I got a plain jane 67 390 2bbl out of a full size car in a F250 4x4. I haul a lot of weight with this truck all the time. I know the engine is somewhat tired, never been apart. When ever i go up a hill it pings a bit. I have lately been running high octane fuel in it and it seems to help but it still pings a little. Does anyone know what the compression ratio is for this engine and what i can to to stop it from pinging?

Thanks
Jeff

 

I don't know the compressin ratio off the top of my head but the quickest thing you can do is check your timing and retard it to halt pre-detonation under load.

 

If I'm remembering rightly today, the compression would be 9 1/2 to 1. There was also a 'premium fuel 2 bbl' available in the mid 60s that had 10 to 1. Don't see too many of them out there though......You might want to back off on the initial timing a bit, or you can play with the vacuum advance. Are you running ported or full manifold on the dizzy ? DF

 

Carbon buildup in the combustion chambers increases the CR. These carbon deposite glow red hot and contribute to pre ignition and fuel detonation problems. Try this (cheap and kinda fun), run the engine at a fast idle and slowly pour a gallon of water down through the carburetor. Don't stall the engine! Then change the oil and filter and take it out and run it at least 20 miles at hi-way speeds. If it still rattles back off the timing a tad and re-test. The water/steam cleans the combustion chambers really well. I do this trick on all older hi-mile engines and the results are usually good! It is also a good idea to do this before you do an overhaul. Now here is one my Uncle Sonny told me about. Take the exhaust manifolds off, fire it up and rev it up pretty good and throw a handfull of pop corn down the carburetor. I've personally never tried this (I will someday), so if any out there try this let me know how it turns out.

 

Ever hear of hydrolock? Not pretty. A gallon of water down the intake? Are you kidding? Popcorn? Even funnier...

art k.

 

It's Hydrostatic lock! And the trick here is not letting the engine stall. The water business is a for real deal. The popcorn was a test! Altho you never know with my uncle.

 

All I can say is, DO NOT pour a gallon of water down the carburetor. Way too much. If you really want to try the water trick, put some in a windex squirt bottle (pure water only, do not mix with windex). Then, with the carb off, and the windex bottle set to spray (not stream), rev up the engine a little, enough for the throttle plates to not break up the spray of water, and squirt it in there, about 15 times should do it. Test drive, and repeat if necessary. Also, a bottle of STP fuel system cleaner in the next tank of gas might do something.

 

Hydrostatic lock, hydraulic lock, hydrolock... same things.

Still not a good idea. You might be able to use a mister/sprayer, but set to very fine mist. As mentioned by someone else here already...

If it really is carbon build up a couple of good high-RPM runs will help that. My '74 had a 360 in it when I got it and I took it apart at 120K miles after putting 60K on it myself. Didn't have ANY carbon in it - why? Because I beat the crap out of it, thats why!

ak

 

Hey I've used the water trick before, it's old school but really works! You should see the looks I get when they see me with the garden hose dribbling water down the running engine! Learned it from an old fart heavy line tech when I used to work at Ford. That's how he kept those big Lincolns from pinging themselves to death.

Barry

 

Instead of water I like to use cold injector cleaner. Has the same carbon busting effect but also clean a little. I pour it down the carb very slowly at about 2,500rpm. No need to ruin the wife's squirt bottle. I have seen chunks of carbon come out of an old toyota doing this.

 

There is NOTHING wrong with using water to clean the deposits off the inside of an engine..Again the trick is to not let it stall..Any of you guys ever have a head gasket let go ? ( I am not talking just FE's but engines in general) usually the cylender that is ''bad'' is the cleanest..I think there is a guy on this page that had a head gasket let go on his FE ..There are even pictures on his site of the engine torn down..and guess what ! Clean piston (s)!!! ..Give it a try it works ..By the way belive it or not but tranny fluid works also ...William..I havent heard of popcorn but I have heard of "nut shells" lol Its supposed to work quite well . I dont like the idea of "nut shells" in my exhaust ! lol ! The nut shell idea is in one of my Collage engines books .. I went and looked at my book ..The process is like this ..remove the intake then use the " carbon blaster " It uses shop air to blow crushed walnut shells into the intake side of the cylender head. (scary) The point of the walnut shells is that if any are left in the combustion chamber they will be burnt off . There is a outlet hose that goes into the spark plug hole. Interesting but not my idea of fun.. Nothing works better then some high quality h2o !!

 

OK, I got a funny one: Have someone standing near the tail pipe for this! spray brake cleaner full force down the carb at fast idle for a couple seconds. It turns the exhaust into a white smoke show. I don't need to with my Dodge, it has plenty of black fog readily availabe .

 

That reminds me of my buddies 79 ford. He had a problem when he hit the brakes the engine would start smoking and would run very rough. He was adding brake fluid all the time and couldn't figure out where it was going. Turn out it was filling his booster up and when he hit the brakes it would pump fluid into the vaccum hose.

 

DO NOT DO THAT! That white smoke is some kinda gas, probably pure chlorine. My friend was standing behind his '82 Mustang 5.0 when I was spraying trichlorethane (it's in brake cleaner) around the carb to find a vacuum leak. Spray, wait for white smoke. Found the carb gasket was leaking.

HOWEVER - my friend was standing behind the car at one point and got a SMALL whiff of the smoke. He was coughing so bad for over an hour, I wanted to take him to the emergency room.

You've basically made mustard gas doing that...

art k.

 

Not mustard gas. Mustard gas raises huge blisters wherever it touches you - skin, eyes, nasal passages, bronchial tubes, lungs. Nasty stuff.

Nasty, nasty stuff.