engine and drivetrain Cam Timing

[doug73cs]

After a year of ignoring this I am ready to reassemble the engine and getting my 76 Sahara back on the road – hopefully solving old problems without creating any new ones.

 

In order to get the head and block playing nice I need to set the cam sprocket to the crank and I want to get it right the first (second actually) time.  It’s a 1974 E12 head and unknown block ( #5461577) with flat top pistons rebuilt approximately 10,000 mi ago.  A decent stock motor that doesn’t burn oil.

 

As it sits, the piston in cylinder 1 is at TDC (as is #4), the cam lobes on cyl 1 both point down with the exhaust coming on next and cam lobe #4 is fully open on intake.

 

There is only one set of notches on the crank pulley and it is after TDC relative to the tab cast into the lower timing case at the bottom of the photo (my white mark on the pulley opposite the tab is at TDC). 

 

The cam sprocket mounting flange is set with mounting holes are “square or parallel” to the plane of the cylinder head and the dowel is at 7 o’clock. 

 

 

The mounting flange has a line followed by the number 2 cast into the edge preceding my white mark that indicates where the cam sits (with the flange square and parallel to the head) centered on the oil bar.

 

With the #1 piston at TDC, is the line on the mounting flange with the #2 what I set the cam sprocket to using the oil bar as the centerline? 

Edited June 23, 2014 by doug73cs

[Stevenc22]

There is a mark cast into the head under the oil bar to which you line the mark on the sprocket with.

 

In your first picture, the cam looks out of alignment. The line cut into the cam sprocket next to the "2" should be lined up with the center of the oil bar.

 

http://www.bmw2002faq.com/topic/142843-changed-head-gasket-will-not-start/?p=935689

Edited June 23, 2014 by Stevenc22

[Preyupy]

Look at the timing mark on the flywheel through the hole in the bell housing just above the starter.  You want to see the "OT" mark that is true TDC.  The White mark you have on your camshaft is WRONG!!! the notch next to the "2" on the cam is the true TDC mark and it should line up with the mark on the head right below the oil spray bar (your white mark is in the correct location, it is jus the wrong mark).  The timing mark on the front cover is a pin that is at about 1 o'clock if you are looking straight at the front pulley 

[Hans]

I don't think later blocks had the pin on the front, and I was not aware of that flange being appropriate. Best to use the flywheel, and then perhaps transpose mark to front pulley in a convenient spot.

[doug73cs]

Thanks to all for confirming that the line marked 2 is the correct reference to align with the oil bar - the casting under it doesn't have a notch so the bar will do.

 

As far as setting the #1 piston to TDC, I marked the pulley and the tab cast into the lower timing cover when I had the head off so that should suffice.  I can't see the OT mark on the fly wheel but that could be for any number of reasons (rust, dirt, human error).

 

Thanks again - I may be back.

Edited June 23, 2014 by doug73cs

[TobyB]

yeah, there's just a flat on the head, maybe 5mm or so wide.  Center the cam line in that flat.

 

And the flywheels are not always safe- if the dowel's been left out to let the starter chew on a 

different part of the ring gear, then it'll be off by some /8th's of a rotation.

 

I do it by feel with the head off, and make a TDC mark somewhere easy.  

 

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