Engine Builder advice Q....

[hardtimes]

I've put my B short block together. Now I rec'd my cut down A flywheel which is about 32 lbs at this time. I'd rather had the crank/flywheel/disk/pressure plate ALL balanced at same time, but that is not happening now.
Therefore, is there any process whereby , I can balance the cut down flywheel/disk/pressure plate now, or just not a major concern/worry , in you opinion

[BRENT in 10-uh-C]

Yes, you can still recover. Hopefully your engine builder balanced the reciprocating parts (-minus the flywheel). What you need to do is have the flywheel & pressure plate balanced and then bolt it on. My experiences are that most flywheel's that are lightened DO require re-balancing.

[CarlG]

My lightened flywheel and pressure plate were balanced together.

[hardtimes]

Originally Posted by CarlG

My lightened flywheel and pressure plate were balanced together.

Ok, then I'll have the cut flywheel/disc and pressure plate balanced. How is that done , i.e.- dynamically , statically, what methods?

[CarlG]

I don't know what the method used was to balance the assembly. The shop that did the work is in Texas, I'm in Alaska. It was all match marked so it could be taken apart and re-assembled without loosing the balance.

[MikeK]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by hardtimes

Ok, then I'll have the cut flywheel/disc and pressure plate balanced. How is that done , i.e.- dynamically , statically, what methods?

WOAH! The disc must not be in the pressure plate/flywheel assembly during balance! The disc will orient randomly every time the clutch is re-engaged and any disc imbalance will screw things up. If you need to balance the disc, it must be done separately.

Make sure you mark the pressure plate and flywheel so they can be taken apart and put back together in the same orientation.

[hardtimes]

Originally Posted by MikeK

WOAH! The disc must not be in the pressure plate/flywheel assembly during balance! The disc will orient randomly every time the clutch is re-engaged and any disc imbalance will screw things up. If you need to balance the disc, it must be done separately.

Make sure you mark the pressure plate and flywheel so they can be taken apart and put back together in the same orientation.

Hey Mike,
Great info/advice from you !
I've just spoke with the old gentleman who cut the flywheel down. He says that he will 'statically' balance the pressure plate/flywheel on a setup that he has. I would have preferred to have had it done all together, as Carl's builder did, but you do what you must,eh.
BTW...just thinking back to the old days. I can never remember one time ever having the flywheel/pressure plate balanced. I guess the Model A/B engine requires all the help , balance wise, that it can get ?

[James Rogers]

Static balance is a shot in the dark, good luck with that.

[J and M Machine]

I can balance the cut down flywheel/disk/pressure plate now, or just not a major concern/worry , in you opinion


Yes by all means balance the flywheel and clutch as a unit. You have lightened it so it needs to be balanced, As seen in the photo.
cut down flywheel and clutch shipped to us with engine. This set up was told to customer when purchased that's already balanced.
As you can see it was off 24 grams. after balancing .2 tenths of a gram.
Night and day difference.

If you 're spending the money to do an engine properly and want it to last by all means spend the extra few dollars and get it balanced.

[Kohnke Rebabbitting]

"Agree"

[hardtimes]

Hey J & M,
Thanks for the reasoned advice and great support pictures !
Would a guy search for an auto machine shop , or other, to locate someone with the Hines type balancing equipment that you have
Yes, I have way tooo much $ into this current B short block, to shorten longevity by imbalance.

[J and M Machine]

Originally Posted by hardtimes

Hey J & M,
Thanks for the reasoned advice and great support pictures !
Would a guy search for an auto machine shop , or other, to locate someone with the Hines type balancing equipment that you have
Yes, I have way tooo much $ into this current B short block, to shorten longevity by imbalance.

Hardtimes : YES: any good automotive engine rebuilder will have a balancer.
Doesn't have to be a Hines that was an old picture I've posted.

They have to set up your clutch and flywheel as i have shown on a mandrel and spin it to find the heavy portion and make the correction by removing iron via drilling holes.

As a matter of fact. Recently a customer contacted us and said engine was rebuilt but still had vibration. He brought us clutch and flywheel and it was off similar amount of 30 grams .

After balancing customer called back to say made big improvement.
30 grams doesn't sound like much but when you get a 40-65 lb flywheel turning the grams add up to pounds.

[1ton]

I have some doubts with this. With all of the disc and pressure plates that I've replaced over the years on muscle cars and trucks, it's been standard procedure to reface the flywheel. Never have I thought to balance the flywheel and pp as a unit. Are the replacements for model a's way out of balance? Plan on running some high rpm's? If there was some imbalance, couldn't you just unbolt and reclock the pp into another position? Just curious

[Vic in E-TN]

1ton
1. Years ago I did a Corvair. I believe that the flywheel was 11 lbs and the pressure plate was about 5 lbs. Quite a difference in weight between a Model A pressure plate and flywheel even though the Corvair was good to about 4500 RPM.
Just unbolt the pressure plate and reposition it?? You must really like the major disassembly of heavy components.
There is a speed shop around here that does work for these hi performance dirt track trucks and short track racers. It cost me about $50 or 60 to get the job done.

Vic

[Pete]

I have had a balancer since the mid 50's.
For just a flywheel and clutch assembly, I balance the flywheel on a mandrel first, then bolt the clutch cover on and balance the assembly by weight adjusting the cover ONLY. Punch marking each piece for proper indexing on reassembly.
As Mike K noted the disc is balanced on a separate mandrel by itself.

Absolutely NO welding, grinding or drilling should be done on the clutch cover.
It is weight adjusted by drilling the spring posts.

[colin1928]

I always get everything balanced individually (not rods or pistons they are matched ) it cost a little more but means I can swap parts without losing balance

[hardtimes]

Hey Pete,
Thanks to all of you guys for this very informative discussion. Now that I know the correct process, I've just got to locate a business with proper equipment.

Getting anxious/close Pete to listening to your cam setup !