Doc's woes

RL Chilton
RL Chilton Administrator, Member
edited November -1 in HUDSON
Many folks have been asking me about Doc, our '52 Hornet Sedan. Some of you know that we started out going to the Nat'l. and made it about 30 miles from home before I had to call AAA and have it hauled home. After spending a couple of months off and on getting her ready and a furious last two weeks working on her, it was a real disappointment not being able to take her on the trip.



Early the morning of our departure, and on the side of the road, I finally isolated the problem, but for the life of me, couldn't figure out the why of what was happening.



Doc's got Twin-H, and after swinging the air cleaners out of the way, I noticed that the front carb was working properly. If you held your hand above the venturi 1" while it was running, the vacuum would suck your hand down and the engine would die. If you did the same to the rear carb . . . nothing. No vacuum on rear carb, healthy vacuum on front carb. Additionally, it seemed to me, that the front half of the engine was running, and the rear half was not. Pulling the brand new spark plugs out of #6, yielded tremendous carbon build-up.



At that point, and after several frantic calls to other Hudnuts, I decided to haul her home and take alternate transportation.



Through the course of the Nat'l., my talks with half-a-dozen mechanics yielded interesting theories. 4 of them all resounded with the same prognosis: broken camshaft. 1 though sure it was an intake problem, so much so that I bought an extra Twin-H manifold at the Nat'l. just in case that was the problem.



Today, I finally "got into it". First thing I did was pull the valve covers to check the broken camshaft theory. Happy to report that the camshaft is alive and well. Second, I checked the plugs on the bottom of the intake manifold and looked everywhere for cracks, and felt for vacuum leaks. No problem with the manifold that I could find. Off came the carb, adjusted the float, checked for vacuum at the intake . . . part of the problem, but only a minor thing. Let's see, got fuel where it's supposed to be, got great spark . . . still doesn't make any sense.



I thought, what the hell, I picked up a brand new distributor from Dave and Tim at the Nat'l. I'm gonna put it on and see if it makes a difference.



This is where it gets weird. :eek: After finding TDC at #1, the rotor is pointing at 7:00. O.k.fine. Pull the distributor, put in the new one, line up the rotor at 7:00 . . . distributor won't go in. Hudson dist. (at least in 308's) only go in one way. The key at the end of the dist. shaft is offset, so you can't put it in backwards. So, I rotate it around so the rotor is pointing at 1:00, and PRESTO, dist. drops in. Why? I don't know. I re-wire the cap to represent the proper firing order . . . and bada-bing bada-boo, she runs like a top. What happened? :confused: How does the dist. get turned around 180-degrees by itself? The car had been running fine until we hit the road. New distributor and it's off by 180? I still haven't figured it out, but, regardless, after some dialing-in still to go, she's rip-roaring ready to go. :D



At least it wasn't something major like a broken camshaft . . .

Comments

  • Unknown
    Unknown
    This should sum it up. :D



    http://www.youtube.com/watch?v=R9EoyEb1wTs
  • [Deleted User]
    [Deleted User]
    Russell:

    I want to know what Miles was doing while you were tinkering with the Twin H carbs and other stuff? Bob
  • RL Chilton
    RL Chilton Administrator, Member
    bobdriveshudson wrote:
    Russell:

    I want to know what Miles was doing while you were tinkering with the Twin H carbs and other stuff? Bob



    Playing with his video game in the backseat . . . but give him a few years, he might have more of an interest. Personally, I think #2 son, Hudson will be the mechanically inclined one. Miles is more of an intellect.
  • RL Chilton
    RL Chilton Administrator, Member
    Dave53-7C wrote:
    This should sum it up. :D



    http://www.youtube.com/watch?v=R9EoyEb1wTs



    O.k., that's hilarious right there. It's also one of my favorite movies of all time, and yes, it was very much like that today!
  • Aaron D. IL
    Aaron D. IL Senior Contributor
    I don't have the issue of balancing carbs like your Twin H but I have experienced the timing off. It doesn't seem the timing chain jumped at all and I can't explain it myself why I had to move the plug order over one.
  • hudsontech
    hudsontech Senior Contributor
    I've been playing around with automobile mechanics for some 50 years and this is the first time I've ever heard of a problem like this. Well, it is a Hudson. :D



    It almost sounds like what you are saying is that 1/2 the distributor was not working - firing order being 1-5-3-6-2-4 (off the top of my head) I don't see how only half a distributor can work with only 1, 2, and 3 firing. Obviously, 4, 5, and 6 weren't - hence the carbon build up. Only way I can see is if the terminals in the distributor cap are gone or the wires were bad on 4, 5 and 6.



    Well, if you think mechanics will drive you up a wall, try doing research and REALLY join the "banging-head-on-wall" crowd. :D



    Hudsonly,

    Alex Burr

    HudsonTech

    Memphis, TN
  • RL Chilton
    RL Chilton Administrator, Member
    I hear that, Alex. Ken Cates informed me that firing order (which you have correct, 153624) is determined by having #6 at TDC and not #1, as in Brand X engines. Hence, that was certainly part of my confusion. Regardless, that aspect is now correct and about as good as I can make it.



    The front half working, and back half not working was in part due to the vacuum leak at the rear carb. That problem is also now cleared up. Currently, she runs like a top, just have to "dial-it-in" with synchronizing the two carbs and then running the UNISYNC with the proper procedure.



    Eventually, I'll probably get one of Russ Maas' timing chains and put a new one on her . . . can't hurt and can only help with future problems. Additionally, one of his bronze oil pump gears would be a plus.
  • Geoff
    Geoff Senior Contributor
    Just a long shot, but is it a possibility that the choke was stuck closed on the rear carb? This would account for the blackness of the plugs, and no vacuum at the intake.
  • RL Chilton
    RL Chilton Administrator, Member
    Geoff-



    The choke was slightly more closed than wide open, like the front one (hot here) and I adjusted it a couple of notches to match them up, but by no means was it closed up tight.
  • RL Chilton
    RL Chilton Administrator, Member
    Hudson308 wrote:
    Interesting you ask that, Geoff.

    My 95 year-old grampa (alive and well in the next room, I might add) likes to regale the tale of when gramma came back from shopping with half a tank of gas gone in his (Twin-H) '53 Hornet sedan. She wouldn't admit to any extra errands, so he dropped the subject. After a quick trip around the block however, he pulled back in the garage to see where all the power went, and viola! He had tightened up the rear air cleaner clamp to the point that the rear choke butterfly was wedged closed. :D



    I just read that recently! I think it was in the Shop Manual about not overtightening the air cleaner.
  • RL Chilton
    RL Chilton Administrator, Member
    Geoff-



    Sent you an e-mail.
  • Jon B
    Jon B Administrator
    Russell, what you're saying is that the thing was running fine when you left and then suddenly it started acting up? The distributor shaft suddenly got oriented incorrectly? Wouldn't the only logical explanation be that the timing chain 'jumped"? Unless somehow the gear (at the bottom of the distributor shaft) "jumped" the camshaft gear, this would be the only possible answer, I'd think. What other explanation could it be? Ghostly intervention?
  • RL Chilton
    RL Chilton Administrator, Member
    Jon-



    Yes, those are two possibilities, although it didn't jump one position over, it was 180 out. I believe the new distributor was oriented opposite the old one. However, your logic is correct, it either has to be one of those two things, or a broken tooth on the oil pump gear would create havoc with timing as well. Without pulling the oil pump, I don't know exactly what is what, but Jack Clifford built this engine and I would like to believe that since he originated the new roller timing chains and bronze oil pump gears, that he used those two parts when the engine was assembled. I've hooked up an oil pressure gauge to monitor oil flow, and if and when I lose pressure, the oil pump gear would be my #1 candidate (culprit). Until then, I'm going to go with what we've got, because somehow, I can't exactly explain how I got here from where I was, but all seems back the way it should be.
  • MikeWA
    MikeWA Senior Contributor
    RL Chilton wrote:
    Jon-



    Until then, I'm going to go with what we've got, because somehow, I can't exactly explain how I got here from where I was, but all seems back the way it should be.



    Or, put differently, at least we feel more now like we do than when we started.
  • RL Chilton
    RL Chilton Administrator, Member
    I think I've lost about half of the hair I had left on my head in the last week from pulling it out.



    I've never been so confounded by a car before, but Doc is making me crazy!

    I've been running diagnostics on this car till I'm blue in the face and cannot figure out her problem.



    Thought I had it all taken care of, but now I've been through the run-around so much, I'm just confused.



    At the National, I picked up a Uni-Sync tool to adjust the carbs properly (re-built carbs from Walt Mordenti). Twin-H, they need to be balanced and fine-tuned or so I thought. After fiddling with it for a few minutes, and following my Twin-H adjustment procedure very carefully, all of a sudden she starts running like she did on the morning we left for the National. Like, super rough, maybe missing, back carb acting up, no rev whatsoever. Barely idling.



    For a complete list of "fix-this-try that-replace this thing over here", send a SASE to my home address and please address it to the resident crazy Hudnut.



    Just kidding. So far it's been (and for the new guys, it's a 308 with Twin-H in a '52):



    1) Installed re-buillt carbs from Walt Mordenti

    2) New distributor (not counting vacuum advance) from Dave K. Right one, too: 4009A.

    3) New wires, plugs (three different sets), cap (two different ones), rotor (three different ones), condenser (two different ones), points (three different sets).

    4) Compression test: #1-#5: 115 lbs., #6: about 105 lbs.

    5) Checked vacuum: pulling a vacuum but not sure how strong it should be

    6) Checked for broken cam: Cam's good

    7) Checked for vacuum leaks, including inspecting casting plugs on bottom of intake: all good, although I did buy another Twin-H manifold at the National, just in case.

    8) Put in-line spark plug testers in #1, 3 and 5: all good, strong spark.

    9) Checked damper valve in exhaust: it was stuck, so made sure it was wide open, considering removing it entirely

    10) Realized the other day, that the gas tank was filled up on the morning of July 10th, enroute to the National, and no Sta-Bil, so I drained the entire tank, put in new gas: no help

    11) Voltage Test at distributor: 8 volts on a 12V car--- might be too high for points? Old points seemed to have a "hot spot" on the contacts.

    12) Added Fuel Filter at intake pipe, right before the "split" in lines for carbs: no crud came out of the tank (tanks clean as a whistle), no crud in lines or in carbs: Result: No difference in engine

    13) Checked fuel pressure: not with a gauge, but there is no shortage in fuel with a huge healthy surge coming out of the fuel line at the carbs: not the problem



    Basically all this adds up to clean, healthy gas all the way to the cylinders and good healthy spark all the way to the cylinders and at the proper time or damn close to it. And yes, the firing order IS correct and properly wired, 1-5-3-6-2-4.



    Anyone have any other good ideas? I've sent an e-mail to Ken-U asking him to come down and help me out, as I'm out of ideas.:o:confused::mad:
  • rambos_ride
    rambos_ride Senior Contributor
    Russell,

    I'm no Hudson expert but here's some thoughts

    Vacuum - was it steady or jumping around?

    Did you try swapping front and rear carbs around?

    Do you have any other carbs to try?

    What type of needle valves where used? There was a guy on the forum not too long ago selling Craig-Valves that might work better?
  • [Deleted User]
    [Deleted User]
    If a carb has a vacuum leak we would spray carb cleaner or starter fluid around the manifold at idle. If the RPM changed you knew you had a leak and could make a good guess where.
  • [Deleted User]
    [Deleted User]
    Russell

    Sent you and email buddy
  • RL Chilton
    RL Chilton Administrator, Member
    rambos_ride wrote:
    Russell,



    I'm no Hudson expert but here's some thoughts



    Vacuum - was it steady or jumping around?



    Did you try swapping front and rear carbs around?



    Do you have any other carbs to try?



    What type of needle valves where used? There was a guy on the forum not too long ago selling Craig-Valves that might work better?



    Vacuum: Steady

    Haven't switched them yet, but that was in the plan. First, it should at least run somewhat normal, then I was going to switch them. Actually, when I was trying to balance the carbs and she seemed to be running mostly right, I couldn't quite get them balanced to each other and thought about switching them so at least I would know if it was the carbs, or something else. Still might do this, but see below.



    I had another set, but sent them to Walt M. and they are almost completed. Have one more set, but they need to be re-built and wouldn't put them on a car as it appears they've been sitting on a shelf for some time. I have 7 total 968S's, four good ones out of those: 2 on the car and 2 at Walt's house.



    I read about the Craig-Valves and that thought has crossed my mind, but have yet to pursue it (see below).



    Ken U sent me an e-mail and he seems to think that either A: the distributor gear is worn, or B: stretched timing chain. He gives his reasons for the prognosis and it makes sense to me and it's two things I have not checked into. He is planning a trip to come down and see me and help with Doc in the next few weeks, so hopefully, whatever it is, it will be resolved. :)



    Thanks for the thoughts, though, that's what I need.
  • RL Chilton
    RL Chilton Administrator, Member
    Super 7 wrote:
    If a carb has a vacuum leak we would spray carb cleaner or starter fluid around the manifold at idle. If the RPM changed you knew you had a leak and could make a good guess where.



    Did that! Couldn't find a leak.
  • onerare39
    onerare39 Expert Adviser, Member
    Russell,



    This may not be the cure but it may be of some help.



    When I lived in the Northwest I had my 308 with Twin H completely rebuilt. It sat in the garage for years waiting for the car to get painted. Six years later I finally got the engine installed and running. As soon as the engine would warm up to operating temperature it would die. I was baffled. The symptoms to me indicated an electrical problem as when the engine died it died quickly and pumping the accelerator did not keep the engine running, hence… electrical. I checked the timing, changed the points, plugs condenser, coil, circuit breaker and nothing alleviated the problem. I would take it out on a test run cold and would end up sitting on the side of the road waiting for things to cool down and the electrical problem to reset itself. After a week of trying to isolate the problem by researching almost every topic on Classic Car I stumbled on the answer… VAPOR LOCK! I went out to the garage and took the air cleaners off and got the engine running and sure enough when I got the engine up to operating temperature and it died, I there was no gas in the carburetors.



    In between having the engine rebuilt and getting it running again I had moved from the Northwest to the Midwest, a distance of 2000 miles and an increase in elevation of 1800 feet. And in those six years the gasoline formula had also changed dramatically, ethanol and alcohol were now part of the mix, all of which turned the occasional minor vapor lock issue into a major one. By simply adding Marvel Mystery Oil not Stabil to the gas tank I was able to keep the engine running like a champ. I also have an electric fuel pump back at the gas tank, and am putting in a bypass system as described in Walt’s Tech Tips (I also found this solution listed on a Packard website).



    As much as I wanted to keep the car completely stock I realized that there are a number of factors that have changed over the last 55 years that need to be dealt with. Hope this adds some insight.



    John
  • RL Chilton
    RL Chilton Administrator, Member
    It does, John, thank you. The Marvel in the tank is an interesting move. I know of some Hudnuts that use it as an additive for engine oil, some even having slow-drips (essentially) mounted inside the engine bay. That's certainly one I will take you up on. Is there a ratio you go by? Pint per tank or so?



    And, I understand the vapor lock issues (at least to some degree). On the convertible, I planned on doing Walt's conversion with the return line gong back to the tank. It's a good, sound move, along with the three fuel filters. I've also been toying with info put into another thread from Rambo's Ride about the 1/2" spacers underneath the carbs. Certainly in the convertible with 7X mods and probably a slightly hotter spark, it's a good move. Gets the carbs a little further away from the heat, a little more time for fuel to atomize. I might even do this on Doc. Also, you are right about originality. Changes in gas and oil have made us make changes in order for everything to keep working properly and some concessions have to be made, it's just the way it is. No problem with that, from me.



    As far as vapor lock being my problem with Doc, I just don't think that's it, although I can't rule it out. It starts out with the problems, cold or warmed up. I'm not saying vapor lock isn't an issue, but something else is the issue at least at first. Ken's really got me thinking there might be something to the worn dist. gear and or stretched timing chain, and either of those things would and could corrupt the timing enough (more than enough) to make it almost not run at all, and miss the way it is currently. I'll really get into it in the next few weeks and isolate the problem. Sometimes, diagnostics suck, but are so very educational. If nothing else, I'm getting a good dose of Hudson Tech that you really can't get any other way. It's one thing to read about it, but entirely another to put your senses to it.
  • [Deleted User]
    [Deleted User]
    What's the history of your engine? Is it a well worn road veteran or a relatively new engine. Your lack of vacuum in the back half sounds like sticking exhaust valves. Having the vacuum signal for a whole half engine disappear is really a head scratcher. On a new engine, the exhaust guides sometimes can have too little clearance and bind up the exhaust valves as the guide heats up and expands. On an old engine, the guides can be so worn that the valves just aren't seating concentricly as the engine gets hot - but you usually can hear a squeaking/chirping sound out your tailpipe and have some compression/vacuum.



    No mystery on your distributors being oriented different. When they are disassmebled, the cam plate can be put in two different ways. This is the piece that the rotor button slides down on, is the point cam, and is oriented in the distributor by its limit slots for the mechanical advance weights. The one you bought has its cam plate put in 180* from the one you took out. No biggie. Take the breaker plate out, lift the cam plate up and turn it 180* - then it will be just like the one in the car now and you won't have to re-wire the plugs to switch them in and out.



    If you suspect your distributor gear is worn, or if there is excessive slack in your timing chain - a quick test. Take the distributor cap off and rock your crankshaft back and forth until you see the rotor move. The more you can move the crank before the rotor responds, the more slack you have in the gear, the chain, or both. The degree of lost motion and problem become self-evident.



    Maybe some of that is helpful.



    Mark
  • RL Chilton
    RL Chilton Administrator, Member
    `Hudsonator wrote:
    What's the history of your engine? Is it a well worn road veteran or a relatively new engine. Your lack of vacuum in the back half sounds like sticking exhaust valves. Having the vacuum signal for a whole half engine disappear is really a head scratcher. On a new engine, the exhaust guides sometimes can have too little clearance and bind up the exhaust valves as the guide heats up and expands. On an old engine, the guides can be so worn that the valves just aren't seating concentricly as the engine gets hot - but you usually can hear a squeaking/chirping sound out your tailpipe and have some compression/vacuum.



    No mystery on your distributors being oriented different. When they are disassmebled, the cam plate can be put in two different ways. This is the piece that the rotor button slides down on, is the point cam, and is oriented in the distributor by its limit slots for the mechanical advance weights. The one you bought has its cam plate put in 180* from the one you took out. No biggie. Take the breaker plate out, lift the cam plate up and turn it 180* - then it will be just like the one in the car now and you won't have to re-wire the plugs to switch them in and out.



    If you suspect your distributor gear is worn, or if there is excessive slack in your timing chain - a quick test. Take the distributor cap off and rock your crankshaft back and forth until you see the rotor move. The more you can move the crank before the rotor responds, the more slack you have in the gear, the chain, or both. The degree of lost motion and problem become self-evident.



    Maybe some of that is helpful.



    Mark



    Yes, very. Especially the last paragraph, thanks Mark.



    2nd paragraph: Yep, solved that one, easy once you know that. Trying to figure that one out on my own was a head scratcher, for a while, as well.



    1st paragraph: I wish I knew more specifics. What I have been told was, that my engine was at least one of, if not the last engine Jack Clifford himself re-built. Have no documentation to back it up, but believe the former owners when they told me that. Recently? No, best guess is early to mid-90's, possibly even later. Car has 122K original miles. Best guess on miles on the re-built engine is somewhere around 9K-12K. This car simply has not been driven very much it's whole life. Unfortunately, the former owner had passed away and I purchased it from his widow and son, who I'm sure couldn't tell me as much as the husband/father could have. Now, I know that's not many miles to have on an engine to have a stretched timing chain, but who knows, maybe Mr. Clifford re-used the old one. Who's to say? I wouldn't think he would do such a thing, but there's no way of knowing without at least a look-see. Same goes for the worn distributor gear.



    Best part of all this is that I now have a new direction to take, and if it turns out to be either of the above, I know Russ and Randy will fix me up.
  • Unknown
    Unknown
    Im wondering if the oil pump drive gear pin is broken but still holding but slips and lets the timing get off, it would be easy to pull the oil pump and check it - just an idea ?
  • RL Chilton
    RL Chilton Administrator, Member
    stateline wrote:
    Im wondering if the oil pump drive gear pin is broken but still holding but slips and lets the timing get off, it would be easy to pull the oil pump and check it - just an idea ?



    I picked up a new bronze oil pump gear from the Maas' at the National. I bought it for the convertible, but was considering putting it in Doc. It would most likely be the last time that would ever need to be done, wouldn't take very long, and couldn't hurt in the least. I think it's a grand idea.
  • rambos_ride
    rambos_ride Senior Contributor
    Russell,

    Maybe a dumb question but, I know you feel fuel is getting up to the carbs - have you tried actually squirting gas in the rear carb while it's running, or visually checked that gas is being sprayed in the rear carb?

    Dan
  • onerare39
    onerare39 Expert Adviser, Member
    We're all pullin for you Russell. We ought to set up a poll while we await the outcome!



    John
  • hudsontech
    hudsontech Senior Contributor
    rambos_ride wrote:
    Russell,



    Maybe a dumb question but, I know you feel fuel is getting up to the carbs - have you tried actually squirting gas in the rear carb while it's running, or visually checked that gas is being sprayed in the rear carb?



    Dan



    Dan, there's no such thing as a "dumb" question - answers on the other hand...................... :D



    Hudsonly

    Alex Burr

    Memphis, TN
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