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Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 12:34 pm
by StephenB
Some of you might remember that I am rebuilding a 600cc /5 engine to match my frame. I pumped some money into your (US) economy and had the crankshaft and camshaft professionally installed. Obviously, they are not aligned or connected through the chain yet. And there exactly lies my problem: the block is COMPLETELY empty with just the camshaft and crankshaft installed plus their respecting gears that don't seem to have OT marks. Never mind that without rods and pistons, I don't know where OT is anyways.

So, I need a How-To: how to install a camchain when you have lost your alignment between cam- and crankshaft and have no rods or pistons installed.

Thanks, Stephen

(I usually know what I'm doing and I can follow instructions so fire away!)

Re: Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 1:21 pm
by melville
Is the flywheel on? How do things look at OT?

Re: Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 1:36 pm
by StephenB
Flywheel is on, read the post again for OT related question.

Re: Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 6:23 pm
by Deleted User 72
When I replaced the timing chain on my '73 /5 there were marks on the sprockets (cam & crank) which had to be adjacent when installing the master link.

Re: Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 8:03 pm
by StephenB
Flywheel is installed, so OT can be set for the crankshaft by the looks of it, the camshaft gear however has no mark, hence my question: "how to install a camchain when you have lost your alignment between cam- and crankshaft and have no rods or pistons installed"

Stephen

Re: Cam-/crankshaft installation ... lost alignment

Posted: Wed May 30, 2012 9:59 pm
by Motorhead
Since OT has both pistons out

cam alignment is oneside exhausting

other side in fireing position

use right and left for which to choose

but the real question why no marks to align?????

Re: Cam-/crankshaft installation ... lost alignment

Posted: Thu May 31, 2012 5:56 am
by ME 109
There was a time when a question like this would be answered in short order.
I don't know Stephen, sorry.
A sign of the times I guess.

Re: Cam-/crankshaft installation ... lost alignment

Posted: Thu May 31, 2012 7:29 am
by StephenB
Motorhead wrote:but the real question why no marks to align?????
I am past that point but it is strange. I know from own experience that replacement crankshaft gears don't necessarily have a mark, so if it was all lined up you knew where the camshaft set at you just removed the worn gear and ball bearing and, put the new ones on and Bob's your uncle. I guess the keyways could give it away?

Re: Cam-/crankshaft installation ... lost alignment

Posted: Thu May 31, 2012 6:36 pm
by Deleted User 72
You might try this...
When at TDC one side's valves are "rocking." That is, the exhaust is just closing as the intake is just opening. Those two lobes of the cam would be "pointing" to their cylinder head. Of course, neither lobe would actually be aligned with the cylinder, but the average position of those two lobes would be. So you could get an alignment this way, and then check it very carefully after full assembly, before ignition.

Re: Cam-/crankshaft installation ... lost alignment

Posted: Thu May 31, 2012 7:39 pm
by vanzen
A degree wheel, a dial indicator, and some improvised fixtures
will allow mapping of TDC and the relationship (valve opening) of the cam.