help me diagnose a problem here ASAP!!!!

[Moisabamf]

info:

Datsun 510

L20B (just rebuilt, were trying to get it to start now)

weber 36/36 non progressive carb(worked on our L16)

problem:

weak spark(not that big of a prob, timing or something)

BIG problem: as we crank the engine, gas shoots out of the carb in a gasseous POOF

suggestions?

(Sliding_Creep suggested iether the cam was off 180 degrees or a prob in the machining of the engine)

any other places to check?:confused::confused::confused::confused:

Edited July 6, 2009 by datzenmike

[Duke]

Sounds like cam timing to me as well. Easy to check.

 

I can't really think of anything else that would cause a good amount of pressure in the intake manifold.

[datzenmike]

Sounds like plug wires mixed up, distributor timing off or an intake valve it too tight and is open. Check the plug wires are correct, 1342 is the firing order. Number one plug wire should be generally in the 4 o'clock position on the cap as viewed from the driver's side fender. If all seems ok:

 

Remove valve cover and dizzy, and turn motor so that the number one intake and exhaust lobes (bumps) are facing upwards at about 10 and 2 o'clock as viewed from the front of the motor. Rocker arms should NOT be on either cam lobe. With cover off, this is a good time to check valve clearances.

 

Set the motor on TDC compression stroke using the timing mark or notch on the rear crank pulley and the timing scale bolted to the timing cover just behind it.

 

With distributor removed, look down the hole from the driver's side fender. The distributor drive spindle slot should be not quite vertical... it should be at about 11:28 . If it isn't, drop the oil pump and re-position it until it is. Helps if you have a friend. Because of the helical gears it does not go straight in and turns as it is installed so you may have to make several attempts. You will also notice that the drive spindle has a slot to engage the distributor that is slightly off-set to one side. This off-set should be to the front of the motor in order for the distributor to align with the #1 plug lead on the cap.

 

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Once the drive spindle is set at the 11:28 position the distributor and oil pump can be bolted down. The rotor should be pointing to (or within adjusting range) of the #1 plug wire on the cap.