Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 11-18-2018, 09:56 AM   #1
1938 Woody Cape Cod
Senior Member
 
1938 Woody Cape Cod's Avatar
 
Join Date: May 2010
Location: Cape Cod Ma.
Posts: 125
Default Vibration

I just purchased a restored 31 sedan. Everything done correctly and first class.
It has Float-A Motors. It has an engine vibration sitting in neutral when bringing up the RPM's, with the clutch in or out. Also on deceleration. It seams
fine when driving along at a steady speed 30-45. Any ideas........Bob
1938 Woody Cape Cod is offline   Reply With Quote
Old 11-18-2018, 01:50 PM   #2
Jacksonlll
Senior Member
 
Jacksonlll's Avatar
 
Join Date: Jul 2012
Location: Michigan-- Member of Oakleaf of MARC
Posts: 1,115
Send a message via ICQ to Jacksonlll
Default Re: Vibration

Make sure your exhaust pipe is not touching the frame or body.
Jacksonlll is online now   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 11-18-2018, 03:51 PM   #3
1938 Woody Cape Cod
Senior Member
 
1938 Woody Cape Cod's Avatar
 
Join Date: May 2010
Location: Cape Cod Ma.
Posts: 125
Default Re: Vibration

Thank you, It's not a rattle, but a vibration. Seems to be from the engine.............Bob
1938 Woody Cape Cod is offline   Reply With Quote
Old 11-18-2018, 04:18 PM   #4
WHN
Senior Member
 
Join Date: Mar 2017
Location: Old Lyme Connecticut
Posts: 964
Default Re: Vibration

Has your Float-A-Motor allowed some sag or alining problems in your drive train?
WHN is offline   Reply With Quote
Old 11-19-2018, 05:54 AM   #5
1938 Woody Cape Cod
Senior Member
 
1938 Woody Cape Cod's Avatar
 
Join Date: May 2010
Location: Cape Cod Ma.
Posts: 125
Default Re: Vibration

FAM seem OK
1938 Woody Cape Cod is offline   Reply With Quote
Old 11-19-2018, 08:08 AM   #6
big job
Senior Member
 
big job's Avatar
 
Join Date: Sep 2013
Location: Dighton, Mass
Posts: 691
Default Re: Vibration

A proven fact: anything or everything that goes around has a moment more like a
moment of insanity. Clutch in or out no change = that rules out drive line. So I bet
a dollar to donuts its the pressure plate / flywheel I doubt, but could be. My machine shop
has yet to find a new pressure plate from venders way out and I mean way out. My personal car engine all first class new a 59A V8 Findings = Flywheel ah couple grams:
pressure plate almost 90 and that aint going to fly with me. New plate and we had to
weld 90 + or minus grams a stack of washers on it because USA don't make nothing no
more, and those who do across the pond could care less. Hate to say pull the motor A's
are easy and have flywheel and pressure plate balanced.....sam been there on this.
big job is offline   Reply With Quote
Old 11-19-2018, 12:50 PM   #7
Jim Brierley
Senior Member
 
Join Date: Jun 2010
Location: Temecula, CA
Posts: 2,684
Default Re: Vibration

Make sure the F-O-M's bolt is snug, or replace them with stock mounts. I replaced mine and the engine was as smooth as before and had less clutch chatter.
Jim Brierley is offline   Reply With Quote
Old 11-19-2018, 12:54 PM   #8
Purdy Swoft
Senior Member
 
Purdy Swoft's Avatar
 
Join Date: May 2010
Location: Alabama
Posts: 7,000
Default Re: Vibration

If the bolts on the float-A- motor mounts are TOO tight it can cause vibration .
Purdy Swoft is offline   Reply With Quote
Old 11-19-2018, 02:42 PM   #9
wensum
Senior Member
 
wensum's Avatar
 
Join Date: Apr 2011
Location: New Zealand
Posts: 404
Default Re: Vibration

If all else fails, try a Harmonic Balancer Pulley. It certainly transformed my motor. These are made in New Zealand "These dampers are made by Murray Horn in Levin N.Z. His Company is Engine Restorations Ltd. His email is horn@xtra.co.nz
Murray says this is the best way to contact him.
The dampers are a straight fit to replace the standard Model A pulley. An added benefit is a shallow reverse scroll in the rope seal area to help contain oil.
"
wensum is offline   Reply With Quote
Old 11-19-2018, 03:24 PM   #10
BRENT in 10-uh-C
Senior Member
 
BRENT in 10-uh-C's Avatar
 
Join Date: May 2010
Location: Eastern Tennessee
Posts: 8,639
Default Re: Vibration

Quote:
Originally Posted by 1938 Woody Cape Cod View Post
I just purchased a restored 31 sedan. Everything done correctly and first class.



It has Float-A Motors. It has an engine vibration sitting in neutral when bringing up the RPM's, with the clutch in or out. Also on deceleration. It seams fine when driving along at a steady speed 30-45. Any ideas........Bob


Bob, just to poke fun at you, I like your first sentence however the verbiage in the second sentence does not seem to agree with the next paragraph!




While the above ideas all have merit, I tend to think by you saying the vibration is only happening during idle while accelerating/deaccelerating in neutral, my guess is the flywheel has been lightened a tad too much which is showing up from the impulses of each cylinder firing. When you are driving it, items such as transmission cluster, driveshaft, U-joint, wheels, etc. all are mass that adds to the weight of the flywheel which in-turn masks those impulses.
__________________
.

BRENT in 10-uh-C
.
www.model-a-ford.com
...(...Finally Updated!! )

.
BRENT in 10-uh-C is offline   Reply With Quote
Old 11-20-2018, 06:23 AM   #11
1938 Woody Cape Cod
Senior Member
 
1938 Woody Cape Cod's Avatar
 
Join Date: May 2010
Location: Cape Cod Ma.
Posts: 125
Default Re: Vibration

Brent..The car looks like it was done by a pro about 12 years ago with attention to detail. That's why the vibration doesn't make sense. Very few miles.....Bob
1938 Woody Cape Cod is offline   Reply With Quote
Old 11-20-2018, 07:34 AM   #12
jhowes
Senior Member
 
Join Date: Jul 2010
Posts: 691
Default Re: Vibration

Harmonic Balancers are on most modern engines and I thought that they reduce the twisting action on the crankshaft. Does this have anything to do with vibration which seem common in the Model A engine? Jack
jhowes is offline   Reply With Quote
Old 11-20-2018, 09:07 AM   #13
Dave in MN
Senior Member
 
Dave in MN's Avatar
 
Join Date: May 2010
Location: Jordan, MN
Posts: 1,144
Default Re: Vibration

From my experience: Anytime you change the mass of the rotating assembly, the rpm range where the vibration is felt will change. The Murray Horn dampers do eliminate felt vibration with some engines. I used on on a project last about a year ago with good success.
Good Day!
Dave in MN is offline   Reply With Quote
Old 01-23-2019, 03:54 PM   #14
ryanheacox
Senior Member
 
ryanheacox's Avatar
 
Join Date: Apr 2013
Location: Northwest CT
Posts: 333
Default Re: Vibration

Gonna dig this one up. How much vibration is considered "normal"? My Fordor does tend to vibrate a bit on decel but nothing that seems too bad to me considering how the engine is mounted.
ryanheacox is offline   Reply With Quote
Old 01-23-2019, 04:40 PM   #15
ursus
Senior Member
 
Join Date: May 2010
Location: Oregon
Posts: 961
Default Re: Vibration

Quote:
Originally Posted by big job View Post
A proven fact: anything or everything that goes around has a moment more like a
moment of insanity. Clutch in or out no change = that rules out drive line. So I bet
a dollar to donuts its the pressure plate / flywheel I doubt, but could be. My machine shop
has yet to find a new pressure plate from venders way out and I mean way out. My personal car engine all first class new a 59A V8 Findings = Flywheel ah couple grams:
pressure plate almost 90 and that aint going to fly with me. New plate and we had to
weld 90 + or minus grams a stack of washers on it because USA don't make nothing no
more, and those who do across the pond could care less. Hate to say pull the motor A's
are easy and have flywheel and pressure plate balanced.....sam been there on this.
My engine was balanced and everything proceeded well until the flywheel was checked with the pressure plate attached - a huge imbalance! The pressure plate needed considerable correction with weights attached.
ursus is offline   Reply With Quote
Old 01-23-2019, 07:07 PM   #16
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,288
Default Re: Vibration

Quote:
Originally Posted by 1938 Woody Cape Cod View Post
I just purchased a restored 31 sedan. Everything done correctly and first class.
It has Float-A Motors. It has an engine vibration sitting in neutral when bringing up the RPM's, with the clutch in or out. Also on deceleration. It seams
fine when driving along at a steady speed 30-45. Any ideas........Bob
"Everything" was NOT done correctly and first class or it would not shake.
If it vibrates when idling, it has a first order harmonic. That generally means something is REALLY out of balance in the engine.
Pete is offline   Reply With Quote
Old 01-23-2019, 07:20 PM   #17
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,288
Default Re: Vibration

Just as a side note here while balancing is the subject, it is a VERY bad idea to weld weights on a clutch cover to balance it if you value your lower body parts.
The proper way is to drill the spring posts.
Pete is offline   Reply With Quote
Old 01-23-2019, 08:42 PM   #18
figment
Senior Member
 
Join Date: May 2010
Posts: 289
Default Re: Vibration

Make sure that the fan is balanced and if original check for cracks .
figment is offline   Reply With Quote
Old 01-23-2019, 08:56 PM   #19
duke36
Senior Member
 
Join Date: Jun 2015
Posts: 960
Default Re: Vibration

Perhaps start with the easy stuff 1st: as mentioned, fan, front motor mount tightness and springs (if original), replace FAM biscuits if 12 years old and side frame rubbers(vendors sell new ones. See posts 2,3,4. Are engine pans attached? Check front alignment of pulley thru the radiator shell and clearance of service brake rod to torque tube, etc.
Also, check the engine in neutral thru the spark rod range and see if vibration persists.
duke36 is offline   Reply With Quote
Old 01-24-2019, 01:01 AM   #20
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,288
Default Re: Vibration

ALL engine vibrations are caused by MOVING PARTS.
If the engine is not running, there is no vibration. Changing engine mounts, muffler clamps,
brake rods, drive shafts and anything else can and does sometimes minimize or mask the problem by changing the resonant frequency of the vibration, BUT it does not address the root problem. BAD BALANCE JOB.
Pete is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 07:52 AM.