Vibration at 2000 rpm

[TestPoint]

I have been chasing a drive line vibration for almost 2 years on a '00 302 swap into a Volvo. I bought the engine/transmission on a pallet in dry storage with only 11k miles on them. Everything was just as it came from Ford. Engine/trans only have 15k miles since now. See the long and sordid story on the link below.

First thought it was the drive shaft. Built two, one the two tube/3 u-joint/center bearing Volvo configuration, one the single tube/2 u-joint as the pretty standard US configuration. Both balanced, the single tube twice, aligned the engine/trans, shaft and rear pinyon to less than 1 degree on each joint.

That helped a lot but there is still engine vibration in Park at 2000 rpm. Removed the mechanical fan and went to duel electrics since it made too much noise anyway. That got rid of a lot of noise but not the vibration.

Today I pulled the serpentine belt off and found the lower right idler pulley had a lot of play and a rattle. Removed the pulley and found the bearing is smooth and tight and the vibration is significantly reduced without the belt on. While the center bolt is tight the rattle is because the pulley is not tightly held to the nub of a shaft on the accessory casting and the plastic insert on the bolt head.

Any suggestions?

 

[TestPoint]

While the idler pulley seemed good held in the hand it had some play when bolted in place so it got replaced. That didn't change the engine vibration.

Still looking for vibration advice.

 

[Runnin'OnEmpty]

The first things that come to mind are the flexplate
and harmonic balancer. Since these were a matched
set from Ford, you probably can rule out an imbalanced
flexplate. I'd take a good look at the harmonic balancer
to see if it's indeed the stock one. Also, the HB rubber insert tends to deteriorate over time and allow the HB halves to slip and get out of balance.

Since the engine has sat for awhile, the HB would be
the first thing to check...

Congrats on finally getting that project on the road.

 

[TestPoint]

I visited with my local Hot Rod shop that installed the exhaust system today. While they could not find any exhaust problems they suggested the only solution in their area of concern is to isolate the engine from the large/long exhaust system with a flex coupling such as this:

http://www.ebay.com/itm/2-1-4-ID-Ex...8551b94&pid=100033&rk=3&rkt=4&sd=271133100345

We are going to try that and see what is accomplished.

 

[TestPoint]

. . . a week later and . . .

I got the exhaust isolators installed.

. . . and installed some industrial vibration damping material between the custom engine swap motor mount brackets and where they are bolted to the frame of the Volvo.

Pulled the flex plate inspection plate and verified that the torque converter nuts were tight. That is one honking big balance weight on the flex plate.

No change in the vibration. It is definitely engine related or at most HB through TC.

Again, this engine/transmission only has 15k miles on it, 11k when acquired from dry storage. Initial clean-up consisted of a small paint brush and an air hose to blow the dust off. Other than separating the engine from the transmission for transportation everything is undisturbed since Ford built it. It does have Ford Racing headers rather than the iron original exhaust manifolds. Nothing is touching anything that it should not be that I have found. Idles perfectly and runs smoothly up to about 2000 rpm.

Seeking inspiration . . . .

Is it really worth while to pull the HB for inspection? Can't see anything amiss in place.

Considering replacing water pump because my parts counter guy says he has seen an out of balance WP although there is so little rotating in there it is difficult to imagine that being my problem.

 

[Runnin'OnEmpty]

If you're concerned that the vibration is in the water pump,
you can remove the serpentine belt to test. It won't hurt
anything to run the engine up to 2K rpm for a few seconds
to see if the vibration is still there. That will eliminate
everything on the front of the engine except for the
harmonic balancer.

I'd triple check everything before tearing into the innards
of the thing. Even the firing order. And also the possibility
of crossfiring between the plug wires. This is elementary
stuff but sometimes it's something simple.....

 

[TestPoint]

I've had the belt off with the vibration remained so I guess the WP is exempted as is the alternator et. al.

Here is the cylinder/spark plug wire arrangement that is not documented anywhere that I could find. Even got the local Ford store technicians in a discussion and they could not find any documentation on the physical connections on the coils. Said that they just replace wires as they find them. You might want to keep this picture as it is the only place on the planet where this information exists.

Keep tripping over the fact that the engine runs perfectly smooth below 2000 rpm and that a misfire has never been logged in the PCM.

I am going to check timing with a timing light this morning. That should verify if the balancer has turned.

Not sure how to check for cross fire. Wires are in their original looms.

 

[TestPoint]

I got the big green Ford books out to check on spark plug wiring routing for the crossfire question. There it is in great detail on page 303-07C-6. Then I wondered why the coil connections are not provided. It was good on the left side, required swapping the 1/3 wires in the loom at the coil.

Thinking with my fingers one might surmise, in a wasted spark system, that pairs of cylinders on a common crank journal reaching TDC at the same time would fire at the same time one on the compression stroke, one on the exhaust stroke. Ergo cylinders 1 and 5 reach TDC at the same time and both should fire at the same time. Same with 4 and 8. That makes sense if you assume that the coils fire front/back in pairs. I'm not sure how to confirm that.

What doesn't make sense is that cylinder pairs 2/6 and 3/7 are not wired that way on my coils.

Before I go switching plug wires around could someone with the same wasted spark system on a 5.0L please verify the wire configuration . . . pretty please?

 

[Turdle]

Your firing order is good.

Had this issue on my son's 98 and found a slightly cracked spark plug ceramic. Replaced the plugs, which were new by the way, and this stumble, vibration was fixed.

Seemed to me like the vibration, miss was only at 2k RPMs when any force was applied to the gas pedal. After the vibration, stumble, it ran fine otherwise.It only stumbled right at 2 k rpms.

 

[TestPoint]

Your firing order is good.

Thanks for the response and it is not that I don't believe you but I can't get my head around the fact that cylinders 1/5 are next to one another as is 4/8 but not 2/6 and 3/7. Why wouldn't the other crank journal mates use the same configuration? The internal schematic for the coils show coil pairs triggered together.

. . . found a slightly cracked spark plug ceramic.

Well . . . I went into the garage prepared to rip out my 4k mile $8 Iridium pin plugs and guess what . . . . The entire right side plugs were not even finger tight and 2 boots on the left side were not snapped on the plugs.

Obviously I had installed the plugs finger tight and only tightened the left side . . . 4k miles ago.

I had replaced the exhaust header gasket on the right side in an attempt to eliminate the ticking but that didn't help. Now I know why.

Tightened everything back up and went for a test drive. That moved the vibration from 1900 - 2300 to the 3000+ rpm range but it has not gone away.

I am going to put a timing light on the harmonic balancer to verify that ignition timing is good. If plug 1 fires at about 10* BTDC then I have to declare the HB still in place and there is still a vibration in the engine.

Maybe I should redo the belt-off test of accessories as the 2k vibration moved upward without going away.

It is the simple things that will kill you.

Appreciate all the help but it is not over yet.

 

[TestPoint]

Got my 40 year old chalk box out and marked the balancer for 10* BTDC. Timing light put the marker right there.

Never thought a 15k mile balancer, even 15 years old would separate.

Hope that verifies that the balancer has not moved.

NOW . . . the problem remains that there is a unnatural engine vibration at now above 3000 rpm.

Guess I will remove the belt and verify none of the accessories are out of balance . . . again.

I was finally able to find a spark plug wire connection drawing. It is only labeled 'Ford DIS' and there is no link directly to the 5.0L. Since I do know the 4.6L used a different layout I assume the following is for the 5.0L and matches how mine is wired. Guess I can put that away but that leaves the coils, wires and plugs to consider.

New plan of action required.

Divine guidance needed.

 

[TestPoint]

Devine guidance

Back to researching the aggravating engine vibration. Sometimes it is there, sometimes it is not. 2000 to 2400 rpm has what feels like a miss vibration but doesn't show up as a P030x code. In fact, no codes.

Just got to be a spark plug wire or spark plug, or . . . .

Haven't found it.

Have fun directing the fool to try things.