Trick / Tips for DUI instal

[JR74CJ5]

Hey All,

Going to be installing a DUI distributor, MSD ignition box, and some 8.5 mm Wires tomorrow...

Any tips or tricks i should know about? Read something about not "bottoming" the distributor? very bad apparently, not sure i understood it very clearly, maybe will with the instructions all in front of me...

Also have heard .045 gap for HEI / DUI distributors (spark plug gap) but am reading .050 / .055 gap on some things too, any advice?

Anyhow, just looking for some advice.

 

[BusaDave9]

Some people take the + 12 wire from the old coil and wire that to the distributor. Some HEI instructions even say to do that. But it's best to route that wire to a relay. This relay then will be able to supply a higher voltage to the coil on the HEI distributor. The HEI distributor runs much better with this relay.

Once the HEI ignition is installed you will be getting a higher voltage to the spark plugs and for that reason you can (and should) increase the gap on the plugs.

 

[xena1]

I went with .045 on my plugs and worked very well. .055 may be pushing it a bit but probably will still be OK. To check for bottoming out, install distributor with no shaft gasket and cap off. See if you have any play in shaft as you should. Then put shaft gasket back on and/or add distributor shims to eliminate bottoming out. If you tighten distributor down and run with no play, you will damage oil pump.

 

[JR74CJ5]

Busa, I don't know much about Relay's... What type do I look for? are there different ones to use? etc? I'd love to do it right...

I need to see a diagram of the part that should have play... and where... Don't want to damage anything for sure!

I'm going to be doing some heavy researching when i get back from sparks, NV warehouse picking this all up tonight...



~ JR

 

[Old Dog]

Chevy has always suggested .045 for the plugs, it works for me.
Any 30 or 40 amp relay should work for wiring it up. A.Z. keeps them by the aftermarket lites around here.

 

[BusaDave9]

Old dog is right, a 30 or 40 amp relay will work fine. These are common. They are often used for off-road lights.

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These will have 4 or 5 connections. Either will work. The terminals will be labeled 30, 85, 86, 87. (Do NOT ask me how they came up with this numbering scheme). If there is a 5th terminal it will be labeled 87A but you don't need to use it. (as an FYI the one with 5 terminals is a DPDT and 4 terminals is a SPDT) These numbers on the relay match up with the drawing above.

 

[rr41mag]

I hooked mine up yesterday, I gapped the plugs at .050 and ran a hot wire to the selinoid, 14 gauge wire. I purrs like a kitten. I adjusted the timing by ear. It sounds great

 

[JR74CJ5]

Does any of the above change when also installing a msd ignition box? As far as relay, i assume wiring changes a bit.

Do i need to / should i be installing a inline fuse as well somewhere?

 

[BusaDave9]

Does any of the above change when also installing a msd ignition box? As far as relay, i assume wiring changes a bit.

Do i need to / should i be installing a inline fuse as well somewhere?

My bad. No need for the relay since you have a MSD Ignition.

 

[BusaDave9]

I ran a hot wire to the selinoid, 14 gauge wire.

To the starter solenoid? Did you use a relay? If not you will run you battery down when it sits. The starter solenoid always has 12 volts.

 

[JR74CJ5]

My bad. No need for the relay since you have a MSD Ignition.

Dave, got it all installed,

Ill post some pics monday

Thanks again all

~Jr

 

[JR74CJ5]

Got all hooked up and running good...





Then Went Fishing...




Even caught a couple small strippers. Tossed them back to grow up a little...



Good Weekend!

~ JR

 

[Niedhogg]

That's not very nice posting pics of sunshine and fishing! Been cold AND rainy here in Pa, fow a week or so, now I'm depressed...

I did buy a new fly rod and reel this weekend though, gonna go after some Steelhead Trout in a week or two!!

 

[BusaDave9]

Looks great! Any problems?
Did the vacuum advance fit in without clearance problems?
Good job

 

[JR74CJ5]

Well. I could only get initial timing set to 10 degrees instructions said 12... Runs great though... But yes the vac advance is hitting steering pump if i want to go over 10 degrees...

What do people do about this? Just move distributor around and rewire cap to compensate?

Dont think i need to, unless you all say it would be a huge differance between two degrees...

 

[xena1]

You can just re-position thr distributor and move #1 firing order to compensate. There is not much room with the p/s tank in the way. The summit version of the DUI has several possible cap positions to get everything so it fits.