• Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech

Results of a 347 with a bone stock balancer?

  • Thread starter Thread starter 85_SS_302_Coupe
  • Start date Start date Nov 10, 2005
  • 1
  • 2
Next
1 of 2 Next Last

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 10, 2005
#1
  • Nov 10, 2005
  • #1
Friend of mine just assymbled a 347, and had to resort to using a stock balancer. I had no idea it was stock untill i asked. The problem is the car vibrates like a damn jack hammer.

Two questions on this one:

1) he's using home made solid motor mounts....now, when i say solid, i mean 2 inches of solid steel plate. I know solid mounts cause some extra vibration, but how much more?

2) i personally think he needs a Fluidyne or equivelant balancer, so wouldnt the stocker cause more vibration, and wouldnt the two make it really bad?


Basically the car idles fine, just a little cam shake (X303) but shakes progressively worse as the RPMs go up, to the point of literally jack hammer-like at 3500+.
 

bubba-dough

Active Member
Dec 28, 2004
1,044
2
38
Indiana
Nov 10, 2005
#2
  • Nov 10, 2005
  • #2
Kinda a dumb question but was the kit balanced? And what was the balance? I am using the stock balance and no issues what so ever.
 
P

proxses

Founding Member
Dec 12, 2000
620
0
0
Dayton, Oh
Nov 10, 2005
#3
  • Nov 10, 2005
  • #3
Yeah, you need to find out if the kit was balanced.
Also, what it the imbalance of the flywheel or flexplate?
Most stroker kits have a 28oz imbalance, while the stock balancer is 50oz.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Nov 10, 2005
#4
  • Nov 10, 2005
  • #4
Is this the guy from the other thread? What is the imbalance on the flywheel?

The 50 oz imbalance is going to create havoc (obviously shelf the car till the new balancer is installed). Solid mounts will transfer any imbalance, so yeah the solid mounts are letting you and him feel every little bit possible. In this case, this is good. Otherwise durometric mounts could dampen the sensation and mask it to the driver - not good.

I would verify the balance specs and make sure everything is of the same balance (zero, 28, 50 oz, etc).

Good luck to him.
 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 10, 2005
#5
  • Nov 10, 2005
  • #5
HISSIN50 said:
Is this the guy from the other thread? What is the imbalance on the flywheel?

The 50 oz imbalance is going to create havoc (obviously shelf the car till the new balancer is installed). Solid mounts will transfer any imbalance, so yeah the solid mounts are letting you and him feel every little bit possible. In this case, this is good. Otherwise durometric mounts could dampen the sensation and mask it to the driver - not good.

I would verify the balance specs and make sure everything is of the same balance (zero, 28, 50 oz, etc).

Good luck to him.
Click to expand...


Thanks for the quick reply guys. No, this is a different guy (i've got TONS of Mustang friends ). The kit was balanced, i'm not sure how close but he went so far as to double check the pistons and rods. The flywheel and balancer are the same that came off the 302 when it was stock...which is where i'm guessing he's gone wrong.

What weight/balance flywheel and balancer should a 347 have? From all i know about engines i know nothing about strokers (yet )
 

Grn92LX

Fidanza Man!
Founding Member
Jan 14, 2001
6,819
64
129
New York
Nov 10, 2005
#6
  • Nov 10, 2005
  • #6
85_SS_302_Coupe said:
What weight/balance flywheel and balancer should a 347 have?
Click to expand...

That depends what the shop balanced the assembly to.

Your typical cast steel crank stroker kit will balance to 28oz, but it depends..
 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 11, 2005
#7
  • Nov 11, 2005
  • #7
Grn92LX said:
That depends what the shop balanced the assembly to.

Your typical cast steel crank stroker kit will balance to 28oz, but it depends..
Click to expand...

It's an Eagle crank and rods...i'll have to ask him what the balance was and get back.
 

HISSIN50

"How long does it take to get help in here?
15 Year Member
Nov 29, 1999
31,179
34
129
Nov 11, 2005
#8
  • Nov 11, 2005
  • #8
Mike is right on. have him get on the horn with the machine shop to find out what they did, since everything else (balancer, flywheel, etc) is predicated upon that.

I guess you do have a lot of stang friends.

EDIT: did not mean to seem redundant - you posted again after Mike did, while I was pecking.
 

bubba-dough

Active Member
Dec 28, 2004
1,044
2
38
Indiana
Nov 11, 2005
#9
  • Nov 11, 2005
  • #9
Yeah its all personal prefferance on the balance. And that depends on who balanced it and your builder. Some builders swear by a 28oz on a stroker but most if not all builders will agree any balance will work fine.
 

bubba-dough

Active Member
Dec 28, 2004
1,044
2
38
Indiana
Nov 11, 2005
#10
  • Nov 11, 2005
  • #10
HISSIN50 said:
EDIT: did not mean to seem redundant - you posted again after Mike did, while I was pecking.
Click to expand...
I was a little slow on the return also
 

DMAN302

My mom says thanks for the pearl necklace.
Nov 8, 2003
2,120
2
59
windsor, Canada
Nov 11, 2005
#11
  • Nov 11, 2005
  • #11
You definately can't use the 302 flywheel.
 

Rick 91GT

Mustang Master
Nov 29, 1999
9,692
95
99
PA
Nov 11, 2005
#12
  • Nov 11, 2005
  • #12
I don't like solid mounts on a stock 302 block, there is not a lot of meat to the block there and this adds a lot of stress when your dealing with a healthy motor. If the chassis is not up to par the solid mounts will create issues.

Like everyone said you need to find out what the kit was balanced to...that stock 302 flywheel is 50oz along with your stock balancer. The shop he uses should have clearly stated what the balance was and that should have been discussed before the work was done.
 

Michael Yount

Mustang Master
Apr 10, 2002
9,039
6
79
Charlotte, NC
Nov 11, 2005
#13
  • Nov 11, 2005
  • #13
...heckuva a deal when the chassis is so flexible that solid mounts turn the block into a stressed member and distort the block huh Rick?

85SS - tell your friend not to run the engine any more til he gets it figured out - he can really tear up things big time with this problem.
 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 11, 2005
#14
  • Nov 11, 2005
  • #14
OK so....i talked to the guy about the kit and he said he didn't think to check the balance....so 28oz is probably the issue. The whole kit is pretty budget, i think he's only got about 600 into everything. Where could he find the right balancer/flywheel for cheap? Can we get any of this stuff used off a stock car?
 
8

89white50

Member
Nov 16, 2004
440
1
18
central MA
Nov 11, 2005
#15
  • Nov 11, 2005
  • #15
i talked to the guy about the kit and he said he didn't think to check the balance
Click to expand...

honestly, how would you forget somethign as critical as making sure you have the correctly weighted balancer/flywheel. Owell live and learn i guess. i sure hope he didnt ruin his bottom end. You can get nodular iron FRRP balancers and flywheels fairly cheap on the internet. like DSS has them for a 100 bucks each part. if you are a good friend you need to your friend for stupidity.
 
T

tjm73

Founding Member
Aug 3, 2000
2,418
2
48
Rush, NY
Nov 11, 2005
#16
  • Nov 11, 2005
  • #16
85_SS_302_Coupe said:
OK so....i talked to the guy about the kit and he said he didn't think to check the balance....so 28oz is probably the issue. The whole kit is pretty budget, i think he's only got about 600 into everything. Where could he find the right balancer/flywheel for cheap? Can we get any of this stuff used off a stock car?
Click to expand...

FRPP has both parts. Shop around and you will find a fair deal pretty easy.
 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 11, 2005
#17
  • Nov 11, 2005
  • #17
89white50 said:
honestly, how would you forget somethign as critical as making sure you have the correctly weighted balancer/flywheel. Owell live and learn i guess. i sure hope he didnt ruin his bottom end. You can get nodular iron FRRP balancers and flywheels fairly cheap on the internet. like DSS has them for a 100 bucks each part. if you are a good friend you need to your friend for stupidity.
Click to expand...


Man, don't confuse stupidity with lack of experience. His car ran 12.20s all motor before the stroker kit and he's done every bit of the work himself...that's pretty good IMO, he's just never built a stroker. A mistake, yes, but most guys wouldnt even have the guts to take on a build like this.
 
8

89white50

Member
Nov 16, 2004
440
1
18
central MA
Nov 11, 2005
#18
  • Nov 11, 2005
  • #18
i wasnt really bashing him as much as i was joking around, sorry if it cam across like that. Eithery way i would look at DSS or other places online to find the cheapest prices.
 

85_SS_302_Coupe

it sucks (I know) to be on the receiving end
15 Year Member
Nov 11, 2003
6,945
1,598
223
Northern KY
Nov 11, 2005
#19
  • Nov 11, 2005
  • #19
89white50 said:
i wasnt really bashing him as much as i was joking around, sorry if it cam across like that. Eithery way i would look at DSS or other places online to find the cheapest prices.
Click to expand...

Yea it's cool, i busted his balls over it plenty though. I think he may have been under the impression that it was a 50oz kit.
 

vristang

15 Year Member
Mar 31, 2005
4,933
101
124
Seattle
Nov 11, 2005
#20
  • Nov 11, 2005
  • #20
Most balance shops can re-balance the flywheel. If it is otherwise in good shape, it is fairly inexpensive. If the flywheel has already been surfaced, and is on its last leg, it may be worth while to just buy new, or at least a good used piece.
 
  • 1
  • 2
Next
1 of 2 Next Last
You must log in or register to reply here.

Similar threads

Engine Bad engine shaking at idle
  • sav22rem22
  • Jan 2, 2024
  • Fox 5.0 Mustang Tech
  • 2
Replies
26
Views
6K
Fox 5.0 Mustang Tech Feb 2, 2024
sav22rem22
J
Progress Thread Family member 1989 GT- Backstory and updates
  • JRC99
  • Apr 19, 2025
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
Replies
15
Views
1K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 26, 2025
JRC99
J
Fuel Fuel Pump Rewire, New Fuel Lines, and Installation of New Fuel Pump Hanger with AN6 Connections
  • AeroCoupe
  • Mar 12, 2023
  • Fox 5.0 Mustang Tech
  • 2
Replies
33
Views
13K
Fox 5.0 Mustang Tech Apr 16, 2023
AeroCoupe
Took some pics, i do really own a mustang...
  • 2000xp8
  • Jun 20, 2023
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • 6 7 8
Replies
148
Views
19K
1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk- Oct 1, 2024
Mustang5L5
SN Mustang Magnum T56 swap
  • revhead347
  • May 24, 2024
  • 1994 - 1995 Specific Tech
Replies
15
Views
6K
1994 - 1995 Specific Tech Jun 28, 2026
GearHeadGuy
Share:
Bluesky Email Share Link
  • Mustang Forums
  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
  • Fox 5.0 Mustang Tech
Menu
Log in

Register

  • Forums
  • What's new
  • Media
  • Resources
  • Contact
  • Sponsor
X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?

X

Privacy & Transparency

We use cookies and similar technologies for the following purposes:

  • Personalized ads and content
  • Content measurement and audience insights

Do you accept cookies and these technologies?