383/400 - Distributor shaft length and seated depth Q's?

[Sweet5ltr]

For those that have been around these engines, my main question is how deep or shallow does the shaft sit into the distributor gear on the oil-pump drive shaft? Is there a factory specification on the required depth?

From my research, the mounting surface to distributor drive shaft tip is 3.5" on this (B) engine series.

 

[cryplydog]

If you use a flash light you can clearly see that the drive lug slot is prob. only 5/16"deep if that and the dist. drive shaft drops down into the rectangle slot. You are going to have to make sure it is timed correctly. Do you have a factory service manual or chiltons, Motors manual.

 

[HEMI-ITIS]

Funny you should ask,,,,,I never checked the length of the distributor shaft into the oil drive gear.Just assumed it was the right length.But the oil pump drive shaft was always carefully checked to be certain it was not stressing the big Milodon oil pump!!

 

[Sweet5ltr]

Funny you should ask,,,,,I never checked the length of the distributor shaft into the oil drive gear.Just assumed it was the right length.But the oil pump drive shaft was always carefully checked to be certain it was not stressing the big Milodon oil pump!!

Only reason I’m asking is gauging the wear pattern, my MSD pro-billet only engaged around 1/8” into the drive gear with the correct 3.5” mounting surface to tip. New MSD Distributor is 3.375” (slightly out of spec) so it’s an 1/8” shallower. I’m not sure if this actually makes a difference and what the actual load is on the distributor tip. If they weren’t side by side most wouldn’t notice. I’m just surprised these don’t actually seat deeper. Oil pump drive is from Mopar Performance.

 

[HEMI-ITIS]

If the spade went all the way in,,,,how much penetration would it have??

 

[cryplydog]

Sweet5, measure it. Do you have a dial caliper.

 

[khryslerkid]

I get 3.5" also. I'm wondering what your bushing under the oil pump gear drive looks like, height of the bushing's flange?

Never checked but does a BB use the same drive shaft as a RB?

 

[Lefty71]

Never checked but does a BB use the same drive shaft as a RB?

Yes, only distributor shaft is different, to make up the difference in the deck hgt.

 

[Lefty71]

The maximum engagement of the slot into the oil pump drive is very close to .500". I checked this on some stock pump drives, as well as Melling and Mo-Perf ones. I'll have to look at a couple distributors that are laying around for a comparison of the total engagement though... There is an adapter to correct the deck height difference, which will allow you to run RB distributors in a B engine, for those who may not have known.

 

[Sweet5ltr]

Yes, the (RB -> B) adapter spacer is another $80 so I would rather not have to do that for another 1/16” and have MSD correct it in this case. This is a relatively brand-new offering from MSD (labeled under Holley) for the Sniper EFI system, we’re hoping it’s a one off issue (and they can overnight/two-day me a new one!) but it could be a production line problem.

It doesn’t seem that many people actually measure the depth the shaft tip rests into the slot. Just thought it was a bit interesting that the correct (to spec) Distributor has a wear pattern only slightly over 1/8” on the tip. Check out the grease on the new one, and this is from MSD, everyone would expect it to be correct and it sits into the slot correctly (1/16”) so no one would even know unless they measured, and why would someone if it dropped right in with no issues?

 

[Sweet5ltr]

MSD Pro-Billet vs. MSD Hyperspark

 

[Lefty71]

I know it probably makes no difference, since they are both MSD, but in order to make a valid comparison, you'd have to compare from just above the orings, where the true mounting surface is. HTH, Lefty71

 

[Sweet5ltr]

I know it probably makes no difference, since they are both MSD, but in order to make a valid comparison, you'd have to compare from just above the orings, where the true mounting surface is. HTH, Lefty71

Oh sorry, yes, this image was just comparing the two. From the mounting surface, the new Hyperspark was an 1/8" shorter than the Pro-Billet. Both are built by MSD, the Hyperspark is branded by Holley. The MSD Pro-Billet was exactly 3.5" from the mounting surface to tip of distributor shaft. The Hyperspark was 3.375" from mounting surface to tip of distributor shaft.

 

[Sweet5ltr]

Well, the engineers at Holley / MSD are now requiring me to send BOTH of these distributors to them, they've prepared an overnight label. Was really hoping this was going to be an anomaly and a new Distributor would arrive on my doorstep.

(Holley Technical Rep) --- Just spoke with the engineering head directly on the issue. We’d like you to get both distributors back in to us so they can check measurements on your MSD reference distributor versus factory spec versus the Hyperspark. I’m going to have a UPS overnight call tag issued in the morning if that’s acceptable to you. Email it to this address? Thank you for your patience while we unravel this! We will do whatever it takes to have a solution in place well before your event.

 

[5.7 hemi]

Hey, they’re doing what’s right, and I’m sure Holley will take care of you.

 

[1967coronet440]

That’s customer service. I’m sure In the end you’ll see something for your troubles.

 

[cryplydog]

Tell Holley to send a complete EFI kit for the troubles.

 

[Sweet5ltr]

No doubt, customer service has been excellent. They just sent an 02 sensor to me last week, no questions asked. Don't try that with other manufactures of TBI EFI systems.

 

[1967coronet440]

No doubt, customer service has been excellent. They just sent an 02 sensor to me last week, no questions asked. Don't try that with other manufactures of TBI EFI systems.

Tell them send a note to tech dept to answer my email regarding the stealth 4500

 

[Lefty71]

We will do whatever it takes to have a solution in place well before your event.

It will be interesting to see what the response is..... hopefully you told them your event is this weekend.