How much is normal??

[racing302]

Hey guys! (and ladies...)

Quick question. This is my second Fox ('87) that i have (first one was to be a complete rebuild project, but was sold because of my lack of time to put in it, so i bought one already decent and, as much as i know, well builded...);

When i shift it passed 3700rpm, it does vibrate a lot and i don't know if something is wrong or if it's just me and my experience driving "foreign" (and weak) cars.

I have been told that the two things that will destroy any motor is heat and VIBRATION......so now, here i am, scared to death to shift my car higher that 3500 because i don't want to ruin it...i just wish i could have someone with tons of experience drive it and tell me if all is ok or should i have it checked for any specific things...

Help!!

Chris from Chambly, Qc

 

[jrichker]

You posted a TECH question in Talk. This limits your chances of getting some really good advice, since most guys aren't looking for Tech stuff in the Talk forum. PM one of the Mods (85ragtop, Killercanary, Mustang5L5, Celeb, FrankenStang, FastDriver) and ask them to move it to 5.0 Tech. You’ll get a lot more responses to your question.

Having said that, here’s some help…

The first place to look is the harmonic balancer. On 5.0 Fords, the rubber ring that bonds the inner and outer hubs together tends to shear. This allows the outer hub to rotate and get everything out of balance. Sometimes the outer hub just slips a little and it is more difficult to spot.

 

[CDQICKGT]

+1 had the same deal countless times. While parked with tranny in neutral rev the engine to the rpm that's giving you trouble. If you feel the vibration this narrows it down by taking the drivetrain out of the picture. A new balancer from oriellys is $59 and takes all of 25 minutes to install. Hope this helps bud...

 

[CDQICKGT]

Also to add, trying to set timing with a balancer that has slipped is a hit or miss game.

 

[Mustang5L5]

No vibration is normal. Check the balancer and see if the vibration is present with the clutch pushed in


Could also be a dead cylinder as well.

 

[Cobra912]

Gonna need somemore info than that. Where do you feel the vibration is coming from? Engine, tranny, rear end, driveshaft etc?

 

[racing302]

Thanks y'all!

I already took a "good" (untrained) look at the harmonic balancer and it seemed right...no rubber coming out or out of place...

The vibration is present on neutral, with or without the clutch engaged, so i know that it is not the tranny...

Some sort or noise (like something loose) seem to be coming from under the car, dead center, in the back of the motor...some suggested loosed clutch or unbalanced flywheel...

BTW, does the clutch and flywheel need to be balanced when we get them or are they good right out of the box?

I'm planning for a new King Cobra clutch (and maybe a flywheel, if that is the part of the problem...)...

So, i gues everyone seem to be thinking about the harmonic balancer...i'll have my car in he garage next monday to have it checked\changed...hope it helps because i have just been passed by by a *** car tonight because i was scared to shift it at what people tell me it could be (around 6000), and that did not make me happy at all!!!

The motor has been rebuilded not too long ago (E-303) and everything is new on it...only making things more frustrating! But maybe it's just me being a newbie and being scared of ruining 10K i just paid for that Fox...?!?

 

[Cobra912]

well when did it start making the vibration. right after the rebuild, or quite sometime after. What was re-used or replaced? Did you replace teh flywheel or balancer? If so, just making sure it was all stock 50oz

 

[racing302]

Not my rebuild

Cobra,

I wasn't the one who did the rebuild...i just bought it like that, so i can't answer any of your questions...

From what we can see, everything that can be looked at (without dismantling everything) is new...but as far as the internals go, i don't have a clue...!!

 

[2000xp8]

Probably is the balancer or the flywheel.
IMO, when in doubt replace the balancer, a new ford racing stock replacement is only $85.

When you do the clutch, just buy a new flywheel, last i had checked a ford racing stock replacement was $110.

 

[HISSIN50]

Also check spark plug wire routing. There was a TSB regarding crossfire inductance.

 

[racing302]

ok

So i guess there's a new harmonic balancer in my car's future this week...

As far as the plugs wiring, i've seen what other Mustang and my car has a good MSD unit and wire (ecept for the wire for the coil because i had to buy a long wire to change the coil's location; the last owner had it too close to the passenger's side head and i cooked it good with too much heat from a ride to Montreal in very hot day...so now it has a new coil and wire placed on the shock tower on the driver's side).

Thanks for all the infos!