Balancing Question

I finally have a 68 302 in the 65 mustang after the original 289 and other replacement 302 crapped out. I had to put a new flexplate and harmonic balancer on the engine. Since they are new do I need to have them balanced? The engine runs preaty good for the most part, need to rebuild the carm though, but it looks like it shakes a bit more than it should, at least to me. I only have 1,200 miles on the engine and would like to know if I need to balance the 2 items to help prevent premature wear. The 302 is externally balanced correct?

Thanks,
Travis

It is a 302 for a 68 to 72 mustang purchased from a engine place in Spokane, WA. I purchased the parts from NAPA. Here is the information

Flex Plate:
Part: BK 6005010
Product Line: Balkamp
Attributes

# Flex Plate Teeth : 157
Balance Weighted : Yes
Crankshaft Diameter : 1-3/4"
Flex Plate O.D. : 13 1/4"
Manufacturer : Pioneer Automotive Industries
Manufacturer Part Number : FRA-203
Application Information: 1968 Ford Mustang
Engines : 5.0 L 302 CID V8
Comments: w/ Automatic Transmission;Except Heavy Duty
Per Car Qty.: 1
Balancer:
Part: BK 6003267
Product Line: Balkamp
Attributes
Diameter : 6 17/32"
Manufacturer : Dorman Automotive Manufacturing
Manufacturer Part Number : 594-271
Weight : 8.95 lbs
Width : 3 5/32"

Application Information: 1968 Ford Mustang
Engines : 5.0 L 302 CID V8
Per Car Qty.: 1
Thanks,

Travis
65 Mustang "A" Code Coupe (Now a 302) C4
66 F-250 Custom Cab/Camper Special 352 (soon to be a 390) NP435 4speed
58 Mercury Monterey 4 door Sedan MEL 383 Dual Range Merc-O-Matic
05 Ford Freestyle 3.0 CVT

horseballz said:

Were these new parts for "28 ounce" imbalance or "50 ounce" imbalance? If you post the brands/part numbers of the parts, we can likely help you figure it out.
HTH,
Gene

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Drain plug is lined up correctly (wasn't paying attention when I put the original back on and warped it with the drain plug hense the replacement )

No pilot bushing or bearing.

The accessory belts could be an issue I had to so some funky lining up of stuff to get the pullys to line up. I may need to re-check the alignment.

No metal to metal contact I can see. However the exhaust does not quite line up creating some leaks and its possible I just didn't notice one of the pipes hitting the body. I'll be correcting the leak issue this weekend when I can get it on the lift.

It dosen't seem to be an entire body vibration. It just looks to me like the engine is vibrating more than I have typically seen, so the issue is it could just be me being parinoid after all the work I've done and money put into it.

I'll take a closer look at things this weekend and check things you have suggested. I appriciate the assistance, troubshooting vechicle issues is something I'm still learning. Been doing computer for over 20 years and preaty good at that but always wanting to expand my vechicle knowledge which usually leads to lots of research and asking questions Which reminds me of a C4 question I need to post on this site.

Thanks much!!

horseballz said:

Unless boxed/packaged incorrectly, they certainly seem to be the right units. Several things to think about/check:
A>Did you make sure to line up the drain plug of the torque converter to a corresponding hole in the flex plate?
B>Is there any possibility that there was a pilot bushing/bearing for a manual transmission in the rear of the crank shaft?
C>Remove the fan/accessory belts and see if the vibration goes away or lessens. I have certainly seen fans and other accessories cause vibrations.
D>Make SURE that there is NO metal to metal contact from engine/transmission to body/crossmember/oil pan to crossmember/frame/exhaust/etc. Exhaust should only "touch" the mounting at the engine and rubber mounts to the frame/body.
E>Does the vibration happen only when car is moving, or does it still occur when sitting still with the engine "free wheeling" in neutral/park? At what RPM?
Small, subtle vibrations can be extremely difficult to track down! Some are simply annoying and some can cause fatal engine wear/damage.
Gene

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Man I wish it did but I didn't want to void the warranty. The rebuilder said they get the engines as close to stock as possible. In a few years it will probably be getting some upgrades though.

Thanks,
Travis

horseballz said:

Does the engine have a slightly upgraded/performance cam in it? Higher than stock lift and/or longer duration than stock can cause a "loping"/rougher idle.
Gene

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