Results of a 347 with a bone stock balancer?

[85_SS_302_Coupe]

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]

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.

 

[proxses]

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]

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]

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.

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]

What weight/balance flywheel and balancer should a 347 have?

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]

That depends what the shop balanced the assembly to.

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

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

 

[HISSIN50]

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]

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]

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

I was a little slow on the return also

 

[DMAN302]

You definately can't use the 302 flywheel.

 

[Rick 91GT]

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]

...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]

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?

 

[89white50]

i talked to the guy about the kit and he said he didn't think to check the balance

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.

 

[tjm73]

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?

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

 

[85_SS_302_Coupe]

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.

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.

 

[89white50]

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]

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.

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]

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.