Cam Swap

[cstmwgn]

Malc

I mean no offense BUT if you merely rotate the cam 180* to get the pin on the right side - doesn't that also rotate the gear 180*? On my Ford junk there is only one dowel pin hole in the gear. If the Chevy stuff is the same doesn't that put the dimple in the cam gear on the top (away from the crank gear)?

Again, I commend your ability to perservere - hang in there.

[65RHDEER]

If you rotate the cam 180deg it will still be phased the same in regard to the crank, if the piston is at TDC compression rotating the cam 180deg will make it at TDC at exhaust/induction. 180deg cam = 360deg crank.

You say it's running but iffy, if that's the case moving the cam 180deg will make no difference, it will still be the same.

Before it gets pulled apart that crank needs to get a degree wheel on it to find out where the cam is in regard to the crank.

Do you have a degree wheel and a micrometer, a vernier will also do as a micrometer in a pinch.

[malc]

Iīve done it, rotated the crank one full revolution installed the distributor,
rotor pointing to number one.

Lashed all the valves going by firing order...quicker and easier, running out of patience.

It still runs bad, the vac gauge in the car doesnīt even twitch....no vacuum at all....

I put some advance in it and itīll run but with some throttle, let off the throttle and itīll sign off with a pop through the carb.

I did the valves twice and noticed all but two lifters showed resistance as I tightened the nut down, exhaust 2 and 8 were not pumped as youīd expect after running the motor.
Oil pressure showed 50psi.

I was going to do a compression test on all cylinders but Iīm too tired.

[malc]

Malc

I mean no offense BUT if you merely rotate the cam 180* to get the pin on the right side - doesn't that also rotate the gear 180*? On my Ford junk there is only one dowel pin hole in the gear. If the Chevy stuff is the same doesn't that put the dimple in the cam gear on the top (away from the crank gear)?

Again, I commend your ability to perservere - hang in there.

Right, Iīd remove the gear and chain, re install the gear...rotate gear and cam then re install the chain.

But Iīve done it the easy way given to me....hurrah !!

[anotheridiot]

Hereīs where it all went pear shaped, and itīs right back at the beginning with me ordering parts.
I ordered the cam, instructions told me I needed to order Edelbrock springs for roller cam.....did that.
The instructions told me I had to purchase their timing chain too or Iīd be taking a big risk.
I didīnt, I ordered a Comp cams timing chain and installed using my Camaro manual.

The factory installation is cam gear locating pin to the left, dots lined up, number 1 piston at TDC.

Well now Edelbrock does it different, just checking their timing gear instructions which I SHOULD have
done shows they put the locating pin on the cam gear to the right.....

So now I get to go right back in and fix it.
Does it matter if I rotate the cam clockwise or counter clockwise to get the locating pin in the proper place ?

if you turn the engine by hand one revolution, the cam button is on the opposite side. ITs like people lining up the timing marks with both of them pointing up, not at each other. you turn the crank one revolution and the mark will get there. Its where you drop the dizzy either 1 firing or 6, and if you were that far off you would not be running, you would be popping thru the carburetor.

The only difference was doing a chevy 3.1 motor where the timing mark for some reason is supposed to be at 3:00.

I have been down this road, really, time it to the vacuum gauge.

[malc]

The vacuum gauge inside the car tells me there is no vacuum.
It does not respond when the motor has fired.
It's connected to the second port on my Speed Demon carb., the first is distributor vacuum.
As per carb instructions.

[65RHDEER]

You may have a large vacuum leak, that may be why you see no vacuum on the gauge and the motor runs so poorly.

[anotheridiot]

The vacuum gauge inside the car tells me there is no vacuum.
It does not respond when the motor has fired.
It's connected to the second port on my Speed Demon carb., the first is distributor vacuum.
As per carb instructions.

I dont know locations on the demon, I just know you have manifold vacuum and port vacuum. Port vacuum only comes up when the throttle blades open since they are above the butterflies, the manifold vacuum where the gauge needs to be should be under the butterflies or in the manifold itself.

The load is lighting with a valve open, so there is no chance for vacuum. The fire is pushing the air the opposite way.

I just see you at the same place you were a few thousand dollars ago, so a vacuum gauge on the manifold vacuum and turning the distributor when its running should find you some vacuum. You just have to stop trusting the marker and the balancer. Its the most difficult thing to do. It blows that the only way to check rotor phasing is by destroying a cap, but if you get vacuum turning the distributor when its running, you will need to drill a cap and correct the rotor to be able to use your marks again.

[fatguyzinc]

ok, just went thru the whole thread again and didnt see specs on the cam--
if its over [email protected] or high 280's advertised duration, and a 110 or a 108
LC, its gonna have really crappy vacuum. maybe also check the bottom
edge of intake gaskets (edge into lifter valley) for a leak.

persevere, brother--tough times dont last. tough people do.

[malc]

If I donīt freeze out there today Iīm going to put a dial on the number one lifters to find out where I am.
Also Iīll do a compression test.

Iīve done everything as Iīve done it many times before, after getting the intake manifold on I always
wait 24 hours to let everything dry out, never ever had a vacuum leak before.

Hereīs the cam card, it didīnt come in the package, I had to download it off Summit.

[65RHDEER]

That cam should pull at least 11 inches of vacuum at idle, I have a 224 @ .050 in a 327 that pulls 9.5 inches.

I looked up a diagram of a Demon Carb, the way Malc explains the way the vac ports are makes sense. Ported/throttle vac is in the base plate on a Demon.

[malc]

I managed a compression test, all cylinders came in at 150psi, except number two that was 160psi.

Compression ratio is 9.80:1.

[65RHDEER]

I managed a compression test, all cylinders came in at 150psi, except number two that was 160psi.

Compression ratio is 9.80:1.

I think that they may be a little low, my 327 with 64cc chambers is about 175 in each hole.

Pointing to cam timing...

[malc]

I think that they may bg
e a little low, my 327 with 64cc chambers is about 175 in each hole.

Pointing to cam timing...

S'what I thought too...before this farce I had 180 but that was with 10.25:1 compression.
I'm using a thicker head gasket now.

[anotheridiot]

we had low vacuum with a .600 lift cam and .310 duration, which was what we wanted to build with a lopey idle and we paid for it.

compression is great and is just going to start reducing as the valves start to get full of carbon again since you are firing with one of the valves open.

Like I keep saying, trusting your distributor is firing correctly since its always supposed to happen is the hardest thing to accept, but mechanically you are all right. Your compression is proving you are right. This is what the distributor does, drives you crazy questioning all your mechanical mistakes, but you have made none. Just break the distributor loose, put a vacuum gauge where you can see it and rotate the distributor a little. This drove me more insane than your motor is driving you, just see if you get a response. At that point you can choose to change it or just borrow one.