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Username Post: 235 jerking        (Topic#353636)
Alegm 
Poster
Posts: 25
Alegm
Reg: 01-05-13
10-27-18 09:11 PM - Post#2749743    

My car is beginning to be a real pain to drive. I cannot get a good idle from it and when I'm coasting, the car starts jerking back-and-forth. At low speeds, this jerking can get pretty violent if I don't release the clutch. it got a YF carter automatic choke on my 235 6cyl. Is it possible to have a vacuum leak here but I sprayed starting fluid in likely leak areas and the only area that caused an increase in rpm was on the choke stove in the exhust manifold.
When I atach a vaccum gauge the needdle doesn't stay steady as they say it should be. Here a link to the video
https://www.youtube.com/watch?v=p2MlsLpnbBs
Any idea what may be causing this??
maybe a valves problem?



 

Ecklers AutoMotive

Dave in VA 
Contributor
Posts: 168
Dave in VA
Age: 68
Loc: SW Virginia, USA
Reg: 03-11-18
10-28-18 05:31 AM - Post#2749755    
    In response to Alegm

I had this same problem with my '50 216. I replaced the points with a Pertronix electric ignition module. Problem solved. Very affordable thru your local auto parts store.



"Knowledge is Good" -- Emil Faber

U S Navy MM2 1970-75 USS Canisteo AO-99, USS Miller DE-1091 (The Champagne of Ships)

1950 Styleline Deluxe 2dr, mostly stock, driver quality...new to me 3/18
2016 Equinox LTZ
2017 Silverado LTZ 6.2


 
Shepherd 
Frequent Contributor
Posts: 1554

Loc: Lake George, NY
Reg: 11-11-15
10-28-18 05:39 AM - Post#2749757    
    In response to Alegm

Without driving the vehicle, jerking is tough to understand, a misfire, timing to far advanced, both are possible. Fluctuating vacuum readings can be a valve problem in the engine. Start with the basics, do a compression test, engine sounds rough.



Edited by Shepherd on 10-28-18 05:41 AM. Reason for edit: No reason given.

 
jdk 
"9th Year" Gold Supporting Member
Posts: 436
jdk
Age: 68
Loc: columbus, ohio
Reg: 02-15-10
10-28-18 06:23 AM - Post#2749760    
    In response to Shepherd

if you have a vacuum can, disconnect it and adjust
the engine. jim



 
Alegm 
Poster
Posts: 25
Alegm
Reg: 01-05-13
10-28-18 07:52 PM - Post#2749822    
    In response to Shepherd

probably i should do a compression test...althoug I dont think i've got rings or pistons problems since there is not oil in the plugs
i've tried combinations of all kinds, gaping the points and the plugs.... and I've found that what it likes the most is gaping the plugs close to .40(gaping them less than .34 make them dirty)....the only way i've notice that stops these problem is retarding the time at the point that the egine hesitates when you suddenly push the gas pedal wich is basically not a solution



 
acardon 
Ultra Senior Member
Posts: 11105
acardon
Loc: DFW TEXAS
Reg: 03-25-05
10-29-18 07:17 AM - Post#2749867    
    In response to Alegm

Does the timing jump around in tune with the vacuum changing? It could be a loose distributor shaft. Try opening the points wider than spec.
It sounds like a whistling sound when the vacuum changes. Check for a intake manifold leak.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
bowtiefan 
"11th Year" Gold Supporting Member
Posts: 2289
bowtiefan
Loc: Vacaville, CA
Reg: 02-19-04
10-29-18 12:12 PM - Post#2749905    
    In response to acardon

I had a similar problem. After trying everything I could think of, a friend suggested I check the gear on the bottom of the distributor. It was so loose that I could turn it half way to the next tooth. I put in an HEI ($130) and it has never run better. More power and easier to start.
Ken

36, 38 & 39 2dr sedan, 41 coupe, 54 convertible, 56 Nomad, 57 210 2dr sdn, 70 Camaro RS, Corvettes; 57, 61, 65 396 coupe, 67 427 convert, 72 T-top, 88 coupe,91 ZR-1, 07 Z06, 16 Z06, 07 Silverado, 09 BMW 135i vert.
http://www.picturetrail.com/ken


 
Alegm 
Poster
Posts: 25
Alegm
Reg: 01-05-13
10-29-18 06:38 PM - Post#2749947    
    In response to bowtiefan

today someone came with the idea that the jerking may be caused by "excess clearance in the rear gears"
is that possible??



 
acardon 
Ultra Senior Member
Posts: 11105
acardon
Loc: DFW TEXAS
Reg: 03-25-05
10-30-18 07:26 AM - Post#2749982    
    In response to Alegm

It's not likely the drive train, with the sound it's making while idling.

Don
66 Corvair (driving)
57 2dr HT (driving)
56 2dr HT (waiting to be restored)


 
Alegm 
Poster
Posts: 25
Alegm
Reg: 01-05-13
11-04-18 03:38 PM - Post#2750457    
    In response to acardon

thanks guys... i've bought a Langdons mini HEi set and the engine runs like crazy



 

Ecklers AutoMotive

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