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  #1  
Old July 30th, 2010, 08:17
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CUengineer CUengineer is offline
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Engine Rebuild Help!

1989 Limited XJ. I6 4.0
The long story:
I bought the jeep last year for a hundred bucks from a roommate who lacked the patience to try and fix her. A mechanic friend of mine got her running but the engine sounded very tired. I spent the next 9 months in between classes pulling the engine, rebuilding and putting her back following the FSM. I have resorted to the forum because I have two weeks left at my place in Boulder.(I graduated!!!) De-glazing the cylinders, new piston rings, and a new piston where it was apparent that the broken rings had worn away the ring grooves to the point where the top and second compression rings where worn almost into one(A complete photo documentary is available on Facebook but I figured there is nothing you guys haven't already seen).
The shorter story:
The engine runs beautifully (in my inexperienced opinion). Oil pressure is a little high at first but has dropped down to 40 PSI. Temperature seems to idle at or around 200 and the engine itself seems quiet and smooth. Problem #1: I am hearing a clicking/binging noise coming from the bell housing. At a 700 RPM idle it is random in timing but if I were to average it out I guess it's about once a second. But any RPM above idle the noise goes from bad to worse. I have also noticed that when I turn on the AC it gets worse. I have a hunch that it might be a balance thing. Tom Houston, without being able to hear it, thinks it might be a cracked flywheel(What a nice guy. Even offered to come down and listen to her had he not been out of town this whole week) But trying to watch a flywheel spin at 700 RPM and listen isnít easy. I spray painted the 4 bolds going into the torque converter to see if there was any dragging going on. Doesnít appear to be.

Problem 2: She wonít rev past 1.1k RPM without puttering out/losing power and shaking badly. I wouldnít go as far as a full backfire (again, novice thinking) from the tailpipe but there is a pop taking place. With tons of forum reading about possible backfires (if that is indeed what it is) I decided to buy vacuum and fuel gauge. Fuel is a 32 PSI with the vacuum pressure regulator hooked up. FSM seems to think thatís okay. As for vacuum, I have diagnose the EGR and found that I have a bad EGR solenoid. Would this be the cause? Iíll get around to replacing it as soon as I can convince the guy at NAPA what Iím talking about. I canít afford to replace everything and just cross my fingers otherwise I would.
Any help, advice, even criticisms at this point would be much appreciated. If there is no reply to this then I hope everyone else is following Tom's lead and enjoying themselves and I hope to join everyone on the next trip.
Brent Motz
303 917 9145
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  #2  
Old July 30th, 2010, 08:50
Talyn Talyn is offline
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Re: Engine Rebuild Help!

Could be a cracked flexplate/fly wheel. Make sure the bolts are tight as well. The not revving past 1.1k could be a mis indexed distributor.
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  #3  
Old July 30th, 2010, 09:36
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Re: Engine Rebuild Help!

Quote:
Originally Posted by Talyn View Post
Could be a cracked flexplate/fly wheel. Make sure the bolts are tight as well. The not revving past 1.1k could be a mis indexed distributor.
First two things I'd look at. 9 out of 10 posts in regard to poor running on a rebuilt engine on these forums ends up being distributor 180* out or mis-indexed.
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Old July 30th, 2010, 09:39
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Re: Engine Rebuild Help!

I guess it wouldn't be hard to try rotating it a click CW and CCW. I'll try that after work. Thanks.
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Old July 30th, 2010, 09:46
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Re: Engine Rebuild Help!

I'll also try and rotate 180. But I didn't think the cap would allow for this given that the screw holes aren’t 180 across from each other and the distributor itself has that forked bracket that bolts into the block. If I rotated it 180 there wouldn't be a place to bolt it in. Unless does that bracket rotate? It's been a few weeks since I've looked at it. Thanks for the advice. I'll look into it after work.
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Old July 30th, 2010, 10:01
Talyn Talyn is offline
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Re: Engine Rebuild Help!

You are shooting in the dark. When it is 180* out, it means you set the distributor on the wrong stroke of the engine, and you have to pull it out, find TDC on the compression stroke and restab it. Rotating the distributor 180* isn't the way to do it.

http://www.angelfire.com/my/fan/dist_index.html Try that.
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Old July 30th, 2010, 10:32
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Re: Engine Rebuild Help!

Ok. Yes, I know what you mean. I used my finger through the sparkplug hole to determine compression stoke cylinder 1 and then lined up the timing mark to 0. So I don't think I am 180 off. The next thing I guess would be to check the position of the rotor but I'm pretty sure that I set it at the 5 o'clock position after it seated itself. I will double check tonight that way we can check this one of the list. Just a quick question, could the engine even run with your crank and cam shaft 180 out of phase?
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Old July 30th, 2010, 10:40
Talyn Talyn is offline
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Re: Engine Rebuild Help!

Don't know if it would run or not. Never actually ha dthat problem.

Instead of going off the harmonic balancer use a wood dowel through the plug hole when the piston gets close to the top. When it stops moving that would be TDC, or close enough. The outer ring on the harmonic balancer can slip, throwing the mark off. Make sure that the dowel is long enough that it won't fall into the cylinder.
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Old July 30th, 2010, 11:11
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Re: Engine Rebuild Help!

Great advice. I actually used a long straw to do this but I bailed on the idea thinking that this wasn't scientific enough and just used the timing marks. I should have guessed that any timing mark that has weathered 200k miles probably isn't as accurate as it once was. I'll give it a world. Thanks.
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Old July 30th, 2010, 12:03
joe_peters joe_peters is offline
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Re: Engine Rebuild Help!

No, the engine won't run 180 out.

Off a tooth or two, yes it will run. Try moving one tooth CW, probably not more than two teeth, if it doesn't improve then try one or two CCW.
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Old July 30th, 2010, 12:05
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Re: Engine Rebuild Help!

Thanks Joe. Will do.
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  #12  
Old July 31st, 2010, 18:35
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Re: Engine Rebuild Help!

Wow. One tooth CW was all it took!!! Being a new engine and all I want to take it easy. I'm keeping it under 2k RPM. Does anyone have any good rule of thumb on how long I should run it at lower RPMs? Also, does anyone have any other ideas about my problem number 1? The flexplate only seems to be rattling when I accelerate. Coasting it's quiet. Thoughts?
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Old July 31st, 2010, 19:25
Talyn Talyn is offline
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Re: Engine Rebuild Help!

Nice! Easy fix. Don't stick to under 2000 RPM. You will most likely be lugging the engine at that RPM. I.e. vehicle won't go any faster unless you push the pedal more and drop it down. The engine just sits there and bogs down. Don't drive it like you stole it, but don't baby it. Did you check the torque on the flex plate bolts? Also, what did you do about the cam? Old one, new one? Did you do the proper cam break in?
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Old August 1st, 2010, 11:28
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Re: Engine Rebuild Help!

Ha. Sure thing. I'll have a little fun with her. See what she's got. No. Broke college student=stock parts whenever possible. Same cam, crank, and 5 old pistons, one new. All new seals of course. This was more of a learning experience the first go around. I'll splurge on the next rebuild.
I checked torque specs on flywheel/torque but not flywheel/crank. I have access to another one (flywheel that is, two separate sources are thinking it's a cracked flywheel) but before I went to the trouble of messing everything else up by having to move back the trany, I wanted to get a few other opinions.
Side note: My A/C worked but then stopped. I found a rusted/corroded connection on the A/C clutch wire about 10" from the compressor. It looked like there was some sort of circuitry component in series with the wire. Was this a fuse, or diode? Maybe this wasn't stock. Wiring diagram in the FSM wasn't too helpful.
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  #15  
Old August 1st, 2010, 20:31
Talyn Talyn is offline
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Re: Engine Rebuild Help!

Quote:
Originally Posted by CUengineer View Post
Same cam,
What did you do about the lifters?
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