Very Low Compression 8BA - No Fire

[Eagle43]

I'm still struggling with the 8BA flathead in my 1952 F1. When I worked on this motor originally I stitched 2 cracks between exhaust valve and cylinder wall on #2 and #3. I replaced the hardened valve seats. Last year I finished the restoration and it ran fine last fall. This spring it started to misfire on the first run to a club meeting. Eventually I discovered that the insert on #2 had popped out. I replaced the insert and valve. I shared this experience in https://www.fordbarn.com/forum/showt...hlight=Eagle43
It ran fine again on our last club fall tour but #2 wasn't doing much. I decided to try to fix this before putting the truck away for the winter. I took off the right head and the intake and found that the insert was loose again. This time I put in some shim stock and the glue and again ground and lapped the valve. Since the left head had a small crack next to the spark plug hole #6 and was weeping, I replace both heads with a good ones. I also replaced the head gaskets.

I have everything back together and the engine won't fire no matter what I do. It has good spark, the timing is on the mark, it has gas squirting in the carburetor. I checked compression and all of them are very low. Blowing compressed air into the spark plug holes shows air escaping out of the oil filler. For some reason the rings aren't sealing enough to fire. All of the cylinders except #2 had around 60 - 70 pounds before I took things apart and the truck had lots of zip and no blue smoke. I squirted oil in the cylinders and it makes no difference.

Anyone have any ideas as to what I can do to get this thing running? My frustration level is pretty high and I'm looking for a different engine.

[tubman]

I would suspect the last thing you changed; the heads. I'd take them off and compare them with the ones you took off.

[Eagle43]

I checked that. I put the old heads back on and there was no improvement. I checked the left bank with Plastiguage at various places on the deck and they all squeezed out at 0.001 torqued at 45 pounds without a gasket. The heads are identical to the old ones except the left one doesn't have the extra bolt holes for the oil filter.

[ford38v8]

Did you check your timing gear?

[Eagle43]

I have not taken the timing gear cover off. It would be a lot of work and I can't see where that would be the problem since TDC on #1 lines up with the timing mark on the pulley. I did have the distributer out but I think I have it back in correctly. The rotor lines up with #1 wire when the timing mark shows TDC and the piston is on top and the valves are both closed.

[Mart]

Sponsored Links (Register now to hide all advertisements)

Are the valves in No.1 closed or just at the point of "rocking"? Are they both closed for 1/4 turn either side of TDC? If No.1 is closed you should be able to observe No.6 valves "rocking" as you move either side of TDC. Just a sanity check for whether you are really firing on No.1 or not.

[Eagle43]

Thanks, but since I have the heads and the intake back on, I can't really check and torquing head bolts while the motor is in the truck and leaning over fat fenders at my age is no fun so I don't really want to take the heads off again. I should point out that nothing involving the timing or the valves have been changed since it ran fine on 7 cylinders before I opened it up except for the exhaust valve on #2. I think I have it narrowed down to the rings not sealing enough to get the cylinders to fire. I base that conclusion on the fact that air blown into any cylinder via a spark plug hole comes out of the oil filler tube and not the carburetor.

[cas3]

I have a test stand for motors, and every time I buy one that is loose I like to run it to see what I bought and splash some oil around to preserve it. I've had motors that run pretty darn good on the stand with compression figures like you have. Perhaps not ideal, but they run.

It seems you have done all the proper tests, its odd that even squirting oil in does not seal the rings up enough to fire up. sorry...I have no advice

[Mart]

You can observe the valves with the heads on by looking down the spark plug holes. The one that is easy to see is the exhaust valve.
If the engine ran ok before it will run ok now. It can't lose compression overnight. Something you have done has caused the non run condition. Ignition is the number one culprit if it has been disturbed in any way.

[chap52]

OK, I confess that I once installed my distributor 180 degrees out of position. Had the same symptoms. There now I feel better about telling everyone. Thanks for being there for me... Chap

[Eagle43]

Success at last. I again checked everything - the valves on #1 and #6, 180 degree distributor error. Everything checked out. I gave each spark plug hole a good squirt of 600 gear oil. I squirted lots of starter fluid into the carb and hit it with my 1200 amp jump starter. This little device really spins the motor but only for a couple of seconds. It was really blowing out of the oil filler but after a number of tries it finally fired and ran normally. It died after a few minutes and I discovered that the fuel pump was not working. Taking the fuel pump off and on has got to be one of the worst jobs but I persevered and it's all good. The little cup on the lever was bent and not holding on to the shaft. Many thanks to those who responded with helpful advice.

Just a comment on these neat little jump starters that came on the market a few years ago. Once you get one you wonder how you ever did without it. No more booster cables and another vehicle needed. Although mine is designed for 12 volts I found that it can be made to work with 6 Volts without the need for a helper. I attached a short piece of wire to the starter solenoid. That way I can touch the end to the positive terminal and run the started from under the hood. To use the jump starter I attach the negative cable to the negative post, touch the wire to the positive post to run the starter and then touch the positive cable to the positive terminal. Usually it kicks in. It has to be almost fully charged and needs a rest between tries. Of course if you have a helper you can sit in the cab and run the starter while your helper makes the connections under the hood once the engine is turning over. For 12 Volts it's really easy - connect the terminals and hit the starter.

[ford38v8]

Don’t need all that stuff. Get it rolling out your garage in 1st or 2nd gear pop the clutch and if it’s going to run at all, that’s all you need. Your neat little jump starter can do damage to your 6v Ford in ways you wouldn’t have thought of. First 3 on that list would be the Bendix, then the ring gear, followed by the starter motor itself. Do your old Ford a favor and save that jumper for your modern car.

[GB SISSON]

Edit: That's what I get for writing a dime store novel on the subject. He already fixed it.... D'oh

[Eagle43]

Originally Posted by ford38v8

Don’t need all that stuff. Get it rolling out your garage in 1st or 2nd gear pop the clutch and if it’s going to run at all, that’s all you need.

That might have worked if the driveway and roads weren't covered with ice and snow. The rear wheels would have just skidded and then I'd have the fun of pushing the truck back uphill into the heated garage when it's freezing cold outside.

[tubman]

Actually, it's good to hear that they work. I just bought one (mainly to pump up my bicycle tires) and can't believe that there is that much power in such a small package. (My confidence in the device was further eroded when I realized that it was charged by my USB phone charger.)

After hearing this, I may even consider (shudder) an electric car.

[Eagle43]

Originally Posted by ford38v8

Your neat little jump starter can do damage to your 6v Ford in ways you wouldn’t have thought of. First 3 on that list would be the Bendix, then the ring gear, followed by the starter motor itself. Do your old Ford a favor and save that jumper for your modern car.

Whatever works for you is great and nobody can tell you what to buy or not to buy. There are risks no matter what method you use to boost start your antique. Boosting with your modern 12 volt is hard on your bendix, ring gear, etc. not to mention the risk of damaging the sensitive electronics in your modern. Your antique rarely stalls on top of a hill but usually at a red light in rush hour traffic on an upslope so you can't roll to start. Pulling or pushing your antique with another vehicle can cause damage to either one or both vehicles. I've seen people get hurt trying to help push start a friend's vehicle. Even cranking to start can do damage to your body if not done correctly or if you're old like me. There is no provision for a crank on my truck.

All things considered, unless I'm missing something, my method with my little jump starter is pretty safe. The motor starts cranking over with the regular 6 volt battery and then gets a 3 second power boost which turns the motor over really fast so it starts. Most damage to the bendix, ring gear, etc. happens when the regular starter kicks in as normal. The power surge from the jump starter is unlikely to do any damage to the starter motor wiring since they are probably as heavy or heavier than the connecting leads from the jump starter. Use your own judgement but it works for me and has saved my bacon a few times already.

[ford38v8]

I had a small financial stake in a 40 coupe while in high school. It was used for transportation to and from school during the week, and at the drags on the weekends. This little coupe had no starter motor, no upholstery, no fenders, a full race flat motor with magneto and a quick change. Sadly, I was never able to witness any runs on the weekends due to my being a newspaper carrier for the Oakland Tribune. That engine with straight pipes attracted every kid in school to witness the after school push start by whoever was fortunate enough to participate! Those were the days!

[GB SISSON]

Originally Posted by ford38v8

I had a small financial stake in a 40 coupe while in high school. It was used for transportation to and from school during the week, and at the drags on the weekends. This little coupe had no starter motor, no upholstery, no fenders, a full race flat motor with magneto and a quick change. Sadly, I was never able to witness any runs on the weekends due to my being a newspaper carrier for the Oakland Tribune. That engine with straight pipes attracted every kid in school to witness the after school push start by whoever was fortunate enough to participate! Those were the days!

Alan, there you go, painting pictures again. Nice one too.