how to check and change your distributor to a non computerized distributor

[superj]

this is for the guys who have the 4.2 liter inline six cylinder and have swapped their carburetor or done the nutter by-pass.

the factory distributor for the computerized carbureted i6 is not set up for lots of fun because it is designed to work to get lowest emissions possible, at the cost of performance. i am going to show you how to check your current distributor to see what kind of timing advance spring plate you have and then show you how to swap the no fun distributor for an old school none computerized version from an earlier cj that can be bought for 45 bucks plus a refundable core charge of 15 dollars.

here is our fun distributor, part number 30-4691, available from advanced auto parts (and probably others too). it is for a 1980 cj7 with an a 4.2 liter motor.

let me give you some insight to why i did this as you are going to learn i made a mistake in doing this to my poor old 87 wrangler. i bought this old jeep and was told the motor had been changed by the kid who owned it previously. he knew nothing about it as he was not a mechanic and that is why he was swapping me my 87 cherokee straight across for this 87 wrangler. he said the guy told him it had a 4.0 bottom end and that was all he could remember on the motor. i thought ok, means nothing to me because i have only owned 4.0 cherokee and grand cherokees. so he fried the lower end and couldn't find a 4.2 to throw in again. turns out, i was wrong and him changing the bottom end means a whole crazy bunch of power is available to me, if i can unlock it.

what the previous owner had done is stroke this jeep. he put a 4.2 crank and connecting rods into a 4.0 block using 4.0 pistons which translates to a 4.5 liter monster that rides a bit over 200hp. and that is on a carburetor!! with fuel injection and a 4.0 head, you are looking at a hair over 250hp at the crank.

one of the things needed to achieve that 200hp is the proper distributor that gives you the correct advance. the computerized distributor is limited to 8 or 9 degrees of advance because the slots in the spring plate are just not long enough to allow more advance. i have no pic because when i pulled the distributor apart on this cj7, i just forgot to snap one.

but, on with the instructions.

unscrew your distributor cap and set it on the valve cover

pull the rotor (the blue piece in the center of the distributor) and set it in the cap

here is your distributor, be it out of hte vehicle or still in the block, you can do this either way. it is actually easier in the block so you don;t even have to pull your distributor to check what kind of unit you have.

that little star looking piece in the center needs to come off. you just put two screw drivers opposite each other slide it up. don;t forget to undo the screws though or you will be looking at it like i was and wondering what the hell??

once you get the star to move to the top, start being a bit careful as their is a roll pin in it that holds it from spinning on the shaft. that roll pin needs to not drop and get lost or you are going to have a heck of a time driving to the hardware store or autoparts place to find another.

luckily, the little black box on the plate you unscrewed is magnetic so you can stick the roll pin to it and it will be safe.
slide your whole plate and star off and set it somewhere safe

you want to look into the distributor at your spring advance plate

see how this one says 13r and 16r? yours will not say that, it will say 7r and 9r or 8r. (this is the dumb part i warned you about earlier. i never actually opened my distributor up prior to buying the new one. i assumed mine was the older version and now have two of the good distributors)

what you want is purchase the one i showed up above sitting on the box and then open it up and remove everything we just did and swap your plate so the little metal arm is sitting in the 16r slot which will allow you to have the max advance you can get.

once you have purchased your distributor and swapped that plate around you will have to pull your old distributor and replace it with your new hot rod distributor though, this is how you do that.

 

[superj]

you are starting here with your handy dandy screw driver, wrenches, and sockets

put the sockets back, you will not need them

unscrew the little weird screws holding the cap on and lay the cap on the valve cover again.

pull rotor (remember where it is pointing, you will need to know later) and put in cap, again

pull vacuum line and lay it on top of valve cover too

unplug electrical line (what hte heck is that!!!!!? that is corrosion, our evil arch nemesis who is always trying to stop our beloved jeeps from running. by some electrical cleaner in a spray can and get hte out)

underneath the vacuum cannister is probably where you clamp and bolt are, like mine was

take that bolt out and keep it with the clamp somewhere safe. its another important piece

now, you will just pull the distributor straight up and out of hte block leaving a large hole so don't drop anything into this hole. no dirt, leaves, nuts or bolts, anything!!

that slot in the bottom is your oil pump slot. the teeth are from the cam gear. that is why you don;t want to drop anything in that hole. it will just screw up your oil pump and cam gear causing you to have to take some other stuff apart that will take way longer then the half an hour or hour this takes.

now you are up to the reinstalling your distributor point. it will just drop right back into the slot but will invariably not line back up exactly as before so you will have to adjust your timing a little bit. we will go over that too.

put your distributor base gasket onto the block.

see this slot on top of the distributor shaft, it is what aligns your rotor. it needs to be open end to the way your rotor was pointing when you pulled it off originally. this one is 180 out so turn the shaft until it points roughly where the rotor pointed in the earlier pics

and then put the rotor back on

your cap only goes on one way so be sure to align this slot up with the wires coming out of the distributor body

oh man, don;t forget to put the bolt and clamp back on or you will never stay in time.

now we are up to the learning to time your jeep portion of the write up

 

[superj]

your distributor rotor should be pointing roughly where it did when you first started

this is hte earlier shot of the removal

when i say roughly, it has to be fairly close. see the differences in my roughlies? it was enough that the jeep would not start and was having a hard time cranking so try and align it as close as possible. to align it without pulling the distributor over and over, just twist the vacuum cannister to where it is inline with the rotor more.

get your timing gun and lay the leads out so they will not get caught in your fan or any belts.

i run mine in front of the radiator. hook your red to the positive on the battery, black to the negative, and the inducer to the number one spark plug wire.

be sure to not have your vacuum hooked up to the distributor and make sure the end from the intake is plugged or you are going to be off a bit

now, go put your key in the ignition and crank your jeep over. if it starts right up, hell of a job!!!! if not

, and you are like me with a slow cranking jeep, head out and turn the distributor a little bit in a counter clockwise direction. go back and turn the key. does it crank faster or the same? if its faster, but doesn;t start, then turn it some more in a counter clockwise direction. if it stayed the same, turn it clockwise past your starting point and try cranking again. did anyone get it to fire this time? good job!!! if not (like me), turn the distributor some more in either direction till you get some the jeep to start.

once it starts, you want to look here for your timing marks

point your timing gun at those marks and pull the trigger (a note on your timing gun: make sure the knob is set at zero, if you have a knob. if your using a timing light (no know) then you are good) you will probably just see nothing, like i did. this means your timing is way off in never never land and probably about 40 or 50 degrees out. its ok, the jeep started. your idle is probably way up there too, around 1k or 1200 rpm? don't worry, it is running and easily fixable now. :shades::shades:

you are doing great and almost done!!!

go over to your distributor and turn it clockwise a bit, while the jeep is running. your idle will drop while you turn the distributor. what you are doing is bringing your timing back to where it is supposed to be, around 8 or 9 degrees. keep turning until your idle sounds like it did before, about 700-800 rpm.

now go grab your timing gun and point it at the marks again and you should see this.

whooops, we are a hair to high on our timing. since i accidentally cut the numbers off the mark when i took the picture, that line with the white dot is the crank pulley on the engine showing top dead center on the crank (tdc). those little lines on the right are the timing marks showing before dead center (bdc) with a 2, 4, 6 ,8, 10, and 12, if i remember the numbers right. either way, that line with the dot is about 10 or 11 degrees which is still a bit to high as you will probably get knocking when you go up the on ramp in warm weather at this setting.

turn the distributor a hair more, please, and then check your marks again. this is pretty much where you want to be, 8 degrees. everything runs good here. you start easily, idle smooth, and can run up on the highway with no knocking or pinging under load.

you can now turn the jeep off and tighten your distributor clamp bolt back down so the distributor doesn;t rotate on you

pull the plug from your vacuum line and hook the line back up to your vacuum cannister on the distributor

put everything away and take your jeep out for a spin. i bet it feels like a totally different jeep now.

you should get an improvement in acceleration and an improvement in gas mileage.

have fun and know that you have now

1: removed your distributor
2: disassembled and checked it to see what style you have
3: reassembled and reinstalled your distributor
4: set your timing

you are now a man among men. you can walk with your head held higher because you can work on your own vehicle in a world of people who only know how to turn the key and push the gas pedal.

 

[superj]

we have a limit on how many pics we can put into a post. this limit required me to remove some smilies that were added for comedic effect.

 

[YJ-Ray]

Great thread man keep it up

 

[superj]

you can tell when i am bored at home because i do this kind of stuff.

i am waiting to hear how to adjust the star ring on the shaft to change to the 18r instead of the 13r so i can get some performance benefit from swapping to the same distributor.

 

[superj]

ok guys, i made some adjustments to the old distributor i removed in the write up and reinstalled it but i was unable to get pics because i was in a rush to have a running vehicle to get to work in.

i removed hte advance head from the top of the distributor shaft by pulling the little c-clip in the top where the rotor normally sits. then i unhooked the springs from the raised arms and lifted the whole plate off the distributor and reinstalled it 180 degrees. this adds 18 degrees of advance in stead of 13 degrees when everything is at full advance. so add your vacuum advance of whatever the cannister applies when vacuum is sucking and hten add 18 degrees and add your initial 8 or 10 degrees you set the timing at and that is what i have changed.

what it has done so far is made my jeep take off from the line a lot quicker. it accelerates quick now. before it would take off quick every once in a while and would smoke the tires if you got a good take off but now it accelerates quick every time. i haven;t broken the tires free but i can out accelerate other vehicles pretty regularly now. i am hoping to see an improvement in gas mileage on the tank i am going to put in tonight so give me about a week or so and i will report on the gas mileage for the plate flip.

 

[carnutt]

you mentioned having two of the same distributors..if so ..would you be willing to part with one? my poor 89yj is in need of one ..shaft slightly warped..

 

[absolutemoon]

You mentioned smoking the tires in your last thread. You runnin a 258? Mine barely gets out of it's own way. Thanks for the write up. I will try this. Anything to get this old girl moving better.

 

[superj]

you mentioned having two of the same distributors..if so ..would you be willing to part with one? my poor 89yj is in need of one ..shaft slightly warped..

I took the one I bought back since my old one was already the noncomputerized version. That distributor is super cheap new though

You mentioned smoking the tires in your last thread. You runnin a 258? Mine barely gets out of it's own way. Thanks for the write up. I will try this. Anything to get this old girl moving better.

Mine is not a regular 258 so I am not sure how it compares to a stock one. The previous previous owner did some mods to this engine, like make a stroker and changed the carb already and everything. The kid I got it from could barely drive it because he was not mechanical at all so we swapped my 87 lifted Cherokee for this "stock" wrangler. Turns out, the engine is not stock at all.

 

[absolutemoon]

Nice. On my to get distrib. With mine being stock, still worth the upgrade?

 

[superj]

pull hte cap off yours and rotate the shaft while looking in the tiny holes. the numbers will go by (they are hard to see) if you already have the 13r and 18r on your distributor, then there is no reason to get the new one. if you had the computerized carb though, you should see a 7r or 6r and an 8r or 9r in the holes. if you see the low numbers, get hte new distributor.

if you do have the 13r/18r distributor, pull it out and clean it and spray some pb blaster on it to make sure everything is working good.

 

[absolutemoon]

Gotcha. That's tonights project.

 

[superj]

cool. i am learning how to use a vacuum gauge to set the distributor and idle mixture screws for the optimum settings. once i get everything figured out, i will put up a post on how to do it. so far, i have learned my good idle mixture i had was not right and was too rich by 3/4 of a turn. i also learned my engine is healthy and i have no vacuum leaks in the lines.

 

[Brunson210]

cool. i am learning how to use a vacuum gauge to set the distributor and idle mixture screws for the optimum settings. once i get everything figured out, i will put up a post on how to do it. so far, i have learned my good idle mixture i had was not right and was too rich by 3/4 of a turn. i also learned my engine is healthy and i have no vacuum leaks in the lines.

Superj - Thanks for all the useful tips. I finally got sick of cranking mine over and over to get it started (I think the fuel in the float was boiling off or leaking after I turn her off at operating temp though I could be mistaken).
I will be purchasing a new carb along with taking my distributor apart as you have done. With regards to my temperature issue, I have a header that needs to be wrapped and I have considered building a heat shield to place between the carb and manifold. Wondered if you or anyone reading this post has seen something like this done aftermarket?

Also - did you ever get around to mastering the vacuum testing? I will have to do some more searching for your post if so. link? I would really like to know that my mixture screws are set correctly once I have installed the new carb.
Lastly, I am interested in installing a snorkel to act more as cool air intake (I doubt I will be crossing any rivers in the near future). I think this will improve the performance of my Jeep and I am curious if you have any input or have read any good posts on this?

Keep up the good work and I look forward to seeing future progress.
Best Regards,

- Miles (brunson210)

 

[69jeepcj]

Super J. This is some more info on timing. For max performance, you actually want more timing on the crank and less in the dist, staying under your total timing figure. You can advance the crank so far that the starter kicks back or wont start once warmed up, if so just bring it back down a bit. you have to know the total timing figure to do this though so you don't ping while driving. another thing I noticed is your dist has a adjustable vac can, so you can add or subtract some vac advance if you have any bucking at low speed or pinging at part throttle cruise, usually 10-15*vac advance. Just an example I have no idea of you total timing figures (use the 13R, 13*crank=26*total) It will advance quicker because the springs in the dist only brings in 13 instead of a higher figure (the dist gets there faster, the crank is already there if that makes since). Then your vac advance is added on top of that. I LOVE IGNITION TIMING

 

[superj]

Reading your vacuum gauge

I have found tons of pages on using a vacuum gage but basically, you hook it into your system and adjust your jets a quarter turn at a time and blip the throttle after each adjustment. Let the engine settle down and check the gage. Keep adjusting a quarter turn at a time until your needle stops climbing. Once you have read he'd the highest vacuum you can, you turn it back half an inch or vacuum. Then, you adjust your distributor the same way, a little twist at a time till your reach the highest vacuum. Google how to use one and you will be impressed on how much better your jeep runs.

As far as the adjustable advance, I did read about that bit never got that far into doing it. I know that does also have a huge effect in making your jeep run a lot better though.