Engine vibrations

[gibson]

Engine:
http://www.fordracingparts.com/parts...tKeyField=7368

- Changed to aluflywheel (ford 50oz according to website), changed to forged pistons without rebalancing the crank (not ford forged pistons).

I have major vibrations that increases with rpm, when standing still and driving.

All new bushings, bolts, mounts, trans. No loose bolts.

It responds very quickly on the throttle, but is there a small change it can be a bad plug or should I prepear for pulling the engine and balance the crank??

Can the flywheel be mounted wrong, there are no guide-pin - are the bolts offset? Can the 302 81-95 flywheel be mounted any direction??

Thanks in advance,
Peter

[mjlangley]

I can offer some confirmation: the flywheel bolt pattern is offest, it will only bolt in one direction to assure the balance weight is in the correct spot.

I would contact the piston supplier/ manufacturer to get their thoughts on getting the rotating assembly ( crank, rods and pistons, balancer and flywheel) re-balanced.

In the OEM, as-manufactured engine, you should be able to interchange flywheels as long as they are for the late, 50oz. imbalance ( vs. the older 28oz. set-up).

-Matt

[Hankl]

Peter,

If you changed the pistons with out re-balancing the rotating assembly, that's most likely your vibration problem. Often times you can change parts of the rotating assembly, but only if the difference between the two parts is minimal, which in this case probably isn't. Did you weigh the old and new pistons?, if you did what was the difference in Grams?

Hank
[img]graemlins/darkbluecoupe.gif[/img]

[Jeff Hamilton]

There are 2 differnt flywhels for 302 motors. The early one is 28 oz and the later 1981 and up is 50 oz balance. Did you install the guide pins in for the pressure plate?
Jeff Hamilton

[Just_Bitten]

I had the exact same problem and it was b/c I had the wrong weight flywheel like Jeff mentions above. Had to pull the engine and change the flywheel. Not fun.. That reminds me that I still have that flywheel basically brand new in the box and need to list it in the parts for sale section.
Raul

[Mike Forte]

Hi Peter,
You might just need a 28oz flywheel. Is it a Ford steel billet flywheel? They have balance weights that are a bolt on. Call me with any questions.
Mike

[gibson]

I´ve looked thru all other variables, and the only thing than can be wrong is 3 things:

1. Wrong weight on the flywheel from Ford. Their site says that the 50 oz alu-flywheel has a 7.2" long weight - and as far as I can remember the weight wasn´t that long (but I´m pretty much guessing).

2. The damper on the front of the engine is a 28 oz mounted when the crate engine got here. I can´t imagine Ford making this mistake -but hey, F5 sent me 2 driver-doors so I guess no one is perfect...??

3. I need to take the engine apart and rebalance the crank to match my forged pistons.

Any ideas??

Peter

[BS]

Since you changed pistons also, I would have the entire rotating assembly balanced to be sure. That would include the crank, pistons/rods, flywheel, balancer, and possibly the clutch if your mechanic deems it necessary. At least this way it will be perfect when you're done and you won't have to worry about it again later.

[forrest1]

If you have a 28 oz damper and a 50 oz flywheel, one of them is wrong and that's your problem. They must either both be 28 or both 50 oz, depending on your crankshaft.

The catalog specs a 50 oz damper for that motor currently, so if I were you, I'd call the FRPP tech hotline (586-468-1356). Maybe it's an older version that came with 28 oz damper and flywheel.
Was this a brand new crate motor, taken apart for a piston swap and then reassembled? Could the damper have gotten swapped during the reassembly?

Pistons would have to be WAY off to cause a "major vibration" like you describe. While it certainly is always a good idea to balance evrything while it is apart, I seriously doubt that they could even be that far off if they are all of the same manufacture.

F

[ May 27, 2006, 05:49 PM: Message edited by: forrest1 ]

[gibson]

I agree on the far off-issue. The crate-engine was brand new with damper and flywheel installed - I changed to forged pistons (since I plan to go overload) and changed to alu-flywheel since I want the engine to respond very quickly. I can´t imagine Ford putting the wrong damper on, but there is a chance that they´ve supplied the wrong weight on the flywheel. I THINK it was a 4" weight but I cannot confirm it until I´ve looked at it again. I will pull the whole driveline tomorrow (thank god I have the Coupe) and have a look. I´ll get back to this topic to make sure the topic get solved.
Peter

[forrest1]

Good luck! Please let us know how it turns out!

[Jeff Hamilton]

Do you have the pressure plate dowel pins in the flywheel?
Jeff Hamilton

[gibson]

Yep, three of them.
The vibrations are not so much during idle, almost none accually but the intake is moving about 1cm when holding it at 2500 rpm or at 4000 rpm....

[gibson]

Pulled the engine today, and found that the weight on the flywheel is 4" long. FRPP-site says that the 4" long is for 28.2 oz and the 7.2" is for the 50oz. I will have Ford ship the correct weight to me asap, a bit dull since I had to skip registration and move registration-date at least a month...
Peter

[SuperHart]

Not to beat a dead horse here but you said that your damper is a 28 oz. one. You must be certain that BOTH your flywheel and damper are 50 oz. IF the rest of your reciprocating assembly is 50 oz. If Ford incorrectly mounted a 28 oz. damper on a 50 oz. reciprocating assembly then you definitely have a legit claim against them for damages. IMHO, any tech who can spell the name FORD should know to match all the rotating components before assembly.

[forrest1]

As my boss says: "You don't get what you EXpect, you get what you INSpect".

[gibson]

Ops, my bad - the damper is of course a 50oz one, at least I assume it is. It came mounted on the crate-engine together with a flywheel that I´ve changed to the one with the 28oz weight (that I thought had the 50oz weight since the orderingnumber and website says so...)

I´ll have a chat with Ford and see...
Peter

[Rickster]

While you have the engine out, check the part number on the balancer and cross refrence it just to make sure it is in fact 50oz.

[gibson]

It was E4, made in 84 I assume but have no idea of where to check it...ideas? Email a Ford-dealer??

Thanks
Peter

[gibson]

Changed to the right weight and the engine runs smooth and perfect...
Peter