I have the same issue with my MSD distributor in the 511 that i had with the 408. When i rev the engine 3-4* timing comes out or retards. I fixed the SB issue by adding a crank trigger. Don't want to spend any more money right now and i think i might know why these distributors have this issue. Its not uncommon, just look it up. I believe the oil pump shaft gear is lifting when engine is rev'ed and turning as it lifts causing the timing to retard a bit. How can i stop the oil pump shaft from lifting? Thanks

They make a thrust collar that goes on the distributor shaft to keep the intermediate shaft from jacking itself up on the cam gear.

http://www.billrolikenterprises.com/proddetail.asp?prod=2932988-HD

Kevin

That link does open, but i'll look that up. thanks

Just thinking about that collar. Wouldn't shimming the shaft solid do the same?

I would drive out the roll pin & add some flat (non beveled) shims to reduce the axial play to .005" & you may need to in addition add the collar but first lightly twist the rotor back & forth with the dist still installed, not enough to get into the springs & see how much rotational play you have right now (you want very near none). speedway motors has a kit for $10. this may not be the issue for this situation but it is good to address it (it mainly causes spark scatter when timing it on the dampener) & a sloppy timing chain will do the same thing & a sloppy chain will skew cam degreeing readings.

Someone (Mopar Performance?) sold a shim kit for on the shaft to move it up and minimize end play between the two. I would think timing chain slack, cam twist, timing light electronics not keeping up, etc., would all contribute to this. They all bounce to some degree. All reasons for using a crank trigger.

I had the exact issue with my small block. Crank trigger isolated the distributor from the problem. I'm sure its the distributor. I used to think it was electrohysteristis or something with the pick up. I was just thinking today that if the oil shaft were to lift it would twist as its lifting being the gear is helical cut and hence moving the timing. I some how need to hold the shaft down as well as tighten up the distributor shaft wouldn't hurt.

I think they commonly shim the shaft up to reduce the play between the shaft and the distributor. Adding material to the tang of the distributor shaft and then machining or grinding it up to proper length is another option. Either way, it would have to be tuned with the intake or oil pump off to accurately adjust the end play without having it bind.

Sounds like may be easier to add a crank trigger.

All you need to do is buy a collar that fits the dist. shaft and set it to have a little end play. They sell them at McMaster-Carr along with the bronze thrust washer to protect the intermediate gear if you are running a coated or bronze unit.

So the collar fits on the end of the distributor shaft? Any idea how much clearance is needed?

set the collar on the end of the shaft reasonably snug then install the dist which will push it up then pull the dist & loctite the setscrew with the collar located at the height that it gets pushed up to.

Ok Thanks. Ill give that a try.

I had a firecore distributor in it perviously, the shaft must have been longer as i did not have this issue.

IIRC, the instructions with the collar I bought from Hughes said .006 or .008... not much!

Ok. Was gonna see if i could find one at the bolt store. Think ill just order one from Hughes.

Any good hardware store will have what you need for less money.

You can try a bearing distributor as well like Motion Industries or Applied Industrial.

I like the style McMaster-Carr (I think) carries better. If you compare the two, you'll see how they're secured to the shaft is different, and I think the Hughes collar could be more likely to come loose, since it's being "pinched" by a set screw, rather than clamped all around by the other style.

I do have the Hughes collar on mine now. I needed to find a new screw to tighten down my other one after I botched up the hex hole where the Allen key fits. So I used the Hughes -- which I also had on hand -- since I was in a time crunch.

What size is the msd distributor shaft?

I think...going by my used up memory...the shaft should measure .485-.490 so a set collar with a 1/2 hole will work.


Forgot to mention they usually only have one set screw. I put two more in the collar so I have three. I'm just chicken like that.

Ill see if i can find a collar that fits snug on the shaft. Thanks

What i could do is take the roll pin out of the collar thats on the msd shaft now and see if the guys at the local nut and bolt store can match it up another collar to that one, but with a screw in it..

I shimmed mine years ago to have .002-.003 up n down movement and added a rubber/nylon bushing instead of the collar and it compresses nicely when the lock down is tightened. I also added a new bronze gear and had Pettis machine the difference off the gear to add a 3-piece torrington bearing deal and the timing is more stable than ever..........The bronze bushing and gear don't seem to play well together and wear quickly.........

Ok thanks Dom. Ill see if i can find something in nylon instead of metal.

Dom has a good point about taking the play out of the distributor shaft as well. I always do it, just forgot to mention it.

If you do both your timing will be rock steady.

Its been in my plan to tighten it up to .005. I have to remove the pinned collar any way. Hoping to really dial the timing in.

Go to Tractor Supply and get a 1/2" collar for $1.25...unless you just like paying $20+ for the same part. I've had one in my hemi for probably 5 years now. Fixed the same issue you're having.

Does the tsc collar fit the shaft snug?

IIRC it fit pretty good. Like I said, been in there for around 5 years...no trouble. Must be good.

They don't have to fit real tight.

Like I said...I'm a chicken so I add two more set screws. I've never had one come loose and I've done probably 40 of them over the years.

Ok. Then ill just go to tsc then. I may already have one. Just have to go thru my nuts and bolts can. Second thought, ill go to tsc. Its quicker.

I've spent hours looking for a bolt I could have run to town and bought. Someday I'll organize that stuff better.

Believe me, i understand.

Anyone have a a reference photo they can post? I am pretty sure I understand but a Photo would be great. Thanks.

If you had no problems with a Firecore distributor in the same engine, my money is on the MSD as the culprit. I have seen several in the past few years that had crazy timing issues. MSD quality isn't what it used to be.

See what i can do.

a touch of blue or red loctite on the screw [after properly cleaning the screw and collar] would ease your mind about things coming loose in operation. just remember if using red [the permanent stuff], a touch of heat will be required to remove the screw. also, my local ACE hardware has those in stock for $1.00 and change. and is only a block from my house vs tractor supply, which is 18mi. away. [i like them both. ] you would be surprised at what ACE carries in auto related items !

Perfecto.

I have to go to Ace i a bit . see i can find one and maybe add another screw.

Gonna get an extra screw and drill another hole. Will i need too grind flats in the shaft where the screw hold it?

I wouldn't grind on the shaft

Hmmm,

I recently pulled my MSD billet distributor apart to do some maintenance on it after 10,000 or so miles and did indeed notice some play in the shaft. Took the dial indicator to it after I cleaned, changed advance bushing to a custom 16 degree bushing and installed new springs. The play was around .015. Assembled everything back together and up revved the engine and the timing advanced steadily to 36 degrees with no bouncing or retarding. Do you know how much play you have?

Cab, thanks. Didnt really want to grind on it anyhow. No, but not much. Took it out of the box locked timing and installed. I picked up 3 collars. 3/8 7/16 and 1/2. I dont believe the msd has a 1/2" shaft, but i should have it covered with 1 of the 3. Robbed a tap from my dad so im golden. Thanks guys

Worked on installing the dist collar today. First tried installing it with no extra clearance, just tight. still had 2* retard with rpm, so took dist back out and set with about .010" clearance between the collar and gear and I tightened up the reluctor wheel gap to .010" as well. Put back together and same 3* retard with initial rpm. I'm thinking my cam is moving. I did not use a button on that when I installed it. so add a button or a crank trigger. crank trigger is easier.

How much slop in the intermediate gear and the tang on the end of the shaft..........I had mine brazed thicker than stock then hand ground it till it fit tight in the gear..........

I hope you are not seeing the Multiple spark function of the MSD.

I use ice ignition. .006 in the dist shaft and about .010 between collar and gear. With no clearance at all i had 2* retard. Something else is going on here.

Again, i had a firecore distributor before this msd and the firecore was rock steady with the timing. What could be different between the two that one has steady timing and the other pulls timing at rpm?

So it's an ICE ignition and MSD distributor? Doesn't ICE make a distributor?

For most of my life I used a magneto because I hate electronic stuff.

I'm not a fan of mix and match stuff.

Yes. Mag pick up on both. Ice dist are not mag pick up and cost about $400.

If the firecore distributor was rock steady why did you change it to an MSD?