Topic: Heres a good one, another jeep 4 cyl failure

[Backroads]

I just have no luck at all with this engine! Heres the current dilemma.

FINALLY thought I had all the bugs worked out. Put a couple hundred miles on it, was running good, running strong! Then on friday I drove to work, parked it, went to the bank and when I started it up to leave I heard some rattling from the back of the engine. Lasted a few moments then stopped, sounded like valve chatter. Thought that was kinda strange, but carried on.

Drove less than 1/2 a mile and it just shut off! Now I'm coasting thinking.....WTF now!!!! keep coasting, and as I slowed I put it in second and let the clutch out, it fired a couple times then died again, luckily this was all around the corner from work and was on enough of a hill to coast through a stop sign and into my work parking lot  

Completely stumped I tried starting it, which is now irrelevant, but obviously wouldnt start bla bla.

Towed it home (thank god for a tow bar....again) started to check the timing, so I pulled #1 plug and my distributor cap and cranked it by hand for TDC. Rotor doesnt move......

To keep it short, I pulled the distributor, the gear was stripped right off.



So I dug deeper, put a screwdriver into the oil pump from the dizzy hole, to try and turn that thinking maybe that froze up...only to discover one of the ears of (unsure of the proper name for it) the top of the oil pump was snapped off....

So that probably caused it to lock up and shave that gear down...

I pulled it all apart and heres the broken piece



Nothing out of the ordinary I can see anywhere else, of course there were shavings in the pan from it stripping the gear, but no chunks. I took the oil pump apart and found no signs of it eating a chunk of anything and locking itself up. Only thing that wasnt really normal was there was a lot of what looks and feels like carbon chunks in the bottom of the pan. Mostly small but a couple descent little 'stones'

So just what exactly could have caused all this?

I have a spare motor in pieces so I have another pump to put in, and another dizzy. Just wonder how long before it does it again!!!

[sharpxmen]

did you replaced the dist before due to the same reason (i can't remember exactly but i think you did) - if the answer is yes then maybe the gear on the cam is worn out and it caused the new one to get stripped again, once that occurred the teeth walked on top of each-other and pushed the shaft out causing the pump shaft to break.

best theory i can come up with.

[Dylan]

With the amount of buildup on that distributor, I'd believe it to be the original... I do think you're definitely on the right track as far as a worn out gear, eventually trying to mesh edge-on and that leading to the broken oil pump.

To the OP:  How does the distributor feel when you turn it?  Does it spin freely or is there a fair bit of drag?  Any binding?  How does the cam gear look?

[sharpxmen]

With the amount of buildup on that distributor, I'd believe it to be the original... I do think you're definitely on the right track as far as a worn out gear, eventually trying to mesh edge-on and that leading to the broken oil pump.

To the OP:  How does the distributor feel when you turn it?  Does it spin freely or is there a fair bit of drag?  Any binding?  How does the cam gear look?

someone had a post about replacing the distributor due to worn gear, i can't remember if it was him or someone else and too lazy to do a search.

another thing to check is probably the play in the dist shaft, if that wanders off the center would cause the exact same problem breaking the oil pump shaft.

[Backroads]

Well that was the original dist from the previous engine that already blew....its probably got close to 200K on it. First time i've had trouble with the dizzy or anything like that on this engine.

I ended up pulling the oil pump apart and didnt really find any hard evidence of something getting in there and causing it to lock up.

Put a new (used) pump in it last night and have another dist for it...so I guess well try again...

[Backroads]

oh and the gear on the cam looked ok. A little wear but nothing that looked excessive to me.

[sharpxmen]

oh and the gear on the cam looked ok. A little wear but nothing that looked excessive to me.

i would suggest take the cam out and have a good look at it if not replacing it (just to save you the trouble of doing this all over again).

[Backroads]

Really as much grief as this motor has given me...I'm close to moving on from it. Its been in the garage more than its been on the road! I dont know if I'm feeling up to tearing everything apart to get the cam out, then spending money to buy another cam. I think I'm gonna run it til it goes then go from there.

[sharpxmen]

Really as much grief as this motor has given me...I'm close to moving on from it. Its been in the garage more than its been on the road! I dont know if I'm feeling up to tearing everything apart to get the cam out, then spending money to buy another cam. I think I'm gonna run it til it goes then go from there.

i hear you. You don't need to tear everything apart to take the cam out but is not a small job either. Maybe you can inspect it thru the dist hole while turning the crank just to make sure there's no worn or broken teeth, otherwise will fail again soon.

[yjeep93]

I just had this exact problem. only i was in the hills in a few feet of snow.  like you i spun the oil pump to see if it had got jamed up at all but it all felt fine. I still plan on replacing it this weekend. I had a hell of a time getting it timed again. If you decide to replace it and had any problems let us know i will let you know how i finally got mine running. GOOD LUCK!

[sharpxmen]

I just had this exact problem. only i was in the hills in a few feet of snow.  like you i spun the oil pump to see if it had got jamed up at all but it all felt fine. I still plan on replacing it this weekend. I had a hell of a time getting it timed again. If you decide to replace it and had any problems let us know i will let you know how i finally got mine running. GOOD LUCK!

why don't you tell us anyway,everyone would probably like to hear about it. Did you end up replacing the cam? Did you find out the cause eventually?

[Backroads]

I just had this exact problem. only i was in the hills in a few feet of snow.  like you i spun the oil pump to see if it had got jamed up at all but it all felt fine. I still plan on replacing it this weekend. I had a hell of a time getting it timed again. If you decide to replace it and had any problems let us know i will let you know how i finally got mine running. GOOD LUCK!

Ya really share the wealth.

Fwiw i got it all back together with a new used oil pump and dizzy. Only took it for a spin around the block but everything seemed ok. Been too tied up to give it more testing and didnt wanna risk trying to drive it to work just yet!

As for timing... Its cake heres my version. Pull #1 spark plug. Turn the engine over til you feel/ hear air pushing out the #1 spark plug hole. Then i stick a long screwdriver in to feel the top of the piston and ease theengine over until you see it stop rising and start descending.

Check the timing mark against the timing cover and it should be within spec.

Now with the long screwdriver turn the oil pump just past 3 oclock. Set your distributor in and when it locks down it should fall between 5 and 6 oclock. Check and make sure your rotor is pointing to #1 plug wire and your good to go.


I was fully confident i could get it running again, im just more concerned about the longevity of it at this point so pleasr share!

[yjeep93]

Here is the link to when it happened to me. http://4bangerjp.com/forums/index.php/topic,9527.msg80988.html#msg80988

With all that i listed in that post i finally replaced the distributor. First thing... if you have AC TAKE OFF YOUR PUMP! i learned this the hard way. almost to embarrassing to tell but also funny.  Sense i was to lazy to take off my pump i decided to use a file in the #1 cylinder to tell when it was at TDC then line up my timing marks. very bad idea. The file broke off when it hit the AC pump and dropped into the cylinder. No fun and a HUGE PITA to get out.

I followed the FSM and my Chilton to the T but every time i went to fire it wouldn't run or it would run very bad. the book says when the distributor is fully seated the rotor should be pointed in the 6 o' clock position and the timing marks at zero (on the compression stroke of course)  This did not work at all FOR ME. I did a weeks worth of research on this and never really found much. On another forum i did read that a guy seated his at the 6 o' clock position just as the FSM says but instead of lining the timing marks up at zero he went with eight. I also tried this but did not work.

What FINALLY did work for me was i got #1 to TDC (on the compression stroke) with the timing marks at zero then put in the distributor in and had it seated so that the rotor was pointed right at the #1 plug wire inside the distributor cap. she fired right up and runs amazing now. I dont drive it on the street so i do not have many miles on it so time will tell.

I never did find out what caused this. I did not take out my cam but i did feel around its gear that mates with the distributor. it felt fine. i also spun the oil pump with a flat head and didn't feel any grinding or resistance. the one thing i did not check was to see if the pin that holds the gear onto the distributor shaft was still there or if the gear had moved at all. like you i feel like it was more then likely my oil pump so i am going to replace that this weekend.  

I hope that all this rambling will help some or at least give ya a laugh.   also i know that your having some bad luck with your engine but give it a good chance. I beat the hell out of mine and this is the first big problem. Ill never swap i love my squirrels! just my 2 cents.  again good luck and if i can help any at all let me know. ill try and make myself more clear.  

[yjeep93]

Ah you beet me to it while i was writing my book. glad to hear that you got it running though.

[Backroads]

Yea I sort of mis understood, I thought you had already fixed it.

Just a tid bit I of info that may or may not be relevent to the situation on timing. On 87-90 engine is shows the rotor pointing more towards a 4 oclock position, and on later model engines it shows it more at 6 o clock. just something i observed.

Gonna romp mine around town this weekend so I'll let ya know how many miles I end up walking home this time 


no really, I'm a 4 cyl fan, but I hope this is my last arguement my jeep and i have this year. Its almost wheeling season!