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Help! Re-installation of distributor?

Vette79

Well-known member
Joined
Jan 23, 2007
Messages
1,392
Location
Millersville, MD
Corvette
1979 L-48 Black Coupe
Long story short, I removed my Intake Manifold due to some oil leaks and re-installed. Trying to re-install the distributor back in the same position as it was before I removed it and have not been able to do so. I can eventually get it to drop but the rotor is about an inch clockwise further then the position it was previously. Is there any tricks or tips that could assist me with dropping this damn thing back in the way it was? This is suppose to be easy and obviously the last piece...
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I understand your fustration, I did exactly the same thing but for the life of me I can't remember how I got it to go back in. I am trying to remember, getting too old, when I do I will let you know. Seems like it was just keep playing with it, hehe, I am sure someone will let us know.
 
The problem is that the distributor gear is helical, so, as you pull it out, it turns the oil pump drive slightly. On reinstallation, though your rotor and dist. body will be in the right places, the oil pump drive shaft will not index to the dist. gear because the end of the shaft and the slot in the distributor gear are not aligned.

If you properly marked the rotor and distributor body, index to the marks, drop the distributor in place then bump the starter to turn the engine over. As the starter cranks the engine, the oil pump drive will line up with the slot in the bottom of the gear, then the dist. will drop the rest of the way.

If you didn't mark things, then you need to turn the engine by hand to TDC #1,
 
I'm thinking about using a long slotted screwdriver and turn the oil pump shaft counterclockwise a bit to get the distributor to drop.
 
the distrib won,t fully seat unless the oil pump drive shaft seats up into the distib gear, as you remove the distrib the helical gear interface tends to turn the pump drive shaft slightly, you can use a long flat tip screw driver to turn that back to the correct location and with a bit of practice youll learn to gauge the amount the rotor rotates as it seats into the cam gear.

The CLOYES true roller style is vastly superior to the factory link belt design
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how come its 180 degs out of phase?
I get this question all the time, well here’s something I see lots of guys don’t understand, ONCE YOUVE INSTALLED A CAM WITH THE TIMEING MARKS YOU MUST ROTATE THE CRANK 360 DEGRESS BEFORE DROPPING IN THE DISTRIBUTOR, while its true that if the, timing marks are positioned so the crank is at 12 o,clock and the cam gear is at 6 o,clock that the cam lobes will be in the position that fires #6 cylinder that HAS NO EFFECT AT ALL (on finding TDC,) for aligning the degree wheel with TDC,or THE timing tab pointer, for degreeing in the cam, the piston passes thru TDC TWICE in every firing cycle once on the firing/power stroke and once on the exhaust stroke, the cam rotates at exactly 1/2 the speed of the crank so to make it easy to line up the marks they install it with the marks at the closest point 6/12 for easy indexing, rotate the engine 360 degrees to the #1 TDC power stroke and the crank gear will still be at 12 oclock 12/12 but the cam will be at 12 o,clock also, rotate another 360 degrees and your back where you started. its simply easier to index the cam at the point where the index marks align closely. look at how the cam lobes themselves open the valves when the cam is just installed the #1 cylinder valves are slightly open and the #6 are closed per "Lunati" ‘’YES YOU ARE RIGHT - WHEN CRANK IS AT TWELVE AND CAM IS AT SIX THEN #6 CYL IS FIRING AFTER YOU LINE UP YOUR MARKS AND INSTALL GEAR THEN ROTATE YOUR CRANK ONE REVOLUTION AND THEN DROP THE DIST. IN - AT THAT POINT
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http://boxwrench.net/specs/chevy_sb.htm
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look here

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drop the distrib in with the rotor pointing at the #1 cylinder, and YEAH! it physically possiable to get the distributors rotor to point at any place you want it too by changing the oil pump drive shaft alignment with a large flat blade screw driver while the distributors out of the engine and thats easily changed, but to do it correctly,you want the rotor to point at the #1 cylinder on the compression stroke, so pull the #1 plug, get a large ratchet/socket on the damper and put your finger over the open plug hole and slowly rotate the engine by hand in its normal rotational dirrection untill you see pressure build under your finger as the rotor approaches #1 cylinder location on the distributor base which you should have marked as its supposed to be in dirrect alignment between the distrib and the number 1 cylinder on the engine, remember the distributor and cam gears are heilical and the rotor turns as it seats so compensate slightly. and the rotor should be just coming into alignment as pressure builds under your finger, once thats done re-install the distrib cap and plug and use a timing light to set the timing, you normally want about 6-12 degrees BTDC at idle and watch it advance to about 37 degrees as the rpms build to about 3000rpm
 
This is good information but I do know where the rotor and base of the distributor are suppose to be. I just need to get there. The oil pump shaft is what is preventing me from dropping the distributor all the way down. I'm going to adjust it slightly to see if I can get it to drop.
 
just use a long flat blade screw driver and rotate the shaft back about 1 /8th of a rotation and try to seat the distrib, if you get it correct it will fall back down into place, if not tweak the angle untill it does with a few more adjustments with the long screwdriver, remember to compensate for the rotation as the helical gears mesh
 
Got it seated on the first try! Distributor back in the way it came out. Thanks everybody. All I did was turn the oil pump shaft back about 1/8th of a turn. not much. Like HIB said, it must turn the oil pump shaft a bit when you remove the distributor.
 

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