NEW engine is skipping

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duster360

duster360

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Freshly rebuilt engine has a skip. Car has headers with duals all the way out the back. I can put a dollar bill at either exhaust tip and the exhaust is pushing it outward as well as trying to pull it in. The heads were completely redone with new valves and the works. I am thinking either I have the valves too tight or burnt valves.
Also, I adjusted the valves according to the Hughes engines chart ( using their rocker arms ) and tightened 1/2 turn after the slack was taken out of the pushrod.

:banghead:

HELP HELP
 
Have you tried running a compression test?

run a compression test wet and dry.

first run it dry as is (warmed up with throttle blades open).

Then take an oil can and put a few squirts of oil down the spark plug hole and recheck it again. Record the readings for each test and then post them.

Start with the basics and work from there....
 
Did you take a good look at plug color when you pulled them? What ignition are you running? Did you break cam in properly? You may have a wiped cam lobe.
 
If your compression is good, your valves should be ok.

How about spark?

Do you have a timing light with an inductive pick-up? Put it on each plug wire and see if they are all firing or if you see one missing.
 
67cudafb said:
Did you take a good look at plug color when you pulled them? What ignition are you running? Did you break cam in properly? You may have a wiped cam lobe.
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If he wiped a cam lobe, that cylinder should have low compression. His compression is ok.


But plug color is a good idea.
 
Swapped the intake for another one and looked at the cam, it looks great.
 
I will hook up the timing light and see if all cylinders are sparking. I think I may have tried that already but not sure. I have been fighting this problem for a while. Car has not been out of the garage yet.
 
I don't have any vacuum fittings in my intake. Where would be the best place to hook it up to a Holley street a anger carb.
 
duster360 said:
I don't have any vacuum citing in my intake. Where would be the best place to hook it up to a Holley street a anger carb.
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Look for a vacuum port coming off the base plate of the carb and check it with a vacuum gauge to make sure it is manifold vacuum.

If not, usually there will be a plug in the intake near the throttle bracket. Remove the plug and get a nipple to use for the vacuum gauge. You can put a vacuum cap on it to use again in the future.
 
Pull the wires off one at a time with it running and find the one that makes no difference. Then inspect as necessary.
 
Just did a vacuum check. I hooked the gauge to the big port at the base of the Holley street avenger. Engine shakes and at idle ( around 800 rpm ) the gauge was reading back and forth from 8 to 10.
 
What did you use to adjust the carb with?

And what is the timing set at , this sounds like a tuning issue to me
 
Idle adjustments are turned out 1 1/2 turns for a starting point. Timing- initial 18* and total is 34* all in by 2500.
 
duster360 said:
Idle adjustments are turned out 1 1/2 turns for a starting point. Timing- initial 18* and total is 34* all in by 2500.
Click to expand...


Using the vacuum gauge set the mixture screws until you have the highest reading .

If you have two do one then the other back and forth until it has the highest readings , if you have 4 then do one and work your way around to all 4, probably have to do it 3 or 4 times to get the best results.
 
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