Engine - Which Stroke?

[jtiels]

Hi Ratsun,

 

I'm putting together an engine for my Datsun 510. I'm ready to put the head on to the block. The block has the first piston straight up. How can I tell if the block is set for the compression stroke or the exhaust stroke? I don't want to install the head and have the timing chain wrong.

 

Thank you for any help,

 

Jason

[jvb5577]

Check you head.  Are the valves closed or open?  You should of had it all set at TDC on the compression stroke when you disassembled the motor.  The piston doesn't know what stroke it is on without the timing chain and head connected.  The head is going to tell you the stroke. 

[TENDRIL]

http://youtu.be/6WCSh_6GA0k

[jvb5577]

http://youtu.be/6WCSh_6GA0k

I forgot about this video!  Best video for this, I watched it about three times

[TENDRIL]

yea ! , also i think the crankshaft woodruff  key should be at 12 oclock  on tdc not 6 oclock

[DanielC]

If the crankshaft key is up, one and four are at TDC.  

The cam shaft determines if one or four are on the firing stroke.

[Driftease]

Install the head and set the cam timing and you will be on comp TDC on one

[ggzilla]

How can I tell if the block is set for the compression stroke or the exhaust stroke?

Good question, because when the crank is turned to the 0° mark, the engine may be at TDC on compression stroke or it might be at TDC on exhaust stroke.

 

What determines which stroke its on is the camshaft. And since its an OHC engine, the cam is not in the block. So ... the block is simply turned to TDC. That's all. Until you put the head on there is no difference between TDC strokes.