installed new cam and now a miss

[simplyconnected]

You take too much for granted in your build which provokes even more questions.

• Did you have any machine work done?
• Were the heads or block milled to make them straight?
• What head gasket thickness did you use?
• Did you check 'valve-to-piston' clearance? <--this is important

I verify my cam/crank timing by comparing the rocker arms to the crank's TDC. Here's how:
Look at your firing order:
Since this is a 4-stroke engine, it takes two revolutions to complete a cycle.
1-5-4-2 <--first revolution
6-3-7-8 <--second revolution

That means, when #1 piston is at TDC so is #6. If #6 rocker arms start motion as you rotate the crank in the correct direction, the exhaust comes up first, then the intake starts motion. Right then, when both rockers are dead even (use a straight edge on the rocker arms) they are both slightly open. That means #1 is on its power stroke. STOP right there.

At this point, the crank timing should point right at TDC. The distributor's rotor should point a hair before #1 spark plug tower, which should also be lined-up and pointing at #6 piston.

If your crankshaft timing marks are off, so is your timing chain. This requires, pulling the chain off and doing it over.

Let's assume cam timing is ok. If the distributor rotor is not pointing directly at #1 spark plug tower, your distributor is off a tooth, which makes spark happen between distributor towers. Sometimes the spark 'jumps' to the correct wire and sometimes it jumps to the wrong spark plug. If it is off, re-drop the distributor at the correct gear mesh.

I don't like playing, "what if..." but all I can go by is your answers. We have all made these common mistakes but as you learn more about the mechanics of your engine you will realize, all these settings can be verified before sealing with gaskets. - Dave

[StealthSRT10]

[*]Did you have any machine work done? no i did not. there were no issues before heads pulled. i know that doesnt really mean much but anyways.
[*]Were the heads or block milled to make them straight?
[*]What head gasket thickness did you use? fel pro headgasket dont know thickness. origional was metal.
[*]Did you check 'valve-to-piston' clearance? <--this is important no i did not.

I verify my cam/crank timing by comparing the rocker arms to the crank's TDC. Here's how:
Look at your firing order:
Since this is a 4-stroke engine, it takes two revolutions to complete a cycle.
1-5-4-2 <--first revolution
6-3-7-8 <--second revolution

That means, when #1 piston is at TDC so is #6. If #6 rocker arms start motion as you rotate the crank in the correct direction, the exhaust comes up first, then the intake starts motion. Right then, when both rockers are dead even (use a straight edge on the rocker arms) they are both slightly open. That means #1 is on its power stroke. STOP right there.

At this point, the crank timing should point right at TDC. The distributor's rotor should point a hair before #1 spark plug tower, which should also be lined-up and pointing at #6 piston.

If your crankshaft timing marks are off, so is your timing chain. This requires, pulling the chain off and doing it over.

Let's assume cam timing is ok. If the distributor rotor is not pointing directly at #1 spark plug tower, your distributor is off a tooth, which makes spark happen between distributor towers. Sometimes the spark 'jumps' to the correct wire and sometimes it jumps to the wrong spark plug. If it is off, re-drop the distributor at the correct gear mesh.

I don't like playing, "what if..." but all I can go by is your answers. We have all made these common mistakes but as you learn more about the mechanics of your engine you will realize, all these settings can be verified before sealing with gaskets. - Dave

I do appreciate the time everyone takes to help with problems.

[simplyconnected]

I straightened out your quote.
Some new cams come with a lower profile. They need a different rocker arm ratio in order to work correctly. I'm not sure what cam you bought, so I can't tell. I don't know if you advanced/retarded the cam timing or not. Aftermarket head gaskets are usually ~.040" thick. If you still have your original head gaskets, measure them.

As a rule, I never throw any parts out until the job is complete, but that's me. I also take LOTS of pictures as I go.

If you don't understand the technical part of my post, read it a few times. There are many mechanics who don't fully understand engines but they know how to change parts. This can be dangerous if clearances aren't tested.

Lifter preload is right up there as well as piston-to-valve clearances. Your new cam has a different profile than the OEM cam. - Dave

[StealthSRT10]

I bought the comp cams kit
#33-207-4

the camshaft is a 265DEH-10

[simplyconnected]

That cam is a very mild, nearly stock camshaft. You shouldn't have any problem with it. I checked the spec's and it is very compatible with standard rocker arms and pushrods.

Be careful with shorter pushrods, since you had nothing milled and you are using a thicker head gasket than stock.

Your lifter pre-load should be .025" to 0.040". I like to target .030" when the lifters are on the cam's base circle. That gives plenty of elbow room in case a lifter sticks or collapses. - Dave

[StealthSRT10]

ok so push rods are good now. didnt solve the problem. i think its the spark plug wires only thing left. So swapped them out. thats all good but randomly the positive terminal on the ignition coil has almost no voltage when cranking . it has 12volts when in the run position. i have been doing a little research and just dont want to start hacking into wiring. exaggerating of course.

any ideas on why i have no voltage on terminal at crank?

The car did run after pushrods btw.

[StealthSRT10]

i had a warranty on my accel ignition coil so i replaced it just to save a trip to the store when i got the new wires. same problem before and after.

[jopizz]

When you crank the engine you bypass the coil resistor and have straight 12 volts from the solenoid on the small brown wire. Running you should have 6-9 volts. That's assuming you still have conventional points and didn't convert to electronic ignition.

John

[simplyconnected]

You have a dead cell on your battery causing a bad voltage drop under load. Swap with a known good battery.

[StealthSRT10]

gonna give that a try this morning. thanks guys.

[StealthSRT10]

ok so i wasnt paying enough attention before. got the car running again. part of my issue is i wired the coolant temp sensor and the positive terminal on the ignition coil backwards. red and white wire and red and green. so thats fixed.

Now my engine coolant temp gauge doesnt work. did i fry the gauge or the sensor?

Also the car doesnt have a miss when i drive it only if the vacuum advance is completely disconnected and plugged. WTH!!

[jopizz]

Ground the sender wire to the engine and turn the key on. If the temp gauge doesn't move then either the wiring, the CVR or the gauge is bad. If you have a test light put it on the wire. You should have a pulsing light. If so the wiring and CVR are good and it's probably the temp gauge that's bad. If the temp gauge goes all the way to H then the sender is bad.

John

[scumdog]

Also the car doesnt have a miss when i drive it only if the vacuum advance is completely disconnected and plugged. WTH!!

Possibility of a hole in the diaphragm? i(nside the vacuum can) - put a hose on it and suck to see if air comes through.

[StealthSRT10]

The distrobutor is brand new. the old one was doing the same thing. i have been reading about adjusting the vacuum advance by using an allen wrench and turning it. i just know the engine shakes really bad with the way the vacuum is currently set up.

[StealthSRT10]

nvm my distro isnt adjustable that way.