With an entire summer of work performed on my '49 F-2 to get it running and here to where I now live in Columbus, IN, one of the tests I wanted to do on the engine never got done. The compression test.

To bring folks up to speed on the truck, it has a 239 flatmotor that had sat for almost 14 years without ever being started, much less moved. Owned by me for around 30 years, I rebuilt the enging around 22 years ago. At that time, I had two cracks stitched up and two bores sleeved, the block tanked, crank and cam mag'ed and polished, bored .030" over, new pistons, adjustable lifters, valves ground, NOS heads and carb, plus various and sundry other things. There was only about 20K miles on the motor when I parked the vehicle. In June, when I decided to resurrect the truck, I determined that the block was apparently not cracked (oil was dirty, but at the correct level, and coolant was low, but clean). Furthermore, although the engine was stiff, it wasn't seized.

After changing the oil and filter, battery, plugs, cap, rotor, etc., etc., I cranked to engine for a significant amount of time to bring up oil pressure. Only after being satisfied that oil was distributed throughout the motor, did I fire her up. Oil pressure was good by the dash gauge, and the engine idled reasonbly well, though rough. As I worked on various issues on the truck over the summer, I would run the engine occasionally to help loosen it up, and address performance problems as they arose.

On September 29th, I made the big move and drove Gertie the 48 miles to Columbus. Although the idle and running of the engine was still somewhat rough, the trip was uneventful except for the four times I had to pull over and clear the fuel line at the tank valve (kept getting plugged with hard chunks of varnish from inside the tank). Since that day, I have driven the truck back and forth to work, continuing to work on issues such as getting the horn to operate, installing exhaust manifolds, etc. All the while, the engine has ran better with every start.

That last two or three weeks have seen the engine stabilize. Now, the motor fires after the first crank of the starter and runs well (when cold, half choke and two pumps on the accelerator pedal), albeit a little rough until it warms up. Oil pressure is good.

Yesterday, I finally got around to doing a compression test to allay my fears that there may be some damage to the rings, bores, or valves from sitting for such an extended time. I have put a little over 500 miles on the vehicle since resurrection, so I figure that if there are mechanical problems, they should show up by now.

Was much relieved by the results of the test. Ford states in their Service Manual that the 49-50 239 should produce 110PSI @ 60 RPM (full battery cranking speed).

The results from my test were as follows (cold block, dry cylinders, all plugs removed, maximum reading):

1. 120
2. 110
3. 110
4. 113
5. 112
6. 117
7. 117
8. 118

I am quite pleased. The higher numbers I suspect are from carbon build-up, and are most likely attributable to the slow speed, short trip driving the truck has experienced lately. The plugs all looked about the same, with a tan color around the electrodes and porcelain, and a light coating of carbon down inside the body.

I am still not entirely pleased with the performance though. It seems to me that the idle could be smoother, and under power it should be a little more even. When at operating temp., engine vacuum is at a relatively stable 20 inches, with occasional, erratic fluctuations of less than an inch. I suspect there may still be some issue with the carb. (threw a kit at it a couple months ago), and I really ought to rebuild the distributor and have it strobed.

Still, I really lucked out. Leaving the truck to the elements for such a long time should, by rights, have left me with a real basket case.

As an aside, what compression test readings do others here on the forum get from their flatties?

J.D.

 

I'd say you are golden with those numbers! Especially since I assume you are still 6v, with resulting low cranking speeds?

I am at high altitude (5300') which affects compression readings, so they aren't directly comparable:
88-85-88-90-85-88-90-90

From sitting so long, your valves could be a little sticky, so just regular use may reduce the roughness at idle. Adding a little SeaFoam to the gas and oil can't hurt, but just regular running at operating temps with good clean oil will likely do the trick. Have you cleaned the carb thoroughly?

 

Howdy there Ross.

Yeah, she is still 6 volt. Cranks good though, since I replaced both battery cables, new battery, etc.

Ran two cans of Seafoam through the gas tank. Really was surprised at how well it cleaned the tank, and improved the operation of the engine. Completely eradicated the "plugged tank valve-remove valve and blow out-get drowned in gasoline" problem.

Regarding the carb., I took the thing completely apart and soaked it in Gumout cleaner (the nasty tank type that eats flesh from your bones). The kit I chucked into it was a Sorenson. Was not real happy with it, as the valves (economizer, etc.) were not exactly like the originals. Been thinking of doing a little research, and getting a better kit. Saw somewhere an article concerning the differences between kits, the failings of some, and the prefered brands.

J.D.

 

You are getting over 100psi with less than a 10% spread , that's awesome for the old girl . If you have any starting or running issues look to you're fuel and electrical systems .

 

The Sorenson kits aren't bad other than they usually have the 2110-style (late model) power valve. Check to make sure the PV isn't preventing the throttle plate section from fully seating on the main body (too tall). But with your vacuum readings, it doesn't sound like it is. Nothing in the late-style kit would affect idle, as long as the PV isn't leaking by. Personally I have found that occasional misses/pops at idle are typical with points.

I'd be curious if you are getting vacuum advance at idle? (any vacuum in the line to the distributor at idle)

 

Thanks Allan. You can bet I was happy.

Ross: There are still some things I need to check. As far as vacuum advance, I am not sure it is working properly. Some d**khead several years ago stole my MAC tools vacuum pump with gauge, so I have not checked the advance diaphragm. Have not check the ported vacuum from the carb. either (yet).

The truck has a pronounced hesitation when cold that gradually improves as the engine warms, but even at full temperature, never completely goes away. The hesitation, combined with the light black on the plugs, and lousy fuel economy (it has always been lousy, courtesy of the low gearing: around 10.5 mpg) which I estimate is around 8 mpg (been doing a lot of idling, between warm-ups, and tweaking, so am not really sure), I suspect fuel issues. However, given that the advance diaphragm is the original unit, I certainly can't rule it out as being contributory.

Regarding the occasional misses, I know you are probably right. Frankly, I don't ever remember the truck running "dead smooth". Although I didn't use a tach and vacuum gauge, I did tweak a little on the idle jets last night, and was able to improve the idle markedly. I had adjusted them initially just before I drove the truck home to Columbus, and had not messed with them since.

J.D.

 

Just to clarify, I don't know if vacuum should be present at idle with the stock system. My carb doesn't have any vacuum at idle, but it seems like it should. I now have an MSD distributor and use manifold vacuum for the advance, with mechanical advance in the dizzy. It gives about 8 deg of vac advance at idle, which changed it from an absolutely dead-smooth idle to one that has the typical points-like occasional miss and pop. Overall, it runs just great, no complaints.

 

Just got through with checking operation of the vacuum advance with the timing light (kind of a pain, as the light is 12 volt, and I have to park my Jeep in front of the truck to power it). Since I do not have the degrees marked upon the pulley, it is anyone's guess how much advance there is. That said, when the rpm is increased, the mark moves smoothly, and apparently as it should. Although this simple check is not completely conclusive, it does show the advance diaphragm doesn't have a massive split in it.

I also ran a vacuum check at the manifold, and the needle is steady at 20 inches. I also went ahead and carefully adjusted the idle screws again. Doesn't run bad at all, actually slightly better than it did, but still has the hesitation. Also noticed that at higher rpms, the vacuum reading settled at a lower number, around 18 inches but stilll steady.

I am thinking more and more that the carb. isn't quite right.

Or.... I am being seriously ****. Probably where my fuel economy is going, dinking with settings all the time. Oh well.

J.D.

 

20" of vac sounds like the holy grail to me. If I ever get the 53 there I guess I will throw a party. It sounds like you are keeping her pretty stock. I'm not sure what the mileage was when new on these things. the flat f100 was advertised at 14mpg. I've heard of fellows getting in the low 20's but not stock. Modern carbs and distributors etc.

 

She is pretty much bone stock bk53, except for the .030" overbore and the adjustable lifters (which need adjusting I might add, a little noisy).

Mileage was always terrible for Gertie. After the rebuild, and the subsequent break-in period, she never got much above 10 mpg.

This past week, I filled her up, ran it for a few days, then filled it up again. The calculation came to about 6.5 mpg. OUCH! When I drove it from Bartlettsville (where she sat all these years) to Columbus, I figure the mileage at around 9.5.

Like I said, I think I have been idling too long for warm-ups, and spending too much time fiddling with it in the drive and garage. It doesn't help that the drive to work is only about 4 miles through city streets. Truck really can't get good and up to proper temerature.

J.D.

 

I've found it makes a big difference is gas usage to use higher-temp thermostats, and not block the heat riser in the manifold. (You didn't put pennies in the risers, did you?) I don't think the 94's atomize well, and the heat helps. Even in the summer my carb's base gets ice cold after a few minutes' running.

What jets are you running? #51 or #52 is stock.

 

No pennies in the riser Ross. I am running 160's at the moment. Regarding the thermostats, you are quite right about it screwing economy. It also makes for a cold natured engine to boot. I was going to go with the hotter 'stats, but have such a fear of overheating (not well founded, I know. Block is clean, radiator good, etc.). May go ahead and get the hotter 'stats in the next week or so.

As for the carb., it is a Holley 2100, and I have no idea what jets are in it.

J.D.

 

I used to run a 2100 (really a ECG-2110), with 1-1/16 bores. I had to jack up the accel pump a notch because of the greater airflow of the bigger throttle section. You may want to drop the PV to a 5.5" also. At sea level I would guess your jets should be around #54, but it's just a guess.

 

I assume by "jacking up the pump a notch" you mean moving the rod to the next, in my case, "winter" setting?

J.D.

 

Yes, exactly