Bad vibration above 1900

[Germy]

New headers and pipes. I will mess around tomorrow. I am off to a pre school graduation. Wtf. I have never heard of such a nonsensical event. Friday night/lost

 

[jasonmark1993]

ha! Let us know what you find tomorrow.

Might as well pick up a compression gauge while you are out and about.

Sounds like everything on the jeep is brand new.

 

[IOPort51]

Jason, you are doing a great job of walking through this and I do not want to distract anybody but I am curious if Germy can find a vacuum gauge to put on the manifold. This will tell a lot about the condition of the valves and lifters.

 

[Germy]

I have a compression gauge. Do I need a vacuum gauge too? Everything is new minus heads intake and block. I want to see what is wrong, but have a feeling I'm gonna be buying a reman.

 

[tarry99]

Ok, I have more info. This vibration rattles the vehicle at startup, as I let the clutch out. It has a high vibration below around 1500. Past 2 grand is a no go. poopie would rattle to pieces.. The idle has a surge under the hood and a little chop at idle. I have been reading, could my problem be misfiring? How do I test the cylinders? I can check the compression in each, but how do I know if all are getting compression how to tell if they are all firing? If I check spark, how do I know it's not lean misfiring?


Thanks in advance!

You have stated that it rattles "as I let the clutch out" Is that still the case?????? Plenty of people have suggested that perhaps the flywheel is incorrect? It could be that or Your clutch disc or pressure plate or flywheel is loose or the disc has thrown some material off. Maybe even no pilot bushing in crankshaft.
Looking at your plugs it looks like a "Sick" engine but If you have problems in your Bell Housing as suggested above that may be where you want to look next...............
I think its also important that you bring the motor up to Top Dead center on #1 and pull the cap and see how close the rotor is to #1 just to eliminate the timing issue.

 

[jasonmark1993]

I think the vacuum gauge is a great idea. If its running as poorly as I suspect with the way the plugs looked, it going to be real low though. I've always used vacuum gauges to dial in things like timing and fuel.

There def are a lot of variables since we don't have all the details from the PO.

We may have a jumped timing chain and a mismatched flywheel.

I really suspected it was going to be timing/crossed wires. I don't know if I've ever had vehicle so rich/lean that it was shaking so bad and wouldn't rev up.

I think the compression test will tell us a lot.

 

[Germy]

You have stated that it rattles "as I let the clutch out" Is that still the case?????? Plenty of people have suggested that perhaps the flywheel is incorrect? It could be that or Your clutch disc or pressure plate or flywheel is loose or the disc has thrown some material off. Maybe even no pilot bushing in crankshaft.
Looking at your plugs it looks like a "Sick" engine but If you have problems in your Bell Housing as suggested above that may be where you want to look next...............
I think its also important that you bring the motor up to Top Dead center on #1 and pull the cap and see how close the rotor is to #1 just to eliminate the timing issue.

True, tdc will tell me if timing, I'll hit that up with the others. I do agree on the balancing too. When I engage the clutch, there is a jarring shake, then it smooths out till about 1900, then it has this high vibration, doesn't shake the jeep like the start off, but just vibrates to the point of concern. I can drive him, I just shift real low. If I am in n, and I give it gas, it vibrates and holds true not wanting to go above 2000. Did this clarify? I am just torn, doing a load of troubleshooting to find the problem and make the ill motor better or just get a reman, replace the clutch, flywheel and mounts?


Edit: the zone has a reman for 1870.any thoughts? Any other places to look?

 

[tarry99]

True, tdc will tell me if timing, I'll hit that up with the others. I do agree on the balancing too. When I engage the clutch, there is a jarring shake, then it smooths out till about 1900, then it has this high vibration, doesn't shake the jeep like the start off, but just vibrates to the point of concern. I can drive him, I just shift real low. If I am in n, and I give it gas, it vibrates and holds true not wanting to go above 2000. Did this clarify? I am just torn, doing a poopie load of troubleshooting to find the problem and make the ill motor better or just get a reman, replace the clutch, flywheel and mounts?


Personally I think your jumping around looking at stuff that may not matter at all. Your engine is not running that well but it does run. Large vibration concerns as you have stated are normally external from the motor unless you have a broken rod or crank. Yes timing could be an issue and No question it is hard for anyone to diagnose this over the computer but if it was me I would have already had it up on TDC and either pulled the pan off or I would be looking in that clutch can for answers.

 

[jasonmark1993]

Just reread the post; can you rev it up in neutral and the shaking is just while you are moving, or is it shaking all the time and at idle.

I agree with Tarry that its hard to diagnose over a computer, but its real easy to have an engine that is running so poor it shakes, rattles, and won't rev up.

A mismatched flywheel isn't going to make all your plugs black and spew unburnt fuel out the back. Was there anything that led you to think that other than the shaking? You mentioned a knock, does that increase with the rpms? You might have broken a piston and thats why #5 spark plug was smashed with no gap. That would even explain the unburnt fuel and oil/white smoke.


That being said, you may have two problems, but it is more likely that your poor running condition is causing the shaking and inability to pass 2k rpms.

Id fiddle with the enrichment screws and then run the compression test. Pull all the plugs so it can spin over quicker and give you a better reading. Make note of the condition of the plugs; especially if one in particular is wet with fuel.

I just don't want to see you tear everything apart, spend a bunch of money, and then have the same problem when you put it back together.

 

[MN CJ7]

HEI distributors for the AMC engines are known to have hardened gears on the distributor...... The hard gear eats the cam gear adn will put metal in your engine and make the engine run rough as the gear fails....

Not to be gloom and doom.... but pull your dist and test the gear. Try to drill divit with std drill bit. make a divot on the side of gear / same side as the rotar points to. Soft cast gears will dill easy.... if the gear is hardened it will not drill hardly.... This TEST should be done on every HEI use in a AMC engine...

There are MANY pitfalls with the use of HEI in a AMC Engine.... and not jsut the hard gear.... heck some are not even cut right
Read more here..... by the founder of this issue, JeepHammer.
GM HEI vs. Motorcraft/DuraSpark Ignitions

you have a HEI..... read the article above fully
May also have so much ADVANCE you rattled your engine to damage and the failed bearings, connect rod, etc allowed the piston to slap the spark plug...

There is a thread on right now a guy with AMC 304 has a chewed cam gear from using a DUI HEI with a hardened gear.... some on this forum tried to tell me there are no issues with HEI on the V8s.... WRONG HEI and AMC engines is a BIG issue and will be for a few more years till we get these hardened gears out of the market..... The market got flooded with cheap dist gears 7 yrs ago or so and will take some time for them to work out of the market.... till then be well read or stay away from the HEI on AMC.

The Stock Duraspark is a great dist..... Just chaged gears to 3.73 and lockers ft/rear..... Recurved my Duraspark Distributor and rejeted my weber carb because of the new axle gears......... Just got 22-23 mpg hwy on a 100 mile trip today and included some town miles too. ORIGINAL Duraspark Distributor and is 35 yrs old...... my jeep runs like new and I drove jeeps that were new in the early 1970s


Something hit that pllug and closed the strap to electrode gap... not good... Wrong Plug and too long? Failed internal part, Igntiion Issue? Head Shaved/Decked may need diff plug & maybe not std pistons that need more clearnace?

Find top dead center, TDC, write up by JeepHammer....
this will verifty install of dist, TDC, balancer not spun, play in time chain, etc

How To Verify Your Valve/Crankshaft Timing &
Set A Distributor.​

If you don't have a good working knowledge of shop safety practices, DON'T ATTEMPT THIS!
If you don't possess common sense or self preservation instincts, DON'T ATTEMPT THIS!

Safety warnings are in RED, Do Not Ignore These!
I can not possibly list all the potential ways you can get hurt doing anything you read or see here, so YOU MUST ASSUME ALL RESPONSIBILITY FOR YOUR SAFETY!​

ALL STEPS REQUIRED, DO NOT SKIP ANYTHING OR THE RESULTS WON'T BE ACCURATE ​

Finding The #1 Cylinder
The #1 cylinder is the first to fire in your firing order (more on firing orders, click here).
If you are working on an Inline engine (all the cylinders in a row) the #1 cylinder will be the first one, closest to the radiator.
If you are working on a 'V' style engine (V-4, V-6, V-8, V-10), one cylinder will be farther ahead of the rest.
Look to see which cylinder head is closer to the radiator, and the front cylinder that will be #1.




Finding Top Dead Center (TDC).

Disconnect the ignition coil before cranking the engine.

Take out the spark plug of the #1 cylinder.
Cover the #1 spark plug hole...
Use a Lightly pushed in cork or other relatively soft item that won't react badly with gasoline.

DO NOT stick your finger in the hole, only cover it.
Compression on modern engines is sufficient to remove your fingernail and infuse gasoline into your skin.

Crank the engine over until the cork is pushed out. IMMEDIATELY STOP CRANKING!

Locate the crankshaft snout bolt, You will find this bolt in the center of the lower pulley.
Place your finger OVER the hole, and crank the engine clockwise with a hand ratchet by the crank shaft snout bolt.
Removing the other spark plugs may make this task easier. Resist the urge to use the starter...

You will feel the compression stroke start even when cranking by hand.
When you feel the compression stroke start, use a 1/4" wooden dowel rod (wooden chopsticks work well) to feel for the top of the piston through the #1 spark plug hole.
DO NOT USE METAL LIKE A SCREW DRIVER!
You want to use the dowel rod and the crankshaft to locate the piston at the very top of the compression stroke.




Side Bar
It is possible to have the piston at the top, and still not have 'Compression Stroke'.
The crankshaft rotates two complete revolutions for each time the #1 cylinder fires.
The strokes are,
'Intake Stroke', when the piston is going down with the intake valve open, drawing Charge Mixture (gasoline & air) into the cylinder, At the bottom of the 'Intake Stroke', the Intake Valve closes, and the 'Compression Stroke' starts.
The piston comes back up with both valves closed, and compresses the Charge mixture, this is the 'Compression Stroke'
This is the stroke you are looking for Top Dead Center (TDC) of.
The cylinder contents are compressed, then the ignition fires when the piston is more or less at the top.
Expanding gasses drive the piston down, this is the 'Power Stroke'.
When the piston reaches the bottom of the 'Power Stroke', the Exhaust Valve opens, and the piston comes back up, pushing out the spent gasses.
As the piston rolls over the top of the 'Exhaust Stroke', the exhaust valve closes, and the intake valve opens starting the process again.

(Suck, Squeeze, Bang, Blow)​

As you can see, it is very possible to find the top of the 'Exhaust Stroke' instead of the top of the 'Compression Stroke' you are actually looking for.




Once the piston is at Top Dead Center (TDC) of the 'Compression Stroke'...




Verifying The Balancer & Timing Tab
So Called 'Harmonic Balancers' is mounted behind the lower engine pulley, and have a solid hub, usually cast iron, a layer of rubber, and a steel ring on the outside.
The 'Timing' mark is usually on the outside of this steel ring.
There should be a 'Timing Tab' or 'Timing Marks' mounted on the front of the engine that correspond.

Now, if everything is working correctly, the timing mark on the balancer should be lined up with the '0'(zero) mark on the timing scale.



Things that can go wrong are,
The outside ring of the balancer will break free of the hub and slip around the hub, causing the 'Timing Mark' to be in the wrong place.
The 'Timing Tab' can get bent, damaged or completely removed. Also, if the engine has been 'Rebuilt', it's not unusual for the wrong front cover and/or balancer to be put back on.
Some engines required an offset key to hold the balancer in the correct position, if that key has been replaced, it may not be the correct one.
Aftermarket parts (like chrome parts) are often, "One size fits all..." and are not appropriate for your engine.




If you have found the top of 'Compression Stroke', and verified the balancer and timing tab, you are ready to set the new distributor in place or verify the timing of your current distributor.

Verifying An Existing Distributor
(If you are installing a new distributor, skip to the next step.)
Use a 'magic marker' and mark the position of the #1 spark plug wire tower on the base of the distributor and remove the distributor cap.
If you have the piston at the top of the 'Compression Stroke' on the #1 cylinder, the Rotor nose should be pointed at the mark you just made on the distributor body (within a few degrees).

If the rotor pointed exactly away from the #1 mark you made, then one of two things is probably wrong,
1. You located the top of the 'Exhaust Stroke' instead of the 'Compression Stroke',
OR...
2. Your distributor is installed '180° Out'... (this is very common on inline engines)

If your Rotor nose is anywhere else, you need to start over and VERIFY EVERYTHING...
It's possible for the gear to be installed incorrectly on the distributor shaft, it's possible for timing chains to have stretched and jumped teeth, it's possible for distributor to camshaft gears to be so worn they will 'jump' teeth, ect.




Installing The Distributor
Distributors have sprial cut drive gears, so the distributor shafts rotate when installed as the distributor gear moves around the stationary camshaft gear.
To Compensate for this, you will have to know what direction the distributor rotates, what your firing order is, where #1 plug wire is supposed to be located, and mark that location on the distributor base.




1. To determine rotation direction, vacuum advance always pulls against distributor rotation, Look Here.
2. #1 plug wire tower is usually marked on good quality distributor caps, if not, Look Here.




Install the rotor and distributor cap on the distributor and mark the location of the #1 plug wire terminal and direction the rotor travels on the distributor base.
Remove the cap, but leave the rotor in place.

Now, back the rotor nose against rotation about half way between terminals. This would be between the last terminal fired, and the #1 terminal.

Drop the distributor in the hole until the drive gears meet. DO NOT FORCE THE DISTRIBUTOR GEARS!

Most distributors will NOT engage fully when dropped into the hole.
The problem is the oil pump drive shaft is turned by the bottom of the distributor gear, and the two pieces will not line up on the first try.
To get the distributor to seat fully, you will have to rotate the engine BY HAND, TWO COMPLETE REVOLUTIONS, while putting some down pressure on the distributor (don't push hard).
The distributor may drop into place in just a few degrees, but you will have to make TWO COMPLETE REVOLUTIONS of the crankshaft to bring the engine back to Top Dead Center of the #1 cylinder determined by the timing mark and timing tab you verified earlier.
Resist the urge to turn the engine backwards, always turn the engine clockwise (top of the crankshaft pulley towards the drivers side fender). Turning backwards is VERY hard on crankshaft bearings.

Once you have seated the distributor housing and found TDC of #1 again,
Check to make sure the vacuum advance canister is in the correct location, and check the rotor nose in relationship to the mark you made on the distriburor housing.
If the rotor nose is pointing (within about 5° or so) at the mark, you are ready to install the distributor cap and plug wires.

If the rotor nose is NOT pointing at your mark (half way between terminals, too far ahead, too far behind) you will need to pull the distributor and try again, compensating for the alignment problem. (farther forward or backward in the rotation.)
Smaller diameter drive gears (GM, AMC for example) tend to need more rotor rotation before install, and larger diameter drive gears (Ford for example) tend to need less rotor rotation.

 

[jasonmark1993]

Good idea checking the gear.

No need to drill it though.

Cast gears are "soft" and steel gears are "hard".

I don't know what kind of cam your engine has? If its a new enough model it may have a roller cam and need a steel gear.

 

[Germy]

Guys, thank you for all your help. I'm just buying a new one. I don't want to just get it running, I want to trust it! My skills aren't as good as most of yours. I think something fresh is best for me!

 

[jasonmark1993]

Sure thing man.

Hopefully you find something during the teardown.

 

[Germy]

Clutch pressure plate cracked in half, AMC 304 flywheel and firetrucked exhaust valves!

 

[jasonmark1993]

damn...youve been working.

 

[Germy]

Yeah, my buddy gave me a second wind and we tore it down. Rings and bearings are good as is crank and rods/bearings. Really see no need in going any deeper. The clutch was completely in two pieces! How could it still work!?

 

[jasonmark1993]

I dont know...Im surprised.

 

[Germy]

I am confused on clutch replacement. I guess I need a master kit with centering device. The disc is 10.5. Any suggestions on a reasonable kit?

 

[tarry99]

I am confused on clutch replacement. I guess I need a master kit with centering device. The disc is 10.5. Any suggestions on a reasonable kit?

Germy,

I'm glad you finally took my advice and looked in the clutch can.......... Everything you mentioned previously pointed to that being the problem.
Go to the CenterForce Clutch web page...............they have a good selection of clutches available..............have someone check your flywheel for cracks & balance...........if it's OK get it surfaced and put it back together with a new clutch disc, pressure plate & throwout bearing.

 

[Germy]

I got a new flywheel that is 100% for a 360. Really appreciate everyone's help! Dropped off the timing cover, intake mani and heads for a valve job and bead blasting. The timing chain after further inspection has some play. I'm having a mechanic friend look at it to see if it's good. Doing the tie rod flip this weekend hopefully and painting engine compartment!