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 Post subject: Slant six shut off shake
PostPosted: Fri Sep 14, 2018 1:18 pm 
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2 BBL ''SuperSix''

Joined: Thu Aug 16, 2018 12:05 pm
Posts: 19
Location: Rosemead
Car Model*: 1964 Dart 225/Super Six A833 3.55
For some reason my girlfriends slant six 225 when driving warmed up sometime when we turn off the car it shakes like a washer machine. The timing is correct it doesn't ping or anything what do you guys think?


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PostPosted: Fri Sep 14, 2018 5:54 pm 
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Location: Park Forest, Illinoisy
Car Model*: 68 Valiant
Idle speed too high?

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PostPosted: Mon Sep 17, 2018 1:22 pm 
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Joined: Fri Feb 29, 2008 10:49 pm
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Location: Salem, Oregon
Car Model*: 58 Plymouth Plaza 2dr, 63 Valiant Signet 200 2dr
Most likely the engine is "Dieseling" when you shut it off.

This is typically caused by a few things:

Timing set too far retarded.

Idle speed on the carburetor is set too high.

Engine running very hot/lean.

You say the timing is correct, can you explain how the setup is? Does the vacuum advance hose from the distributor go to ported vacuum on the carb? Did you set the timing with vacuum advance disconnected? Are you certain the harmonic balancer timing marks haven't slipped? There are a lot of variables which could affect the shut down, even though the engine appears to operate as intended otherwise.

~THOR~

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PostPosted: Mon Sep 17, 2018 10:31 pm 
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2 BBL ''SuperSix''

Joined: Thu Aug 16, 2018 12:05 pm
Posts: 19
Location: Rosemead
Car Model*: 1964 Dart 225/Super Six A833 3.55
slantzilla wrote:
Idle speed too high?

idles at 650 rpm


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PostPosted: Mon Sep 17, 2018 10:36 pm 
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2 BBL ''SuperSix''

Joined: Thu Aug 16, 2018 12:05 pm
Posts: 19
Location: Rosemead
Car Model*: 1964 Dart 225/Super Six A833 3.55
THOR wrote:
Most likely the engine is "Dieseling" when you shut it off.

This is typically caused by a few things:

Timing set too far retarded.

Idle speed on the carburetor is set too high.

Engine running very hot/lean.

You say the timing is correct, can you explain how the setup is? Does the vacuum advance hose from the distributor go to ported vacuum on the carb? Did you set the timing with vacuum advance disconnected? Are you certain the harmonic balancer timing marks haven't slipped? There are a lot of variables which could affect the shut down, even though the engine appears to operate as intended otherwise.

It has 9.1 compression, my timing is set at 9, the idle speed is at 650, my vaccum checked by a gauge at idle is about 17-18, im thinking my distributor is at fault like the weights are not closing and the advance is in at idle. Spark plugs are tan colored i was also going to change them to colder plugs. really stumped
~THOR~


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PostPosted: Tue Sep 18, 2018 1:03 am 
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EFI Slant 6
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Joined: Wed Oct 01, 2003 11:40 pm
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Location: Etowah, NC
Car Model*: 1974 Plymouth Duster
Dieseling can also occur from vacuum line leaks. If your vacuum hoses look old and have signs of cracking or hardness, might want to replace them.

Also might want to check for leaks around the intake gasket as well.

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PostPosted: Tue Sep 18, 2018 5:30 am 
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Location: North Georgia
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Dieseling used to be common in the late 70s to late 80s because of crummy gas quality. My D100 used to do it, and it was solved with a timing light and fixing the vacuum leak. In addition to looking for cracked or missing vacuum lines, your power brake booster and throttle shaft can also be a source.

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PostPosted: Tue Oct 02, 2018 11:37 pm 
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2 BBL ''SuperSix''

Joined: Thu Aug 16, 2018 12:05 pm
Posts: 19
Location: Rosemead
Car Model*: 1964 Dart 225/Super Six A833 3.55
Found the problem, i went from 7.9 compression ratio to 9.1. the problem was my timing i had to set it back and turn up the curb idle to even reach 650 rpms at idling. i had my dizzy recurved once i poped it back in Zrooom the idle was at 1000 rpms, i lowered the curb idle until it didnt touch. Now the run-on has completely stopped. i guess it is very important once you do one change to make sure you do others to balance.


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PostPosted: Wed Oct 03, 2018 10:01 am 
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Joined: Fri Feb 29, 2008 10:49 pm
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Location: Salem, Oregon
Car Model*: 58 Plymouth Plaza 2dr, 63 Valiant Signet 200 2dr
Glad you got it fixed.

~THOR~

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1958 Plymouth Plaza 2 door Club Sedan
1963 Plymouth Valiant Signet 2 door Hardtop

Find a better way to turn perfectly good fuel into noise; I dare ya.
VP - Cherry City Bombers Car Club
http://www.bomberscc.com


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PostPosted: Wed Oct 03, 2018 10:34 am 
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Excellent!

Lou

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