Distributor rotor arm wont budge a tooth

jpjeep26uk

jpjeep26uk

YJ Enthusiast
Joined
Nov 12, 2022
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203
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UK
Wow, talk about frustrated. I've set my number 1 spark at TDC using the groove and marking on the crank but my rotor is pointing about 6 o'clock on my dist instead of at number 1 location. I've tried to lift the rod that holds the rotor but it's not budging. Took the little washer out of course but it ain't budging. Tried removing the whole thing from the engine block but even though i took off the right hand side retaining bolt it would not budge at all. How do I shift my rotor back by one tooth? Thanks

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First off keep in mind there is 2 top dead centers. One on compression, the other during spent gas out, new charge in. If you have not pulled it out at all then don't worry on that comment. Dependent on how much rotation your dist has you might be able to turn it enough to get what you need in the way of timing it correctly If your thinking its off a tooth and that's why it runs crappy. Id ask myself if it ever ran right , then how did it get off a tooth? Id be thinking timing gear/chain skipping a tooth from being worn and stretched. 1 tooth out of wack on that dist will make it run like SXXT, been there done that on my 4 banger. To pull the dist you need to remove the hold down bolt and pull the entire body up. It may be somewhat stuck in the block due to the seal O ring being hardened up from age and you'd need to wiggle and jiggle it to get it out. Mark the body and shaft or take a pic of it before yanking on it. As you pull up on it the shaft will rotate some due to the angle cut of the dist drive and cam gear teeth so pay attention there.
Not to confuse the issue but you can literally set the rotor pointing in any direction you like once the dist is set in place BUT, you must rearrange the plug wires in the correct order to accommodate TDC and the #1 cylinder if that makes sense.
At any rate your gonna need a timing light to set the timing if you moved things. Have you or did you check the timing before hand to see if it was off??? Im not sure of your year jeep, but most computer controlled engines these days one can set the base timing for lack of a better word, but as long as its within a certain margin or error, not 1 tooth off which it to much in my experience, the computer will put it where it wants it to be. For example you cant simply advance the timing a few degrees cause you want to see how it runs. The computer will make it go back where the computer said its programmed to be basically. Again, not sure what electronics your jeep has.
 
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Wow Gilaguy, thanks for the detailed reply. OK, here's the short version of my 6hrs out in the UK cold! I figured out how to get the dist base out by a gentle tap with a rubber mallet. The very thin metal washer was busted so I guess I need one of those!. I put the crank at TDC and then eventually got the rotor pointing at #1 position. All good, put dist cap back on, plugged sparks and leads and cranked her up. She cranked healthily but just wouldn't fire to life. Figured id perhaps gotten the wrong TDC so I put the crank back to TDC and turned the rotor 180deg and tried again. Even worse, she turns over healthily but after 5 churns she comes to a sudden stop, almost like someone is a break on the crank if that makes sense.
I'm literally at the very limit oof my mechanic skills and fear I may have messed up the timing completely as at least she started this morning! All this effort to get rid of a backfire.
 
Gilaguy23 said:
First off keep in mind there is 2 top dead centers. One on compression, the other during spent gas out, new charge in. If you have not pulled it out at all then don't worry on that comment. Dependent on how much rotation your dist has you might be able to turn it enough to get what you need in the way of timing it correctly If your thinking its off a tooth and that's why it runs crappy. Id ask myself if it ever ran right , then how did it get off a tooth? Id be thinking timing gear/chain skipping a tooth from being worn and stretched. 1 tooth out of wack on that dist will make it run like SXXT, been there done that on my 4 banger. To pull the dist you need to remove the hold down bolt and pull the entire body up. It may be somewhat stuck in the block due to the seal O ring being hardened up from age and you'd need to wiggle and jiggle it to get it out. Mark the body and shaft or take a pic of it before yanking on it. As you pull up on it the shaft will rotate some due to the angle cut of the dist drive and cam gear teeth so pay attention there.
Not to confuse the issue but you can literally set the rotor pointing in any direction you like once the dist is set in place BUT, you must rearrange the plug wires in the correct order to accommodate TDC and the #1 cylinder if that makes sense.
At any rate your gonna need a timing light to set the timing if you moved things. Have you or did you check the timing before hand to see if it was off??? Im not sure of your year jeep, but most computer controlled engines these days one can set the base timing for lack of a better word, but as long as its within a certain margin or error, not 1 tooth off which it to much in my experience, the computer will put it where it wants it to be. For example you cant simply advance the timing a few degrees cause you want to see how it runs. The computer will make it go back where the computer said its programmed to be basically. Again, not sure what electronics your jeep has.
Click to expand...
Oh and no, I didn't do any timing stuff, I'm literally learning everything as I go along and dont have tools or access to timing tools. TDC has proven to be my mechanic brickwall!
 
It sounds like you have the timing even further off then before. To far advanced and its like somebody is pushing back as it trues to crank over. To far retarded and its just like it has no compression to run itself kinda. first off its possible the Harmonic balancer has spun a bit and the timing TDC mark is off. As I said there are 2 TDC's and you must find which is the compression stroke TDC. To find TDC if the marks are off folks have actually pulled a spark plug and with great ease and caution used a small wood dowel or screw driver to feel the piston come to the very top, that being TDC. This takes somebody turning the engine over by the crank shaft bolt in the middle of the crank pulley. Can be done solo but its easier with 2. Once that is established then its back to the distributor. Without seeing myself that shim you mentioned may be a spacer to space up the distributor body and shaft. You do NOT want it bolted down so tight the shaft is pushed down there is 0 up and down play in the shaft. The body is snugly bolted down, but the shaft can move up and down a touch, thousandths of and inch is all.
Once TDC is set back to dropping in the dist and setting the leading edge of the metal part of the rotor tip at where the # plug wire terminal is in the cap. Once you get this close it should fire up or try. While cranking it you may have to rotate the dist body one way or the other to hit the right spot and it should run. But...as I said before you will need to set the timing to the factory spec to get it to run right.
You might also try turning the crank bolt back and forth a tad and watch how far in an estimated degreed of rotation you can go before you see the dist shaft starting so move. Its kind of a indicator of how loose/sloppy the timing chain and sprockets are which can effect cam timing and engine timing if extremely worn or stretched.
 
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Gilaguy23 said:
It sounds like you have the timing even further off then before. To far advanced and its like somebody is pushing back as it trues to crank over. To far retarded and its just like it has no compression to run itself kinda. first off its possible the Harmonic balancer has spun a bit and the timing TDC mark is off. As I said there are 2 TDC's and you must find which is the compression stroke TDC. To find TDC if the marks are off folks have actually pulled a spark plug and with great ease and caution used a small wood dowel or screw driver to feel the piston come to the very top, that being TDC. This takes somebody turning the engine over by the crank shaft bolt in the middle of the crank pulley. Can be done solo but its easier with 2. Once that is established then its back to the distributor. Without seeing myself that shim you mentioned may be a spacer to space up the distributor body and shaft. You do NOT want it bolted down so tight the shaft is pushed down there is 0 up and down play in the shaft. The body is snugly bolted down, but the shaft can move up and down a touch, thousandths of and inch is all.
Once TDC is set back to dropping in the dist and setting the leading edge of the metal part of the rotor tip at where the # plug wire terminal is in the cap. Once you get this close it should fire up or try. While cranking it you may have to rotate the dist body one way or the other to hit the right spot and it should run. But...as I said before you will need to set the timing to the factory spec to get it to run right.
You might also try turning the crank bolt back and forth a tad and watch how far in an estimated degreed of rotation you can go before you see the dist shaft starting so move. Its kind of a indicator of how loose/sloppy the timing chain and sprockets are which can effect cam timing and engine timing if extremely worn or stretched.
Click to expand...
Blimey, awesome instructions. You answered my first query which was how do I know which TDC to use. I knew there are two, and the one to use is the compression, so I used my finger in spark hole 1 to feel for the air pushing out and set my rotor to that mark and I put a screw driver in and could feel something at the top. Saying that though, the rotor was between the 1 mark and the 2 mark so I pulled the whole thing out to move the rotor back to point at the 1 mark. It didn't want to start. Just kept cranking. So I figured id put it out if whack by 180deg as in some videos they say thats possible. I started again and moved to TDC and shifted the rotor 180deg and turned her over. That's when it did what you said, cranked about 5 times then its like something is pushing back.
 
Gilaguy23 said:
It sounds like you have the timing even further off then before. To far advanced and its like somebody is pushing back as it trues to crank over. To far retarded and its just like it has no compression to run itself kinda. first off its possible the Harmonic balancer has spun a bit and the timing TDC mark is off. As I said there are 2 TDC's and you must find which is the compression stroke TDC. To find TDC if the marks are off folks have actually pulled a spark plug and with great ease and caution used a small wood dowel or screw driver to feel the piston come to the very top, that being TDC. This takes somebody turning the engine over by the crank shaft bolt in the middle of the crank pulley. Can be done solo but its easier with 2. Once that is established then its back to the distributor. Without seeing myself that shim you mentioned may be a spacer to space up the distributor body and shaft. You do NOT want it bolted down so tight the shaft is pushed down there is 0 up and down play in the shaft. The body is snugly bolted down, but the shaft can move up and down a touch, thousandths of and inch is all.
Once TDC is set back to dropping in the dist and setting the leading edge of the metal part of the rotor tip at where the # plug wire terminal is in the cap. Once you get this close it should fire up or try. While cranking it you may have to rotate the dist body one way or the other to hit the right spot and it should run. But...as I said before you will need to set the timing to the factory spec to get it to run right.
You might also try turning the crank bolt back and forth a tad and watch how far in an estimated degreed of rotation you can go before you see the dist shaft starting so move. Its kind of a indicator of how loose/sloppy the timing chain and sprockets are which can effect cam timing and engine timing if extremely worn or stretched.
Click to expand...
I'll try everything above and grab some photos. Miserable weather here! Hopefully it'll at least fire up and I can then get it to a repair shop to get professional assistance. Jeep dealer won't touch it-too old so my options are very small for mech help where I live.
 
Just a thought. Is you distributor fully seated with the end into the oil pump? The pump has a slot and the distributor has a tab. The tab goes inside the slot and my thinking is if the tab is crossways and not in the slot the distributor may be elevated slightly and the gear will be off by a few degrees.

It's been several years since I've had the two apart

The shop manual says this:
(2) Check the position of the slot on the oil pump
gear. On the 2.5L engine, it should be just slightly
before (counterclockwise of) the 10 o’clock position
(Fig. 10). On the 4.0L engine, it should be just
slightly before (counterclockwise of) the 11 o’clock position (Fig. 11). If not, place a flat blade screwdriver
into the oil pump gear and rotate it into the proper
position.

Screenshot 2022-12-05 100707.jpg
 
Lets make this simple....First thing, If you have a Mate that can lend a hand, Put him to turning the motor by hand with all the spark plugs removed to make turning it by hand easier. Get a compression gauge and screw it into #1 cylinder and facing the motor turn it clockwise until you start to see the needle on the compression gauge start to register compression meaning that you are on the stroke needed to set your distributor rotor. STOP when the needle starts to move and remove the gauge from the port...Now, Take a very long shafted phillips screw driver small enough in diameter to easily insert into the #1 cylinder until it touches the top of the piston and then you or your Mate SLOWLY continue rotating the engine while watching the screwdriver, When the screwdriver reaches the very top of the stroke and starts to drop back down STOP, Gently reverse the turn of the motor and get the screwdriver back to the top remove it,
Now your TDC marking groove on the crank and the big 0 on the timing gear cover should be matched up nicely...If not, You could have a timing gear/chain problem. Then line up the rotor in the distributor to number one on the cap, Alot of caps now come with numbers embossed on them, Then before inserting take a light looking down the hole the distributor is going, Make sure the slot of the oil pump is going to line up and accept the male end of the distributor. Once you feel good about that, The gear on the distributor should match up to the cam gear that turns it....But you might have to wiggle the rotor button back and forth just a smidge to get it to seat...With the end of the rotor button pointing directly at #1 contact in the distributor cap.....If you can't get to a compression gauge.. Just shove whichever finger fills up the cylinder port and when the motor hits on the compression stoke, You'll know :)
Hope it goes Tickety-Boo for you!!
 
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T-Rex Jeepster said:
Lets make this simple....First thing, If you have a Mate that can lend a hand, Put him to turning the motor by hand with all the spark plugs removed to make turning it by hand easier. Get a compression gauge and screw it into #1 cylinder and facing the motor turn it clockwise until you start to the needle on the compression gauge start to register compression meaning that you are on the stroke needed to set your distributor rotor. STOP when the needle starts to move and remove the gauge from the port...Now, Take a very long shafted phillips screw driver small enough in diameter to easily insert into the #1 cylinder
until it touches the top of the piston and then you or your Mate SLOWLY continue rotating the engine while watching the screwdriver...When the screwdriver
reaches the very top of the stroke and starts to drop back down STOP, Gently reverse the turn of the motor and get the screwdriver back to the top remove it,
Then line up the rotor in the distributor to number one on the cap, Alot of caps now come with numbers embossed on them, Then before inserting take a light looking down the hole the distributor is going, Make sure the slot of the oil pump is going to line up and accept the male end of the distributor. Once you feel good about that, The gear on the distributor should match up to the cam gear that turns it....But you might have to wiggle the rotor button back and forth just a smidge to get it to seat...With the end of the rotor button pointing directly at #1 contact in the distributor cap.....Hope it all goes Tickety-Boo for you!!
Click to expand...
Success! Between TRex Jeepster and Flyer58, she's running again. Followed your pictures and Instructions folks and she booted up nicely. Whew! I thought I'd killed her with my venturing into areas I should leave to professionals. Thanks guys, that really made my day. She drives a little better as well but still backfires like hell when I slow down. I've literally hit the limit of my mechanical skills now and will be handing it over to a one man band Jeep fixer in Jan to get it checked out ready for Spring. Thanks for getting me moving again guys! I did notice the gasket was pretty much gone, just a half of it left on there. Its really thin! Could probably make one from thin card. Also chipped a bit off the bottom of the shaft when I tightened it back onto the engine with that clamp. So I guess a new unit will be winging its way from your country to mine over Christmas. That'll teach me for meddling! Ouch.
 
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jpjeep26uk said:
Success! Between TRex Jeepster and Flyer58, she's running again. Followed your pictures and Instructions folks and she booted up nicely. Whew! I thought I'd killed her with my venturing into areas I should leave to professionals. Thanks guys, that really made my day. She drives a little better as well but still backfires like hell when I slow down. I've literally hit the limit of my mechanical skills now and will be handing it over to a one man band Jeep fixer in Jan to get it checked out ready for Spring. Thanks for getting me moving again guys! I did notice the gasket was pretty much gone, just a half of it left on there. Its really thin! Could probably make one from thin card. Also chipped a bit off the bottom of the shaft when I tightened it back onto the engine with that clamp. So I guess a new unit will be winging its way from your country to mine over Christmas. That'll teach me for meddling! Ouch.
Click to expand...

Excellent....By chance....Are you around Yorkshire/Leeds area?
 
Just a heads up....If you have alot of mileage and you really can't be sure of the previous owners maintenance habits, It might behoove you to have your techs give you the run down and expense on replacing the timing chain and gears to tighten up your Ol' Girls timing and distribution.
 
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T-Rex Jeepster said:
Just a heads up....If you have alot of mileage and you really can't be sure of the previous owners maintenance habits, It might behoove you to have your techs give you the run down and expense on replacing the timing chain and gears to tighten up your Ol' Girls timing and distribution.
Click to expand...
It's got 158,000 miles on it and although it has literally hundreds of receipts between 2001 and 2017 they sort of peter out after that. I have zero history from when it was in Germany 1988 to 2001. So yeah, I'm going to get him to give her a good going over and quote for a few things whilst she's laid up.
 
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T-Rex Jeepster said:
Lets make this simple....First thing, If you have a Mate that can lend a hand, Put him to turning the motor by hand with all the spark plugs removed to make turning it by hand easier. Get a compression gauge and screw it into #1 cylinder and facing the motor turn it clockwise until you start to see the needle on the compression gauge start to register compression meaning that you are on the stroke needed to set your distributor rotor. STOP when the needle starts to move and remove the gauge from the port...Now, Take a very long shafted phillips screw driver small enough in diameter to easily insert into the #1 cylinder until it touches the top of the piston and then you or your Mate SLOWLY continue rotating the engine while watching the screwdriver, When the screwdriver reaches the very top of the stroke and starts to drop back down STOP, Gently reverse the turn of the motor and get the screwdriver back to the top remove it,
Now your TDC marking groove on the crank and the big 0 on the timing gear cover should be matched up nicely...If not, You could have a timing gear/chain problem. Then line up the rotor in the distributor to number one on the cap, Alot of caps now come with numbers embossed on them, Then before inserting take a light looking down the hole the distributor is going, Make sure the slot of the oil pump is going to line up and accept the male end of the distributor. Once you feel good about that, The gear on the distributor should match up to the cam gear that turns it....But you might have to wiggle the rotor button back and forth just a smidge to get it to seat...With the end of the rotor button pointing directly at #1 contact in the distributor cap.....If you can't get to a compression gauge.. Just shove whichever finger fills up the cylinder port and when the motor hits on the compression stoke, You'll know :)
Hope it goes Tickety-Boo for you!!
Click to expand...
'Tickety boo!' Haha, haven't heard that for ages.
 
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jpjeep26uk said:
It's got 158,000 miles on it and although it has literally hundreds of receipts between 2001 and 2017 they sort of peter out after that. I have zero history from when it was in Germany 1988 to 2001. So yeah, I'm going to get him to give her a good going over and quote for a few things whilst she's laid up.
Click to expand...
You can't go wrong....I had a 2.5 when I bought mine and bought a wreck that had a 4.0 and transplanted it..My Girl is a '95 and I put a '94 4.0 in her that had 169,000 on it. When I pulled the 4.0 out of the wreck I scoped the cylinders...All good..Flipped her pulled the oil pan and replaced the oil pump, Rear main seal, Pulled and replaced the water pump, Timing chain, Gears and cover...New high output distributor and wiring, Radiator and heater core... It gets just as cold here in Tennessee as it does in The Empire ;) And She sounds and drives like a new one......Guess what I'm trying to get across is, If you really have a YJ groove thang going on, Indulge it...I promise you'll never be disappointed, And your Mates will all be a little jealous of Her.....
 
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jpjeep26uk said:
From Leeds? A 'Yorkshire lass' as they say over here.
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Oh yeah....I was born there, And I had three Uncles and a Auntie....All gone now, I used to visit quite a bit, But They're kids have all grown up with families and we've lost touch as different generations are apt to do....Man, I really miss the good Ales and Stouts, And I'd kill for a good pork pie or a Cornish Pastie!!
 
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T-Rex Jeepster said:
You can't go wrong....I had a 2.5 when I bought mine and bought a wreck that had a 4.0 and transplanted it..My Girl is a '95 and I put a '94 4.0 in her that had 169,000 on it. When I pulled the 4.0 out of the wreck I scoped the cylinders...All good..Flipped her pulled the oil pan and replaced the oil pump, Rear main seal, Pulled and replaced the water pump, Timing chain, Gears and cover...New high output distributor and wiring, Radiator and heater core... It gets just as cold here in Tennessee as it does in The Empire ;) And She sounds and drives like a new one......Guess what I'm trying to get across is, If you really have a YJ groove thang going on, Indulge it...I promise you'll never be disappointed, And your Mates will all be a little jealous of Her.....
Click to expand...
Haha, she's a pain in the asre right now but I really do love owning her. She's a Jurassic Parker - I had her sprayed in Sept- and always get a smile from folks...until she backfires and then its like a Tarantino movie, running, screaming, swat teams etc. I've heard of folks dropping 4.0L in but to be honest I'll be happy just getting my little 2.5 running sweet haha.
 
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