Wrong balance?

289 - 351 cid Small Block Performance

Wrong balance?

Postby rjones35 » Wed Feb 22, 2017 8:43 am

How obvious will it be if I put the wrong balance flywheel or balancer on my 302? I noticed, and it's probably always been there since I put it together, a vibration I can feel in the shifter in fourth gear. Not high rpm, probably 2000ish. Used 302, a flywheel that was supposed to be right, a new balancer that's supposed to be right. I just don't know if something was wrong how bad the vibration would actually be, being the new Ford guy that I am??
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby vicegrip » Wed Feb 22, 2017 9:48 am

If you can only feel it in 4th gear,it's probably not the motor IMO.
vicegrip
 
Posts: 220
Joined: Tue Jan 08, 2013 11:12 am

Re: Wrong balance?

Postby rjones35 » Wed Feb 22, 2017 11:07 am

vicegrip wrote:If you can only feel it in 4th gear,it's probably not the motor IMO.

That's kinda what I was thinking/hoping. Seems like the rest of the time it's pretty smooth.
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby StPro » Wed Feb 22, 2017 11:57 am

The wrong balance on the engine will increase with rpm. Balance issue in high gear leads me to driveshaft, u-joint ,trans output bearing or shocks and tires in that order.
Only use the brakes to stop and get gas.
Projects
65 Comet 421Stroker
93 Mark VIII Supercharged w/Fogger
70 Torino GT
User avatar
StPro
 
Posts: 310
Joined: Wed Mar 30, 2011 5:44 pm
Location: Coon Rapids MN

Re: Wrong balance?

Postby rjones35 » Wed Feb 22, 2017 12:17 pm

StPro wrote:The wrong balance on the engine will increase with rpm. Balance issue in high gear leads me to driveshaft, u-joint ,trans output bearing or shocks and tires in that order.

Thanks. I'll pay more attention now, but I don't think the engine rpm itself effects the vibration I notice. Hopefully not driveshaft, it was built new and supposed to have been balanced. Could be trans, it was used and gone through. Definitely could be tires/shock/rear-end, all old and haven't messed with yet.
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby Comechero65 » Wed Feb 22, 2017 2:47 pm

If either one were the wrong imbalance you should feel the vibration all the way from idle up and getting worse at higher rpm's. Let it go on for long could be damaging to the engine. Should feel it without putting un gear. If only at high rpm's I would look at driveline issues.
A 302 should be 28 oz imbalance on both dampener and flywheel.
Ron
Image
Comechero65
 
Posts: 1870
Joined: Wed Mar 12, 2014 8:37 pm
Location: Santa Clara, Ca

Re: Wrong balance?

Postby rjones35 » Wed Feb 22, 2017 2:59 pm

Comechero65 wrote:If either one were the wrong imbalance you should feel the vibration all the way from idle up and getting worse at higher rpm's. Let it go on for long could be damaging to the engine. Should feel it without putting un gear. If only at high rpm's I would look at driveline issues.
A 302 should be 28 oz imbalance on both dampener and flywheel.
Ron


Good! Thanks! Definitely don't feel it the majority of the time.
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby Rocket989 » Wed Feb 22, 2017 3:53 pm

Not necessarily...I bought a 'Stang back in the early 90's that had a 50-oz flywheel on a transplanted 289 (I can't remember if the balancer was incorrect also). It did vibrate but I can't say it got worse at higher RPM...and it wasn't THAT bad... This was pre-Internet so I'd recently read a SuperFord and article - called the guy back and yep...used wrong stuff!

I got a 28oz flywheel and swapped 'em out - much better...only way to know is to check balancer and flywheel/ flexplate. If you're confident the shortblock is original (crank at least) you can use a the block casting # and date code to know what they should be!!

Ford switched sometime in late '81...all 302's (or 5.0's) after that are 50-oz!
'cause Johno says you gotta have a sig pic!! :)
Image
Rocket989
 
Posts: 1562
Joined: Sat Jan 11, 2014 1:53 pm
Location: Kansas City Metro

Re: Wrong balance?

Postby Comechero65 » Wed Feb 22, 2017 7:11 pm

Got any pics of the back side of the dampener and flywheel? That tells a lot.
Ron
Image
Comechero65
 
Posts: 1870
Joined: Wed Mar 12, 2014 8:37 pm
Location: Santa Clara, Ca

Re: Wrong balance?

Postby Jims65cyclone » Wed Feb 22, 2017 8:04 pm

rjones35 wrote:Definitely could be tires/shock/rear-end, all old and haven't messed with yet.


If it's the tires, you shouldn't feel a vibration until you get up to about 45 mph. Between 45 and 60 mph is when the "loping" of the out of balance tire begins to match the natural frequency of the spring, and it sets up a harmonic where the bouncing of the wheel is amplified. Bad shocks will make it even worse since they will provide very little damping. Until the two frequencies come close to matching, the vibration may be barely noticeable, but as you approach the "magic speed" the vibration will get worse, and if you continue to speed up, it may decrease again as you pass through that harmonic. The speed at which it occurs will depend upon the tire diameter, gear ratio and how far out of balance the wheel is. It can also be caused by an out of round tire or separating belt, even if the wheel/tire are perfectly balanced. You can check that by jacking each tire off the ground and rotating it while holding a tool or stick near the tread to act as a reference. If the problem were with the front tires, you'd feel the vibration mainly through the steering wheel. If it's the rear tires, you'd probably feel it through the seat, or, since it's a floor shift, through the gear shift. You're problem may have nothing to do with tires, but we saw a lot of symptoms like yours at the tire/suspension company I worked at when I was in school.
Jim
Image

15x7x3.75BS TTII's all around
215/65/15 front, 235/60/15 rear
User avatar
Jims65cyclone
 
Posts: 1193
Joined: Sun Nov 23, 2014 9:29 pm
Location: Lexington, SC

Re: Wrong balance?

Postby rjones35 » Thu Feb 23, 2017 8:35 am

So I paid closer attention yesterday on the way home. Definitely not there all the time and doesn't increase or decrease either engine rpm, so that's good! I'm leaning more towards rear tires or rear-end or something. Don't really feel it in the seat, although kinda hard to tell that for sure. Definitely feel it in the shifter, just at a certain speed then it goes away, doesn't get worse, and the vibration I feel isn't terrible, like shaking the car apart or anything, just a vibration. Thanks for the help and suggestions, I feel better about the engine now!!
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby Comechero65 » Thu Feb 23, 2017 5:04 pm

I was asking about the back side of both as the balance weight part is very obvious between 28 oz and 50 oz.
Ron
Image
Comechero65
 
Posts: 1870
Joined: Wed Mar 12, 2014 8:37 pm
Location: Santa Clara, Ca

Re: Wrong balance?

Postby rjones35 » Fri Feb 24, 2017 11:44 am

Comechero65 wrote:I was asking about the back side of both as the balance weight part is very obvious between 28 oz and 50 oz.
Ron

I haven't crawled under there yet, but the Ford guy that helped me with the clutch stuff said was right, so that's what I was going with. Same thing with the balancer. Up until this point we were all assuming that it was a later model engine, I think it was based on the heads with egr? ports in the ends and a one piece rear main maybe. I'll scope it out tonite. I should have written all this stuff down back when I was actually doing it!!
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Re: Wrong balance?

Postby Comechero65 » Fri Feb 24, 2017 1:04 pm

Don't know when ford relocated the egr ports to the ends of the heads. they used to have a port near each plug.
Ron
Image
Comechero65
 
Posts: 1870
Joined: Wed Mar 12, 2014 8:37 pm
Location: Santa Clara, Ca

Re: Wrong balance?

Postby rjones35 » Sun Aug 13, 2017 2:16 pm

Ok, i know its been a while, but I'm back to driving the car more and I've replaced front and rear wheels and tires, and rear springs and shocks, and the vibration is still there. Been trying to pay more attention to it. Its not there all the time. Cruising in 4th at 1500-2000 rpm I do feel a vibration in the shifter, but above about 3500-4000 I REALLY feel a vibration. Can't tell if its engine, transmission, driveshaft, or what. I haven't gone a whole lot higher than 4000-4500ish, but it feels like the vibration gets worse with the higher rpm. I know I've got a 50oz balancer and according to the Ford guy I got the engine and flywheel from, that should be right for this setup. Is there a way to check the flywheel without taking things apart? Could there be another reason for the vibrating? Don't know anything about the engine, maybe it was put together wrong at some point. I could just drive it until it explodes then worry about it.
rjones35
 
Posts: 628
Joined: Tue Jan 01, 2013 6:15 pm

Next

Return to Small Block V-8 Performance

Who is online

Users browsing this forum: No registered users and 1 guest