Two questions (170 engine)

-
62 Val

62 Val

Active Member
Joined
Dec 27, 2008
Messages
28
Reaction score
0
Location
Federal Way,WA
My bone stock 170 cu. in engine runs great and quiet up to approximately 45mph, and then has a louder resonating sound beyond that speed. By letting off the gas slightly and just feathering the throttle, the noise settles to a more tolerable roar...

Is this a sign of an exhaust restriction (have a new muffler installed) or is this just normal?

Question 2.
A short time after shutting off the (warm) engine, the garage has a strong gasoline smell which goes away after the engine cools (approx 45min-1hr.) Could this be caused by fuel in the carb boiling from the heat of the exhaust manifold sending vapors through the open air filter housing?

DSCN1539.jpg
 
Your right on with your 2nd question. If you dont want to stay original looking ,ie shows. Go to slantsix.org and look for FUEL LINE MOD this will keep the fuel from boiling out so bad. I need more info on the first question. Maybe a video with sound ???
Frank
 
I think you should redirect your fuel line,also you can use foam insulater on the line to keep fuel cool and away from heat.Give it a try and see how it works out for you.
 
Is the noise more of a drone? Like a strong bass note ( harmonic )?
What kind of muffler did you put under there? glasspack? :)
That can be caused by a tail pipe that stops under the car or exits out the side in front of the rear wheel or a unusually long run of larger diameter pipe under the car (greater than 16 in length and about 2.5-3 inches diameter)


I'd have to STRONGLY agree with the fuel line mod, I'm in FL and even during the "winter" months I had the boiling fuel problem. I'm even testing a heat shield under the carb to keep it from experiencing hot start issues

Two different symptoms are caused by fuel that is too hot:
1. Drivability problems caused by the fuel boiling on the way to the carb (usually in stop and go traffic)
1a. The fix is the fuel line mod (move the line away from the manifold)

2. Hot start/flooding is caused when the fuel boils in the carb after sitting for 5-15 minutes. sometimes accompanied by black or dark brown sludge appearing around the orifices and seams of the carb
2a. The fix is a heat shield between the carb and manifold and/or plastic carb spacer to keep the heat from the manifold from bleeding up to the float bowl. The fuel line mod helped this a little but did not completely remedy the issue for me.

I've done the fuel line mod and now the line is cool to the touch when running, but let it sit with the hood closed after a short trip...the float bowl will burn your fingers
 
Thanks,for your help, guys. Looks like maybe we'll have a couple of nice, dry days ahead. I'll do some experimenting and see what happens. As for that droning sound, it sounds and feels like it occurs foreward at the exhaust manifold or the junction to the exhaust pipe. The manifold and pipes are original, and the new muffler is a stock-like quiet design.

-Dan
 
Kinda sounds like the fuel level is too high....both symptoms runit hard one dark night and make sure the exhaust manifold isn't glowing red......sounds like you need a new float for the carb.......this is just an opinion
 
lol try putting clothes pins on the fuel line. just clip some on spaced out a little. it will cool the line some. this is an easy fix to vapor locking and if the fuel is getting to got it might help. its a lot easier then much else tho lol
 
Hey Waggin and Tyler,
You may be on to something..I am getting some fuel staining along the side of the carb at and below the air horn gasket...the carb was rebuilt less than 1,000 miles ago by a reputable carb shop. Maybe I'll run back down there and see what they think.
-BTW, what type of clothes pins did you have in mind? Don't think wooden ones would dissipate much heat...Now if i were to add a little wet laundry that might do the trick!



-Dan
 
i have actualy seen wooden ones work great. i was doubtfull at first to but it worked. when air blows by them they suck heat out. maby cut some ribs in them so they cool faster
 
Player 1 up
Is right on with the carb isolator after the fuel line mod. Do this and most if not all of your problems will disappear.
Frank
 
Well, I went to the "carb guy" today, and he said the float level should be OK since I dont get any hard starting when the engine is hot (which I don't, as the engine starts immediately without depressing the gas pedal at all). I'll keep looking for more clues and keep ya'll posted
-Dan
 
I have the same problem in my 63 dart with the fuel problem, so I will be trying a few of these ideas
thanks

As for the noise are you sure this isn't a driveline problem and not an engine problem?

Try this: run the car up to 45 mph or so and shut the engine off
it the noise persists then you probably need rear-end oil or need to replace a bearing somewhere.
 
wet laundry Lol
62 Val said:
Hey Waggin and Tyler,
You may be on to something..I am getting some fuel staining along the side of the carb at and below the air horn gasket...the carb was rebuilt less than 1,000 miles ago by a reputable carb shop. Maybe I'll run back down there and see what they think.
-BTW, what type of clothes pins did you have in mind? Don't think wooden ones would dissipate much heat...Now if i were to add a little wet laundry that might do the trick!



-Dan
Click to expand...
 
Well, we had a pretty nice day for a test drive today... I believe the noise is now almost definitely a sympathetic resonance within the exhaust system, It will still appear at approx. 45mph and will dissipate when throttle is let-off. I believe the noise occurs at a specific range of rpm. I can duplicate the noise with the engine in 2nd gear at a lower mph, and also in neutral at a specific rpm range.

OK, now what? Anything to do without replacing the entire exhaust system?
Turn radio volume up? Noise cancelling earphones?
 
Thanks for the pics J.R.! That was a great day until the rains came in the afternoon. Hope to see you at one of the local shows this year. Is there going to be a spring show in Bellevue/Issaquah this year?
 
You must log in or register to reply here.
-

Back
Top