Camshaft Installation question
Thread Starter
Racer
Joined: Jan 2004
Posts: 463
Likes: 0
From: South Haven MI
Camshaft Installation question
My compcam instructions specify to have the engine at #1 TDC and the timing marks on the crank and cam gears are aligned together (next to each other). Now, in my Haynes manual it states that #1 TDC has the timing marks on the gears aligned in the 12 o'clock posistions.
What is correct? Can anyone clear this is up for me?
What is correct? Can anyone clear this is up for me?
Racer
Joined: Jun 2004
Posts: 322
Likes: 0
From: The Dirty, Dirty South
My Comp Cams instructions said the same, the Haynes manual I have has a picture showing the two marks aligned next to each other, but the text said both at 12 o'clock, so I asked a mechanic, and he said all the ones he's built have been next to each other, but to call Comp Cams since I was using their timing gear set. I installed it with the marks next to each other, and I have had no issues, but I still wonder, so I'll be waiting for the replies also, to see if I need to adjust my cam!!!
Racer
Joined: Jun 2004
Posts: 322
Likes: 0
From: The Dirty, Dirty South
Ok, after further investigation, if the two marks are next to each other, that would be TDC on the exhaust stroke for the #1 cylinder. If both are at 12 o'clock that would be TDC for the compression stroke for the #1 cylinder. So either way will work, just make sure you are at TDC on the compression stroke for #1 when you re-install your distributor. Somebody correct me if I am wrong.
Thread Starter
Racer
Joined: Jan 2004
Posts: 463
Likes: 0
From: South Haven MI
I'm not installing new gears or timing chain. This engine has only about 10K on the rebuild but I wanted a lopier cam. I installed via the compcam instructions. Valves are closed on the #1 and the piston is at the top of the stroke and the distributor points at the #1. Given all that the cam must be installed correctly right?
Race Director
Joined: Mar 1999
Posts: 10,258
Likes: 1
From: Calif.
Originally Posted by Contrail
Ok, after further investigation, if the two marks are next to each other, that would be TDC on the exhaust stroke for the #1 cylinder. If both are at 12 o'clock that would be TDC for the compression stroke for the #1 cylinder. So either way will work, just make sure you are at TDC on the compression stroke for #1 when you re-install your distributor. Somebody correct me if I am wrong.
We have a winner!
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
Newer been there - but still one qustion to add! If I would plan to change a cam myself in my garage as do-it-yourselfer should I plan a 1/2 day or whole day or how much time for that operation alltogether? 
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Instructor
Joined: Jun 2004
Posts: 233
Likes: 0
From: algonac michigan
here is how i did it
install gears w/ marks together
only because you will bee sure that you are dead on and not a tooth off
then turn crank 360 till both marks are strait up
now ready to put in dist
install gears w/ marks together
only because you will bee sure that you are dead on and not a tooth off
then turn crank 360 till both marks are strait up
now ready to put in dist
Race Director
Joined: Mar 2001
Posts: 11,322
Likes: 1
From: Living in the Hartland
I would not rely on the marks to determine tdc, use them to install the cam then rotate eng until the #1 intake valve opens and once it starts to closing spin the eng around to tdc. To be 100% certain you should degree the cam but few people do.
Burning Brakes
Joined: May 2003
Posts: 789
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From: Centerville Ga
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Not uncommon and a big mistake by many "do it yourselfers" .Very simply put, is that with the dots together, the engine is firing on 6 and not 1. The engine would be properly timed in relation to the valve and pistons, but the ignition for firing would be 180 out, so just aim the rotor at 6 in the cap and it should start up if all the valves and ect. are adjusted correctly. 
