Engine knocking or pinging, cause distributor ?

Henk_Brough
Henk_Brough Expert Adviser
edited January 2014 in HUDSON
The engine ( 212 from 1937 ) I bought about 2 years ago from Texas still has the original pistons.
So, not done to many miles. I take out the distributor and it was blocked. ( IWG 4012A )
I take it in peaces, clean it, makes the mean shaft free and it was almost a brand new one.
After the complete overhaul of the engine I placed this distributer on the engine.
Idling was perfect but accelerating the car, there was a terrible engine knock. I thought : what I have done wrong restoring the engine. The sound was like the big end was out as on the other engine. A friend of mine pointed to the distributor and was convinced the centrifugal governor was not working properly.
From my old 1938 engine I replaced the distributor and the problem was solved. Mechanically the engine sounds perfect.
( later I had many problems with the LPG, etc. but that is beyond this problem, later I will tell you about that )
I dismantled the distributor again and found nothing wrong. I checked the centrifugal governor very carefully.
So again on the engine.
Indeed : the engine was knocking again. I cannot find any problem in the distributor.
The only thing : the two springs from the centrifugal governor are a little different. The wire from one is a little thinner than from the other.
I would like to use this distributor because it has no free play at all.
Some one has an idée what is wrong ???

Comments

  • Park_W
    Park_W Senior Contributor
    Henk, how are you setting the timing after installing the distributor? If the timing at idle is set OK, then maybe one of the springs for the centrifugal advance is absent, or stretched, so that the advance is going too far as the engine speed increases.
  • Henk_Brough
    Henk_Brough Expert Adviser
    Thank you, Park. I set the ignition with a stroboscoop. I take it about 5-6 degrees earlier because of the modern fuels. Both springs are there, one is the wire where the sping is made from a little thinner. Shape is correct.
    Perhaps a not strong enough spring. Indeed I have not realized that ignition can go to early.
    If the engine knocks from wrong time of ignition, is the ignition than to early or to late ??
  • J Spencer
    J Spencer Expert Adviser
    If the springs appear to be the original, unless they are really weak I would't think that is the problem. Spark knock is to much advance, I would start by retarding the timing a couple of degrees and test drive it. Better, Worse? how is acceleration?. I'm assuming you have fresh fuel in the car?? If you have a timing light with the advance meter buil in you can check total centrifigal advance against manufacturse specs. What is the octane rating of your fuel. Is it pure fuel or does it have ethenol in it??
  • Geoff
    Geoff Senior Contributor
    Henk, can you describe better the "knocking". Does it idle quietly and knock when speeding up, or is it a constant knock?
  • Glowplug
    Glowplug Expert Adviser
    As an overall suggestion, you have taken the distributor apart, this could and sometimes does lead to improper reassembly. I would take the position that there is a problem in that distributor and it is causing the engine distress you note. I would also take the time to carefully examine the cap, rotor and interior wiring to determine if the there is insulation failure, cracks in the cap/rotor, miss connection to one or more plug wires. Also the vacuum advance maybe at fault. Once you have exhausted these actions, take the distributor to a shop that has a distributor machine where the distributor is tested against the specifications.
  • Geoff
    Geoff Senior Contributor
    There is no vacuum advance on these earlier models.
  • SuperDave
    SuperDave Senior Contributor
    What jumps off the page to me, is the 5-6 degrees initial advance .

    Most distributor advance springs are different from each other. t's a way to have a long advance curve.
  • Henk_Brough
    Henk_Brough Expert Adviser
    Thank you all for your comments.
    Geoff : Idling is o.k. With speeding up the knock is there. It is really hard, like one of the big ends is out. The 1937 engine has indeed no vacuum advance.
    Oldfarmer : ( is that you on the photo ? ) All is new ,cap, rotor,cables, plugs, etc.
    You are right I will take the distributor in bits again and build it up very carefully with the springs from the other distributor. Next testing with different timings.
    Spencer : Thank you for the statement engine knock only occurs with to much advance.
    Modern patrol in Europe has about 5 % ethanol.
    Dave : Your remark about the timing : I read somewhere that with modern patrol it is better to advance 5-6 degrees and not at TDC as in the manual. Perhaps the combination from Spencer and Dave come to the conclusion the 5-6 degrees advance is wrong. Someone else has experience with this ??
    Ken : Sorry but I do not own a vacuun set. I make the conclusion that you also think : no advance to the manual setting. Modern patrol quality is indeed poor ?
    I learn a lot about this subject and are very happy you not alone give me the advise to use the 1938 distributor where the engine runs on rather good.
  • Geoff
    Geoff Senior Contributor
    If there is slightly more clearance in a con rod than recommended (.0005' to .0015", then it will probably not be noticeable with timing at t.d.c., but will make it's presence known when timing is too far advanced. To ascertain which rod is making the noise, short out each plug in turn. You may need to adjust the bearing. However, even with modern fuel timing too far advanced will put undue strain on the motor.
  • Glowplug
    Glowplug Expert Adviser
    Herk -
    is that you on the photo ?
    Yes
This discussion has been closed.