evaluating vibration
01-09-2017, 07:14 PM
#1
3rd Gear Member
Thread Starter
Join Date: Oct 2004
Location: Arizona
Posts: 887
evaluating vibration
Hi guys, just curious to see if anyone here has experienced any vibrations at certain RPMs while car is in N in the driveway. I've eliminated most of the driving vibrations already. now getting one between 17-1900 RMP with clutch engaged AND disengaged.
just to throw these out of the way , the motor , trans and motor mounts are all brand new. harmonic balancer can not be the issue and zero vibes coming from inside the motor. I'm leaning towards the flywheel or misfire but almost positive it can not be a misfire at all. I do not know the weight of the flywheel but I do know it was cut and balanced. do you think its possible to have a improper weight to the early style 289 ( now 331) OR a bad combo if the H balancer and flywheel
just curious if anyone has experienced certain shaky vibrations at certain RPM, NOT having anything to do with the car driving down the road.
just to throw these out of the way , the motor , trans and motor mounts are all brand new. harmonic balancer can not be the issue and zero vibes coming from inside the motor. I'm leaning towards the flywheel or misfire but almost positive it can not be a misfire at all. I do not know the weight of the flywheel but I do know it was cut and balanced. do you think its possible to have a improper weight to the early style 289 ( now 331) OR a bad combo if the H balancer and flywheel
just curious if anyone has experienced certain shaky vibrations at certain RPM, NOT having anything to do with the car driving down the road.
01-23-2017, 10:17 PM
#4
4th Gear Member
Join Date: Aug 2008
Location: Goodyear, AZ
Posts: 1,674
Okay, I am fighting a similar battle and have been through everything....
Does it vibrate while driving as well as sitting still? Or driving only?
Do you have stock rear Springs or lowering Springs?
Have you checked your pinion angle, transmission angle, and drives haft angle. What is the working angle of the drive line? It makes a huge difference.
Have you tried to wiggle the pinion gear on the rear end. My bronco drove me nuts until I found that the pinion bearing was shot and causing a vibe....
Answer these to the best of your ability and I will move on to additional items.
Does it vibrate while driving as well as sitting still? Or driving only?
Do you have stock rear Springs or lowering Springs?
Have you checked your pinion angle, transmission angle, and drives haft angle. What is the working angle of the drive line? It makes a huge difference.
Have you tried to wiggle the pinion gear on the rear end. My bronco drove me nuts until I found that the pinion bearing was shot and causing a vibe....
Answer these to the best of your ability and I will move on to additional items.
01-23-2017, 11:19 PM
#5
3rd Gear Member
Thread Starter
Join Date: Oct 2004
Location: Arizona
Posts: 887
It happens when driving and also at stand still. so all driving components out of question really. Most noticeable at 1700 rpm, clutch in out out and clutch while in gear at stand still. Levels out about 2k and very slightly back again at about 2300 then gone again higher than that.
Went st through all the plugs and made sure no wires were crossing. Im assuming it's flywheel clutch related . The flywheel was cut and balanced so here also lies the issue
Went st through all the plugs and made sure no wires were crossing. Im assuming it's flywheel clutch related . The flywheel was cut and balanced so here also lies the issue
01-24-2017, 12:46 AM
#6
4th Gear Member
Join Date: Aug 2008
Location: Goodyear, AZ
Posts: 1,674
From my knowledge, all stroker kits for the 28o/302 s us the 28oz imbalance crank. Meaning, if you have a 8t or newer flywheel it is the wrong one. It should be a pretty 1985 28oz imbalance flywheel.
Also, you state it was balanced. What was it balanced with? To balance it, it should be balanced with the crank and the harmonic balancer together, othwise your rotating assembly is not balanced and that is the cause
Also, you state it was balanced. What was it balanced with? To balance it, it should be balanced with the crank and the harmonic balancer together, othwise your rotating assembly is not balanced and that is the cause
01-24-2017, 01:00 AM
#7
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Join Date: Oct 2004
Location: Arizona
Posts: 887
Not sure the weight of the flywheel at all. The clutch is good and strong so of that was an excuse I would replace all those components. Clutch, flywheel, throw out bearing ... I just don't want to take the tranny out again quite yet. But at this point about 90% sure it's clutch/flywheel related. From your knowledge what else besides flywheel would make it vibrate. ( what part of clutch assembly would cause this ) to be more specific
01-24-2017, 08:27 AM
#8
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Join Date: Aug 2008
Location: Goodyear, AZ
Posts: 1,674
The actual wieght of the flywheel does not matter. It is how itnis balanced that matters. Ford engines are externally balanced. So the crank is out of balance either 28 ounces or 50 ounces depending on the year. Pre 1985 they were 28 Oz. 85 and newer are 50 Oz out if balance. Ford used the flywheel and the harmonic balancer to counter wieght the crank and balance it. So it is referred to as an externally balanced engine.
If you started with an 85 or newer roller block it would have a 50 Oz counter balance flywheel. So then if you had a 331 stroker kit installed in it without having the flywheel balanced with the new crank then that MAY be your problem. You may be running a 50 Oz counter balance with a 28 Oz off balance crank.
If you bought the 331 and then used an old flywheel from a previous 1985 engine, then you should be fine.
So to rule out the flywheel, you need to know which one you have. You need to be running the older 28oz part.
In my opinion, since it vibrates bad with car sitting still, that is your issue. Or, you need a new harmonic balancer.
Also, what cam do you have installed? You may have the firing order iff. It seems crazy but my old 302 idled fine and ran with the wrong firing irder. I didn't realize until after it ran like crap that the cam I had installed used the 351 firing order. So after I corrected it, it was fine.
If you started with an 85 or newer roller block it would have a 50 Oz counter balance flywheel. So then if you had a 331 stroker kit installed in it without having the flywheel balanced with the new crank then that MAY be your problem. You may be running a 50 Oz counter balance with a 28 Oz off balance crank.
If you bought the 331 and then used an old flywheel from a previous 1985 engine, then you should be fine.
So to rule out the flywheel, you need to know which one you have. You need to be running the older 28oz part.
In my opinion, since it vibrates bad with car sitting still, that is your issue. Or, you need a new harmonic balancer.
Also, what cam do you have installed? You may have the firing order iff. It seems crazy but my old 302 idled fine and ran with the wrong firing irder. I didn't realize until after it ran like crap that the cam I had installed used the 351 firing order. So after I corrected it, it was fine.