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Posts posted by hchris

  1. I'm a little confused, you say backfire out the exhaust?  technically a backfire is through the carbs; afterfire is through the exhaust. 


    Afterfire is pretty rare and is more likely to be a timing issue, wouldn't entirely discount carbs but more inclined to look at timing particularly when you mention cam,coil and distributor; assuming these have been newly installed  ?

  2. Looking at your photo I'm sort of amazed that whoever did the conversion didn't aim to get the threaded portion of the plugs to sit at the same depth of the originals, I'm guessing that the 45s is at least 1/8" or more longer than the 10mm plug; wondering how far above the piston the electrode sits ?


    As to the plugs themselves, the 45s is going to run much colder having almost twice the ceramic insulation of the original, but I'm assuming, it's  been running ok with them for some time, would be interesting if you could find some plugs of similar size to the originals in 14 mm (i.e. electrode depth and insulation)  and see if they made a difference in performance. 


    Re plug location,  as Dusty explained their positioning in the combustion area is critical for design performance, engine designers go to a lot of trouble in positioning valves, plugs etc to achieve the best performances.


    Although it's probably not worth it now, a better solution to going upsize with the plugs would have been a screw in adaptor to accommodate the 10 mm plugs in the 14 mm hole. 

  3. What Brian said; beyond that I'm a great advocate of tuning with a vacuum guage.


    If you can find a port in the manifold to hook up a vacuum guage it's so much easier to get timing/mixture etc. sorted, bearing in mind fuel properties have changed so much since these cars were built.

  4. 7 hours ago, padgett said:

    So light weight, low rpm, flat torque curve, not much HP/cid. Doubt that MPG is that great.


    Correct - having said that, with fuel injection and engine management systems plus the ability to lean out the mixture in cruise they`re not too bad.

  5. 2 hours ago, gossp said:

    8:1 and can run on Mid-grade. 


    And the thing about (light)  aircraft engines in the main, is that max rpm is generally around 2700 - 2800 and for cruise 2300 - 2500. Typical Cessna/Piper run 160 - 180hp, so overall they are pretty low stressed engines, the design emphasis is really on big bore, big torque and low revs, not forgetting that a boxer configuration makes it easier to cowl and streamline. 


    Different story when you get into turbocharged and higher output engines, using 98/100 octane low lead. 




    On 1/5/2020 at 12:50 PM, Steves Buick said:

    Hi guys, I'd like to swap out my mechanical dual point distributer for a single point with an petronics modual that has a vacume advance. I have a new distributer from a 1935 buick, 8 to use.. my dual point is on my 1932 series 90. My question is ...can I run the vacume line off the manifold as my Marvel does not have a ported vacume port .. Looking for thoughts and ideas at this point.. 




    If you have an accessible vac port hookup a vac guage  and see how it's behaving,  great diagnostic tool.



  7. During the casting process an open ended passage is formed, there's more than one of these within most carbs, so these plugs are used to close off the internal passages for fuel and airways to function.


    Where there's a need access these passages in service for cleaning etc you will find a removable/replaceable aluminium plug, and of course at the other end of the passages are jets or vacuum ports as required. 

    • Thanks 1

  8. When vaccum is drawing fuel into the upper housing of the tank you will feel the feed pipe go cool/cold,  then warm up when the flow stops; the temperature changes are not drastic but you can feel the difference with your hand. The other indicator, if you listen carefully at idle, is the change in engine revs as the vac cuts in and out in time with the fuel being drawn into the tank.


    Beyond these indications there's not much else other than opening up the tank after the engine has been running.

  9. 3 hours ago, Dave Mellor NJ said:

    Looks to be a fuel door in the lower skirt of the trunk


    Yep, that  would be an access panel to the fuel cap. There would have been an extension pipe from the standard filler opening in the beaver panel, the extension would pass up through the bottom  of the aftermarket trunk.

    • Like 1

  10. 10 hours ago, Bloo said:


    No condenser used for points even approaches those values. I don't expect that will work well. I can't remember offhand what is typical, but I could believe the 0.2 - 0.3uf mentioned earlier in this thread.



    You CAN be off, and it will run, but if you are the points will burn up right away with contact damage that looks like a mountain. Metal transfers from one point to another. You can tell whether the capacitance (uf) is too high or too low by which point has the mountain on it. Old service manuals like Motor or Chilton have pictures of this. RPM affects it, so driving habits play a part. If a car runs ok, and there is no metal transfer on the old points, I don't change the condenser.





    Yep you got me there, but my point really was just try another condenser,  save messing with the multi meter. 

    • Like 2

  11. 3 hours ago, 37DodgeSedan said:

    My multimeter is digital and shows 1 when separate and 0 when the leads are touched together. I had the ohm setting for 20000k which internet searching yielded comments to choose the highest setting. I thought I could energize the condenser from the multimeter by black lead to condenser body and red lead to the detached power lead from the coil. this should have caused a change in ohms over a 15-20 sec interval and then reverse leads to discharge. However, no change occurred at all. I will try the method stated by Trini tomorrow and provide an update.


    Or perhaps just spend a buck or two on a new condenser (20 - 30 uf)  and hook it up as Trini says anywhere on the distributor, so long as it's in the primary circuit to the points.  Saves messing around with the multi meter. 


  12. Aand of course what everyone keeps forgetting is the fuels today are light years away from that available when those cars were built. The issue of having a starting mixture that's vaporizing enough when it's cold will always be a problem, there's little relevance in what happened when "Dad" owned the car back in the day.

  13. Have you considered just moving the plug wires to suit proper firing order, if as you say you're 180 out, just swap the wires  from  1 to 4 etc.


    Reading your  problem again, were you in fact at TDC #4 instead of TDC #1 when you viewed those timing marks, remember the cam turns  at 1/2 crank speed 

  14. 1 hour ago, plymouthcranbrook said:

    The carb icing had not crossed what mind I have left even though I have dealt with it in the distant past. I am using the original oil bath air cleaner. Do you think that this could contribute to the problem by allowing a longer and perhaps faster Venturi effect? I will look and see if I can see any icing this weekend. I didn’t think it would be cold enough for that to occur yet although with Lake Michigan about two miles east humidity is often an issue here. Thanks for the idea.  What have you done if this is the problem to help minimize it?


    The oil bath cleaner is not significant, the issue really centres around the throttle plate area, the laws of physics dictate that a venturi affect, small throttle opening, moist air and the chill effect of vaporising fuel create the ideal conditions for ice to form and build up around the throttle plate, this will only last as long as the combination of the above effects prevail.


    What changes these conditions is warmer air around the throttle plate as the engine itself warms up, a combination of manifold heat plus warmer under hood air entering the carb intake.


    You mention not being cold enough, the fact is that the temperature of the air will drop rapidly as it passes through the venturi (physics again) with a moisture (humidity) content carrying the necessary icing component, I reiterate that the ideal conditions are about 10 - 20 degrees ambient above freezing to 5 - 10 degrees below freezing, the humidity content is a major influence in this range  In fact in the Arctic the problem isn't as bad simply because the air is dryer, certainly colder but dryer thus no moisture to freeze.


    So what  to do; the easiest thing is introduce some warm air into the air cleaner intake. I have (a not very pretty) flexible duct with one end just above the exhaust manifold and the other pushed into the air cleaner nozzle. With an oil bath cleaner this isn't easy to do, but I have seen where someone drilled some holes in the upper out side of the casing and fashioned a fixture to accept a piece of flex duct to the side of the air cleaner, again not pretty. With this approach of course, you don't want it there when the weather warms up as the other laws of physics could lead to detonation with the intake of too much hot air.


    Finally, forgetting about the physics, just live with the problem and adapt your driving to accommodate it. In all of the above of course, your problem might not be icing at all !!

    • Like 1

  15. 5 hours ago, Ben Bruce aka First Born said:


      Carb icing up?




    Exactly what I was thinking , classic symptom.


    First few minutes of running causes a large chill factor across the throttle plate,  due to  low pressure and high velocities through the venturi, mix this with cold fuel, cool air and moisture you've

    created a perfect refrigeration effect.


    As the manifold and carb base warm up the symptoms disappear,  modern fuels are part of the problem as they are more prone to this condition. 


    If you are able; first start of the morning feel the carb base on and off for a minute or two, you will feel the chill as it happens, in severe cases you can actually see an ice ring form around the carb base on the outside.


    Without wanting to bang on too much, throttle ice is most likely to occur 10 to 15 degrees ambient  above freezing point and is influenced by the moisture content in the air, any of you aviators reading this will know what I'm talking about. 

    • Like 1

  16. 21 hours ago, Buffalowed Bill said:

    The discussion here assumes that there are new bearings are available for the application. In the case of the Ford new bearings are available, but in a broader sense there are some cars that become derelict because inserts don't exist. Case in point of real world concert for those of us who own 1936-42 Studebaker Presidents. Insert bearings for this engine have not been available for years, and that's how long some people have been looking for them. In this case trying to piece together a bottom end from parts from another engine beats the alternatives. 


    The fact remains that if you fit bearings that don't conform precisely to the crankshaft dimensions then you have every chance of damaging the crankshaft, and then you're back to where you started. 

  17. 3 hours ago, AHa said:

    All of this looks to be in good shape and working order. Of course anything is possible but there are no visible cracks in the top housing and the float seems to work perfectly. Although I threatened to roll the car out in the yard for the guy to come pick it up, I didn't have the heart to do it and it has resided in dry storage. It was running when it was parked, I don't understand why I'm having this problem? The motor fired right up after setting 11 years and purred like a kitten.


    Okay,  but as stated above what about the valves and vents in the top housing? 

  18. On 9/13/2019 at 9:46 AM, Frank Wilkie said:

    I have a 1954 Chry N.Y. 331 v8. I'm trying to replace my water temperature sensor. It does disconnect at the sensor by unthreading the nut disconnecting  the flared tube fitting.. As I ask about a new one it seems that several has mentioned that the original sensor was affixed to the tube and directly with the dash gauge.  Is this correct..  I have the original dash gauge but like I said , it unscrews off of the sensor.   I need to just replace the sensor. Does anyone know where I can purchase one?


    As Tom has said, the sensor to gauge is a sealed unit. If you break any of the connections the enclosed fluid will escape  and it's really a specialist job to repair, or if you are an industrial chemist, avery tricky job.