Hello folks.

I have a 51 F2 with a 226 h flathead. She runs and drives but I just can not get it to run well. Idle is terrible and she falls on her face when you first give her gas. Runs smoother at higher RPMs (1000+). Carb was just rebuilt. Plugs, cap and rotor just replaced. Running a Pertronix electronic ignition module. Replaced the vacuum line from the carb to the distributor. The rough idle and extremely poor throttle response make the crash box transmission near impossible to use. And ideas on where I go from here would be greatly appreciated.

Thanks
Phillippio
51


F2

 

Have you checked the coil? Is the coil the correct one for the Pertronix ignition?

 

Also did you test the vacuum advance can? The distributor advance is totally vacuum controlled

 

Check compression. I just went through something similar with the 226 in my '49 F-2. I had low compression for a long time but year before last it started spitting and popping. I did everything you did, rebuilt the carb, complete tune-up with all new parts. Finally pulled the head off and found the rear exhaust valve was burnt. The engine was old and tired so I ended up rebuilding another 226 I had in my shop. Took it for it's first test drive last night and it was a world of difference.

 

Did it start before the Pertronix install, or did you try that because it was running poorly on points?

What condition are the fuel lines and fuel pump in? If fuel lines are original or an unknown entity, make sure they are clear and pump is pumping/not clogged. Who rebuilt the carb? Accelerator pump is definitely the correct one for that carb? Choke is not sticking?

Definitely check vacuum mechanism in the dizzy is working (as simple as sucking on the vacuum line with the dizzy cap off to see if it moves).

For ignition: What module did you put in there? What electrical system are you running? From the pic, I'm going to assume it's a 12V positive ground conversion. Have you checked the voltage going to the pertronix/coil? Is it getting full voltage while it's running? They can get wonky if you are getting voltage variations in what is being supplied to it. As asked above, that coil is for THAT module/ignition system? Is it hard to start along with poor idle? Maybe the electrical system is weak and the voltage to the ignition system is low until the alternator starts spinning faster (above 1K RPM)?

Have you checked the new plugs again to see if they are fouled from weak ignition (black and sooty)?

Any smoke when it's running rough? If so, what color is it and what does it smell like (ie: not running too rich)?

 

One more thing Ive noticed, On my 226 with petronix ignition and flamethrower coil. The choke has a sweet spot where it runs great when it is warm. If its a little off runs rough.

 

Sorry for the slow reply everyone, I am on a work trip so I am limited on resources. I really appreciate all the advice.

Hello abe
The coil is a flame thrower that was matched to the pertronix ignition. However, that does not mean it is good. I will through a ohm meter on it when I return home on Friday.

Hi tinman52, I will have to test the vacuum with my gauge and also check the advance mechanism when I get home. I replaced the vacuum hard line and tested for leaks with the old spray a flammable cleaner around the carb and all vacuum lines.

Hello ReForder, the poor old girl was left unattended for quite a while since I put in the pertronix. I know it was still rough back then but the carb was junk. I have since replaced the carb with a new freshly rebuilt carb. Maybe I can through some points and a resistor in there quick and just try it.
The fuel lines are all new as well as the fuel pump, gas tank, fuel and filters. And a click-clack set up below the tank. It pumps a lot of fuel at low pressure. Choke is free.

I will test the vacuum mechanism as soon as I can. I did test the diaphragm on the distributor side. After I would advance it and cover the vacuum port with my thumb it would hold until I released it.

It is a 12v negative ground. I will check the voltage at the coil first thing. Wow, I should have checked that first. The coil was a part of a package deal for the pertronix.

The plugs were just replaced and I should have taken a picture of those. No too bad in my opinion.

She is a smoker! Very slight hint of blue until she is warm. Plenty of blow by as well. I would think she was past her time if she did not run so well at 1000 rpms and higher.

Rusty 48, I will check the choke as well and fiddle with that. It fully opens when the handle is set to that.

Bobj49f2, I will check the compression again now that I have warmed her up several times after sitting for a while. I checked them 2 weeks ago when I jumped into getting here going. They were all over the place. 30ish to 80ish. I wanted to run here for a little bit to see if the rings would seat a little better and run her up to speed and blow out the cobwebs.

Also, she has no exhaust past the exhaust manifold.

If I need to pull it for a rebuild what should I expect to pay for a rebuild at a machine shop. I will do everything to prep the engine for the machine shop.

I like the old flathead so I would like to keep it going.
​​​​​​​
Thanks again everyone. This place is great!
Greg

 

Hello Folks,

Finally got back into town from work trips and checked on some things. Electrics all tested fine. However the compression is low. From 80psi in cylinder 1 and works its way down to 40 in cylinder 6. Time for a rebuild! I would like to keep the 6 but a 302 sounds nice as well. I will have to replace the crash box whatever I do.

Thanks For all the input!
Greg

 

Here is your problem, take off the air cleaner. it is way too small and i know fron experience that small air filters choke out those old carbs to the point that they barely run.
you need an adapter for a bigger filter (Round) and about 10-14 inches wide for it to run smooth.

 

also did you hold the throttle wide open with no air filter for the compression test as that is what you should do for the tests.

 

I drove my 226 with just as bad or worse compression. I caused problems once in a while but what really did the engine in was the burnt valve.

I wasn't so bad to rebuild the engine. I never dug so deep into an engine before and had some technical advice from people with a lot more experience than me. I did all of the physical work myself and had the Ford shop manual by my side every step of the way. Checked everything three times and it's running. Very noticeable improvement over the old engine.

I bought the majority of internal parts from Falcon Performance. I found other parts on eBay and even some at the local MacParts stores, mainly O'Reilly's.

 

Hi Bob,

Did you take the block and head to the machine shop for milling or anything? Did you have the crank turned or balanced?

I am missing a few tools to do the rebuild myself. Probably only the piston ring compressor and the valve spring compressor. Or, those are the two that spring to mind.

Thanks,
Greg

 

before you go rebuild the engine just take the filter off and check compression and how the engine runs without the filter.
no use rebuilding it if it is still usable.

 

I had my neighbor, a retired machinist, measure the bores of the cylinder with a cylinder gauge and they measured within tolerance. The engine I rebuilt was rebuilt before, it had a tag on it but I have no idea when it was rebuilt. The cylinders were .060 bored over. The crank wasn't as good but was able to use the crank from the original engine. I took it in and had it ground .010 under. The cam looked good with no slop so I left it alone. The block deck checked out flat with a straight edge so I didn't need any work on that.

Getting the valve springs proved a challenge. I have three people lend me their spring tools, only one worked. The tools used on V8s didn't work. I had to use the big "C" type and even then I had to come up with a two step procedure using a spacer.