1927 Engine Problems

Jon B

A Hudsonite of my acquaintance owns a '27 Super Six. He says it really hasn't run right since about 1999, and after replacing or rebuilding most of the ignition and fuel components. A year ago he drove it to a meet and had to have it towed home, and he hasn't driven it since, totally frustrated. He says it runs roughly, and he suspects something in the fuel system (though he's had the carb rebuilt, gas tank boiled out, etc.).



It's hard to diagnose a problem without actually seeing the engine, but I wondered if any of our 'older Hudson' owners know of anything inherent in the 1927 engine that might have caused problems, even when the cars were fairly new? Is there some common problem that seems to crop up again and again? Do you have any tips for troubleshooting, which he might attempt? It may be that, at this point, he's thrown up his hands and given up....but I'd like to at least make two or three suggestions to him!



I'd be grateful for your ideas!

hudsonsplasher1

Jon;

I had a simular problem with my 28 Essex ( same engine as his 27) last summer. Because I don't drive it much, the carb had gumed up and it ran very rough. It was just a matter of taking it apart and cleaning. This might be a place to start.

Gene.

Unknown

First of all, where is the car located?



I'd pull a compression test first and see if there's a valve stuck open, and evaluate the condition of the internals. While the plugs are out have a look at them, and gap .028". Then, check for crap in the carburetor, and proper function of the vacuum tank. I advise removing the lid from the top of the vacuum tank, filling it with gas, disconnecting and plugging the vacuum line that goes to the intake manifold (the most important step) and see how it runs. If it's better, there's the problem, rebuild the vacuum tank. If no change, hook things back up and go to something else. If the vacuum tank is malfunctioning it could be sucking gas into the vacuum line, creating a severely rich condition. If he's using an electric pump, make sure the fuel pressure is regulated down to no more than 1 psi. Check out the resistance on the wires, point gap .018-.019" and polish the contacts, and condition of the cap and rotor, and especially the carbon button in the cap that contacts the rotor. Digging deeper, have a look at the ignition timing; the best method is to sit a 12V battery beside the car and hook up a timing light, and set the timing 4 flywheel teeth BTDC at idle with the spark lever fully advanced. If no timing light, I can advise on setting the timing without one. Assuming the vacuum tank and carburetor are functioning correctly, and the ignition system looks good, if there is still a problem, check the valve springs, intake especially, and then pull the front cover and see if the timing chain is mis-indexed or has jumped a tooth (a common problem here). To set the valve timing, roll piston #6 to TDC, with the rotor firing on that cylinder. The two punch marks on the crank sprocket will be at 6:00 position. Then roll the cam sprocket to the 2:00 position. There are two punch marks on the cam sprocket as well, each on a tooth, so that there is a "V" in between them. Then to set the chain, count starting from the timing chain pin sitting in the "V" between the crank sprocket punch marks, this is pin number ZERO, not one, and count 20 timing chain pins back to the crank sprocket, and position the cam sprocket so that timing chain pin #20 is sitting in the "V" between the punch marks. This is the most common mistake made in assembling a Hudson engine. Hudson said to count the pins "As when measuring distance", so you start on zero, not one. I can send a drawing if necessary.

Jon B

Thanks for your thoughts, especially the timing chain and vacuum tank suggestions. Every make, model and year of car has a 'weak point', and it was my purpose to detect what the weak points are for the '27 Super Six. Those would be the first places that this fellow should look, since (it seems to me) that if there's a problem, it's more likely to happen in the weak points than elsewhere.

Unknown

The F head Hudsons don't really have an achilles heel, except for that blasted pot metal float bowl on the '29 carburetors. The timing chain problem is more of an assembly error than a chronic problem, however it is possible if the chain is stretched and the owner hasn't taken up the tension by means of the eccentric located ahead of the water pump, it could jump a tooth. What I have suggested runs the gamut of what could be wrong with that thing, just my personal experience from resurrecting one that ran mediocre, and another that didn't run at all. I should have also suggested setting the valve clearance -- .004" intake, .006" exhaust, HOT. They are going to have to be really out of whack to cause it to run that bad, but it is possible that a tappet unscrewed and a valve isn't opening at all. They are sort of picky with valve clearance having roller tappets, and when everything is working right you should be able to balance a nickel on the valve cover.

Geoff

The most common problem with the '27-'29 Hudsons is burning out of the heat riser tube, between the carburettor and the intake manifold. Check this out.

Geoff

Unknown

I forgot about that Geoff, thanks for mentioning it. Yes the heat riser tube will allow intake mixture out into the exhaust and exhaust mixture into the intake, and a heck of a vacuum leak. I'd check that first-order. Pull the manifold off and inspect it carefully.

hudsonsplasher1

hudsonsplasher1 wrote:

Jon;

I had a simular problem with my 28 Essex ( same engine as his 27) last summer. Because I don't drive it much, the carb had gumed up and it ran very rough. It was just a matter of taking it apart and cleaning. This might be a place to start.

Gene.

I should learn to read the posts more carefully. Sorry, I was thinking Essex, not Hudson.

Jon B

The car runs smoothly when it first starts. When it warms up, it starts acting like it's flooding (runs roughly, finally dies). It currently has an electric fuel pump (its the same pump as another fellow has on his '29 Studebaker, which also used to run off a vaccuum tank). The carb has been rebuilt but right afterwards he encountered the same problem.



Would this indicate any particular problem?

Unknown

I'm thinking two things, one from a theoretical standpoint is too much fuel pressure/volume from the electric pump, which would be easier dealt with when the engine is cold and needing a richer mixture, but would be an increasing problem as the engine warmed and closer to 14.7:1 was needed. I could be way off base about that but I would definately check to see that a regulator is installed, no more than 1 psi, and I encourage installing a vacuum tank as they run much better than any electric pump. I can supply a rebuilt one if necessary and I bet Geoff has one as well, if not, I know he can rebuild one. My second thought is a faulty condensor, as they can act up as a function of heat. Again, check that heat riser tube as well.

Jon B

As regards the heat riser problem, he just has to unbolt the intake manifold (with the carb?) and remove it, to check the riser?

Unknown

Probably best to remove the carburetor to avoid damaging it, but it can be done with it on. If the heat riser/intake manifold flange is bolted to the exhaust manifold with bolts, remove them and you will be able to then remove the 4 long bolts that connect the upper and lower heat riser and slide it out. If however the heat riser flange is connected to the exhaust manifold with studs, you'll have to remove both upper and lower heat riser sections to lift it up off the manifold and get it off the car. Look down the center tube of the lower section of the heat riser with a flashlight and small mirror, and if there's carbon in there clean it out with a bottle brush (here's where the carb needs to be off). If there's holes, the center tube can be pressed out and a new one pressed in.