Attempting to crank new Crate motor - The 1947 - Present Chevrolet & GMC Truck Message Board Network

stingray72 · 11-12-2003, 12:16 AM

My dad has a 1972 Chevy Cheyenne that he has been working on. He's got his new engine in the truck and everything hooked up and is now trying to crank it.

He's got a Mallory magnet breakerless distributor. He's got 12V to the ignition wire when the AC is on. When trying to crank it it drops to 9V on the ignition wire. When the wire is connected to the positive side of the coil there are only 4.75V and there is no fire at the distributor. Tried 2 different coils and had no spark either time at the distributor. The ground appears to be good.

Has anyone got any suggestions to what the problem might be?

dinnut · 11-12-2003, 01:26 AM

that really has to suck. are all the grounds hooked back up? is the battery low/does it need replacing? by ac do you mean air conditiong or accessories. it spins but no fire?did you do everything right installing the distributor?

68c10owner · 11-12-2003, 02:12 AM

are you still running the stock balist resister or resister wire? that will cause a drop in voltage. if you are still running it, make sure your distributer doesn`t need it. some mallery`s are a "unilight" and need the resister. the magnetic breakerless ones should`nt need it but read the instructions before disconnecting the resister.

stingray72 · 11-12-2003, 10:49 AM

Quote:

dinnut - are all the grounds hooked back up? is the battery low/does it need replacing? by ac do you mean air conditiong or accessories. it spins but no fire?did you do everything right installing the distributor?

The grounds are hooked up, the battery is brand new and tests well. AC = accessories. It does spin but there is no fire from the coil to the distributor. The distributor is installed according to the instructions that came with it

Quote:

68c10owner - are you still running the stock balist resister or resister wire? that will cause a drop in voltage. if you are still running it, make sure your distributer doesn`t need it. some mallery`s are a "unilight" and need the resister. the magnetic breakerless ones should`nt need it but read the instructions before disconnecting the resister.

I honestly don't know the answer to your first question but will find out. We've tried with both with the resistor and without. With the resistor there is too much of a voltage drop. We're not supposed to need it according to the documentation that accompanied the distributor (I believe).

Our only guess right now is that it could be a bad distributor. Is there a way to test them?

edit: Thanks for the help so far guys

tom hand · 11-12-2003, 11:43 AM

If you have a meter the distributor is simple enough to test. Set the meter on continuity and connect it to the lead that goes to the coil and connect the other lead to ground. Turn the motor over with a rachet and you should get continuity in 8 places as the motor goes around. You could even use a test light by connecting one lead to positive on the battery.

cdowns · 11-12-2003, 12:55 PM

if you're using the original wire to the distributor that's a resistor wire and should be replaced with a piece of 14ga wire to a switched outlet

jamis · 11-12-2003, 02:20 PM

Run a jumper wire from the batt. to the positive side of the dist. and coil. That would eliminate any switch or power drop probelms.

If that still doesnt work then the problem is in the coil or dist.

You can check those parts just like tom hand said, a couple of threads up.

**Classic Heartbeat** · 11-12-2003, 02:28 PM

This is just a remote chance, but have you checked the starter? Even new or rebuilt ones can cause problems like you are discribing if they are drawing too much amperage. That would be something else to check once you have eliminated everything else. WES www.ClassicHeartbeat.com

11-12-2003, 12:16 AM	#1
stingray72 Red Headed Step Child Join Date: Oct 2003 Location: Atlanta, GA Posts: 1,216	Attempting to crank new Crate motor My dad has a 1972 Chevy Cheyenne that he has been working on. He's got his new engine in the truck and everything hooked up and is now trying to crank it. He's got a Mallory magnet breakerless distributor. He's got 12V to the ignition wire when the AC is on. When trying to crank it it drops to 9V on the ignition wire. When the wire is connected to the positive side of the coil there are only 4.75V and there is no fire at the distributor. Tried 2 different coils and had no spark either time at the distributor. The ground appears to be good. Has anyone got any suggestions to what the problem might be? __________________ "Dinner, the perfect break between work and drunk" -Homer Simpson

11-12-2003, 01:26 AM	#2
dinnut Registered User Join Date: Apr 2003 Location: missouri city, tx Posts: 4,486	that really has to suck. are all the grounds hooked back up? is the battery low/does it need replacing? by ac do you mean air conditiong or accessories. it spins but no fire?did you do everything right installing the distributor? __________________ 70 longbed 496/th400/Ford 9"

11-12-2003, 02:12 AM	#3
68c10owner Registered User Join Date: Oct 2003 Location: Carmichael, California Posts: 3,006	are you still running the stock balist resister or resister wire? that will cause a drop in voltage. if you are still running it, make sure your distributer doesn`t need it. some mallery`s are a "unilight" and need the resister. the magnetic breakerless ones should`nt need it but read the instructions before disconnecting the resister. __________________ Anthony

11-12-2003, 11:43 AM	#5
tom hand CCRider Join Date: Feb 2000 Location: Olive Branch,MS,USA Posts: 2,232	If you have a meter the distributor is simple enough to test. Set the meter on continuity and connect it to the lead that goes to the coil and connect the other lead to ground. Turn the motor over with a rachet and you should get continuity in 8 places as the motor goes around. You could even use a test light by connecting one lead to positive on the battery. __________________ 72 GMC Sierra SWB almost finished---- 84 Softail Olive Branch MS

11-12-2003, 12:55 PM	#6
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	if you're using the original wire to the distributor that's a resistor wire and should be replaced with a piece of 14ga wire to a switched outlet __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

11-12-2003, 02:20 PM	#7
jamis F.A.S.T. president Join Date: Sep 2003 Location: Florida Posts: 1,883	Run a jumper wire from the batt. to the positive side of the dist. and coil. That would eliminate any switch or power drop probelms. If that still doesnt work then the problem is in the coil or dist. You can check those parts just like tom hand said, a couple of threads up.

11-12-2003, 02:28 PM	#8
Classic Heartbeat Project Junkie! Fishing Poor!! Join Date: Dec 1999 Location: Olympia,Wa. 98512 Posts: 10,770	This is just a remote chance, but have you checked the starter? Even new or rebuilt ones can cause problems like you are discribing if they are drawing too much amperage. That would be something else to check once you have eliminated everything else. WES www.ClassicHeartbeat.com __________________ On-line catolog Classic Heartbeat Pickup Parts WEHEPP@comcast.net Call us Toll Free (888) 338-2502 Like Us on Facebook No appointment necessary. 72 BB Chevy Custom Deluxe / Custom Camper 67 I-6 (Soon to be 5.7 LS1) Panel 68 BB Chevy Short Bed 72 6.0 LQ9 Short Bed Chevy 4X4 Olympia's fastest growing truck parts supplier. Olympia's home for Wayward Chevys



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