Just installed a new cam in my 75 vette. Also new headers and exhaust.

I adjusted the hydraulic lifters and put the distributor cap and rotor back on. When I went to start it up it just turns over and will not fire.

I do get a backfire in the headers. I can hear the gas detonating. I have checked all of plugs and I am getting plenty of spark. Also getting plenty of fuel. I tried advancing the timing and still nothing.

Any ideas! ITS NICE OUT AND I WANNA DRIVE!!!!!

Thanks,

Sam Saladino

 

find TDC and re-drop the dist.....sounds like your off by a tooth or two.

 

back to basics....make sure plug wires are correct, did you adjust the valves in the right sequence with #1 at tdc of compression stroke...my guess is the distributor is out of whack...did you take into consideration the distributor dropping in and catching the gear and rotating? why not pull valve cover off the drivers side, and distributor cap watch number 1 valves and hand crank the engine over watching the rotor and the #1 valves....to make sure they line up correctly

 

I bet the distrib is in 180 off. take it out turn it exacly 180 drop in it will fire !

 

found tdc and took out the distributor i looked down into the shaft and the notch is lined up and points at #1

tryed starting it again....it seems like it wants to fire more now, but still nothing? could i still be off a tooth? cause its pointing at #1

 

how you finding tdc?
if your use'n the balancer and it's old, it may be off. old balancer may have turned some and not be tdc with the mark lined up.
i use the finger...pull #1, hold your finger over the hole, slowly bump tell it blows air. this is tdc for sure. then see were the rotar is at. if it's right at #1 then this is not the problem.

 

yah im using the balancer. i'll try pulling #1

thanks

 

The oil pump notch? The rotor is what must point to the terminal to which the plug wire for #1 connects. If this lines up close then try turning the dist. to get it to fire. Also, if it does not fire soon you may want to prime or reprime the oil pump so you don't damage your new cam (Lars mentioned this as a possible reason for cam failures). Good luck.

 

yeah like kevinator80 said? not sure what notch you are talking about? its where the rotor is pointing that is important...and follow the valve cycle to make sure your at TDC of #1 of the compresion stroke.

 

If you have the rocker arms too tight your engine will not fire either. It's a simple thing but will cause you grief.
Bernie

 

First you need to get the distributor fully seated, I have never put a distributor back in after doing a major mod and didn't have to line up the oil pump shaft slot with the distributor gear. You need a long screw driver or something similar to stick down the hole and move the oil pump shaft.

Second the motor will not start if the rotor is pointing directly at #1 spark plug terminal on the cap, this would mean 0 degrees advance so move the distributor so the rotor points a little ahead of the #1 terminal, doesn't have to be exact. Then get someone to crank the motor and while you move the distributor back or forward until it starts.

 

When I worked at a garage, we wouldn't worry about aligning the oil pump shaft. Drop the distributor at the correct location (#1). Bump the starter and the distributor will plop down when the distibutor lines up with the oil pump shaft.

 

I would do that on a stock motor with 100,000 miles any day of the week but on a $10,000 motor with an expensive roller cam I am aligning my oil pump manually

 

I took the distributor out and used a long screwdriver to move the notch on the oil pump. The rotor is lined up just after #1 (at TDC). Try to start it while moving the distributor and still nothing. Still getting lots of spark and gas...it wants to start, but just wont.

How do I go about re-priming the oil pump. Im sure after all the cranking i've done it needs it.

 

I assume you never done this type of work before. Changing a cam is not the big of a deal, the second or third time around. It's too late now, but it's best to read a book or two to get a general idea as to how an engine works and how to work on them. Even better than that is to have someone with experience assist when problems or questions come up. Why would you think you need to re-prime the oil pump? One of things you have been doing by cranking the engine over with the starter is priming the engine with oil. As you are probably aware, there is a lot of wear on the cam when it's new. To lower the chances of wiping a lobe it's best to turn the key, get it fired up, and run it at the 2000 rpm or what the manufacture recommends.

First of all, did you make sure the dots on the cam gear and crank gear were lined up. Are you sure you do not have the rockers adjusted too tight. By cranking the engine the lifters should be pumped up. The next thing is to make sure when you drop the distibutor in is that #1 is at top dead center on the compression stroke. The piston comes up to TDC center twice for each revolution of the distributor. If everything else is correct the engine should start. Timing will be off and can be roughly adjusted to keep it running for the duration of the cam break in period.

 

You are 180 degrees off....turn the rotor so that it points exactly opposite and drop it in.....

 

check to make shure of your fireing order to make shure that you don't have crossed wires

 

Yes the dots were lined up. Then tightened them in this order:

with #1 cylinder Intake Valve at full valve lift .... Adjust #6 Intake Valve
with #8 cylinder Intake Valve at full valve lift .... Adjust #5 Intake Valve
with #4 cylinder Intake Valve at full valve lift .... Adjust #7 Intake Valve
with #3 cylinder Intake Valve at full valve lift .... Adjust #2 Intake Valve
with #6 cylinder Intake Valve at full valve lift .... Adjust #1 Intake Valve
with #5 cylinder Intake Valve at full valve lift .... Adjust #8 Intake Valve
with #7 cylinder Intake Valve at full valve lift .... Adjust #4 Intake Valve
with #2 cylinder Intake Valve at full valve lift .... Adjust #3 Intake Valve

after the push rod became tight, i went 1/4 turn and moved on..then did the exhaust valves

When i turn it 180 degrees, i get a backfire through the carb...thats not right

P.S. I really appretiate all of your help!!!

 

if its your 1st time, the valves are too tight.

 

yup matt i think you are on to something.....

silver 75 what do you mean pushrod became tight?