1942 Dodge "Job Rated" 218 Bearing Knocking

[Tubeviper]

I drove my '42 in a convoy to a car show a couple Saturday's ago and learned a couple things:

1) The folks who were behind me in the procession commented later about the smoke my rig was blowing.

2) Under certain combinations of speed and engine load, I heard a noise I took to be rod bearings.

OK, so the engine needs to be rebuilt. Until then, I am interested in holding everything together. I read in another topic that 10W-30 was acceptable in these engines but I an see now that its not. When I heard the bearing knock, I had 10W-30 plus a bottle of STP zinc additive.

So I am wondering what oil would be good in a WORN 218, 30W is the spec but I was wondering if there would even be permissible to use 40W plus s bottle of Zinc?

 

Thanks!

[Merle Coggins]

  On 7/26/2017 at 12:15 AM, Tubeviper said:

2) Under certain combinations of speed and engine load, I heard a noise I took to be rod bearings.

 

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A rod bearing knock wouldn't come and go. It would be there always. I would suspect it to be a pre-ignition knock. You might want to recheck your ignition timing and/or fuel delivery. A lean mix can cause the same issues, although you say it smokes too. Is it black sooty smoke like a rich mixture, or is it more bluish like oil?

[The Oil Soup]

What sort of oil pressure are you showing? I have a worn 218 and run 15w-40 diesel, it has zinc already.

[Tubeviper]

  On 7/26/2017 at 12:30 AM, Merle Coggins said:

...  Is it black sooty smoke like a rich mixture, or is it more bluish like oil?

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The truck has always had a blackwater spray effect out of the tailpipe. However, the black smoke was greatly reduced when I put the correct carb on...

 

[Tubeviper]

  On 7/26/2017 at 12:41 AM, The Oil Soup said:

What sort of oil pressure are you showing? I have a worn 218 and run 15w-40 diesel, it has zinc already.

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I show about 40 when cool and 30 when hot. 15W-40? What an excellent idea! 

[clarkoh]

Might try a can of STP to cushion the rattle?  Just my 2 cents. Or some "high test" or some octane booster to allow more timing?

[Mike36]

A rod knock will be loudest with your foot off the accelerator, as in going down a hill. Pre ignition knock will be the he opposite, and be loudest going up the hill with accelerator down. Which do you have? If it's a rod knock, STP or no additive will help. The engine needs mechanical repair NOW. Keep driving it and the rod will be sticking out the side of the block. If it's pre ignition, you already have TOO MUCH timing ( advanced too far ).  I strongly suggest you get a shop manual for your car and study it before you lose your engine.

Edited July 27, 2017 by Mike36