Tired 390
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From: St. Libory
Tired 390
The 390 in my old 69 is getting pretty tired. It still has decent power (well for having a 2bbl anyway) but it only has about 7 pounds of oil pressure when it idles hot. I don't have a tach in it, but at 60 mph it goes up to around 30 psi (I have 3.54 gears and 9.50-16.5 tires if anyone wants to figure the RPM....I would but I don't really know how tall the tires are). I'm running 10w40 in it right now. Will it help to go to a thicker oil? If so, what is recommended? What else can I do to make it last besides staying off the loud pedal? Also, it kinda sputters around on the low end until it gets to about 170 degrees. What's the deal there? Carb or what? Thanks in advance
Jake
Jake
Last edited by jseim44; Apr 30, 2006 at 02:10 PM.
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From: Iowa
I dont think it's doing too bad. Run a 15w40 diesel rated oil in it. Most FE's I've seen have low oil pressure at hot idle. I think the rocker shafts get worn and a lot of pressure is lost there. I wouldn't lose any sleep over it as long as it's not burning oil.
The sputtering could be any number of things. First, since it's temperature related, look at your choke. Could be either too rich or too lean. Adjust away and find what works best.
Dont forget to look at your plugs, plug wires, cap, rotor, and points (if equipped). Changing those out can make a world of difference. You'll probably want to set the points with a Dwell meter. These are usually combined with a tachometer and called a Dwell-tach. You want to run about 26 to 28 degrees of dwell. After that, set the timing. Pull the vacuum advance line off the distributor, and plug it. Then, your engine will probably like ignition timing around 12 degrees BTDC. You might experiment with more or less to see what your engine likes the best. If you hear it ping though, back it off about 4 degrees and leave it there.
The sputtering could be any number of things. First, since it's temperature related, look at your choke. Could be either too rich or too lean. Adjust away and find what works best.
Dont forget to look at your plugs, plug wires, cap, rotor, and points (if equipped). Changing those out can make a world of difference. You'll probably want to set the points with a Dwell meter. These are usually combined with a tachometer and called a Dwell-tach. You want to run about 26 to 28 degrees of dwell. After that, set the timing. Pull the vacuum advance line off the distributor, and plug it. Then, your engine will probably like ignition timing around 12 degrees BTDC. You might experiment with more or less to see what your engine likes the best. If you hear it ping though, back it off about 4 degrees and leave it there.
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From: St. Libory
Thanks for the quick reply. I'll pick up a new filter and change the oil. 15w40 is the same that we run in the semi and the tractor, so we get that in 55 gallon drums!!! I don't think it burns oil, but it leaks from various places so bad it's kind of hard to tell on the dipstick. It does seem to burn clean out of the exhaust once it's at normal idle speed.
On the choke...if I keep it pulled out a little then it doesn't do it. So it would be too lean right? (I'm a little new to messin with carbs). I will mess with that some and see what I can figure out.
If I can't get it fixed by adjusting the choke, then I'll do the plugs, wires and all that good stuff. I may do it anyway since I'm sure it's been awhile.
Thanks for all the information, rusty
On the choke...if I keep it pulled out a little then it doesn't do it. So it would be too lean right? (I'm a little new to messin with carbs). I will mess with that some and see what I can figure out.
If I can't get it fixed by adjusting the choke, then I'll do the plugs, wires and all that good stuff. I may do it anyway since I'm sure it's been awhile.
Thanks for all the information, rusty
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From: Charlotte
On the carb, screw the idle adjustment screws all the way in (clockwise) then back out 2 1/2 turns. That should get you ballpark.
Correct way to do it would be like Rusty had said above. Check all plugs, wires, etc. If good, then fire it up, adjust timing to 12 deg (any more than that and you may start running hot) then adjust carb again. You might want to look into doing a upgrade to a Pertronix-like ignition, Crane also has them. Easy to install and much more dependable than points. Or you can do the Duraspark upgrade. A little harder but not much. You can go to a pick and pull/junkyard and often find them in old trucks for as little as 20 bucks. That will help alot. Just my 2
Correct way to do it would be like Rusty had said above. Check all plugs, wires, etc. If good, then fire it up, adjust timing to 12 deg (any more than that and you may start running hot) then adjust carb again. You might want to look into doing a upgrade to a Pertronix-like ignition, Crane also has them. Easy to install and much more dependable than points. Or you can do the Duraspark upgrade. A little harder but not much. You can go to a pick and pull/junkyard and often find them in old trucks for as little as 20 bucks. That will help alot. Just my 2
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From: St. Libory
Well when I hooked the timing light/tach (one of the fancy ones) up to it today I noticed it was only idleing at about 500 rpm. I kicked it up to around 750 and low and behold......I doubled my oil pressure!!! It also seemed to help some with my sputtering problem. It's not completely eliminated, but that did help. I will look at plugs, etc when I get more time.
