engine and drivetrain Paranoia and engine rebuilding

[arminyack]

My 1600 engine rebuild is progressing along....with a couple of hiccups..

 

#1. I installed the head yesterday. Before doing so, I set #1 cylinder to TDC (using a dial indicator). Then I put on the head, torqued it down, the aligned the mark on the camshaft with the oil sprayer bar and then put the timing chain sprocket /w timing chain on. The trouble is when I got around to putting the engine pulley on, and check the timing marks, this is what I see:

 

 

It's a bit off.  I was positive I got it right....but now the seeds of doubt have been sown.The spec reads it should be at the second notch with #1 @ TDC. My question is if I pull the head to check where #1 really is...do i need to replace the head gasket? Are the head gaskets on these cars one-shot items, as in, once they are untorqued, they are history due to a crush factor in the gasket that inherit in the design?

 

#2 I check my crankshaft end play. 

 

 

Spec reads between 0.00355" - 0.00685". I am at little over 0.002". Is this an issue? I should use another indicator that will give me better resolution at this scale....but its what I have availible at the moment.

[jimk]

Seeing a late cam timing and need an adjustable cam sprocket (Presuming you don't want to use a thicker head gasket).  Occurs when the head is planed and bock decked.  Center between crank and cam decreases, chain stays the same, late valve timing.

I made a timing tape and attached to the flywheel, marked a tag taped to the block for TDC with the head off.  After head was on, adjusted the sprocket for best valve timing.

Edited December 12, 2015 by jimk

[FB73tii]

regarding question 1, fine to re-use stock head gasket, particularly since it is brand new. No issue with crush memory. The more expensive multi-layer gaskets are re-usable as well. I probably would not re-use a used cutting ring gasket, though it would likely work in a pinch.

 

Agree with what Jim said, if head and/or block are decked, adjustable timing gear needed to correct. IE has them, and there is a nice one from KM Cams as well.

 

I use the IE timing gear:

http://www.iemotorsport.com/bmw/2002-valvetrain/02camspadj2row.html

 

And I use the KM Cams rockers, they are great. Here's a link to the timing gear:

http://kmcams.com/collections/justerbare-kamdrev/products/bmw-m10-justebart-kjededrev

 

Fred--2.0L, 11.3 CR, 316 cam, adjustable timing gear

Edited December 12, 2015 by FB73tii

[TobyB]

1- that's not unusual.  And not enough to worry about, unless you want to, and then you can, as Jim and Fred say, use an adjustable gear.  Or make your own by slotting the holes in a stock gear and pulling the pin.

And you can do it later if you want, for the cost of a set of front cover gaskets.

 

DON'T reuse the stock- type head gasket.  They just don't cost enough to be worth it.  I have reused them (when I forgot to bring a spare to the track) but it's just not worth the paranoia.  They're meant to be used once.  (sorry, Fred)

 

2- .002" is fine.  As long as there's some, and it runs from 0 to .002 pretty cleanly, with a positive stop at either end.  You may see some early thrust bearing wear- but probably not.  I'd only worry if it felt like it's

binding as it moves back and forth, like something's hitting a radiussed shoulder...

 

t

[jgerock]

Dumb questions: is the pulley original to the engine? Did you double check TDC on #1 against pulley marks before the head was installed? How much did the machine shop remove from the head and block?

[TobyB]

....those are pretty good questions....

 

t

[arminyack]

The engine is a mishmash of parts! A later 1600 block, with an early timing chain cover and pulley. I had to drill out one of the holes in the timing cover to accommodate a larger bolt size...BMW changed from M6 to M8 in the bolt location on the right side of the motor, just above the locating dowel bolt location. WHY they did this...i have no idea, but of course I didn't notice this discrepancy until after i got the whole works back from the machine shop....so I simply drilled the clearance hole in the timing cover in that location out to fit the M8 bolt. 

 

I did not check the pulley against real TDC, as the head was already on at that point. Exactly how much they removed from the block/ head..I do not know.

[jgerock]

Take your calipers and measure the head depth (thickness) and compare it to the Blue book. Still sounds like you need an adjustable cam sprocket.

Wonder if there are different chains for early 1600 versus 2002 blocks. I seem to recall a different chain tension device for the early cars....

[kbmb02]

Take your calipers and measure the head depth (thickness) and compare it to the Blue book. Still sounds like you need an adjustable cam sprocket.

 

To be really precise, he'd have to measure the deck height of the block as well (try finding that spec in the blue book....). -KB

[jgerock]

To be really precise, he'd have to measure the deck height of the block as well (try finding that spec in the blue book....). -KB

Agree with you there Ken - but I'm going on the assumption that it is more likely more material would have been removed from the head versus the block.

[percy]

I did not check the pulley against real TDC, as the head was already on at that point. Exactly how much they removed from the block/ head..I do not know.

 

I would not put too much faith in the markings on the stamped steel crank pulley.   I once compared two seemingly identical pulleys and one did not have any index mark (or at least we could not find one).   If I had to choose a more reliable timing benchmark, the flywheel markings would be my second choice, after manually measuring TDC.   As others have mentioned, milling the head can result in retarded valve timing, unless corresponding changes are also made to the cam drive sprocket.  I hasten to add that gears, teeth and chain wear and stretch, so if you are reusing parts, consider preexisting wear.  Yes, the tensioner will take care of some wear - but maybe not all wear.

FWIW, before the "adjustable" gears were commercially available, it was almost as easy to slightly reduce the size of the timing gear dowel pin and "slot" the gear's bolt holes to get similar results.

Here's slots to ponder:

 

 

 

 

 

 

 

 

 

    

 

Edited December 14, 2015 by percy

[dbmw2002]

Boy seems like a lot of work if The chain is off one notch on the cam sprocket. any chance?

[TobyB]

Nope, that's way too close for one whole tooth. 

 

 

t

[arminyack]

I went ahead and ordered up an IE adjustable cam sprocket, and a  new head gasket....instead of the Victor Reinz variety, it is an OEM gasket. Should any sort of sealant be used on it? I've heard talk of using a sealant on two small holes on the front, and the blue book says to use some other variety of sealant on the back of the gasket. Some here swear by Copper Coat....what should I be doing?

Edited December 15, 2015 by arminyack

[TobyB]

Use a little oil- resistant silicone (Permatex Ultra Black, here) in the 2 holes in the front where the covers join- and only do it when you're putting the top front chain cover on.

 

No other sealant, here- that thing's designed to work on dry, clean metal.

 

But you don't have to take the head off, you know?  Just the upper top cover.

And the VR 2002 head gaskets have worked fine for me for 15+ years.  And I've used at least a dozen...

 

Annnnddddd...  at this point, it's worth finding exact TDC on the crank.  Use a feeler in #1 spark plug holio, and roll the engine

forward and backward.  Eventually, you'll be able to 'feel' the middle of the TDC null- and that will be accurate to a degree.  Or less.

(and you SHOULD degree the camshaft, too, if we're going all the way down this rabbit hole, but really, take the blue pill, use the mark, call it good enough)

 

hee

 

t