Intermediate shaft issue

[straightlinespeed]

Well I've been having some minor issues with my car so I had another gent who owns a Carb shop take a look at my engine. I've still been having issues with my secondaries opening and have tried many things, so I figure he is the next best option. While looking into the carb issue, he didnt initially see anything so he decided to dig a bit deeper and look at the dizzy. So this is the area I want to concentrate on because I do believe it is just another issue I should deal with.

He found a lot of excess play while wiggling the rotor back and forth. He thought that the dizzy itself might be the issue, so we pulled it. No problems with the dizzy at all, nice an tight and the only movement is from the springs. So we look down into the engine and look at the slot itself. It appears to be worn out and only about a 1/4" of tip of the dizzy is engaging the slot in the intermediate shaft. You could see where it was rubbing or wiggling from movement side to side.

So heres a few questions for you engine guys. How far is the dizzy suppose to engage into the intermediate shaft? Is it suppose to be a tight fit with no movement at all once engaged? How about the shaft itself and its gear engaging the cam gear? I can stick a slotted screw driver into it, twist it back and forth and see it move. I assume you shouldnt see any movement if you twist it?

If I have to take a video of the movement I will try the best I can, but I think I explained it pretty well. I had the engine built by a shop and they gave me my old intermediate shaft from my 318 to use, so it is not new.

Thanks for the help guys.

 

[krazykuda]

I would take a new shaft and new dizzy and check them to see how they fit together..

 

[krazykuda]

I just took a new shaft and a new Accel distributor by hand and fit them together, and there was not very much play if you held the shaft and tried to turn the distributor back and forth.

When I measure,

I get .151" - .154" across the outside of the flats for the distributor.


And about .158" for the inside of the slot for the distributor gear.


> measured with digital calipers.

 

[mderoy340]

pull the intermediate shaft out and check the bushing in the block it's probably worn out.

 

[straightlinespeed]

I just took a new shaft and a new Accel distributor by hand and fit them together, and there was not very much play if you held the shaft and tried to turn the distributor back and forth.

When I measure,

I get .151" - .154" across the outside of the flats for the distributor.


And about .158" for the inside of the slot for the distributor gear.

Thank you Karl for those measurements. I will pull mine out and mic mine to find out where mine are at. Just from your measurements that you gave me, mine feels a lot more sloppy than .004-.007 thousandths.

So I was looking at the MP intermediate shafts on Summit Racing. They have the standard one for about $60 and a bronze one for over $200. Why the big difference and when would you use a bronze gear?


> measured with digital calipers.

pull the intermediate shaft out and check the bushing in the block it's probably worn out.

Its a brand new engine only about 800 miles on it. I was going to look to see if maybe they forgot to put the bushing in but then the intermediate shaft would be really sloppy. I'll take a good look and see what it look like though.

 

[mderoy340]

Did you put a new intermediate shaft in it? I've seen new ones with a wide slot cause the timing mark to bounce while running.

 

[straightlinespeed]

Did you put a new intermediate shaft in it? I've seen new ones with a wide slot cause the timing mark to bounce while running.

No the engine builder gave me my old one from the 318 core I gave them. So it is used. I did have the bouncing issue with a prior dizzy that I had in the car, but that was with the current one in my car. After I installed the new MP dizzy I didnt have the bouncing problem but I do have all that extra play.

Curious as to if anyone else has tried to spin there dizzy by hand while its in the car. Just wondering if all they felt was spring tension or did it move prior to feeling the spring tension (which is my case)

 

[rumblefish360]

The movement of the distributor should be as close to nil as possible.
With that said, the parts, distributor, intermediate shaft and the bushing it slides through are not precision fitting parts. The intermediate shaft gear should mesh with the cam really nice and tight. Not forced in. At the bottom, the hex should be pretty snug but slide in easy I to the oil pump. But there's play there and all the way on up.

How much is to much? I'm not really sure. I never crossed a measurement saying *** amount is worn. Normally, these parts are replaced during a rebuild. So I never crossed issues like this.

I figure, if you can move it, it's shot. Replacement time.

 

[Inertia]

I've replaced a few intermediate shafts cuz they were worn as described, with a sloppy rotor, and the total advance would bounce all over the place,,

 

[straightlinespeed]

The movement of the distributor should be as close to nil as possible.

I figure, if you can move it, it's shot. Replacement time.

I've replaced a few intermediate shafts cuz they were worn as described, with a sloppy rotor, and the total advance would bounce all over the place,,

Thanks guys, I will be picking up a new shaft. At least I can eliminate that as a issue.

Im still going to mic mine out just to see

 

[krazykuda]

Thanks guys, I will be picking up a new shaft. At least I can eliminate that as a issue.

Im still going to mic mine out just to see

I recommend getting the special hardened one from MP. they are stronger than the stock ones.

 

[straightlinespeed]

I recommend getting the special hardened one from MP. they are stronger than the stock ones.

There is a bronze gear they offer also. But its very expensive and the other one they offer is hardened but only $60 or something like that. I assuming your talking about buying just the regular one?

 

[rumblefish360]

Bronze gear for roller cams.

 

[straightlinespeed]

Bronze gear for roller cams.

Thank you.. I just ordered a new one. I appreciate everyones help!

 

[straightlinespeed]

Just wanted to give a update on this issue.

I got my new intermediate shaft today. I pulled the dizzy and measured the tip of mine @ .153. Got the old shaft out and measured it up @ .162-.164. :wack:

No wonder I had a hell of a time dialing in my timing. So I measured the new shaft @ .156. Holy cows my old one was worn to hell. I think it will be a paper weight on my desk at work now.

Got everything back together and fired it up. I couldnt believe my eyes. My balancer was nice and smooth, holding steady at what ever I set it to. Thank you everyone again for your input.

 

[pishta]

So your slot opened up to .167 from .153? Wow, i had a guy tell me he put a piece of water pump gasket over the end of the dist shaft with a dab of grease and tap it in for a snug fit. Ghetto but he told me it cleaned the timing right up. You found the proper fix.

 

[straightlinespeed]

So your slot opened up to .167 from .153? Wow, i had a guy tell me he put a piece of water pump gasket over the end of the dist shaft with a dab of grease and tap it in for a snug fit. Ghetto but he told me it cleaned the timing right up. You found the proper fix.

The shaft I had in my car was a used shaft that was in my old engine. I would had never guessed that it would wear that much, but it sure did. I have the MP hardened shaft in the car now... At least It was a nice upgrade.