I moved this post (sorta) over from the 61-66 truck forum...

I'm a first time rebuilder of the Y-Block (done many others...).

I marked the timing chain, noting 12 pins, and set the cam gear and engine gear to 3 o'clock towards oil filter side and installed the timing set.

My question is, now that the heads and valve train are installed, when I spin the rotating assembly to TDC for number one cylinder (which is on the passenger side front - not the filter side) on the compression stroke, the chain and timing blips on the gears are not as they where when installing them.

Is that correct? Valve train seems to be in sync with pistons and when I put the timing cover and pointer on, along with the crank pulley, the pointer is pointing correctly at the mark on the pulley.

I can rotate the assembly and get the blips to 3 o'clock with the twelve pins between them every several rotations correctly.

From what I'm gathering when setting up the timing chain properly, the number one piston is a TDC but on the exhaust stroke, not compression stroke..

Thanks for your help!

Mike

 

You have got it right. Don't worry where the timing marks are once you set them correctly,as you have done. Remember that the cam rotates at half the crank speed, so the marks coincide only every other rotation, none of which is of any concern. All you need to do is to set the no1 piston at TDC in compression, then drop the distributor in with the rotor pointing to the no1 terminal on the distributor cap. If she has fuel, ignition,compression and timing she should fire right up.

 

Thank you!

Just need that reassurance cause I sure don't want to have to take the front end apart again once it is in the truck...

I'm used to the later small blocks where the blips point up and down at each other and number one is at TCD on compression.

 

Every cylinder will be a top dead center during some point on the exhaust AND compression strokes, just like any other 4 stroke engine. At tdc on compression, both valves will be closed.

 

I certainly realize that. I guess I was comparing it to say a 289 where when properly installing the timing chain, the number one piston is already at TDC compression stroke. To carry that further, on the 289 for example you could install the timing chain and align the distributor to point at number one without rotating the crankshaft.

The Y-Block however, after properly installing the timing chain, apparently needs to have the crank turned one revolution to get number one at TDC compression to install and align the dist to number one.

 

Oooohhhh, I see.

You don't have to turn the crank. Just install the distributor with the rotor pointing to #6. That works out to be the same thing.