two steps backward...

[blueskies]

I'm inclined to think the problem could be a faulty HEI distrib.

I thought so at first too. When I first got the engine running after it's rebuild, I noticed a slight wobble in the distributor. I called Tom, and he agreed to send me a new one, with a precision sleeve on the tip of the shaft to fit precisely into the oil pump. I installed the new HEI, and found that with the precision sleeve, the wobble was FAR worse. The better the fit, the worse the wobble. I even put my old factory dizzy in and turned it over with the starter. It too wobbled.

So, I pulled the oil pump and examined it for an obvious out of round or out of true situation. I could not find anything wrong with it (but I didn't have an accurate measurind device either). Before I put it back on the engine, I shaped the tip of the distributor so that even at quite an angle, the shaft would not bind in the oil pump as it spun around, acting like a U-joint in the connection. Put it all back together, and the wobble was all but gone. I assumed at the time that the block was not bored true from the oil pump to the distributor, and that the very very slight movement in the distributor that was left was going to have to be good enough. I drove the car for 4500 miles this way, with no issues.

Then, along comes the noise, very sublte at first, and then growing louder over time. After inspecting the bottom end, and finding nothing amiss in the bearings, I became convinced that the noise must be coming from the oil pump. I changed the oil pump, and now the wobble is back. This leads me to believe that the oil pumps are the issue, that they aren't concentric or that the mounting boss is not milled perpendicualr to the shaft of the pump. There is a huge difference between the two pumps that I have on hand in terms of the wobble. With the two HEI units and the stock dizzy, they all had the wobble, so I don't think it's the HEI.

Pete

[blueskies]

Pete;

Have you tried sticking your stock distributor in the hole to see if it wobbles. Spinning the engine with the starter (spark plugs removed) should tell the tale.

Yup, see my reply to Norm that I just posted for the history of the issue...

Pete

[Normspeed]

Prolly a dumb question but when the wobble came back with the new oil pump, was there any noticeable change or increase in the odd noise? Sounds like you've surely eliminated the distributor if even the stock unit wobbled.

I'd be looking hard at that fuel pump for the noise. Mostly because of your stethoscope results plus I personally experienced a brand new Airtex that knocked at idle. Maybe set up a gravity feed for gas and just remove the fuel pump for a test. Pete, I have a spare home made blockoff plate that I can stick in an envelope and mail off to you for testing purposes.

[blueskies]

Was there any noticeable change or increase in the odd noise?

Nope, the noise is the same. So, I think that the wobble issue/oil pump/dizzy is seperate from the noise.

Maybe set up a gravity feed for gas and just remove the fuel pump for a test. Pete, I have a spare home made blockoff plate that I can stick in an envelope and mail off to you for testing purposes.

Thanks for the offer of the fuel pump block off plate. I think I'm just going to swap the pump for a new one, it's the same amount of work. It doesn't eliminate the pump completely from the system to check for noise, but if it's the pump, the noise should go away unless the new pump is identical...

I want to have a spare pump anyway for the long road to Tulsa.

Pete

[Normspeed]

Good idea. When you have both pumps out, compare the action of the arm. See if your old pump doesn't have excessive play at the pivot pin.

I carry a spare brand new 6v electric pump. Hope I never need it but it's a quick fix if the old one goes south.

[James_Douglas]

Pete,

I know that the following is "out there" but..

Examine the distributor shaft very carefully. With the over bore and longer stroke, it is just possible if the skirt length on your pistons in a little too long that one is rubbing up against the distributor shaft at the bottom of its stoke. I know this is a long shot and it would have to be a minimal contact to not crack the piston. But, just a little touch would cause a vibration.

If it is pump alignment related, I just don't see how it would be fine then start up again.

A long shot, but one to give some thought to in any event.

Best, James

[blueskies]

Pete,

I know that the following is "out there" but..

Examine the distributor shaft very carefully. With the over bore and longer stroke, it is just possible if the skirt length on your pistons in a little too long that one is rubbing up against the distributor shaft at the bottom of its stoke. I know this is a long shot and it would have to be a minimal contact to not crack the piston. But, just a little touch would cause a vibration.

James-

I thought this might be a possibility in the first round of trying to fix the wobble. I thought it might be either the skirts, or the lobe of the cam bumping the distributor shaft. I used a blue sharpie marker to coat the entire shaft of the distributor, ran the engine for a few minutes, and then did another inspection. None of the marker had been rubbed off.

When I had the pan off recently, I checked the cam lobe clearance, and there is plenty of room there. I didn't think to check the skirt clearance though... but I don't think that's what is going on. The shaft of the distributor is necked down in the middle for this reason. The shaft cannot be removed from the engine when the #3 and #4 pistons are at BDC because the thicker tip of the shaft will not pass by the skirts.

I dug though my recent pics, and found a snippet of the shaft and skirts:

You can see the area that is circled is where the distributor shaft runs between the skirts, and you can also see how far the skirts hang down from the cylinders...

Here's the shaft, it's pretty small in the middle where the skirts are. It's a hair under .5" at the tip, so maybe 1/4" or so at the skinny part:

If it is pump alignment related, I just don't see how it would be fine then start up again.

The difference, is that I put in a different pump, and the wobble is dramatically different between the two pumps, when everything else is the same. I think if it was the skirts, it would be the same no matter what the pump was doing.

Pete

[James_Douglas]

Ok,

So it is the pump alignment. This is how to test it, if it will fit through...

1. Take out the pump.

1. Mic the hole for the pump.

3. Mic the hole for the distributor.

4. Have a VERY good lathe operator make you a set of bronze bushings for each hole.

5. Have him drill a hole in the center of each bushing to the dia. of the distributor shaft.

6. Take a steel rod and run it through the 2 holes.

If it lines up then the block is ok. If not then you can figure out how much and in what direction it is off by pulling the distributor side bushing and using inside gauges to see which way it is off. Then you can have a shim made (tapered) for the pump to block surface.

I know this is a lot, but it will lead to a solution to the oil pump issue. A pain for sure.

Best, James

[1just4don]

of either using a electric pump temp for a bit remove mechanical pump and duct tape the hole long enough to hear knock or no knock. Putting another potential knocker in there is only prolonging you agony. I 'think' I have a working 12v elec (if you want me to mail it)you could jumper to a battery if you wanted to try that. If you wanted to jerry rig a can or jug with a bottom hole to gravity your carb for a quick try, doubt it it has to hold more than about a cup or two volume. Even a bit of hose and a small funnel on top,,,IF you have a helper to keep the funnel half full to overflowing would be easy cheap and quick!!! NOT hearing that knock will "MAKE" you feel twenty years younger,,,for sure!! The quicker the better!!!

[grey beard]

Pete,

You've had tons of advice - most of it right on. There's one thing no one has mentioned that sorta' bothers me. Can you look into the distributor hole while the engine is cranking and see if the oil pump shaft end is wobbling? If not, try loosening the oil pump bolts way out - it'll be messy - and crank the engine a few revolutions. Watch to see if the OIL PUMP itself wobbles.

My thinking is that MoPar distributors don't wobble. They fit into a husky boss in the block. Same with oil pumps. I'm wondering if the camshaft gear that drives your oil pump could be the root cause of your wobble. You surely seem to be fighting a problem that most of us with stock engines have not experienced.

Won't cost much to check, and won't take long either. JMHO:)

[Normspeed]

Dave, a very good suggestion.

[Young Ed]

I'm still voting for a funky fuel pump. Maybe we need a poll or a betting pool hehe

[blueskies]

Ok,

So it is the pump alignment. This is how to test it, if it will fit through...

James- I talked at length with Tom Langdon about this method of checking to see if the block is true. I'm not sure if I could get a rod, long enough to go through both sides of the block, into the distributor hole with the engine in the car. Me thinks not, but not completely sure. I also think, that it is in-part the fault of the oil pump. If both pumps were exactly the same, there would be no change in the amount of wobble found between the two pumps. There is, however, a big difference between the two pumps.

NOT hearing that knock will "MAKE" you feel twenty years younger,,,for sure!! The quicker the better!!!

You got that right... I think my neighbor has a 12v pump, I will try to borrow it for the test.

Can you look into the distributor hole while the engine is cranking and see if the oil pump shaft end is wobbling? If not, try loosening the oil pump bolts way out - it'll be messy - and crank the engine a few revolutions. Watch to see if the OIL PUMP itself wobbles.

My thinking is that MoPar distributors don't wobble.

I don't think the oil pump could be causing the wobble by wobbling itself, unless the .006"-.010" out of round found in the tip of the gear would do it.. The pump is so stout, and is mounted so solidly to the block, that if the cam were that out of round it would have caused a failure by now. I've been wrong before though:rolleyes:. My cam is the same one that was originally in the car from the factory, but re-ground by a professional shop. I can't imagine how it could be bent.

You are right about Mopar distributors not wobbling, they fit very precisely into the think are of the block. My distributor is not stock though, and doesn't fit the same way. There is room for it to move, however slight. I think if the head of the distrubitor were fixed tight to the block, the shaft would be stressed enought to snap off.

I'm still voting for a funky fuel pump. Maybe we need a poll or a betting pool hehe

Funky for sure, just not sure what... I drove the piss and vinegar out of the car yesterday. I did several full speed starts from a stop to 70mph, and nailed the throttle whenever the feeling struck me, loving the sound of the six as I ripped around town. I want whatever is failing to go ahead and let go now, before I'm on the road to Tulsa. At least now I know that it is not a bearing, so I'm not worried about punching a hole in the block with a rod like I was before pulling the pan. By the time I parked the car last night at 10:30pm, it seemed the noise was more prevalant.... Mabye I'm getting somewhere by going nowhere.

[Jim Saraceno]

I drove the piss and vinegar out of the car yesterday. I did several full speed starts from a stop to 70mph, and nailed the throttle whenever the feeling struck me, loving the sound of the six as I ripped around town. I want whatever is failing to go ahead and let go now, before I'm on the road to Tulsa.

Lordy! Lordy! Lordy! Pete, my heart goes out to you! All that work you put into that beautiful car of yours and to have a problem like that. I've been sitting on the outside watching the whole drama unfold, racking my brain trying to think of something that you guys haven't already thought of, but as usual, I'm coming up with ZIP.

Keep plugging away and don't do anything rash. Driving it until it breaks sounds like a tough way to go, hopefully it will get to the point that it is obvious before it breaks so you can finally fix it.

We're there for ya buddy!

[greg g]

Did we discuss the possibility of a loose flywheel bolt transfering the noise to the crank shaft??? Doesn't deal with the dizzy wobble but.......

[Young Ed]

I believe that was checked when the pan was down.

[James_Douglas]

Well Pete,

I suggest a change over to an MSD crankshaft triggered ignition. Then you can toss the distributor and not worry about the problem.

Hell, it would probably take less effort and cost less in the end than running this problem down....

You would also get that "Racers Edge" when the big race takes place...

Best, James

[Chester Brzostowski]

Just a far out thought.., but could the distributor be seated to deep into the oil pump. The slit will allow the shaft to shift right & left but if it was bottomed into the fuel pump there would be no free play and maybe create a wobble.

Don’t know much just throwing something new out there.

Chet...

[Normspeed]

Amazing how many possibilities this gang can come up with. Chet's idea is a real possible. Easy to check by loosening up on the distrib hold down.

Pete, I swore I wouldn't part with it but since ya gotta get to Tulsa, I'll go ahead and swap ya that noisy POS of yours fer my original P24 motor. Ran when parked. It WILL get you to Tulsa and back.

[kevinanderson]

I've never had one of these apart. And i am just throwing out an experience i had with a buick 430. i had a knock after a fresh rebuild. tore the thing down after about 20 minutes of run time. finally found the dip stick hitting a crank weight. i searched and searched. new oil pump, fuel pump etc. checked cam, rods, pistons, rings. tore it completely aprt. finally found a beat spot on the dipstick.

[Normspeed]

LOL Kevin. Had a Honda Magna motorcycle that developed an awful low rpm knock. Sounded like a rod. Turned out to be a broken weld in a factory exhaust collector box under the motor.

[Guest flathead6]

Pete,

I maybe asking a silly question are you sure it is on the inside of engine or something rubbing and bumbing on the outside. As the motor torques up it twists. It could it be rubbing something on the outside... It didn't the first 4500 miles but are your after market tube headers rubbing the frame or something now that it settled in to the new motor mounts?

Is the crank case vent tube hitting something etc. Is your alt bracket tight or broken? Just asking? Your engine rev's so quick to life that it made me wonder is it broke, or did it brake loose from the mount?

Twist = Knock

Our enignes had loose machine tolerences at best as new. Rubber will settle/move more in less time. .001 vs .1

Think back to how well you thought your engine ran before you rebuilt it. If I recall right you opened it up and found a piston had a hole in it! Loose to say the least!

My 2 cents = A free beer next time your in Moscow, Idaho if I'm right.

I doubt the machine work in your block has changed as much as the rubber in the motor mounts in 4500 miles.

Steve Hanks

[Merle Coggins]

LOL Kevin. Had a Honda Magna motorcycle that developed an awful low rpm knock. Sounded like a rod. Turned out to be a broken weld in a factory exhaust collector box under the motor.

That's interesting, Norm. I had (have) a Honda Nighthawk that, after an engine swap, had a bad knock. The service manager at the local Honda shop convinced me that it was just the hydraulic valve adjusters and it would quiet down after it ran a while. It sure did get quiet once it locked up and pitched a rod through the case. BUMMER.

Merle

[blueskies]

Just a far out thought.., but could the distributor be seated to deep into the oil pump. The slit will allow the shaft to shift right & left but if it was bottomed into the fuel pump there would be no free play and maybe create a wobble.

Don’t know much just throwing something new out there.

Chet...

Chet-

I too thought this may have something to do with it. With the engine running, and with the timing bracket bolt removed, I can pull the distributor out of the block about 1/4" and the wobble doesn't change at all.

The timing bracket, or clamp, is the early mopar type, and has a bolt through the side of the bracket that clamps it to the housing of the distributor. This bracket can be positioned anywhere on the housing in terms of rotation and depth. I was going to put the clamp farther down on the housing to reduce the depth, but it didn't seem to make any difference.

Pete

[blueskies]

are you sure it is on the inside of engine or something rubbing and bumbing on the outside.

Steve-

I sure the noise is inside the engine. It can be heard at a range of rpms, and is in time with the rpms.

I'm sure whatever it is, it will be a head slapper when I finally discover it. If the fuel pump doesn't make a difference, then it's got to be a piston or in the valve train. Nothing else left to inspect....

Beers on me for the Tulsa attending forum members if I make it there with the car...

Pete