Reverse Rotation Distributor - Any issues?

[ShelGame]

Does anyone have any issues running the distributor off the end of the cam in reverse rotation? I'm reading Dave Bohrer's instructions and looking at the Chrysler patents for the 2-HEP distributor and I'm not so sure that the distributor can be run backwards at all without causing ignition issues.

But, I know several people have done it this way - on both 2.0/2.4 and the Lotus head conversions.

My concerns:

1) Running it reverse rotation will make the sync pickup 'off' by several degress, even after reversing the pickup order by swapping plugs. Maybe this is not a problem as the sync is used ONLY for sync. As long as the SMEC/SBEC still sync, I guess this could be OK. One of the sync flags has only 11msec to read the hole in the vane to set sync. With reverse rotation, it seems like this could result in an occasional loss of sync - especially at high RPM - due to the timing change between the main and sync pickups.

2) Dwell - If the window is not correctly re-positioned relative to the rotor, it could affect the dwell period negatively. The cap and rotor must have electrical contact for the entire dwell period, otherwise you will get a weak spark. If the window isn't re-drilled correctly, that could happen.

So, I'd like to hear from guys that have run the distributor in reverse rotation and how it worked out. Any ignition or fuel issues?

[contraption22]

I think some modifications to the distributor need to be made. Rich Bryant offers the modified distributors, but I don't know what he does to them.

[ShelGame]

I think some modifications to the distributor need to be made. Rich Bryant offers the modified distributors, but I don't know what he does to them.

Yes, that's correct - the shutter wheel needs to be redrilled and moved, and the HEP connectors have to be swapped. I've seen that the HEP plate needs to turn 180*, but I don't see the point of that.

My point is, even WITH those mods, the timing chart for the 2 HEP's and the ignition point will not match the stock distributor rotation and that could cause some ignition issues.

[PunKid]

I recently just pulled apart my 85 Distributor to re shim it and I noticed that there is a lightly threaded area on the top of the shaft that I think is to hold a little grease and or prevent the grease/oil from flowing up into the cap area. If the 86 and up distributors have this too I think reversing it would turn that thread the wrong way and oil and grease might flow up into the cap easier. Just a thought

[contraption22]

This any help?

http://files.turbo-mopar.com/

[ShelGame]

This any help?

http://files.turbo-mopar.com/

No. I already have that. What I'm saying is, even doing those mods isn't going to result in the correct distributor operation. I'm curious if it actually causes problems or not...

[ShelGame]

Anyone?

[Omniboy]

http://www.turbo-mopar.com/forums/sh...am-ends!/page2

---------- Post added at 09:20 AM ---------- Previous post was at 09:19 AM ----------

I did mine in reverse rotation on my T3 in the minivan several years ago. You need to grind off the shutter wheel and rotate it and swap the trigger wires. Read through the thread and my posts.

[turbo2point2]

I ran my setup for 5+ seasons up to 7500 rpm without any issues of misfire/trouble. Hope this helps!

[ShelGame]

http://www.turbo-mopar.com/forums/sh...am-ends!/page2

---------- Post added at 09:20 AM ---------- Previous post was at 09:19 AM ----------

I did mine in reverse rotation on my T3 in the minivan several years ago. You need to grind off the shutter wheel and rotate it and swap the trigger wires. Read through the thread and my posts.

Thanks, but I HAVE THE INSTRUCTIONS!!!!

Sorry if that wasn't clear in the first post.

My point is this - even following the instrucitons will not result in the same-as-stock operation. I'll try to make a picture later to illustrate.

My question was simple - to those who have done the mods, did you have any ignition issues?

---------- Post added at 11:21 AM ---------- Previous post was at 11:20 AM ----------

I ran my setup for 5+ seasons up to 7500 rpm without any issues of misfire/trouble. Hope this helps!

Thanks, that's the type of feedback I was hoping for...

[1BADVAN]

maybe my rich bryant about some of these questions as he builds them he probably would be a good source for feedback from his customers and what he does to avoid the problems you brought up

[ShelGame]

OK, I looked at the timing chart again and I understand now that swapping the pickups does in fact give the same pulse signals as stock.

What I was concerned about was the 11ms window below for the window to hit the HEP and set the sync bit. I thought there would be a time-shift in the sync pulse, but I see that swapping the HEP connectors is what fixes that.

[rbryant]

Sorry I missed the posts at first. I think you have it now though.

The mods are to change the shutter wheel orientation, flip the HEP 180, and then swap the HEP wiring.
I also drill a recess where the distributor base screw hole is so that the HEP key fits in it when flipped 180 degrees so there is no need to modify the actual HEP.

The wiring can be changed in the alternator/temperature sensor/AC/HEP engine harness by simply swapping the signal wires in the connector.

Feel free to reply or PM me if I can help.

Note that not all of the distributors have the pin in the same place so you can't base the shutter position on it. You have to do it relative to notch for the rotor on the shaft not the pin that holds the plastic to the shaft.

It should look like this:

Notice that the "arrow" points to the side of the windowed shutter.


If you use screws then make sure they are low profile. I chose peel rivets so that they would be as tight to the shutter wheel as possible. I also don't drill the originals I just grind the tops off so that they also hold the wheel tight. BTW be careful because if you drop the shaft it will probably break the plastic.

The distributor mods are based on Dave Bohrer's instructions. My adapter is my own design because his used very non standard thicknesses on the components which would have made it more expensive to machine.

No big secrets here as it was Dave's idea I am just trying to enable people.

-Rich

[turbovanman²]

Gee, forget about me?

Any, yes, there is a huge issue on the TIII, it leaks like a motherf*cker. I have an o-ring crammed in between the bushings, it works for a bit before the seal harden's up a tad. Trying to find some needle bearings with seals but not having much luck. Ignition problems, none.

Why does Rich have to reclock his, the 2.0/2.4 run off the intake cam so they are normal rotation.

[rbryant]

Why does Rich have to reclock his, the 2.0/2.4 run off the intake cam so they are normal rotation.

So your intake and exhaust cams run in opposite directions? That explains a lot.

The direction is set by the side of the engine, not which cam.

-Rich

[turbovanman²]

So your intake and exhaust cams run in opposite directions? That explains a lot.

The direction is set by the side of the engine, not which cam.

-Rich

LOL. For some reason, I thought using the intake cam, nothing would need changing,

[ShelGame]

Sorry I missed the posts at first. I think you have it now though.

The mods are to change the shutter wheel orientation, flip the HEP 180

This one I still don't understand. What difference does it make? You can always turn the whole distributor 180*, no? The HEP and distributor are tied to gether, so I see no reason to flip the HEP.

, and then swap the HEP wiring.
I also drill a recess where the distributor base screw hole is so that the HEP key fits in it when flipped 180 degrees so there is no need to modify the actual HEP.

The wiring can be changed in the alternator/temperature sensor/AC/HEP engine harness by simply swapping the signal wires in the connector.

Feel free to reply or PM me if I can help.

Note that not all of the distributors have the pin in the same place so you can't base the shutter position on it. You have to do it relative to notch for the rotor on the shaft not the pin that holds the plastic to the shaft.

It should look like this:

Notice that the "arrow" points to the side of the windowed shutter.


If you use screws then make sure they are low profile. I chose peel rivets so that they would be as tight to the shutter wheel as possible. I also don't drill the originals I just grind the tops off so that they also hold the wheel tight. BTW be careful because if you drop the shaft it will probably break the plastic.

The distributor mods are based on Dave Bohrer's instructions. My adapter is my own design because his used very non standard thicknesses on the components which would have made it more expensive to machine.

No big secrets here as it was Dave's idea I am just trying to enable people.

-Rich

The whole reason I got into the instructions in deatil in the first place is because I'm going to run my 2.4 this way with the 'stock' SBEC. I thought maybe there was a way I could eliminate the process entirely by modifying the code. So, basically, T-SMEC and T-SBEC would have a flag to set and voila - reverse rotation distributor with no hardware changes. I'm still not sure if I can do that though. I needed to understand exactly how the SMEC/SBEC interpreted the timing signal and I do now. Since it really looks for the rising/falling edges, I don't think it can be done without modifying the hardware.

The other reason is, I want to make a VERY low profile distributor using the stock housing as a starting place. I need to get my cylinder head to finish my sketches and the put it all into CAD.

---------- Post added at 09:57 PM ---------- Previous post was at 09:53 PM ----------

Gee, forget about me?

Any, yes, there is a huge issue on the TIII, it leaks like a motherf*cker. I have an o-ring crammed in between the bushings, it works for a bit before the seal harden's up a tad. Trying to find some needle bearings with seals but not having much luck. Ignition problems, none.

Why does Rich have to reclock his, the 2.0/2.4 run off the intake cam so they are normal rotation.

I thought you ran the distributor in the stock T1/T2 location?

[rbryant]

This one I still don't understand. What difference does it make? You can always turn the whole distributor 180*, no? The HEP and distributor are tied to gether, so I see no reason to flip the HEP.

The whole reason I got into the instructions in deatil in the first place is because I'm going to run my 2.4 this way with the 'stock' SBEC. I thought maybe there was a way I could eliminate the process entirely by modifying the code. So, basically, T-SMEC and T-SBEC would have a flag to set and voila - reverse rotation distributor with no hardware changes. I'm still not sure if I can do that though. I needed to understand exactly how the SMEC/SBEC interpreted the timing signal and I do now. Since it really looks for the rising/falling edges, I don't think it can be done without modifying the hardware.

The other reason is, I want to make a VERY low profile distributor using the stock housing as a starting place. I need to get my cylinder head to finish my sketches and the put it all into

But the shutter also has to be in the right orientation relative to the HEP. The HEP sensors aren't at 180 degrees apart (one is not 90 from the hold down screws) so I think that might have something to do with it.

The SW approach is a cool idea. I think you might end up with a phase problem due to the angles of the sensor though unless you atleast flip the HEP.

I would have to think about it a lot more. At one point I convinced myself that it would all work and everyone else has had good luck so I haven't thought about it again.

-Rich

[ShelGame]

But the shutter also has to be in the right orientation relative to the HEP. The HEP sensors aren't at 180 degrees apart (one is not 90 from the hold down screws) so I think that might have something to do with it.

The SW approach is a cool idea. I think you might end up with a phase problem due to the angles of the sensor though unless you atleast flip the HEP.

I would have to think about it a lot more. At one point I convinced myself that it would all work and everyone else has had good luck so I haven't thought about it again.

-Rich

Yeah, but there's no mechanical connection between the shutter and the distributor housing. I don't think the HEP needs to be touched other that swapping the wires. And, yes, you do have to move the shutter. I still think this needs to be more precise than maybe Dave's instructions make it. If the shutter is 'off' relative to the rotor, then the rotor will lose contact with the cap before the nend of the dwell period (basically a mechanical dwell limit) resulting in a loss of spark energy. Maybe this is only small, but it is possible if the shutter is not placed precisely.

I need to do some distributor drawings myself...

[turbovanman²]

This one I still don't understand. What difference does it make? You can always turn the whole distributor 180*, no? The HEP and distributor are tied to gether, so I see no reason to flip the HEP.




The whole reason I got into the instructions in deatil in the first place is because I'm going to run my 2.4 this way with the 'stock' SBEC. I thought maybe there was a way I could eliminate the process entirely by modifying the code. So, basically, T-SMEC and T-SBEC would have a flag to set and voila - reverse rotation distributor with no hardware changes. I'm still not sure if I can do that though. I needed to understand exactly how the SMEC/SBEC interpreted the timing signal and I do now. Since it really looks for the rising/falling edges, I don't think it can be done without modifying the hardware.

The other reason is, I want to make a VERY low profile distributor using the stock housing as a starting place. I need to get my cylinder head to finish my sketches and the put it all into CAD.

---------- Post added at 09:57 PM ---------- Previous post was at 09:53 PM ----------



I thought you ran the distributor in the stock T1/T2 location?

I did at first then moved it, about a year later, I had a few threads about it. I didn't like the fact that you had to remove the intake to do any servicing of the cap, rotor or HEP.

Also, see my sig,

Yeah, but there's no mechanical connection between the shutter and the distributor housing. I don't think the HEP needs to be touched other that swapping the wires. And, yes, you do have to move the shutter. I still think this needs to be more precise than maybe Dave's instructions make it. If the shutter is 'off' relative to the rotor, then the rotor will lose contact with the cap before the nend of the dwell period (basically a mechanical dwell limit) resulting in a loss of spark energy. Maybe this is only small, but it is possible if the shutter is not placed precisely.

I need to do some distributor drawings myself...

The HEP needs to be rotated 180 because the firing order is altered and the one PU is the injector syn, so if you don't rotate the HEP, it won't know when to sync. That's what I was told, haven't tried to run it without moving the HEP, maybe I should try.

I simply broke off the tabs on the harness connectors so you can swap them without modding anything and ground off the locator on the HEP.