Calling All Jeep Gods! Please help me figure out my MISFIRE! - Page 2 - JeepForum.com
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post #16 of 21 Old 03-22-2019, 05:58 AM
gutthans
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Originally Posted by troyhazard View Post
yep, No CEL. It sputters out and has little power.. It kinda chugs out. When I get on it, it seems to do better than slow speeds though...

Compression numbers before new head were: 145, 145, 141, 140, 145, 149

Compression numbers after new head were: 134, 131, 135, 130, 130, 137

I used a different compression tester both times so I think that is why they are different.

I have not done a leak down test yet. I will try the Map gas tomorrow and see what happens.

I was able to use the scanner yesterday. I am still getting no readings for misfires.. I'm not sure why. I dont know if it is because I dont know how to use the scanner right or what..

https://www.youtube.com/watch?v=XIemh09FsLU

Here's a link to some pics of some of the readings the scanner gave me: https://photos.app.goo.gl/3bvov3yrGEfwRtxa7

I pulled the valve cover today and used a dial indicator. It looks like I may have a worn camshaft... My readings on cylinder 5 were way lower than the others.

I also ran the Jeep with the cover off and didnt really notice anything abnormal from what I could tell. Here is a video.

https://www.youtube.com/watch?v=xrGoyj1auqs


thoughts on the camshaft? do you guys think I would be ok swapping in a used camshaft, or do I need new, and i'd do new lifters, or should I just get another used or rebuilt engine and put it in instead, assuming the cam is messed up. it did have coolant in the oil for quite a while I'm assuming.
From watching the videos: 1. Vacuum is way off for what it should be reading, plus you have a timing/valve type of bounce. 2. I (think) see maybe two valves that don't move enough to open fully, plus I can hear a dull tap in addition to the normal valve noises.

Can't tell if the chain has slipped or some lobes are worn or both, but something below the head isn't happy. If the dial indicator is correct, disassembly is in order.

NO, NO, NO on a used cam. There are NO BARGAINS. You have zero guarantee that the matching lifters are in the proper order, the pushrods are in proper order, and the lobe profiles are good. Using new (aggressive surface) lifters on a used cam is also prone to failure. While you can 'dust them off' with 600-800 grit, unless you have done this quite a bit, it's not a good idea.

Personally, it's your call...IF I had a relatively new engine, I would just swap out cam and timing set. You do have new parts (head), but an unknown lower end. It will save time/money/headaches to buy a short-block from ATK or JASPER and swap your head over.

Did you ever drop the pan and inspect the lower bearings? I would pull off one or two if you're on the fence about a short-block. IF the cam is going, the journals on the crank may have suffered or the bearings could be close to failure.

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post #17 of 21 Old 03-22-2019, 08:12 AM
williambmac
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Looks like #5 valves are not opening enough.
I can't tell by the video, but is the motor tapping a lot?
I would concur with gutthans, it looks like tear down and inspection is in order.
You will most likely find either a bad cam or worn lifters.
Do Not replace with used components.
Check Rockauto, usually much cheaper on parts. Use Melling or Sealed Power for the cam/lifters, Cloyes for the timing chain set and Felpro for the head gasket/bolt kit.

Also being since you had a cracked head(0331) make sure you inspect the cam bearings, I believe #3 usually fails due to coolant leaking on it.

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post #18 of 21 Old 03-22-2019, 11:55 AM Thread Starter
troyhazard
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I'm going to order a new camshaft and lifters. A little mad at myself for not checking out the lifters while I had the head off, but it was my first time tearing it down so I didn't know it was so simple!

The tapping in the video is the evap solenoid.

If I find the cam bearings are too scored, I will find a good engine to swap in and rebuild the current one and either sell it or save it for later..

I'll post an update later, thanks!
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post #19 of 21 Old 04-27-2019, 07:23 PM Thread Starter
troyhazard
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I swapped in a new camshaft, lifters, and timing set. The old camshaft had 2 lobes that were super worn as well as 2 lifters that were worn and smashed. The bearings looked good. I finished installing the cam and left for the dunes before breaking it in, and managed to break my leg and hand while I was there! So I waited 3 weeks before even trying to start it but I had a friend come over and help me start it up and break it in finally (I'm pretty broken lol) and everything is running smooth now!!

Thank you everyone for your input and help!
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post #20 of 21 Old 04-27-2019, 09:10 PM
jpin86
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Good to hear the Jeep is running...sorry about your hand and leg.
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post #21 of 21 Old 04-28-2019, 05:13 AM
williambmac
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Glad to hear you got the motor straightened out. now go take care of your busted up body and get better!

2005 Rubicon Unlimited, 4" Clayton long arm
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