need serious help...79 cam replacement...wont start

Hey guys, need some real help here..my 79 had been running like garbage and was in need of a cam replacement...no big deal... I now have all back together and it wont fire at all...during installation
Itook care to make sure timing marks on cam and crank lined up...when i first removed the distributor i marked the shaft and intake to make sure it went in as it came put.. did have to rotate oil pumpgear during install to get as close as possible to origanal and still have rotor firing on number one...once all was back together, i rotated engine so balancer was lined on 0 degrees, checked rotor, it was one number one...finished assembly, checked wiring to distributor....and voila!!..nothin.......engine just cranks to the point of battery exhaustion without even a fire....gettin fuel..what the hell am I missing????? ignition componetnts are less than 50 miles old... Any suggestions are appreciated either here or at snipped-for-privacy@mindspring.com Im really frustrated and just want my ride back. tia Larry in Va
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You could be one revolution off. Were BOTH valves closed on #1 AND 0 deg on the wheel!
Larry O wrote:

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i wasnt aware Both valves could be closed at the same time..?....with the timing marks on the crankshaft AND the camshaft aligned, was under the impression that the number one cylinder would be at TDC on the exhaust or the firing stroke...if the distributor is 180 out, couldnt i just pull and adjust the rotor to fireon number 6??? larry


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Both valves will be closed at TDC on #1 firing. On #6 firing, you will be changing from exhausting the cylinder to intaking the cylinder, and with some, there is enough overlap that both will be open but not all cams have that much, or that much lift in the overlap, so they will look "closed". However, they will be tight to grab, since there is some pressure on the rockers. The valve may only be open a few thousandths of an inch, which you may not see of detect, but it prevents the rocker from being loose or the pushrod from spinning freely.
I think usually the cam gear and the crank gear align on #6 firing. Most think it is TDC for #1, but it isn't.
You will have to pull the distributor out and adjust, but you have to know where you are first.
Or you can just reposition all the wires. done that on more than one frustrated late night.
Im really frustrated and just want my ride back.

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Do you know the valves are set close enough to be able to run?
Im really frustrated and just want my

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i ws thinking same thing.. the valve adjustments are real critical after the new cam has been installed there is a sequence that must be followed in order forthe engine to run
http://community.webtv.net/jcorvette/MYMOSAICS
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you was thinking the same thing as what ? try using quotes..
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Both valves must be closed on the compression stroke and the power stroke for the engine to fire. Due to overlap the intake valve closes slightly after BDC on the comp stroke and the exhaust valve opens slightly before BDC on the power stroke. so after the intake closed on comp stroke as you get to TDC is when the spark should arrive. If you are one revolution off the spark is coming after the exhaust stroke and before the intake stroke.
Larry O wrote:

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This is the simplest and most common problem people have when doing major work like cams or rebuilding.
Here are some things to do.
Pull the driver's side valve cover off.
Turn the engine over by hand or have someone bump it until the harmonic balancer timing mark is at 6 degrees before TDC. With a new cam, don't crank it more than you have to before break-in, so if your bumper is sloppy, crank it by hand..
As you get close, watch the first rocker. If it is moving, then you are timing for #6. If not, you are timing for #1.
At 6 degrees before, both intake and exhaust rockers (second and first respectively) should be even and at rest. (You should be at the top of compression, and both valves would have been closed for the upward stroke.) They may even wiggle if you grab them.
Put the valve cover back on.
Put your distributor in now, with the cap off. The rotor should point to where the #1 spark plug wire will be in the cap. Put the cap back on.
Put a test light on the negative (-) side of the coil. Turn on the ignition (don't crank).
Turn the distributor very slowly counter clockwise. When the light goes out, stop. You may have to back up and try a few times to get just the right spot where it goes out.
OPTION: Instead of the test light, you can hook a timing light to #1 spark plug wire and watch for the light to flash. Remember, as soon as it flashes in the counter clockwise turn, stop.
Lightly snug the hold down clamp.
Put the timing light on #1 if you haven't already.
Pour a couple of ounces of gas down the carb. I'm assuming the carb is full since you have already been cranking it. Otherwise, pour some gas down the vent tube to fill the bowl.
Start the car. Better to have someone crank it and you work the gas. Keep your face away from the carb.
Check the timing and set the distributor. Tighten hold down clamp.
With a new cam, you need to run about 1500-2000 rpm for 20-30 minutes as soon as it starts, depending on what your cam manufacturer suggestions for break-in. You should watch oil pressure and water temperature, and unless pressure is very low (for example, running 20 when normally 30) or water temperature high (running 200-220 when normally 180), keep running for the full break-in time unless you hear parts breaking or severe fluids leaking (oil pouring out somewhere, water running everywhere.
I have set the hydraulic lifters during this time if you don't have them set already.
After you have done the break-in, drain the oil and pull the oil filter off. Cut it open to check for metal in the filter. You may see some, but if there is a lot, you might have a problem.
If no problems, leaks, metal, overheating, and so on, put in fresh oil and a new filter and go have fun.
Good luck. Hopefully, I didn't leave anything out.


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Good Lawd this is making me crazy..lol...ive done this before altho it was 20 years ago and ive probly killed those brain cells that retain simple process by now.....i had even questioned myself to the point where i opened the front back upto make sure i did have the marks touching on the timing gears... ok..tommorrow i will back up a step and do as youve suggested tom..one question tho...will a simple testlight suffice? such as the type for testing circuits? I told my wife that this is driving me to drink...she told me not to worry, i can walk that far..lol thanks guys..ill keep posted. Larry


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If you want to find out exactly where TDC is, use a manometer, easy to make easy to use, I put a webpage up about it:
http://www.cadvision.com/blanchas/54pontiac/tdc.html
Larry O wrote:

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make
All I do is put my finger on #1 plug hole and crank it. When you feel air pressure it's on the compression stroke.
Al
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That works but if you want to find out TDC exactly to the degree than use the manometer. One bump and the little pointer that you reference to while timing could be out by a couple of degrees or more!
Big Al wrote:

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Here's how I set hydraulic lifters:
http://www.cadvision.com/blanchas/54pontiac/tappets.html
Tried a bunch of methods but this one worked the best.
Tom in Missouri wrote:

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The second method you posted, setting them with the engine running, is the best in my opinion. Use some old towels and work quickly:)
Al
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ok guys....first off...thanks to tom and eugene, al...and all. I took a lil of everyones ideas and got the sumbitchrunnin:)....Tom..i let it run for about 20 minutes at 1500...oil pressures good, water held good at 180 after i added a half gallon..lol...[layed with carb a ll to get a fairly smooth idle...still a little rough and have a rocker tapping on the passenger side..i had gone thru and adjusted valves by eugenes schedule..awsome page btw...after 20 minutes or so..i idled it down and pulled the valve cover in order to try and adjust while running..it did minimizebut not eliminate...i did notice tho that oil was was only "squirting " thru a few rods...i decided to give it a rest for the night..then maybe go thru and readjust tommorrow after it has cooled down...any thoughts???? and thanks for all your help..reminded me again why i come here Larry in Va

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