backfire through the carb.

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siuauto

siuauto

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Hello all, I hope some of you can help direct me down the right path. I pulled my duster out of the gurage today and washed the car. After I was done I put some gas in it. I put 100 ocatine in for the first time. after I started it up. It started poping though the carb pretty bad. I shut the car off and drained all the gas out and put regular gas back in it. The engine is still doing it. I aslo saw when it was running the upper raditor hose was collapsed. Are these problem connected? Could it be a blown head gasket or did a cam lobe get wipped. The engine is hot now, but I am guessing I should do a compression test. I have adjustable rockers and I just adjusted them but I ran the car after that and it didn't make the noise. any help would be appriciated.
 
check your plug wires....

you may have adjusted a rocker too tight and the valve is hanging open....more likely an intake valve...a compression test would point out which one it is.
 
Is it possible water got in the distributor cap when you washed it? That's the first thing I'd look at. The radiator hose collapsing is a different problem. It's generally caused from the overflow being blocked.

BTW: Why did you put 100 octane in it? Is it a real high compression engine? If it's not you just wasted alot of money because the higher octane fuel is the slower it burns so if you use it in a engine that doesn't need it it actually can lessen the power output.
 
I know I don't need the octain but I was taking it to a cruise night and many of us use it for the great smell. I know that it burns slower but I didn't think it would couse any issues. I don't think I will make that mistake again. It has been a day now and I am going to go out and start it again to see what happens. If it was water in the cap that should be dry.

Can someone tell me the symptoms of a warn cam lobe. The reason I was thinking that is I just learned all about the zink phosphate but have been only using regular oil. I am just worried I ruined the cam. It has only been in there a few hundred miles/
 
Yea, I can tell you about a worn out cam lobe, the engine will tap tap tap. Then, you will start to get metal in the oil. If it's backfiring through the carb, you likely have an ignition problem.
 
siuauto said:
I know I don't need the octain but I was taking it to a cruise night and many of us use it for the great smell. I know that it burns slower but I didn't think it would couse any issues. I don't think I will make that mistake again. It has been a day now and I am going to go out and start it again to see what happens. If it was water in the cap that should be dry.

Can someone tell me the symptoms of a warn cam lobe. The reason I was thinking that is I just learned all about the zink phosphate but have been only using regular oil. I am just worried I ruined the cam. It has only been in there a few hundred miles/
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Gotcha on the smell. Can't you just add the smell to regular gas though? I think Jegs and Summit sells cans of it. Alot of speed shops sell it too. Just running high octane won't cause an engine to backfire or do any damage. It just lowers the perf. on a low comp. engine. Actually the dist. cap may not dry out if water got in it unless it's a vented type. Even then it may take several days to dry out. You probably need to take it off and dry it out with clean paper towels. Like Dano said if you lost a cam lobe it'd also have a loud tapping sound. Hope that's not the case. What oil have you been running?
 
A number of years ago, way to many to give you an exact number, my 1965 Barracuda started dumping water, internally, because of a compromised manifold gasket due to improper installation of the foam gaskets on top of the block between the heads. That alone was a lesson to me.

Well, I was about 100 miles from home, and had no money for towing, so decided to drive it home, with water in the oil. Made it to about 18 miles from home, stopped for more water, and a tank of fuel, engine sounded relatively normal, as soon as I put it under load to pull out, it started shooting flames up thru the carb. At idle, it just ticked some, but under power, any power at all, it shot flames.

Well, shut'er down, called my Dad, he came, used his AAA card to get me towed home. Next morning, flew out and back to Biloxi Miss. as I had to be on base(USAF) the next day.

Came back home 3 months later, charged battery, fired the beast up, same symptom, ticking, then popping thru carb under power. Pulled valve covers and started it, #2 intake valve rocker arm not moving, at all. Yanked motor, tore down, lobe rounded, big groove cut in bottom of lifter. Did complete rebuild after that.

FF
 
I would look at something that you did recently like "adjust the valves". You might check over that again. Bad wire, fouled plug, timing way too advanced, moisture, it could be a number of things but usually you can trace things back to something that you changed or did differently. In addition, with the collapsed hose you might check your thermostat to see if it`s opening. Good luck, let us know what you find.
 
Thermostat is stuck closed if the top hose is collapsing because the pump pulls through the bottom hose and pushes out the top hose.
But check cyl pressure
 
Well after I did a compression test #5 cylinder was only at 50psi while all the other cylinders were at 105psi. I went to back off the adjuster on that rocker arm when I noticed it was in two pieces. When you look at the two halves you can see how porous the metal is. It looks like pot metal or something. Anyway I am going to order a new one or maybe upgrade adjusters or maybe a whole new rocker set. The one I have are proform and I have heard nothing but bad things.
Do any of you run a vodoo cam the one that is 513 lift. if so are any of you using your stock rocker arms.
THe other problem I was having was the upper rad hose. I do have a pluged overflow. Well at least that is an easy fix.
 
siuauto said:
Well after I did a compression test #5 cylinder was only at 50psi while all the other cylinders were at 105psi. I went to back off the adjuster on that rocker arm when I noticed it was in two pieces. When you look at the two halves you can see how porous the metal is. It looks like pot metal or something. Anyway I am going to order a new one or maybe upgrade adjusters or maybe a whole new rocker set. The one I have are proform and I have heard nothing but bad things.
Do any of you run a vodoo cam the one that is 513 lift. if so are any of you using your stock rocker arms.
THe other problem I was having was the upper rad hose. I do have a pluged overflow. Well at least that is an easy fix.
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I guess that`s good news and bad news but at least you`ve found the problem. There`s been a lot of trouble with those adjusters. There`s a new adjuster being made that is a softer alloy (less brittle) with a smaller sized Allen wrench hole in order to provide more material at the base of the adjuster hole and reduce breakage. You might try to contact Proform and see if they have the "new improved" adjusters in stock. They may provide an entire set free of charge.
 
This has been the achilles heel for most of the after market more affordable rockers, while the rockers are probably plenty strong for what you're doing, the adjusters are garbage.
I bought a set of off brand needle bearing rockers and the 1st thing the sales person said to do was change the adjusters and make sure to use the right shafts, having done all that I have a reliable trouble free set of rockers.
 
sinauto I'm running the Lunati Voodoo 60404 which has .513 intake lift. I'm running stock type rockers but their the Mopar HD units. No trouble in 4000 miles.
 
cool thanks. How do you like that cam. I have heard a lot of good things about it. I am running a eddie performer RPM now. I like the cam but it requires an adjustable valvetrain and I don't like that. To me that is chevy stuff. I would like to go to an non adjustable set up like it used to have. It is one less thing to worry about.
 
I like it alot and contrary to what is said it may not need an adjustable valve train. Mine is fine with stamped steel arms. You just gotta check the lifter pre-load to make sure it's ok. If so your good to go. BTW: Last tuesday night T&T I ran mine for the first time since I put 3:55 gears in it. The gears really dropped the perf. from what it was like when it had 4:10's but it still ran a 13.61 at 102. But the 3:55's are tons better cruising gears and we do alot of cruising. The night I took it to the track was a screwed up deal. They had super stock cars there and were letting them run 4-5 times to our 1. I got there and tech'd in at 5:55 and my first run was at 9:08. Even after all that idling and running it I checked the fuel mileage and got 12.8 mpg. It'll easily get 15-16 mpg (normal cruising) and runs mid 13's with iron heads and can idle in traffic for hrs. with no trouble.
 
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