timing problem?? urgent

[jrobie79]

so I changed my head gasket, put everything together, had the cams locked in place and the cam gears zip tied to the chain, so I figured everything was ok for reassembly.

I go to start it up and this is what it sounded like:



I knew this wasn't right so I shut it off did some basic reaserch and figured it was the timing. So I took the valve cover off again. There are 15 "dots" between the two arrows on the cam gears. I used the dowel in the flywheel to lock it at TDC cylinder 1, however the square ends of the cams aren't in the same plane when its locked TDC, see below:









How would I go about fixing this?

[roguetoaster]

Is the mark on the vibration dampener lined up with the arrow on the oil filter housing?

That, and you have two pictured things messing you up, your cam squares are not square, your cam sprockets do not have the bolts centered in the slots (both of these might be fixed by squaring the cams).

Fix it by verifying that your dampener mark lines up, lock the FW with something that fits as tightly as possible, and gently square the cams with a wrench/adjust the cam gears (might require removing a cam gear or two to accomplish this).

[jrobie79]

so basically, I take the cam gears off the cams, without zip tieing them to the chain, then I use the adjustable wrench to tweak the cams so the squares are in the same plane? (I think the exhaust one is the only one that needs to be adjusted) once that is complete, make sure the crank is TDC via the flywheel lock and the marks on the oil filter housing, I attached the cam gears so there are 15 chain rivets between the arrows (making sure they are perpendicular to the head surface?)

does all that sound right?

[bmwman91]

Sounds like mine when I had the gears off by a tooth or two. Pistons + valves. LUCKILY, this engine seems to be tolerant of that because I got another 70k miles out of it before something else grenaded.

Set the crank to TDC. The flywheel dowel is all good and well, but you really want to pull the plugs and measure an 81mm difference between the piston crowns in cylinders 1 and 2. Actually, there is probably a bunch of carbon in there so scratch that. Carefully put a metal rod down the plug hole of #1 and rotate the crank until you can see the rod top-out. Mark it if you need a visual reference.

Next, loosen all 8 cam sprocket bolts. Use a big long screwdriver or other metal rod to pry on the chain tensioner rail to make sure that it is tight (the tensioner piston alone isn't enough IMO). This will ensure that the chain is actually tightly referenced to the crank's TDC position. Square up the cams' rear squares and tighten them down. You really want a 2nd set of hands helping you with this...have your helper pry the chain tight. Not TOO tight, but enough to ensure that there isn't any slack on the driver's side.

[jrobie79]

the pistons are all very clean, I cleaned them when I changed the head gasket. To square up the cams just an adjustable wrench will suffice? I can have my dad help me if two people is better

[bmwman91]

Yeah, I have always used a big crescent wrench on the square ends to position them.

Make sure that you have a good flat reference surface. On a stock setup, you just need to get the two cams' ends to sit parallel with your reference block.

[jrobie79]

so there should be no reason to take the chain off the sprockets? once the cams are squared up, regardless of position the bolts are in the sprockets i should tighten it down? I've heard the bolts are supposed to be in the middle of the sprocket holes.

[bmwman91]

It depends on how "off" the timing is. If you are off by a whole tooth, then you will need to get the sprockets off of the chain to reposition them or else the bolt holes won't line up enough. And yes, on a stock M42 the bolts are supposed to be centered in the slots.

[jrobie79]

ok, i think I can figure it out, thanks everyone!

[jrobie79]

got everything aligned...noise went away. However, I still have FU**ING white smoke coming out the back. It's only filled with water right now as I was going to flush the cooling system, but the white smoke is still there. Also when I drive at WOT it stumbles and hesitates. I took the head from my sisters car, which had no white smoke however it did have the WOT issue. Could this be a bent valve? Also since the white smoke is still coming out, possibly my block is cracked? Seems like two problems on this one. Any suggestions?

[bmwman91]

I'd think that a bent valve would lead to poor idle and poor performance at all RPM's and throttle positions. A leaky valve is usually pretty noisy (makes the engine sound like a tractor because of exhaust blowing back up the intake). If it is ONLY at WOT, then a sensor might be pooped.

Does the white smoke occur constantly, even after the engine warms up? If so, then yeah it is probably a cracked head. Removing and reinstalling it may have exacerbated an existing hairline crack.

[jrobie79]

yeah the white smoke is there constantly, obviously as the RPM's climb the output of white smoke goes up too. So that is making me think its the block being cracked - I took the head off my m42 and knicked it up pretty good on removal - so I took the head off my sisters m42 (which was stumbling at WOT - however she had no known white smoke, just the stumbling at WOT). I put "right stuff" on the profile gasket and put everything together correctly.

This makes me think my initial problem could have been a cracked block (I changed HG because of overheating and white smoke) and then the stumbling issue is new since I put her head on (same symptoms as her car before she junked it).

I think I'm just going to find a running m42 and plop that in - I'm going S5X swap this winter when I park it.

[bmwman91]

I would be very surprised if the block cracked. I believe that a crack in the head between cylinders 2 & 3 is very common. The only way for you to end up with white smoke in the exhaust is to have either a cracked head or a leaky head gasket. You should also be getting a lot of air in the coolant system if that is the case. MAYBE you mixed up one of the TB heater hoses and are accidentally shooting water into the intake? It's a long shot lol.

[jrobie79]

very longshot, I'll take a look tonight. I've had an m42 powered car for the better part of a decade haha and the mess under the intake has been performed, no TB heater plate.

I'm gonna inspect my other head and see if I can see anything. Probably going to get that resurfaced and slap that in

[roguetoaster]

You know, the block can be distorted/bowed enough to prevent proper HG sealing. Pull your plugs and see if you can see some liquid in any combustion chamber.

The other possibility is that the fuel has a substantial amount of water in it. Was it sitting over the winter?