Current cam 180 deg out ?

[ofb383]

Ok guys, this looks odd to me, looking at these photos, the current set up in the car and when compared to the new equipment going in, crank at TDC No 1, there looks to be 180 difference in the cam gear position / cam position ?

Did someone put the current one in 180 deg out ? you can see the marker and its up the top and kind of looks like it's pointing down

 

[CBODY67]

Here's something from the small block Chevy world, which I learned from my machine shop operative/engine builder.

Normally, with "dot-to-dot" we PERCEIVE that the engine is at #1 TDC AND is firing #1 cylinder. When, in fact, #6 cylinder cylinder (also at TDC, as it's 180 degrees away from #1 in the firing order), is firing. Actually, with the #1 at TDC AND FIRING, it's "dot top" on the cam sprocket and "dot top" on the crank sprocket.

The engine will not start/run with the cam 180 degree OUT from the distributor.

CBODY67

 

[ofb383]

My assumption put me wrong and the current setup correctly installed, everyday is a learning day. So dot top is the correct way

 

[CBODY67]

Given the multi-keyway crank sprocket, make sure it's at "0" and not "+4" or "-4" locations. Which should be in the instructions.

CBODY67

 

[Badvert65]

Spin your crank one time and you will see the marks properly align.
There are two times the piston is at the top of the bore, once for the power stroke (TDC) and the other time for the exhaust stroke. You just have the crank at the top of the exhaust stroke (#1) in the picture.
Most install directions will state "TDC - Compression stroke", but not always.
Yes, Mopar big block engines are "dot to dot".

 

[ofb383]

Given the multi-keyway crank sprocket, make sure it's at "0" and not "+4" or "-4" locations. Which should be in the instructions.

CBODY67

Yes 0 at the top gives me the correct position for 0 key and tdc on 1

 

[CBODY67]

Also be sure to put the distributor drive "gear" in the correct orientation upon reassembly.

 

[ofb383]

Spin your crank one time and you will see the marks properly align.
There are two times the piston is at the top of the bore, once for the power stroke (TDC) and the other time for the exhaust stroke. You just have the crank at the top of the exhaust stroke (#1) in the picture.
Most install directions will state "TDC - Compression stroke", but not always.
Yes, Mopar big block engines are "dot to dot".

Just found this in the book, dot to dot

 

[Badvert65]

Just found this in the book, dot to dot

View attachment 335716

Yes, exactly.

 

[stubs300]

Just found this in the book, dot to dot

View attachment 335716

The book is loaded with good info, use it!

 

[CanCritter]

[QUOTE="Badvert65, post: 814333,
Yes, Mopar big block engines are "dot to dot".[/QUOTE]

.........phew......

 

[ofb383]

The book is loaded with good info, use it!

I forget what I downloaded it and printed it off months ago

 

[70bigblockdodge]

Dot to dot gives you TDC on exhaust stroke. Dot to Dot on top gives you TDC on compression stroke and where you want to ensure oil pump drive gear is pretty close to parallel with cam then you can drop distributor in with rotor pointing to #1 cylinder terminal on the cap. At this point you should be able to see a almost lined up notch on dist flange and lip on the block if you line them up you will be ready to start up.

 

[ofb383]

I did notice that the slot for the dizzy was almost parallel with the cam before I removed the oil pump drive

 

[Timothy]

There can only be one way to time the cam correctly. The BB book I have by HP books say the timing marks must face each other on a centerline between crank and cam.
I haven't checked my Motor Manual which I usually go by.

 

[Badvert65]

There can only be one way to time the cam correctly. The BB book I have by HP books say the timing marks must face each other on a centerline between crank and cam.

This is exactly correct. I have literally built many dozens of big block Mopars over the years and always done it this way, 'dot to dot', by the book.