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Help with 390 distributor and timing?

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Old Nov 6, 2003 | 08:17 AM
  #1  
zach007's Avatar
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Question Help with 390 distributor and timing?

I pulled my distributor on a "fresh" 390 to prime the oil pump.

After that I set the timing at TDC and set the distributor with the rotor pointing at the #1 wire on the distributor cap.

When I try to start the engine it spews gas out the top of the carb and will not start.

Is my timing off? Did I miss something when I put the distributor back in?
 
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Old Nov 6, 2003 | 09:28 AM
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I would be more concerned with why it is spewing gass out the top of the carb..... The deal with the timing is that if you are at TDC at compress/fire and the rotor is at the #1 spot, you should be good to go, adjusting the timing after it's running is fine tuning. Check that carb before you do anything else.
--MG
 
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Old Nov 6, 2003 | 09:48 AM
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I have an Edelbrock Performer RPM intake with an Edelbrock 600cfm carb. Both are new. The spewing occurs when turning the engine over and it seems that the compression stroke of one cylinder is what is causing the gas to spew from the carb.

Another thought - If the cam is not properly aligned could that cause this problem?
 
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Old Nov 6, 2003 | 10:01 AM
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Ok, are we talking about gas coming out the air intake or just leaking out somewhere?..Could have an intake valve stuck open, or not sealing fully on the comp. stroke, which I guess could cause it to blow the gas out the air intake..Check you valves to make sure they are opening and closing fully..JMO..
 
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Old Nov 6, 2003 | 01:53 PM
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What's your definition of "fresh"? Tell us what's been done.
Does it do it with the ignition disabled? If so, compression is leaking back into the intake. Either a valve isn't sealing or the cam timing is off. If it quits with the ignition disabled, you probably have the distributor 180° off. Make sure #1 cylinder is coming up on the compression stroke by pulling the spark plug and bumping it over with your finger in the hole. Remember, the crank turns twice for each revolution of the distributor.
 
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Old Nov 6, 2003 | 02:09 PM
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I'm with macguyver, your timing is 180* out and it's spitting back out thru the carb.

Barry
 
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Old Nov 6, 2003 | 02:29 PM
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I bought the 390 from an individual like this:
- new Edelbrock Performer RPM intake
- new Crane high performance GTA cam and lifters (No one I have talked to ever heard of this)

- I bought a new Edelbrock 600cfm carb
- stock distributor and coil

I did pull the #1 spark plug when setting TDC.

I have not tried it with the ignition disabled - will try that next.

I have a sneeking suspicion that whoever put the cam in did not align it right?

How can you tell if a valve isn't sealing?
 
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Old Nov 6, 2003 | 05:18 PM
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What kind of fuel pump?

Spewing gas (asuming its not spitting back) sounds like a stuck/bad float.
 
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Old Nov 6, 2003 | 07:30 PM
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just a thought, try setting the #1 piston at TDC again. watching the valves to be sure it's on the compression stroke then setting the ballancer at 0deg. then take anouther look at the dist and make sure its timed right. like macguyver and bb stated it may be as simple as 180 deg out. i've done this myself a couple of times and it's always the last thing i end up checking
 
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Old Nov 6, 2003 | 11:33 PM
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sounds 180 out to me but to check cam timing do as bikerwolfie says get #1 to TDC by watching the valves damper should read zero put a small screw driver into the plug hole touch the piston have a helper turn the crank bt hand one way then the other the screw drive should go down as long as your there check your distributor should be pointing to #1 tower on the cap check your float level to sounds kinda high
 
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Old Nov 7, 2003 | 02:33 AM
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To check if the valves are sealing (or the cam is timed correctly) run a compression test. If you find one (or possibly two) cylinders lower than the rest, do a leakdown test on those cylinders. It could be something as simple as a pushrod that's too long, holding a valve open.
 
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Old Dec 12, 2003 | 08:25 AM
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Did you get it running? You allways have trouble with ford because after you set the # 1 cyl TDC the engine almost allways has to be turned a little to engage the oil pump drive. You are simply one tooth off. Thus the blow back, attempt to fire and hyd lifters? not yet pumped up with oil. Reset on # on 1 cyl when the dist settles put hold down loosely and see if cranking solves your problem. great to have two people or remote starter. great luck!
 
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Old Dec 14, 2003 | 12:07 AM
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Originally posted by cal_rox
Did you get it running? You allways have trouble with ford because after you set the # 1 cyl TDC the engine almost allways has to be turned a little to engage the oil pump drive. You are simply one tooth off. Thus the blow back, attempt to fire and hyd lifters? not yet pumped up with oil. Reset on # on 1 cyl when the dist settles put hold down loosely and see if cranking solves your problem. great to have two people or remote starter. great luck!
I agree. This has happened to me and a few experienced mechanics that I know. Try again!
 
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Old Dec 15, 2003 | 10:45 AM
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I got it running - finally. What you describe is exactly the problem. Although, when I rev the engine I am still getting some backfire through the carb and it diesels when I turn the ignition off. I guess there is still some fine tuning to be done?

Thanks for the info.
 
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