no idea where the final torque value will end up. It's really really critical though that the bolt holes are clear since any debris or oil will affect how far the bolt turns during the initial torquing.
You'll hear the bolts creaking and stretching as you tighten them. Because I'm paranoid, I did those final torque steps with my torque wrench and kept increasing the click-stop value to see how tight the bolts were getting. I found vastly different readings on each of the bolts, so it makes sense why BMW would want to call out the rotation angle rather than a specified torque reading.

[waehrik]

do a online search for the E12. i paid $18.30 online and you can get it at sears for $27.99.

Just make sure it's not too large to fit between the camshaft and the lifter carrier. I'll measure the size of my turned down one when I get home. I wouldn't want one any larger than that.

[Hornung418]

Very good info to have. Thanks guys

[Sapote]

The only problem is that he won't be able to retorque the head back to factory specs since it requires 40NM + 90 degrees + 90 degrees. The head bolts will stretch per their design, thus a recommended 20 minute wait between torque stages. The +90 +90 (use a torque angle gauge!) will leave each head bolt at a different final torque, so just loosening each bolt and retorquing to an arbitrary value won't tell you if your threads are stripped unless they're really bad.

Ask me how I know. I bought a 2000 328i for cheap knowing it had a blown head gasket (blowing white smoke out the exhaust and the temp gauge would start to climb). I checked the head bolts before disassembly by loosening them and retorquing each to 60NM, a safe but optimistic number. They all held. But on reassembly cylinder 5 stripped each of its four surrounding holes during the second 90 degree rotation. I installed Time-Serts in each of the 14 holes on the block in case they had been weakened. Now it's running great with over 1k since the rebuild.

You don't need a special tool to remove the head or camshafts (check the DIY at Pelican Parts for that - it worked for me). But you definitely will for reassembly. It's impossible to time the double VANOS without the tools. I had to buy the set myself to get it right.

So the final torque spec is 40NM, 90, 90; not just only one time 90?
I'm planning for the worst: using time-sert for the pulled thread. In your case, did the damage also got to the cylinder wall and rings, piston?
I had read the Pelican DIY. If I timing mark all parts (cam sprockets, VANOS spline gears, cam ends relative to each other, chains) before disassembly, then could I put them back with correct factory timing without the VANOS tool? if not why?

[Sapote]

Any E12 will fit the bolt head, but the ones you buy at Advance Auto, etc will not fit into the camshaft recess. But you can buy one of those for cheap and take it to a machine shop to have it turned down on a lathe if you need it really quick.

I'm calling around for the E12 since i will start working on this on Friday -- to late for online ordering. If Sears E12 interfere with the cam, then perhaps I can use the sanding wheel to trim the socket down to fit. Any forseen problem with this plan?
I'm still looking for head torque pattern sequence if anybody can post one. My guess is starting from the middle section and go evenly outward to front and back of the head. Sounds like having a flat top hair cut.

[waehrik]

So the final torque spec is 40NM, 90, 90; not just only one time 90?
I'm planning for the worst: using time-sert for the pulled thread. In your case, did the damage also got to the cylinder wall and rings, piston?
I had read the Pelican DIY. If I timing mark all parts (cam sprockets, VANOS spline gears, cam ends relative to each other, chains) before disassembly, then could I put them back with correct factory timing without the VANOS tool? if not why?

You're correct, the final torque is 40NM + 90 degrees twice

I did not have any damage to the cylinder walls, rings, pistons, or valves. The timing was not thrown off by the blown head gasket, it was just leaking coolant into a cylinder. A damage mechanism would be the lack of oil lubrication on the cylinder walls due to the influx of coolant, but the engine was never run for very long after the head gasket blew, so everything was in good shape.

The Pelican Parts DIY you might have read was the one on cam timing instead of cam removal. Their timing DIY is only for the M52 single vanos engine and not our E46 M52TU with double vanos. It's completely different (and our tools are more expensive). You will definitely want to remove the camshafts and have the head inspected at a machine shop prior to reinstalling it. Chances are it will have to be planed because it will have slightly warped. Mine was out of flatness by 0.020" and I used a thicker head gasket to compensate. It still resulted in a minor compression increase, which isn't a big deal (and actually nice) because I'm running on 93 octane gas out here in the east.

The M52TU engine's timing must be set while an alignment block is attached to the end of the timing case. In addition to the normal and easy static timing that is done for a basic SOHC or DOHC engine, our camshafts both have a splined sleeve on them that will allow them to rotate at an additional few degrees advanced and retarded. These splined sleeves must be locked down at a very exact location before the vanos unit is bolted back up, otherwise your static timing will be correct but you'll get a P1519 code thrown because your vanos will be 'jammed' and not able to rotate the intake cam through its entire range of motion. I had to retime my engine twice. Once I tried to do it without the special alignment tools, and once after I sucked it up and bought them. Even with the tool cost, I'm still ahead of having a dealership do the work.

I would recommend doing the time-sert install even before trying to reinstall the head. Once the head gasket has been compressed, you have to replace it. And once the head bolts have had any torque applied to them, you have to buy a whole new set. You're better off taking the extra time and paying the small incremental cost to install time-serts yourself for the peace of mind and preventative measure. It'll only make the engine stronger.

And if you're doing the time-serts, I have the full install kit (paid $200 for it) that I'll sell for $100 if you're interested.
It's this: link
You'll just need 14 inserts like these: link
since I've obviously already used mine

[waehrik]

I'm calling around for the E12 since i will start working on this on Friday -- to late for online ordering. If Sears E12 interfere with the cam, then perhaps I can use the sanding wheel to trim the socket down to fit. Any forseen problem with this plan?
I'm still looking for head torque pattern sequence if anybody can post one. My guess is starting from the middle section and go evenly outward to front and back of the head. Sounds like having a flat top hair cut.

Just make sure you keep a good hold on that socket!

The Bentley manual has the torque sequence for the head. This is absolutely essential for taking on a head gasket replacement:
(edited to remove download link)

[Tom D]

…...I'm still looking for head torque pattern sequence

the head bolts should come with instructions on torque and pattern. you are getting new bolts right? these are stretch type and cannot be reused.

[Sapote]

yes.

I'm kind of surprised that no where I found any instruction mention about clean out any engine oil that might have gotten into the engine block's head-bolt thread holes. This is very important, since oil in the hole could cause wrong torque spec at best, or even can crack the block by hyro pressure when torque down the head bolt with oil in the well. On this, I must assume these thread holes do not pass thru the block. The old iron blocks do not have thru hole thread.

Sapote

[Tom D]

^^ very good point. i always assume that people know this. shame on me.

headbolt socket here. http://cgi.ebay.com/ebaymotors/BMW-H...#ht_500wt_1164

[Sapote]

You're correct, the final torque is 40NM + 90 degrees twice

I did not have any damage to the cylinder walls, rings, pistons, or valves. The timing was not thrown off by the blown head gasket, it was just leaking coolant into a cylinder. A damage mechanism would be the lack of oil lubrication on the cylinder walls due to the influx of coolant, but the engine was never run for very long after the head gasket blew, so everything was in good shape.

The Pelican Parts DIY you might have read was the one on cam timing instead of cam removal. Their timing DIY is only for the M52 single vanos engine and not our E46 M52TU with double vanos. It's completely different (and our tools are more expensive). You will definitely want to remove the camshafts and have the head inspected at a machine shop prior to reinstalling it. Chances are it will have to be planed because it will have slightly warped. Mine was out of flatness by 0.020" and I used a thicker head gasket to compensate. It still resulted in a minor compression increase, which isn't a big deal (and actually nice) because I'm running on 93 octane gas out here in the east.

The M52TU engine's timing must be set while an alignment block is attached to the end of the timing case. In addition to the normal and easy static timing that is done for a basic SOHC or DOHC engine, our camshafts both have a splined sleeve on them that will allow them to rotate at an additional few degrees advanced and retarded. These splined sleeves must be locked down at a very exact location before the vanos unit is bolted back up, otherwise your static timing will be correct but you'll get a P1519 code thrown because your vanos will be 'jammed' and not able to rotate the intake cam through its entire range of motion. I had to retime my engine twice. Once I tried to do it without the special alignment tools, and once after I sucked it up and bought them. Even with the tool cost, I'm still ahead of having a dealership do the work.

I would recommend doing the time-sert install even before trying to reinstall the head. Once the head gasket has been compressed, you have to replace it. And once the head bolts have had any torque applied to them, you have to buy a whole new set. You're better off taking the extra time and paying the small incremental cost to install time-serts yourself for the peace of mind and preventative measure. It'll only make the engine stronger.

And if you're doing the time-serts, I have the full install kit (paid $200 for it) that I'll sell for $100 if you're interested.
It's this: link
You'll just need 14 inserts like these: link
since I've obviously already used mine

About the time-serts, they are only 24.5mm long? this is less than 1" of thread--enough? I thought the bolt thread is much longer.

[Sapote]

Just make sure you keep a good hold on that socket!

The Bentley manual has the torque sequence for the head. This is absolutely essential for taking on a head gasket replacement:
Grab this quick: link

Well, either I missed the clock or I don't know where to find the pdf file, I just can't find it on the link.

[waehrik]

I'm kind of surprised that no where I found any instruction mention about clean out any engine oil that might have gotten into the engine block's head-bolt thread holes. This is very important, since oil in the hole could cause wrong torque spec at best, or even can crack the block by hyro pressure when torque down the head bolt with oil in the well. On this, I must assume these thread holes do not pass thru the block. The old iron blocks do not have thru hole thread.

Sapote

Yes, it is extremely critical that the holes are cleaned before installing the head bolts (I mentioned it back in post #26 too). The initial torque setting will be wrong and the bolts will likely strip. Brake cleaner followed by compressed air works well to clean the holes out. The holes do not pass through the block.

And yeah, the inserts are rather short. Some people have been using the 30mm long inserts with the same kit to extend the thread length. I just used the ones that came with the kit. The threads on the bolts are much much longer than the threads in the block hole. I'm not sure why, maybe to allow for a different head size? I believe the bolts are consistent across a large number of models.

[BMW330CiEric]

I just got done with this job. You can buy the Torx socket at Harbor Freight. It comes in a set for around $10. You will also need an extention. I bought a set of impact extentions for another $10. Also, you dont need the BMW specific Time-Sert kit, They have a similar kit with 30mm long inserts for less than $100. You will probably need some extra inserts as it only comes with 5. You can get this at Thread Kits Co. in Torrance. They have the best prices. Phone is #310-891-1995. Also, if you can't find a machine shop local to you, there is Precision Cylinder Head in Mission Viejo. There phone is #949-586-6680. Make sure to have your head pressure tested. I could email you a copy of the Benley Manual if you would like, as you are getting a lot of mis-information here. Here is a direct quote out of the Bently Manual "Lightly lubricate new cylinder head bolts. Install bolts and
washers finger tight. Install
cylinder head-to-lower timing
chain cover bolts finger tight.
They are not to go in "dry" as some people are suggesting. Good luck on your project.

[Sapote]

I just got done with this job. You can buy the Torx socket at Harbor Freight. It comes in a set for around $10. You will also need an extention. I bought a set of impact extentions for another $10. Also, you dont need the BMW specific Time-Sert kit, They have a similar kit with 30mm long inserts for less than $100. You will probably need some extra inserts as it only comes with 5. You can get this at Thread Kits Co. in Torrance. They have the best prices. Phone is #310-891-1995. Also, if you can't find a machine shop local to you, there is Precision Cylinder Head in Mission Viejo. There phone is #949-586-6680. Make sure to have your head pressure tested. I could email you a copy of the Benley Manual if you would like, as you are getting a lot of mis-information here. Here is a direct quote out of the Bently Manual "Lightly lubricate new cylinder head bolts. Install bolts and
washers finger tight. Install
cylinder head-to-lower timing
chain cover bolts finger tight.
They are not to go in "dry" as some people are suggesting. Good luck on your project.

I spent 8 hrs yesterday studying and planning. I think the best is disconnect the muffler from the exhaust header, but don't try to remove the header from the head (no room for those 11mm nuts - yes 11mm nut for the exhaust header. Edited to correct 10mm previously posted). I had lubed the muffler bolt/nut with brake fluid and let it soak, then will hammer on the rusty nuts via a fitted tube or socket to release the tension before attemp removing them.

I took me more than 5 hrs just to remove the intake manifold without proper guide or instruction. The hardest part is looking for the big nut that support the manifold. I had to disconnect the long vacc hose to the brake power boost, then be able to remove the plastic next to the fire-wall. This give room for unscrew the two tough located hose-clamp for the big throttle input ruber boost, then remove the throttle body, then I can see the big 16mm nut, which is bolted to lower rear area of the engine block, just front and below the starter. It's best to disconnect the big 12v cables from the starter (one goes to the alternator and the other goes up and across the intake manifold which had already disconnected at the beginning.

I also found where some of the oil leak sources: the hose connection at the bottom of the Oil Separator (the other end of this hose connected to the bottom of the oil dip stick). I had been looking for this minor oil leak for sometime when i saw it during oil draining -- the left side of the oil pan wet with oil and so this leak could not come from the leaky cylinder head cover.

So, it would be so helpful for me if you can email the repair manual, which sure will shorten the repair time a lot.

bye now

[White Knuckles2]

I'm reviewing the point suggested to install the inserts prior to pulling the head down. There is sound logic to only do the job once which is efficient. I'm thinking of the inserts as another possible point of failure that may be the final block demise. Seems worthy to buy two sets of bolts and test torque the bugger before yanking the head. Several reports from the dreaded cooling system melt-down have seen this movie where the block threads are not damaged and often heads survive where they simply replaced the gasket. Cost of a throw away bolt set but you'd have absolute knowledge of what you're facing.

Me, I have no luck. My bolts wouldn't hold finger torque and the head would need to be tested with a french curve. Kidding, but there are many variables analyzing effects of metal properties when the heat amount and duration are unknown.

[Tom D]

...I'm thinking of the inserts as another possible point of failure…. test torque the bugger before yanking the head……….. Several reports where the block threads are not damaged and they simply replaced the gasket.

sound advice.

[BMW330CiEric]

To test the threads in my block I used the old gasket and bolts. After I got my head back from the machine shop I put it on with the old gaskets and bolts and torqued it down to specs. The ones that held I did not Time-Sert, the ones that didn't hold I did Time-Sert. If the holes held with old bolts they will definitely hold with the new bolts. If you install the Time-Serts properly they will definitely hold with the new bolts. If you need the Bentley manual shot me your email. I have a pdf I could let you "borrow".

[White Knuckles2]

Guys, I don't recommend distributing or linking pirated manuals. The Internet Police may not get you but the site moderators may. There's a big deal over publications that have copywrite protection. This site is at risk and maintains strict rules as part of your use agreement.

[Sapote]

I worked on the car most of today; release the long muffler from the exhaust manifold. there are four 15mm nuts (need deep socket) hold them together. after soaking with brake fluid for a day, i had to use a torch to heat up the nuts to be able to loose the nuts, then disconnect the muffler rubber hangers at mid and end of muffler. With the entire muffler temp support by stack of wood at the same original level, then pull it out of the exhaust manifold by pulling from the tail end of the muffler.

I also loosen up the 14 E12 head bolts. I almost ran into disaster when i realized there were 2 more E8 bolts which bolt the head tight to the front chain cover piece, and one E8 to the block via the secondary chain guide. Don't forget to loose these three bolts first before break loose the big E12 head bolts.

tomorrow i will pull the head up with the exhaust manifold still attached, myself alone so far.

I think I had made enough notes and measurements that i think i can put the Double VANOS back together without the special tool. Make sure you want to cover the black hole where the primary chain with something -- you don't want a socket a anything drop down into the oil pan.

To remove the big 30mm primary chain tensioner, you cannot use socket and drive -- not enough space for the tool. I end up using the Cresent wrench on it, fit the jaw tight and wack the handle with a hammer. it is not too tight for a 30mm monster.

it took a lot of force to break loose all the E12 bolts. i use a 2 foot bar with 3/8 drive and E12 socket, and the whole thing twisted about 60 deg before the bolt broke loose with a big scary screaking sound. for a moment during the tool twisting i thought either the socket broke apart or the 3/8 2" extension would break in two. I think the break loose torque is greater than 60NM (assemble torque is 40NM, double 90 deg). Judging from this big break loose torque require, i think the threads inside the block had not been pulled from the bad event, and so i didn't even want to re-torque the bolts back to spec for testing the block's thread. my reasoning is that repeating the spec torque would weaken the soft aluminum thread -- i take a gamble here and hope come out as winner.

btw, when working above the uncovered head, be careful with the tools on your hand -- any hard metal tools accidentally drop right on top of the cam lobes will sure chip or dent the lobes. you don't want any more headache.

Sapote

[waehrik]

I worked on the car most of today; release the long muffler from the exhaust manifold. there are four 15mm nuts (need deep socket) hold them together. after soaking with brake fluid for a day, i had to use a torch to heat up the nuts to be able to loose the nuts, then disconnect the muffler rubber hangers at mid and end of muffler. With the entire muffler temp support by stack of wood at the same original level, then pull it out of the exhaust manifold by pulling from the tail end of the muffler.

I also loosen up the 14 E12 head bolts. I almost ran into disaster when i realized there were 2 more E8 bolts which bolt the head tight to the front chain cover piece, and one E8 to the block via the secondary chain guide. Don't forget to loose these three bolts first before break loose the big E12 head bolts.

tomorrow i will pull the head up with the exhaust manifold still attached, myself alone so far.

I think I had made enough notes and measurements that i think i can put the Double VANOS back together without the special tool. Make sure you want to cover the black hole where the primary chain with something -- you don't want a socket a anything drop down into the oil pan.

To remove the big 30mm primary chain tensioner, you cannot use socket and drive -- not enough space for the tool. I end up using the Cresent wrench on it, fit the jaw tight and wack the handle with a hammer. it is not too tight for a 30mm monster.

it took a lot of force to break loose all the E12 bolts. i use a 2 foot bar with 3/8 drive and E12 socket, and the whole thing twisted about 60 deg before the bolt broke loose with a big scary screaking sound. for a moment during the tool twisting i thought either the socket broke apart or the 3/8 2" extension would break in two. I think the break loose torque is greater than 60NM (assemble torque is 40NM, double 90 deg). Judging from this big break loose torque require, i think the threads inside the block had not been pulled from the bad event, and so i didn't even want to re-torque the bolts back to spec for testing the block's thread. my reasoning is that repeating the spec torque would weaken the soft aluminum thread -- i take a gamble here and hope come out as winner.

btw, when working above the uncovered head, be careful with the tools on your hand -- any hard metal tools accidentally drop right on top of the cam lobes will sure chip or dent the lobes. you don't want any more headache.

Sapote

It sounds like you're making great progress! The release of my head bolts was similar, I had to use a 36" breaker bar in order to release them and they all popped loose with an ear splitting squeaking sound.

I was just barely able to use my breaker bar with an 1-1/4" socket to loosen the primary chain tensioner. My breaker bar has a swivel head to it which when it was at an acute angle was able to reach around the AC lines there. Just something to think about since it has to be torqued back up to 52ft-lb. I wasn't able to fit a torque wrench in there, but tested the feel on a lug nut for torque comparison.

Make really really sure that the head is flat and doesn't have any microscopic cracks in it. A machine shop will be able to do this and will typically use Magnaflux for the crack inspection. You don't want to put a warped head back on. This is when they would end up having to shave down the bottom of the head to restore flatness (and when you'd remove the camshafts and bearing carriers so they can do that).

I really hope you can get the VANOS back together without the special tools. You will at least need the camshaft locking blocks though, otherwise you can't determine whether your settings are good and whether the cams are at TDC with the engine. You don't need the flywheel locking tool as long as you keep checking that the flywheel is still located at TDC.
I tried doing the timing without the alignment jig (the plate that bolts onto where the VANOS was removed) by marking everything carefully, but after two tries I kept getting a P1519 error (intake cam position incorrect, VANOS jammed). The flexible camshaft design means that even if the sprockets are tightened down in the correct places, the splined sleeves that run inside the cams are not necessarily in the right relative spot.
You do not need the tool that aligns the two sprockets to one another. As long as you keep the two sprockets and secondary chain together as one unit, it's in the right spot. You will need the dummy tensioner though, since the primary timing chain tension is essential.

You will absolutely need these special tools:
A torque angle gauge (really cheap at Autozone, etc)
Camshaft locking blocks (BMW P/N 11 3 240)
Primary chain dummy tensioner (BMW P/N 11 4 220)
VANOS setup plate (BMW P/N 11 6 150)
A small hex key to lock the secondary chain tensioner down (you don't need a 'special tool' for this)

This eliminates a bunch of the special tools that aren't necessary as long as you're real careful during assembly. By paying attention to the TDC flywheel position you don't need the locking pin and by keeping the two cam sprockets in the same position on the secondary chain you don't need the alignment jig (P/N 11 6 180). You don't need the air adapter either. If the timing is correct with the alignment setup plate attached, it'll be right with the VANOS bolted up. Plus you need a really big air compressor to keep up with the demand of the VANOS supplied with air.

[Sapote]

i'm so thankful by the help of people from this community, and by the invent of the Internet -- without these, i'm sure will make many mistakes during this tough moment. So, thank you so much for helping me here.

As about the double vanos timing, if i understand it correctly, with
1- the crank at TDC (by rotate CW at least couple turns to fully seat the spline cups into the helical gears)
2-intake vanos piston fully retracted (retard) and exhaust vanos fully protruded (advance)
3- both timing chains under full tension

then both the cam end square block's top edge should be parallel to the head's cover edge. Do the special cam locking tool have the two square cutout square to its length, or they are offset with a small angle from 90 deg? Could somebody with the tool check this out for me please? Also, is the tool two identical short pieces or one long piece?i have access to small machining job, and if needed i can have the simple cam locking tool made.

p.s. i did try to remove the long black carbon fiber heater pipe connecting at the lower left of the head to the hose at the firewall. the connection at the head was very tight (just two orings inside?). i wiggle and wedge it out with two flat screw drivers, but after about 2hrs, i gave up and end up disconnected the hose end. so this pipe will stay with the head. should i worry about cooland leak at the pipe to head connection after i had disturbed it? any thought?

Thanks,
Sapote

[waehrik]

i'm so thankful by the help of people from this community, and by the invent of the Internet -- without these, i'm sure will make many mistakes during this tough moment. So, thank you so much for helping me here.

As about the double vanos timing, if i understand it correctly, with
1- the crank at TDC (by rotate CW at least couple turns to fully seat the spline cups into the helical gears)
2-intake vanos piston fully retracted (retard) and exhaust vanos fully protruded (advance)
3- both timing chains under full tension

then both the cam end square block's top edge should be parallel to the head's cover edge. Do the special cam locking tool have the two square cutout square to its length, or they are offset with a small angle from 90 deg? Could somebody with the tool check this out for me please? Also, is the tool two identical short pieces or one long piece?i have access to small machining job, and if needed i can have the simple cam locking tool made.

p.s. i did try to remove the long black carbon fiber heater pipe connecting at the lower left of the head to the hose at the firewall. the connection at the head was very tight (just two orings inside?). i wiggle and wedge it out with two flat screw drivers, but after about 2hrs, i gave up and end up disconnected the hose end. so this pipe will stay with the head. should i worry about cooland leak at the pipe to head connection after i had disturbed it? any thought?

Thanks,
Sapote

1) The spline cups don't unfortunately seat themselves so nicely - they actually try to push out as you turn the crank and engine over. The trouble is that it's impossible to check whether the timing is set correctly because in an unconstrained condition (without the alignment plate bolted up) the camshafts will never return to the correct place. They could be set correctly but without putting everything back together and starting the engine you'll never know (if it's set right you won't get a code). That's another ~4 hours to put it all back together and tear it apart again to the point where you can adjust it. The trouble is that one spline cup isn't *quite* seated and the other isn't *quite* pulled out when the assembly is bolted down.
The camshaft locking tools are very simple - it's just two metal pieces with a cutout for the square nut at the end of the cam that runs 90 degrees to the top of the head. One important measurement to take (as detailed in the Bentley manual) is after the engine is rotated through 360 degrees and the cam lobes of cylinder 1 are once again pointing one another. The exhaust cam locking block (or substitute) MUST be flush with the top of the head. The intake side of the intake locking block may only have 1mm of spacing between the locking block and head. If this isn't the case your timing is wrong. It's nice and easy to check with these tools. Even with the alignment plate I had to redo it three times because the cams wouldn't return to their proper positions. But it only took me 10 minutes to redo it while I had everything apart.

2) The VANOS piston positions don't matter. Once the timing sprockets are bolted up properly they won't move relative to one another except when acted upon by the VANOS unit. There's no sensors in the VANOS itself to tell how far the pistons are out, so just slide it on. The little Torx screws in the middle of the pistons will attach each to the splined cup. Everything stays aligned correctly. You can replace the entire VANOS unit without distrubing the timing on the M52TU engine, unlike the single VANOS M50.

My hose was very tight too, and it is just held in with two o-rings and a hex headed bolt. It seems to get quite hot in that area and the o-rings bond themselves to the aluminum or something. I got mine pried off and replaced the o-rings with Viton versions. The pipe is pretty cheap - for peace of mind I'd just crack it off and replace it while the head is off.

Have you pulled the head off yet? I'm very curious how you fared trying to get it off with both exhaust manifolds attached. It was far too heavy for me even with someone else's help. I had to take the front exhaust manifold off (an air ratchet helps a lot here) in order to lift it. Just take a lot of care not to scratch the hell out of the head or block on the two locating dowels down there. I rocked my head back and forth and stuffed old (clean) socks in between to provide a cushion. It's inevitable that you'll slide the head around trying to get it off.

[BMW330CiEric]

It took 3 of us to get the head with the exhaust manifolds off my car. We used one person to guide it out. Just go very slow and and make sure you don't bang the head on anything, the metal is very soft. Throwing some rags under it after you get it high enough is a good idea.

[Sapote]

It took 3 of us to get the head with the exhaust manifolds off my car. We used one person to guide it out. Just go very slow and and make sure you don't bang the head on anything, the metal is very soft. Throwing some rags under it after you get it high enough is a good idea.

I work alone and my weight is 135lbs. I use a ratchet-robe attached to a long 2x4 (on two ladders) to pull it up, slowly inch by inch, and have stacks of wood pieces between the head and block. after the timing chain were disconnected, i turn the crank about 30 deg backward, and rotate both cams such as the #1 lobes were pointing directly at each other, horizontally. This position gives the minimum protrusion for all of the valves, and all pistons are below TDC.

After the head was up about 4 inches, I found it's impossible to clear the exhaust manifold from the fire-wall -- they were too long, more than 2 ft i think, and the head could not clear forward from the AC and radiator. If the head to be pulled out with the exhaust manifold, i think the only way is to pull the head at a very steep angle, front up. This is too dangerous for one person. At this 4" up position, with little more room around the exhaust, i managed to remove all 16mm nuts from the manifold. Drop the manifolds down, and ratched the head straight up and bought it out.

after using a brand new plastic credit card to scrap the head clean, I used a straight edge to check for warpage. Lenghtwise end to end, the middle section is about 0.003" higher. There is no cracks i can see. The #3 chamber, valves, and piston are so clean, from the hot steam of leakage cooland. I really think this leakage had been going for some times. I guess the gasket started with some small leak a while ago.

With 3 thou warpage, I might just remove the cams to retrack the valves in, and place it on top of a big flat machinist granite with fine sand paper taped down, and lap the head down. if lapped down 3 thou, should i buy the 12 thou over size gasket, or just use the standard?

btw, all the cylinder wall still have the original horning pattern, and my finger could not feel any ridge at the top from the top rings, even after almost 90k miles on it. This engine is still tight -- never have to add a drop of oil during the anual oil change 10k miles/year.

sapote