TDC, I am so confuse

[joww3]

I have a 71 Charger with 383 mag, I am in the process of replacing the camshalf (Purple cam), timing gear, distributor (Mopar electronic), rocker arms, header, intake and carb. I am not pulling the head for now. my question is about TDC, when the dot on cam timing gear is at 6 o'clock and the dot on the crank is at 12 o'clock, is that always mean number one cylinder is at TDC with distributor rotor point at #1 cylinder? Is it possible that the distributor rotor is pointing 180 degress on the opposite side? would the car still run if the rotor was set at 180 degree wrong? I am so confused, please help. Right now the rotor is pointing to number 6 cylinder with cam at 6 and crank at 12 o'clock.

[mikepmcs]

 

[694spdRT]

There is a compression and exhaust stroke to consider. The piston will be at TDC on both but you need to get the #1 cylinder at the top of the compression stroke and then see where everything is at first. The firing order of a big block is 1-8-4-3-6-5-7-2 and if you look at the distibutor the #1 cylinder is directly across from the #6 cylinder. My guess is you are simply on the exhaust stroke instead of compression.

BTW, the engine won't run if it is out of time by 180 degrees either.

Good Luck

[joww3]

Thanks 694spdRT, is this mean the TDC needed for degreeing a cam is (looking at the lifters) when intake valve just closed when exhaust valve still being close and the rotor is pointing number 1 cylinder?

[TylerCharger69]

Okay...to simplify this for you....if the cam gear mark is at 6 o'clock and the crankshaft is at 12 o'clock....aim the rotor on the distributer to cylinder 6.  If you aim it at cylinder 1, you'll be 180 degrees out.  Now...if both marks are at the 12 o'clock position, then put the rotor at cylinder 1.   Assuming the engine is mostly stock, and the cam has been degreed properly.  Some radical engines require so much degreeing, that the little dots application is out the door.

[Chryco Psycho]

I agree with Tyler , with the gears at 6 & 12 the dist should be pointed at # 6 cylinder as the engine will be on TDC firing ofr #6

[694spdRT]

That makes sense...sorry if I confused you joww3.

[joww3]

Thanks for everyone's help. I was confuse on installing a new distributor and degree a new cam. I kelp thinking I should line up the timing gears the same way for both. I think I got it now. To install a new distributor I need rotor pointing to #1, and cam and crank gears both at 12 o'clock. and to install and degree a cam, rotor will be pointing at #6, and cam gear at 6, and crank gear at 12. I have been reading a lot of articles about how to degree a cam and installation. eventually I will get it. Thanks again.

[TylerCharger69]

There's a lot involved in degreeing a cam...it's more than just lining up dots.  A lot of math involved...but as long as you have your cam card....and you've read articles.....you should have no problem....mine took a 2 degree cam key....

[TylerCharger69]

Here's a link for you to help you out.

www.pirate4x4.com/tech/billavista/ PDFs/Crane%20cams%20Degreeing%20a%20cam.pdf - 

[TylerCharger69]

Sorry...apparently...that link doesn't work.    Do a google search  and it's the second or third one down...type in...degreeing a camshaft in the Google search engine

[joww3]

Thanks, TylerCharger69, I had been reading a lot on degreeing a cam, I think I got the math part down, I think I was really confusing myself with the dots, and 6/12 o'clock, #1,#6 rotor positions. But I think I am getting better now. BTW do you live in Tyler,TX or you just use Tyler as your login name?

[TylerCharger69]

LOL...Tyler is my last name....but I live in Corpus Christi Texas