Gain extra benefits by becoming a Supporting Member Click here find out how!

Classic Performance Products Classic Industries
American Auto Wire
Danchuk Catalog
Hellwig Products IncPerformance Rod & CustomNu-Relics Power Windows



Username Post: Decarbonizing        (Topic#360360)
bajones238 
"8th Year" Gold Supporting Member
Posts: 426
bajones238
Loc: South Carolina
Reg: 06-19-11
04-01-20 01:26 PM - Post#2790015    

I am getting a good deal of spark rattle (pinging) when the engine is warm and under load. Experiments with timing have done little good: when I back timing off to the point the spark rattle diminishes, so does the power. I have started burning 110-octane race gas and that has helped but man that stuff is expensive.

What I need, I think, is what the British motorcycle manufacturers used to call "De-coking". Many years ago, Sunoco used to sell a product called Suntune which, when added to a running engine through the carburetor, would cause large clouds of black smoke to exit tailpipes, theoretically getting carbon off the tops of pistons.

I realize the right way to do this job is to pull the heads and (maybe) the pistons. I don't want to pull an engine apart that has been together since December 1964. Does anyone sell a consumer-lever "decarbonizing" product that actually does some good?

1953 3104 1/2 Ton Truck
1965 Impala SS 327/M20
1965 Chevelle SS 327/M20
VCCA #47487
AACA #446449
ALPCA #12906


 


Gaspains 
"6th Year" Gold Supporting Member
Posts: 358
Gaspains
Loc: Mankato, MN
Reg: 11-23-09
04-01-20 02:40 PM - Post#2790020    
    In response to bajones238

I'll probably get snickers on here from some, but Marvel Mystery Oil seems to help my fuel system and upper cylinders. Certainly makes the engine idle smoother and has helped my gas mileage whenever I use it. I keep complete fuel logs on my daily drivers.

Having said that, I don't know of any decoker. Although I did produce a lot of smoke the time I filled with diesel rather than gasoline. (And no, it wasn't from a farm tank... )

Kevin
1965 Impala SS Coupe
Regal Red with Black Interior
L74 327
M-20
3.31 Open, 12 bolt

65-66 FSCC #512
NIA #2832


 
aghaga 
"4th Year" Silver Supporting Member
Posts: 2259
aghaga
Age: 65
Loc: Altavista, Va.
Reg: 07-05-08
04-01-20 03:23 PM - Post#2790023    
    In response to bajones238

make sure your vacuum advance is connected to manifold vacuum



 
62sedan 
Very Senior Member
Posts: 4088

Age: 69
Loc: Above the red Texas dirt
Reg: 08-12-02
04-01-20 03:28 PM - Post#2790025    
    In response to aghaga

bajones238 - - - Have you looked at Sea Foam? Have heard it will do what you are looking at needing to remove deposits. May be worth looking at. Do a Google search.

Chuck






 
steve65 
"5th Year" Gold Supporting Member
Posts: 836
steve65
Age: 62
Loc: new westminster bc
Reg: 09-25-13
04-01-20 03:47 PM - Post#2790026    
    In response to bajones238

Way back in the day we used to take a Coke bottle full of plain water and slowly trickle it into the carb while holding the throttle open just enough to keep it from stalling out.
A whole lot of black carbon deposits would spit out the tail pipes during this, but it would run a little better afterwards.

Steve Duncan
66 Impala 2dr Coupe
Not sure of color yet
work in progress



 
Rick Dorion 
"6th Year" Gold Supporting Member
Posts: 274
Rick Dorion
Loc: Accord, NY
Reg: 09-21-12
04-02-20 02:23 AM - Post#2790059    
    In response to steve65

Second the water treatment. Use a spray bottle to better control the amount of water being injected.

1967 Belair - perfect floor, frame and pinchwelds. Oh boy.


 
Johnny468 
"12th Year" Silver Supporting Member
Posts: 812
Johnny468
Loc: Richmond, Va.
Reg: 10-24-08
04-02-20 06:44 AM - Post#2790077    
    In response to bajones238

I've had good success using GM top engine cleaner. I purchased it at my local GM dealer parts counter. You gradually pour it into the carb while the engine is running. You'll need to hold the throttle part way open to keep it from stalling.

Shut the engine off and let it sit for half an hour then restart. Massive clouds of black smoke will blow out of your tailpipes, which I assume is the dissolved carbon from your combustion chambers.

Hope this helps.

Johnny

1965 Impala SS
505/4-speed/3.90


 
bajones238 
"8th Year" Gold Supporting Member
Posts: 426
bajones238
Loc: South Carolina
Reg: 06-19-11
04-02-20 07:25 AM - Post#2790082    
    In response to Johnny468

Thanks for the great suggestions guys. I'll try the water first, then the Marvel, then the GM stuff if nothing else works and if I can find it. Will report back!

1953 3104 1/2 Ton Truck
1965 Impala SS 327/M20
1965 Chevelle SS 327/M20
VCCA #47487
AACA #446449
ALPCA #12906


 
Verne_Frantz 
Member #574 "61-64 Subject Matter Expert"
Posts: 5757
Verne_Frantz
Loc: Hightstown,NJ USA
Reg: 08-22-00
04-02-20 09:29 AM - Post#2790099    
    In response to bajones238

Sea Foam is a good idea. That's what it's formulated for, but you could also add a gallon of methanol to the tank. A methanol flame consumes carbon.

Verne



 
Oshawa65SS 
Contributor
Posts: 973

Age: 60
Loc: Burnaby BC Canada
Reg: 09-22-14
04-02-20 09:45 AM - Post#2790101    
    In response to bajones238

Way back almost 40 years ago I remember being at the local Mustang parts/cars for sale and restoration place where there was a rat bagged Super CJ '69 they were revving up while pouring ATF down the throat of the big Holley 4150.
Tons of smoke and crap belching out.
It was red with "for sale cheap" painted on the hood.
Not no more these days.

Ryan

65 Impala SS Evening Orchid convertible 283 2V with Powerglide and 10 bolt 3.08 open by PO, originally 3.36
Build date Dec. 21 '64 Oshawa


 
Texasray 
"4th Year" Gold Supporting Member
Posts: 112
Texasray
Loc: Texas
Reg: 11-01-16
04-02-20 10:55 AM - Post#2790110    
    In response to Oshawa65SS

Yeah, we use to pour ATF down the carb for 20 seconds or so during the '70's. It causes alot of smoke, but the cleaning action of the ATF is what was supposed to work. ATF is not the same anymore, so...? Another trick is to pull the spark plugs and soak each cylinder over night with AFT to loosen the carbon. One of my friends dad did this to his 6 cyl. Ford truck. It would stop the ping for about 6 months and he would do it again.
Be sure and rotate the cylinders slow with the spark plugs out to get all the liquid out the next morning, don't want any bent rods.
I would try the Marvel, then the GM top engine cleaner, but if you soak it I bet the Marvel oil would do the trick.

Sam



 
impala 
Frequent Contributor
Posts: 1289
impala
Loc: Pittsburgh, PA USA
Reg: 07-13-00
04-02-20 02:36 PM - Post#2790138    
    In response to bajones238

  • bajones238 Said:
Thanks for the great suggestions guys. I'll try the water first, then the Marvel, then the GM stuff if nothing else works and if I can find it. Will report back!


I would try the water first too because what you want to achieve is to create steam and what better way to do that than with water. An engine that has been run a while with a blown head gasket where coolant has gotten into a combustion chamber will do the job you're trying to do.
impala


61 Impala Convertible, AACA Senior Grand National
99 Jaguar, XK8
13 Avalanche LTZ
18 Equinox


 
docjns1 
Gold Supporting Member
Posts: 78
docjns1
Loc: upstate NY
Reg: 11-12-19
04-02-20 05:59 PM - Post#2790162    
    In response to impala

Years ago working at a Chevy dealer it was always the top engine cleaner you poured down the carb. If you can find it follow directions re: run thru 1/2 can then pour it in fast to choke & stall the engine. Important to let it sit ("hot soak"). Last time I looked all I could find was an aerosol spray form. Otherwise water is probably the best but ATF & Marvel both work well in that form/application. They all work much better than any of the in tank additives.

Steve
*********
'65 Impala SS, Crocus Yellow/blk
327 / 300 L74
M11 3 on the tree
12 bolt 3.31 open dif


 
pauldian 
Contributor
Posts: 313
pauldian
Loc: seligman,arizona
Reg: 05-14-09
04-06-20 08:58 PM - Post#2790531    
    In response to Gaspains

  • Gaspains Said:
I'll probably get snickers on here from some, but Marvel Mystery Oil seems to help my fuel system and upper cylinders. Certainly makes the engine idle smoother and has helped my gas mileage whenever I use it. I keep complete fuel logs on my daily drivers.

Having said that, I don't know of any decoker. Although I did produce a lot of smoke the time I filled with diesel rather than gasoline. (And no, it wasn't from a farm tank... )



This is what I've done in the past , I'm a big fan
of marvel mystery oil.




 


Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

391 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.125 seconds.   Total Queries: 16   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 06:38 AM
Top