| 39Fordfan | -- 07-22-2024 @ 3:35 PM |
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Hello there, My '39 Fordor Deluxe engine has developed a kind of a knock like sound that I am wondering if you might have an opinion of what it is? I'm hoping it's OK to post a link of it and that the sound is good enough that you can hear it. I'm not sure what it is, but the sound seems to spin with the engine and goes up and down with the RPM's. It seems like it is not coming from the top of the engine. The sound is pretty much nonexistent when the engine is cold and becomes more prevalent as the engine warms up and when hot. Hopefully you can have a listen on the video link below (turn your sound up) and let me know what your thoughts are. Let me know if it would be useful to share other videos of it, such as revving it, etc. Thanks! https://www.youtube.com/shorts/80mRSHLk54Q This message was edited by 39Fordfan on 7-22-24 @ 4:08 PM
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| koalanorth | -- 07-22-2024 @ 7:34 PM |
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It's still not clear which part this is because I think it's near the internal combustion part. You should have it checked by the dealer This message was edited by koalanorth on 7-22-24 @ 7:37 PM
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| MG | -- 07-22-2024 @ 7:46 PM |
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39Fordfan - Questions here... Under what circumstances did this noise start? Is your oil pressure okay? Does the noise go away when you push the clutch in? If I'm hearing it correctly, it sounds DEEP, and that's not good. Could be a bearing problem, either rod or main...
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| carcrazy | -- 07-22-2024 @ 8:03 PM |
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Could be something simple like fuel pump noise. The cause could be worn fuel pump pushrod bushing or internal pump wear.
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| sarahcecelia | -- 07-23-2024 @ 3:52 AM |
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If it's a deep sound it is a main bearing, or rod bearing that is bad. Regards, Steve Lee
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| mfirth | -- 07-23-2024 @ 5:24 AM |
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MAYBE a valve stuck partly open and the knock is the lifter knocking at the stem...??? Happened to a friend's 8ba once. Sounds too "light" for a main bearing to me.
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| 39Fordfan | -- 07-23-2024 @ 8:32 AM |
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Hi Koalanorth, Thanks for your reply. I've got an appointment to have a Pro look at it in about a week and a 1/2. I'll keep you posted.
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| 39Fordfan | -- 07-23-2024 @ 8:55 AM |
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Hi MG. Thanks so much for your reply. * It had a bad clutch and so I haven't driven the car as much as in the past. The knock sound seemed to develop since the car got so few miles run on it at the end of last season. I got the clutch replaced over the winter and the knock got worse this season. I've run 20/50 Castrol oil in it for most of the 20 years I've owned it. It doesn't have an oil filter so I change the oil every few hundred, never more than 500 miles. * It seems to have normal to good Oil Pressure. If the dash gauge can be relied upon it always runs above 15. * The noise is ever present with the running engine and pushing the clutch in doesn't affect it, though I will double check that. * The sound does seem as if it is deep, but I'm not completely sure of that. I'm going to put a stethoscope on it and try and isolate it better myself before I take it to the shop in a week and a half. A few years ago I had the timing gear go out on it. I had a shop press a new one on and I've wondered if it might be related to that?
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| 39Fordfan | -- 07-23-2024 @ 9:05 AM |
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Hi Carcrazy, Thanks for your reply! I've wondered about that too, if the noise is being caused by a peripheral component, though I didn't think about the fuel pump. Which is plausible since I haven't had any problems with it since I replaced it maybe 17 years ago. I have been running Skip's remanned water pumps and had a problem with them about 5 years ago and it occurred to me that one of them may be acting up again. The other thing is I had a shop replace a sheared timing gear about 3 years ago with the engine still in the car. It was a pressed in type of gear but we were able to get the old one off cleanly and a new one on with the engine still in the car. Except for a worn clutch which got replaced this last winter the engine has been running trouble free since then.
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| 39Fordfan | -- 07-23-2024 @ 9:17 AM |
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Hi Steve, Thanks for your reply. I agree. I'm hoping that's not what it is. Though it definitely has crossed my mind. I'm going to have a shop help determine what it is for sure, but the knock is quiet enough and I've had a few things done in the last five years like replacing the pressed in timing gear with the engine still in the car and a problem with one of Skip's water pumps that make me wonder if it could be related?
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| 39Fordfan | -- 07-23-2024 @ 9:23 AM |
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Hi Mfirth, Thanks so much for your reply. I have a friend who rebuilt his '39 engine and he was thinking exactly what you are saying that it is a possible valve issue and that the knock is just too light to be a main bearing. I'm going to try a few things before it goes into the shop in a week and 1/2 to see if I can better isolate the problem. Thanks!
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| 37RAGTOPMAN | -- 07-23-2024 @ 3:58 PM |
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does the engine run smooth or shakes. did you try dripping marvel oil down the carb with engine running, you might have stricking valves. what you need to do is some testing, with a insulated plyers remove one spark wire ar a time, if the noise goes away or is less, that cylinder is the problem. wrist pin, piston. or connection rod,, I would also take the generator belt off, see if that make a diference, does the noise get worse when you rev the motor up ? also tempory lift the fuel pump and check the push rod,. for a few seconds, do some testing and get back to up hope this helps 37Ragopman, ,Maine
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| 39Fordfan | -- 07-26-2024 @ 10:40 AM |
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Hi 37RAGTOPMAN. Thank-you so much for your reply! I was definitely going to ask for some tests I could do to try and isolate where this knock is coming from. After doing some tests you recommended here are my best attempts at answering your questions... * The engine runs smooth, no shakes. * Pulling plug wires with it running made no difference to the knock. * Taking the belt off made no difference to the knock. * The knock doesn't get louder when you rev the motor, it just knocks faster. * I didn't test the fuel pump as I wasn't sure exactly what to do? Do you pull the whole fuel pump body off of the manifold? Or are you saying to pull the fuel pump body apart at it's center? * I Dripped Marvel Mystery Oil down the carb with the engine running. It definitely quieted the knock to what I would say no knock for a about 5 seconds! Then after the MMO dripped through the knock came back. For anyone still interested, I made a video of me pouring the Marvel Mystery Oil down the carb with the engine running so you can listen and see if you agree it made a noticeable difference quieting the knock? If so, how would you recommend I go about my next steps with correcting the striking valve or valves? Thanks! Video Link https://www.youtube.com/shorts/caXWZR2PJVM This message was edited by 39Fordfan on 7-26-24 @ 2:31 PM
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| MG | -- 07-26-2024 @ 4:09 PM |
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That sure does sound like rod knock to me...
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| 39Fordfan | -- 07-26-2024 @ 5:01 PM |
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Hi MG. Thanks for your reply. I was wondering if you happened to see the last post of the thread with the 2nd link to the video of me doing a test by pouring Marvel Mystery Oil down the carb with the engine running and the knock disappearing? If it was a rod knock or bearings would it still behave like this during this test? I'm not contradicting you, I'm just trying to get to the bottom of this in order to figure out what to do next. Thanks! Video Link https://www.youtube.com/shorts/caXWZR2PJVM
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| 40cpe | -- 07-26-2024 @ 7:15 PM |
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It sounds like the MMO slows the engine speed when the noise goes away. I'm not there to hear it, but I would slow the engine idle speed at the carburetor to see if it affects the noise.
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| MG | -- 07-26-2024 @ 9:10 PM |
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39Fordfan - I did watch the video where you poured MMO down the carb, and to me, the "knock" sounded even more pronounced than in your first video and not at all "disappearing"...
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| 39Fordfan | -- 07-26-2024 @ 11:59 PM |
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Hi 40cpe. You are right, the MMO does slow the engine speed down. I sped the idle up a bit to start with because I was worried the MMO might stall out the engine. The knock normally occurs at slow idle speed but this time it disappeared with the Marvel Mystery Oil at about the 22 second mark and comes back at about the 27th second mark. Thanks! This message was edited by 39Fordfan on 7-27-24 @ 12:10 AM
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| 39Fordfan | -- 07-27-2024 @ 12:09 AM |
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Hi MG. You are correct, the knock is louder on the second video. But I think it's because I was holding my phone with my left hand while I poured the MMO with my right hand in the 2nd video; I held the phone with my left hand which left the microphone in a better position to record the sound than the way I recorded it with my right hand in the the 1st video. The knock though louder in the 2nd video definitely disappeared with the Marvel Mystery Oil at about the 22 second mark and comes back at about the 27th second mark. Thanks! I appreciate hearing your opinion and we'll see. I suppose it's possible that there's more than one place in the engine that needs attention, though I hope not... This message was edited by 39Fordfan on 7-27-24 @ 12:17 AM
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