New 5.7 distributor installation

13crazyhorse

Petty Officer 2nd Class
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Apr 4, 2010
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147
Let me start by saying I purchased an 86 boat with a 5.7 mercruiser that was not running. After going over it there was no spark. I tested the old Thunderbolt ignition system and after determining that the box was bad I didn't want to put alot of money in the old system so I bought a new Delco Voyager ignition system. I took the old distributor out and put the new one in with the rotor pointing at the same point on the engine as the old dist was. The motor won't start and I don't know if I have the timing close enough. My problem is even though the rotor points at the same plug you could make it point at any plug by turning the dist and cap and then the timing would be way off. If I put the motor at TDC on the #1 cylinder and then align the rotor up with the #1 plug that should work but you can still spin the dist and cap around and make it point at any plug. I guess my question is how do you know when the dist bottom is where it's supposed to be? I know I'll have to adjust the timing once I get it running but I want to get it in the ballpark. Thanks for any advice.
 

achris

More fish than mountain goat
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May 19, 2004
Messages
27,468
Re: New 5.7 distributor installation

To ensure the distributor is all the way down, just look at the base of the distributor housing. There's a boss on it that the clamp plate locks onto. When that boss is hard against the boss on the intake manifold, you're there. If it resists going all the way down, the oil pump tang is not lined up. Here is the procedure for putting the distributor back in the engine is in the service manual. You have?

attachment.php


Chris......
 

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NHGuy

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Re: New 5.7 distributor installation

Get Top Dead Center by bringing the crankshaft around to the timing mark on the crank pulley-harmonic balancer assembly, and then stick something in the #1 spark plug hole to make sure the #1 piston is up to the top. If it's not there go another 360 degrees on the crank and confirm TDC. Now install the distributor making sure to catch the oil pump drive on the bottom end of the distributor shaft. Put the #1 spark plug lead from the distributor cap 8 degrees counterclockwise to the rotor, just eyeball it and snug it there. Start it up, get it warm and set the timing with a light.
 

13crazyhorse

Petty Officer 2nd Class
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Apr 4, 2010
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Re: New 5.7 distributor installation

Yes I have the manual and yes the dist is all the way down. Maybe I'm not explaining it right. At TDC I point the rotor at plug wire #1. But with the hold down clamp loose you can turn the dist all the way around (and the cap also since it's attached to the dist). The rotor does not turn but by turning the dist you are pointing the rotor at any plug you want. Maybe it doesn't matter as long as the rotor points at #1 and your firing order is correct? That means your wiring connections to the dist could point back or front it doesn't matter as long as at TDC your rotor points at #1?
 

NHGuy

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3,631
Re: New 5.7 distributor installation

Yup point it to # 1 on the cap and go back a little. Some folks like to put the distributor in so the rotor is pointing to the front port side of the motor, where the #1 hole is. But you don't have to.
Just get the #1 plug wire on the rotor tip and you are good.
 

81 Checkmate

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Jul 20, 2010
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1,360
Re: New 5.7 distributor installation

Correct but needs to TDC on compresion stroke...... then point rotor to no 1 plug wire to no 1 plug....

You can make no 1 on the cap anyone you want!
 

Don S

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Re: New 5.7 distributor installation

You need to find #1 TDC on the compression stroke. It's a 4 stroke engine, so the piston is at TDC twice in a complete 4 cycle.
Find it this way http://forums.iboats.com/showthread.php?t=427081

Then you set the distributor in with the housing aimed the way you want it, and also turn the rotor so it's where you want it aimed. Then you put #1 spark plug wire lined up with the the rotor.
 

theBrownskull

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Jun 23, 2012
Messages
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Re: New 5.7 distributor installation

If you are having trouble finding if the piston is TDC here is an easy way to find out. Pull the plug for the #1 plug, put you finger over the hole and crank it over till the compression blows it away from the hole. Then you know it is there. I like to point the rotor to the #1 cylinder ...easier for me. Then go from there.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: New 5.7 distributor installation

If you are having trouble finding if the piston is TDC here is an easy way to find out. Pull the plug for the #1 plug, put you finger over the hole and crank it over till the compression blows it away from the hole. Then you know it is there. I like to point the rotor to the #1 cylinder ...easier for me. Then go from there.

Get Top Dead Center by bringing the crankshaft around to the timing mark on the crank pulley-harmonic balancer assembly, and then stick something in the #1 spark plug hole to make sure the #1 piston is up to the top. If it's not there go another 360 degrees on the crank and confirm TDC. Now install the distributor making sure to catch the oil pump drive on the bottom end of the distributor shaft. Put the #1 spark plug lead from the distributor cap 8 degrees counterclockwise to the rotor, just eyeball it and snug it there. Start it up, get it warm and set the timing with a light.


your both wrong. since the timing indicator will ALWAYSpoint to the same point when the piston is up for BOTH the compression stroke AND the intake stroke. the crank and harmonic damper are bolted together, only the cam spins at half speed.

you have to make sure your at TDC of the compression stroke as Don mentioned. Follow the link that Don posted, or the article that Achris posted.
 

theBrownskull

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Re: New 5.7 distributor installation

The intake stroke will not blow you finger off of the hole. The compression will. Try it and find out you can feel and hear the difference.
 

theBrownskull

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Re: New 5.7 distributor installation

Don S method is the correct way, but if the person is having a hard time figuring if it is on the compression stroke, with out removing the valve covers and looking, it works.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Re: New 5.7 distributor installation

The intake stroke will not blow you finger off of the hole. The compression will. Try it and find out you can feel and hear the difference.

both will blow your finger off the spark plug hole on a marine engine. however the pressure built up over the compression stroke is stronger than the minute amount of pressure built up between the exhaust and intake stroke.
 

13crazyhorse

Petty Officer 2nd Class
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Apr 4, 2010
Messages
147
Re: New 5.7 distributor installation

Thanks as always guys you have answered my question. Tonight I will check the distributor position and when I"m satisfied it's close I'll continue. One step at a time I want to get this project boat running so I can spend the rest of the winter working on it getting it ready for 2013.
 
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