Expert opinion needed regarding cam timing

[cooljess76]

Alright guys, finally got some time to work on my 332ti project. Just when I thought things were getting ready to come together, I ran into a little problem. Now this isn't an s52 specific problem as I'm sure m42/m44/m50/m52/s50 and s52 engines have the same design in regards to timing the cams.

First, I made this tool:


It's supposed to fit over the square blocks on the back of the cams and rest on the head to ensure the cams are perfectly level:




The crankshaft is set and locked at TDC. The tool I made is exactly to spec in accordance with the manual(haynes manual has a template). I've checked my tool and I'm certain that it's square and precise.

Now here's my dilema. When I put the tool on the cams, It doesn't fit precisely. Upon closer inspection, I noticed that the blocks on the back of the cams aren't even square! The tool won't sit flush on either side of the head where it's supposed to rest on because the corner of the cam blocks hit the inside of the tool. The exhaust side comes close, but the intake side needs another 1/4" or so before it even meets the head. It appears that the sides of the blocks fit perfectly into the tool, but the tops of the blocks(with the holes drilled in them) are cut diagonally/crooked. This means that all of the vertical edges of the blocks are in line with eachother, but the horizonal edges are nowhere close to being level. The reason is obvious, the blocks are not square. I dunno what to do now. I know Budget76 used a straight edge to level his cams, but I don't think that method will work on mine. Any suggestions?

Also FWIW, I didn't move the exhaust cam at all when installing the tool. The intake cam needed to rotate about 1/16 of an inch counter clockwise to slide the tool onto it. I ran the engine for about 30 minutes before I pulled it. Ran smooth, a little ticking but I attributed that to it sitting for over a month and the previous owner running 0 weight oil. So if a straight edge across the top is the proper way to time them, that would mean that the timing was way off to begin with, which I don't think is even possible. I think if I used a straight edge across the top of the blocks and bolted everything down, it would bend the crap out of my valves.

[cooljess76]

[BimmerBum]

Did you have the head off? or the cam gears?

I just went through this with mine but I bought the tool set... The vanos makes the S50/52 a little more complicated than an M4X in terms of timing.

You a youtube search on BMW Cam removal. There is an awesome hour long video. Also, check out the instructions at drvanos.com.

[b.u.ti-ful]

Is it just the verticals that need to be set?

If so, can you just cut your notches deeper to allow the tool to drop down?

[cooljess76]

Originally Posted by b.u.ti-ful

Is it just the verticals that need to be set?

If so, can you just cut your notches deeper to allow the tool to drop down?

That's what I'm unsure of. I mean, I have 4 sides that all line up with the tool, it's the top ones that don't quite fit. What's the chances of the vertical sides being off and the top sides being right? Lol, I'm not sure which edge to trust!

[cooljess76]

No I didn't remove the head, just the cam sprockets. I had to remove those in order to get to the torx head bolts that go into the lower timing cover via the head in order to replace the gasket. I bought the sprocket tool, but figured I'd make the cam alignment tool to save some cash. The tool I made is perfect though, so I doubt if I were to buy a cam alignment tool that it would work. It's the cam ends themselves that are mis-cut. Yeah, I seen a few of the videos on youtube. Those are very helpful.

[cooljess76]

Well I found these pictures of another misaligned cam. The tool used is one that was actually purchased and apparently it uses the sides of the leveling blocks to align the cams. Note in the pic, the green area is where the tool is supposed to bolt together. The red area is where it's supposed to sit flush on the head:



I also read someone's post on another forum that said all of the s50/s52 cams were cut this way. I find that hard to believe, but it's comforting knowing that I'm not the only person who's encountered this and atleast I know I'm not going crazy.

So I'm starting to think that since it's really close to the way it was before I started working on it, perhaps the tops don't have to be level? I mean heck, it ran fine this way for 8 or so years right? Maybe I'll trim some more material off of my tool so it'll slide all the way down onto the cam blocks. It just seems janky that BMW would let a defect like this slide through their production line. Apparently, I'm not the only one with funky cams

[budget76]

First off Jess, good work making the tool/jig

OTOH, I'm very curious about what you've found here. If I were home, I'd whip out my spare S50 cams and snap some pics and see if they're angled like yours is. I find it very weird that they're sitting like this. I'm going to have to take a look at the spare cams when I'm home though. Too bad that's in a month; I'd be able to give you an answer within a day if I were home.

As for what to do, I'm really not sure. I know my engine's running great with using a straight edge to line up the edges with the dots: but you made the jig to BMW specs and they sit cocked, so I'm thoroughly confused.

I'd say this is a good question for BF.C, as there's more people with experience in this area there. I, as well as you, know how I set up my cams, but it could turn out that PelicanParts was inaccurate in their procedure, though I doubt it.

GL Jess, Feel free to PM me if you've got any questions. I'm no pro with BMW's yet, but BTDT and took my time making sure to do it right.

[b.u.ti-ful]

That store bought tool only cares about the vertical surface.

[b.u.ti-ful]

I'm looking in the Haynes manual and it says you can check the squareness just by using a square to check the sides are square to the top surface of the head.

[BimmerBum]

My cams sat just like this when we took the thing apart but when it went bolted everything back together the cam blocks were flat across the head.

Your cam gears back in the right positions?

Is you vanos unit bolted on?

Tension back on the tensioners?

Also... That tool you made works slightly different than the cam blocks. The cam blocks are shaped different where they go across the cams.

[minicoop900]

hey jess, were doing an m42 timing chain right now and have the engine at tdc with the factory tools and blocks, and the square levels should line up with the mating surface for the valve cover.
as in the squares should make it a straight line to each side

[thesk8nmidget]

damn i hate timing motors its one thing that boggles my mind.

[cooljess76]

Alright guys, I figured it out and it all makes sense now. The tops of the blocks do not have to be level. It's definitely the sides that need to be square with the head. Why you ask? Well I noticed that the sides of the blocks were cut/ground down, not the tops. Meaning that the factory machined them to spec. The tops are still rough as they were never machined like the sides. Therefore, it only makes sense that the tool fit precisely against the machined edge of the blocks. Anyway, I made a new tool with deeper cutouts for the blocks. It fits perfectly snug and sits level/flush across the head profile. The cuts on my tool are all perfectly 90 degrees and there's absolutely no slack where it slides over the blocks. Here's pics of the new tool in action:

[cooljess76]

Notice that the sides of the block have been shaved and not the tops:
(yes I know it's dusty in there, don't worry it'll get blown out before I button things up.)