I posted a few days ago that I was having problems getting my 65 240 6 banger to run as smoothly as I thought it should.
The engine has literally had everything replaced on it now, and after just a couple of days ago putting on a newly remanufactured distributor
it seem to help until the engine gets up to operating temperature. That's when it starts acting like it's starved for fuel or an ignition
short.
When it is cool, like early in the morning it runs
really smooth.
I've checked for vacuum leaks and found none.
Everything is set to factory specification. Does anyone have any ideas what may be causing this condition?

 

I have a 240 that I had given me problems as far as running smoothly. Your problem mightbe one of a few things (all of which you probable know already) 1 check the fuel filter and pump, even if it was replaced, it still can get pluged up or? 2 check the ignition timming and points, that was my problem 3 check the carb out.

But what I really think it is is the coil, if you have a spare one just try it to be sure, when a coil is on its way out they make the engine miss and sometimes die only after they get hot. I
hope this helps,
Mark-

 

Rather than indiscriminately swapping all new parts on....you should try to diagnose the trouble first. I know that is often easier said than done. You might want to check the compression just to get an idea of the overall condition of your engine. You should look for a large inconsistency between the six cylinders not so much what the actual readings may be. Low compression could signify rings or valves. You can also use a vacuum guage to take some readings. The vacuum method is a tremendous way to isolate problems. Chilton's manuals discuss the procedure. I hope this helps.

Stock Man
1967 Galaxie 500 Convertible (HELP!---I need 15 x5 factory rims)
1967 F-250 FE 390 4wd
1966 F-250 I6 240 2wd LWB Flare Side
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

Stock Man,
I have already did all of those things you suggested. Compression is all running 150 to 152
psi on all cylinders, tested for vacuum leaks and
adjusted the manifold vacuum to 17 inches of mercury per the factory service manual.
What ever is causing this condition is heat related because it only does it after is get up to
operating temperature.

 

The suggestion that your coil might be bad is a strong possibility. They will act intermittently sometimes and cut out when hot. Also ignition problems tend to mask themselves like a fuel problem. If you have ruled them out to a certainty then you must forge on. Explain what you did to adjust manifold vacuum? I was not suggesting you needed to adjust the vacuum rather you need to monitor it asa diagnosis tool. If you are not familiar with this let me know. I'll post some information on it. Also what kind of oil are you running? I have seen problems with hydraulic lifters going flat due to thin oil. It is usually a sign that the lifters are bad rather than the oil being thin but the hot oil tends to bring out the worse in a bad lifter. Let us hear from you.


Stock Man
1967 Galaxie 500 Convertible (HELP!---I need 15 x5 factory rims)
1967 F-250 FE 390 4wd
1966 F-250 I6 240 2wd LWB Flare Side
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

STOCKMAN,
I checked the manifold vacuum at the manifold directly below the carb. I had recently replaced the carb. and noticed the vacumm was running a bit
low and erratic. I could not get more than 17 inches of vacuum at stock idle of 550 rpm, but the vacuum is running smoother now. I've only monitored the vacuum sitting still, I don't have any way to do that while driving.
You may have hit on an idea though with the oil and the lifters. I am using Castrol SAE 30 and have recently added Slick 50. You don't suppose
the Slick 50 is making the lifters not pump up
enough after it gets hot?
Now that I think about it, I don't remember having that condition before using the Slick 50.
What do you think?

 

A steady reading of 17 in./Hg is indicative of an engine in "good" condition. You will need to leave that vacuuum gauage hooked up and observe it over the range of engine rpms. You can also bring the guage into yuor vehicle using a length of 1/4" air compressor hose. Just run it out the side of your hood and through the window. The diagnosis is made from how the needle reacts at different RPM's. You will have to get the truck hot and then see if your poor performance condition exists. Observe what the vacuum guage is doing when this is happening.

It's hard to say for sure whether the slick 50 additive is the cause of the problem. A straight weight oil however will be thick when cold and relatively thin when hot. You might try removing the valve cover and observing how well your upper end is getting oil while the truck is running. Careful it may be messy. I suspect that you will be in for a surprise. My engine was running excellent when I tore it down. Surprisingly it was only oiling on two of the twelve lifters. The lifters were quite worn when I took them apart. New ones are only $2 each and they can be changed without any major head-aches while the engine is in the truck. If your lifters are not functioning right your valves may not be opening as far or for the correct duration which will adverselty affect performance because the engine will not be breathing right.

You also mentioned that you recently replaced the carb. Was that a rebuilt or a used unit. Carburation is critical. There are many performance problems caused by so-called rebuilt carbs. There is a lot more rebuilding them than just putting a kit in. There is also the possibility that an incorrect carb is on there. Tell me more about your carb including the tag numbers. The only way to chase these problems down is to eliminate possible causes. Speaking of which--did you change that coil for a "known" good one to see if that helped?


Stock Man
1967 Galaxie 500 Convertible (HELP!---I need 15 x5 factory rims)
1967 F-250 FE 390 4wd
1966 F-250 I6 240 2wd LWB Flare Side
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

STOCK MAN,
I have put a new coil on when I replaced the distributor. The other coil may have been good but
I replaced it anyhow.
The carb is a remanufactured one. As a matter of
fact the third remanufactured one. The first 2
were no good.
The original carb had double pumps on it and the replacement carbs only has one.
I'm beginning to think remanufactured parts are not always the way to go.
The uppers are oiling fine. I also have just recently replaced the valve oil seals and notice oil was squirting clear over to the manifold. One thing I found out is that you can't adjust the valves to the factory manual specs. It won't run worth a flip if you do.
I'm not sure what the adjustment should be with
old lifters. I just went back and barely adjusted
the clicking sound out of them.

 

STOCK MAN,
Oh, by the way the remanufactured carbs don't have any tags on them.

 

Mark H,
Thanks for your input. I've already check and double check all those things you suggested.
It's always going to be something real simple,
you know what I mean?
I'm getting some real good advice from Stock Man.
There's just a lot of variables when you don't have all of the resources to check things out
properly. All of this just creates a challenge
to me and makes me more determined.

 

>One thing I
>found out is that you can't
>adjust the valves to the factory
>manual specs. It won't run worth
>a flip if you do. I'm
>not sure what the adjustment should
>be with old lifters. I just
>went back and barely adjusted the
>clicking sound out of them.

If you were not able to adjust the valve clearance using the shop manual's procedure then it sounds like the lifters mignt be bad. I'm not one to recommend changing parts for parts changing sake but sometimes you can't get by without it. Also it's hard to take a used motor and get new motor performance out of it. Sometimes it's just better to take a good block and start from scratch.

Stock Man
1967 Galaxie 500 Convertible (HELP!---I need 15 x5 factory rims)
1967 F-250 FE 390 4wd
1966 F-250 I6 240 2wd LWB Flare Side
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

I recently had a problem with my 79 300ci inline
six running rough. However, it ran rough all of the time, didnt' matter whether it was warm or not.
But, what I found it was a combination of problems (egr valve sticking, carb needed rebuilt, weak coil, and one wire breaking down) However, the most prevalent problem was my carburretor. It is a Carter YFA 1bbl, (piece o junk), and it needed rebuilding. I bought a rebuild kit and rebuilt the carb with the RIGHT parts. I had noticed that the carb showed signs of being worked on before inside by a possibly drunk (or close to it) mechanic. He had put in the wrong float, the wrong main jet seat, wrong main jet, and the metering rod was not set correctly. After rebuilding it with the correct parts, and setting the metering rod correctly, the engine was back to 95 percent, whereupon I replaced the coil and it runs as smooth as silk. You say the original carb was a double accelerator pump model? They most definitely could have given you the wrong carb. It sounds like you had an early Carter 1bbl on it and they gave you a later 70's vintage Carter YF, which has only one accelerator pump.... But in theory, since it only does the roughness when it is warm, it is probably not the carburretor. I would double check the timing, dwell, and the advance on the distributor before I did anything else.

 

Thanks for the input Mike Platt, any and all suggestions are wellcome. I've just about narrowed
the problem down to the lifters and or carb.
Most likely the lifters.
Hey StockMan,
Someone told me that I should only use a dwell meter reading to set points with hydrolic lifters,
and feeler guage with solid lifters. I know the
dwell meter reads 5 to 10 degrees different from
factory specs. if I use a feeler guage.
Have you heard this before?

 

The reason for the variation is usually irregular contact surfaces (especially with used points) or human error. Using a dwell meter is generally more accurate. However, it is difficult sometimes to get within the specified range. I am not aware of any reason why you would use one method as opposed to the other for hydraulic lifters since the dwell angle has nothing to do with the valve train. I think it's possible to over-tune an engine. I usually set mine by feeler guage and forget it.

Stock Man
1967 Galaxie 500 Convertible (HELP!---I need 15 x5 factory rims)
1967 F-250 FE 390 4wd
1966 F-250 I6 240 2wd LWB Flare Side
<a href="http://www.hometown.aol.com/tbeeee">http://www.hometown.aol.com/tbeeee</a>

 

It could be the jet in the Carb is too small. I had that on my 300 I-6. The problem was the lean mixture overheated the plug's and caused them to quit. Check one or two plugs for 'burnt blue tips' and if you got that, your mixture is too lean.
What about your fuel? Is it 90 days old?
When it's trying to die on you, Spray some fuel down the carb throat to see if revives. If the plugs will still fire, and the spray helps, it's indeed starving for fuel.
Keep the timing light and Vacuam gauge hooked up and see if your are losing spark or Vacuam.
A gasket could be leaking after it warm's up.
The coil is certainly suspect, or something in the circut to the coil. The coil is supposed to be runing through the Resister after it starts.If not the coil will heat up.
A friend bought a set of lifters and had several diffenent size lifters in the box. Do some carefull checking of the 'lift'of the cam.
Wish I could be there, #####