I am trying to install this Proform 66955 HEI distributor on a V8 350 and I am having a heck of a time. I found TDC and once I tried to pop in the distributor it barely goes in. I tried to hand crank to see if it moves and no dice.

I checked the size of that oil pump drive shaft and I believe it is 5/16. I checked the receiving end on the distributor and it is larger than 5/16.

Do I have the wrong distributor for this project? Any suggestions?

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Try moving the rotor 1 tooth back.

 

Just alittle larger than 5/16 right? In addition to one tooth back put a touch of lube on the gears and shaft. Just don't force it, also make sure you don't have any burrs on the top of the shaft. Kind of obvious but check your clearance w/ the back of the manifold, firewall, ect.

Bill

 

Hey Bill,

It is larger than 5/16 the clearance on the firewall is great, but the vacuum from the distributor is a tight fit between the AC valve and it is close to hitting the intake manifold. Where should the vacuum being point to?

This weather needs to cool down so I can actually work more than 30 minutes before sweating my butt off.

 

Install it without the cap and turn the pointing cap/axle when you take it down so it will fall down in right possition.

Example begin some tooths before it hits position cyl 1 on the cap position,first try to find right possition so you will have clearence with vacuum clock and the contacts on the other side and then set the axle down then it can be clearence to adjust timing too..

Well if its to big gears thats another thing...

 

pic of dist'r bottom?

you do often have to wiggle it a lot, rotate the shaft, even jump a tooth one way or another. Vacuum can usually towards RH side, middle of free motion space.

 

If you want Pm me your number and I'll give you a jingle.

Bill

 

Get your vaccume cannister pointing to the passenge side but angled between the firewall and the rear corner your block on the passenger side. You should have plenty of room there. If you subscribe to wild about cars (free) they have every manual and tech bulletin in the world there.

Bill

 

I think I might have to get some Royal Purple on the distributor and the cam just to make the shimming in smoother.

Maybe this is a newbie question, but if the oil pump driveshaft is 5/16 and the receiving end on the distributor is slight bigger how does that work? The last distributor I installed about 10 years ago was on a chevy and it had a slot that the distributor slid into.

I'll try to work on it tomorrow if the weather is a little cooler. Hand cranking this engine is really a workout to a point where I need to put my beer down haha.

 

Pull the plugs, it makes hand cranking much easier.

 

First, the oil pump drive shaft is 5/16" hex, as is the mating hole in the distributor gear. There are no other options.

Second, if this is a brand new distributor, the o-ring seal will be uncompressed, making it very tight in the hole in the block. Be sure to wipe some silicone lube on the o-ring before installing the distributor.

Third, the oil pump drive shaft will never be exactly lined up with the hex in the gear. You'll always need to rotate things slightly to get the distributor all the way down.

Fourth, there is nothing magic about the orientation of the vac advance can or any other part of the distributor body relative to the motor. Simply install it where it fits best, then find TDC and locate the plug wires on the cap accordingly.

Fifth, expect the rotor to move as the helical teeth on the drive gear engage the cam. You need to "lead" the desired rotor position a little to make this work.

Finally, if this is a Chinesium aftermarket distributor, be sure the distributor body is machined to the correct diameter!

 

Joe's last sentence nails it! BT DT. The shop that ours came from took a minimal cut off of the body OD, using a spare block for a test fixture.

 

Oh really?
wow, that is bad
so, if you do not have a spare engine to test fit in then you would have to dismantle the new distributor [mark gear and shaft relative position first], remove o-ring, and start with JUST the housing, see if it fits in all the way w/o issue. Then add O-ring, re-verify fit of the housing.

Also check gear to oil pump drive rod with the bare gear... then after all individual parts are verified and fixed as need be, assemble and install.

Not much savings there if you count your time I guess.

Factory parts- they fit right and work right.

 

Fwiw I have a proform uni I have been running for 7 years on various engines I have had in my car. The proform unit is nice .

 

A friend of mine has one in his 72 as well. @Cooper is this the same model that you have on yours? The model that I am trying to install is 66955 on a V8.

I did add some silicone lube to the o-ring and will grease up the cam and distributor once I try to reinstall it.

Upon inspection the mating hole on the distributor is definitely larger than 5/16 and even larger than 1/4 hex size.

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I bought it 7 years ago I can't recall the part number.

 

If it's bigger than 5/16", it'd better be bigger than 1/4".

The size of the oil pump drive, as stated, is 5/16".
If you put a 5/16" socket on it, it will fit perfectly.
So, put a screw with a 5/16" head, or a 5/16" Allen key, in the hole, and see if it's the same size.

- Eric

 

I'm an idiot and I attribute it to having 4th of July drinks too early. The mating hole is definitely 5/16 and my math was way off.

Sorry guys!

 

It's never too early. You're just showing your patriotism.

- Eric

 

maybe perspective but the pic in post 15 appears to show a hole too shallow. And, what is that crossways hole/ set screw? BELOW the gear teeth?

I agree that use of a hex key or bolt will tell you what size the gear's drive recess is.

Lubing the o-ring I figured was expected... and grease on the gear teeth and thrust surface...

 

The depth of the hole is about 1 1/4 is that too shallow? I know that the driveshaft on the pump the only a couple of inches is the 5/16 hex pattern.