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camshaft installation question
I rebuilt my 69 351w 4v. The rebuild kit included this cam
Clevite 77 RV cam...
270/280 adv. duration, 204/214at.050", 448/472 lift, 107/117 lobe sep.
The cam was installed "straight up", but when I try to turn the car on a big ball of fire comes out of the carb and an explotion is heard. So I know it`s a timing problem. I located #1 TDC and installed the distributor pointing to the #1 plug. So it is not 180º off. Another thing is that it only "starts"(throws the ball of fire) with the distributor in a "retarded" position. (turned to the right from where it apparently is at 0º)It wont start in any other position. Im not 100% sure if the mechanic has tried in an advanced position but i think he has. I checked the firing order by spinning the crank with a ratchet and looking at the valves and it is the same as the one on the intake manifold. So the firing order is OK. So that leaves me with the cam.
Do you think it maybe needs to be installed one tooth or two either advanced or retarded???? Otherwise im gonna have to go with the original cam, but I would rather have the clevite one in since I paid some hard earned money for it. What do you think guys?
Thanks in advance for any help.
Clevite 77 RV cam...
270/280 adv. duration, 204/214at.050", 448/472 lift, 107/117 lobe sep.
The cam was installed "straight up", but when I try to turn the car on a big ball of fire comes out of the carb and an explotion is heard. So I know it`s a timing problem. I located #1 TDC and installed the distributor pointing to the #1 plug. So it is not 180º off. Another thing is that it only "starts"(throws the ball of fire) with the distributor in a "retarded" position. (turned to the right from where it apparently is at 0º)It wont start in any other position. Im not 100% sure if the mechanic has tried in an advanced position but i think he has. I checked the firing order by spinning the crank with a ratchet and looking at the valves and it is the same as the one on the intake manifold. So the firing order is OK. So that leaves me with the cam.
Do you think it maybe needs to be installed one tooth or two either advanced or retarded???? Otherwise im gonna have to go with the original cam, but I would rather have the clevite one in since I paid some hard earned money for it. What do you think guys?
Thanks in advance for any help.
1 - 7 of 7 Posts
I doubt it's got anything to do with cam being installed straight up.
I'm with the others. It's not enough to have #1 at TDC, it must be at TDC of the compression stroke (it will also be at TDC on the exhaust stroke). Also, if the piston is at TDC of the compression stroke, the rotor should be point to just AFTER the no. 1 piston (it should fire BEFORE TDC).
As mstngjoe already mentioned, you'll get the fireball effect also from having the valves not closing all the way.
I'm with the others. It's not enough to have #1 at TDC, it must be at TDC of the compression stroke (it will also be at TDC on the exhaust stroke). Also, if the piston is at TDC of the compression stroke, the rotor should be point to just AFTER the no. 1 piston (it should fire BEFORE TDC).
As mstngjoe already mentioned, you'll get the fireball effect also from having the valves not closing all the way.
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18 Posts
I also echo the 180 deg comments.
Also, what carb do you have on it? A VERY lean carb will do the same thing. Try jetting up a size or 2 if you are sure you are not 180 out.
Also, what carb do you have on it? A VERY lean carb will do the same thing. Try jetting up a size or 2 if you are sure you are not 180 out.
I found #1 TDC by looking at the valves that both were closed and if i turned it a bit more then the #6 intake valve would start to open. So im pretty sure it was on the compression stroke. The carb is a motorcraft 4300, I know it should be an autolite since it`s a 69 but it says motorcraft it was probably changed by the previous owner.
Do you think it might be the valve springs that needed to be changed??? I left the original ones in there. I was told i could leave those in there and i would have no problem. They had a 1.47 OD and i cant remember the Inside diameter.
What do you think???
Do you think it might be the valve springs that needed to be changed??? I left the original ones in there. I was told i could leave those in there and i would have no problem. They had a 1.47 OD and i cant remember the Inside diameter.
What do you think???
Joined
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1,655 Posts
Some additional elementary points...... the distributor rotor turns counter clockwise (looking down on it), and the cylinders are numbered (both from the front) 1-4 on the passenger's side and 5-8 on the driver's side. Also make sure the spark plug wires are connected correctly.
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