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Jschrift

1950 P20 218 put a 1956 P28 Head on it.

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Hi, I have a 1950 Plymouth P20 in my 1948 Dodge B-1 C Barnfind. I have it running really well but I am noticing some leakage around the head. I appears there may be a gap and it may be a bit warped. I have read so much about 230 heads yes or no shave it down yes or no. Anyone have any real life experience? I am new to all of this and I want to do it right but not spend tons of cash. I would prefer to take the 230 head to the machine shop because its off and ready to go. Any help would be greatly appreciated. I have a dual carb with dual exhaust and it runs like a top. 

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The way I see it,you don't have much choice. Your engine is "broken" now,and you have to mill the head to fix it.

 

MY best advise would be to tell the machinist to mill as much as he had to take off to make it flat,and not one thousandth more. Make sure he keeps track of and tells you how much it is milled.

 

You hear all kinds of stuff,but these old heads were thick,and they had very low compression ratios. Since you already have the head off,that makes it a no-brainer.

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The subject of Cylinder head swapping has been pretty thoroughly discussed on this forum .  It should not take too long to uncover the threads.

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Hey just a note the head isn’t currently off. The one on the 230 is but not the 218. It runs fine with very minimal leakage just know it’s gonng to have to be done but didnt know if there was a benefit to using the 230 head! Any threads you could point me to would be great! It seems like I’ve read several that discuss it but none that talk about the outcome! Thanks 

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1 hour ago, Jschrift said:

Hey just a note the head isn’t currently off. The one on the 230 is but not the 218. It runs fine with very minimal leakage just know it’s gonng to have to be done but didnt know if there was a benefit to using the 230 head! Any threads you could point me to would be great! It seems like I’ve read several that discuss it but none that talk about the outcome! Thanks 

There may be some differences that would matter between the 218 and the 230 head,but I am not aware of them. IF you are doing a show-quality restoration the casting numbers might make a difference,though.

Since this is an unknown head to you,have it magna-fluxed  to check for cracks before you spend the money and time to mill it and put it on your block.

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What you need to check is if the head is a bypass version or not. Look for a little bump in the front behind the water pump. If both of them have it or neither of them have it you are good. If one does and one doesn't you'd have to seal that hole. 

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I am a bit confused. You say your engine runs really well but there is a "gap" and you fear the head may be warped??? If your head gasket were leaking the engine would not run well. Have you done a compression check and if so what are the numbers? Is there a coolant leak? If so where is this leak? 

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It runs like a top. No coolant leak it’s more of you can see a tiny bit of seeping of oil I assume on the side of the head. I haven’t done a compression check yet. On this edge see photo. 

 

 

 

 

Hey just a note the head isn’t currently off. The one on the 230 is but not the 218. It runs fine with very minimal leakage just know it’s gonng to have to be done but didnt know if there was a benefit to using the 230 head! Any threads you could point me to would be great! It seems like I’ve read several that discuss it but none that talk about the outcome! Thanks 

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No hump on either head. Cool! That’s good to know! There isn’t any coolant in the oil or anything. Or leaking you could just see some seeping at the edge Of the head on the side above the valves. Figured it had to be head gasket? I was afraid to tighten it anymore that it already is but it’s unknown what the previous owner did. 

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25 minutes ago, Jschrift said:

It runs like a top. No coolant leak it’s more of you can see a tiny bit of seeping of oil I assume on the side of the head. I haven’t done a compression check yet. On this edge see photo. 

 

 

 

 

 

I had a similar,but worse problem with my 1939 IHC pu with the flat 6. The head would leak a quart of oil down the side of the block in maybe 20 miles,and never miss a beat. Pulled the head and it had to be milled 125 thousands just to get the warp out.

When it went back together it had so much rapid pickup it was like it was supercharged. It would easily cruise at 60 MPH before,but took forever to get going that fast. After the milling,it was like driving the 6 cylinder 67 Chevy pu I used to have years ago. It was like a new truck.

 

If someone had told me it was possible for head to be that warped and not smoke or make any of the cylinders miss,I would have never believed it.

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Wow thanks for sharing! I don’t think I’m loosing quite that much oil but that seems to be what’s happening on my end. I have the gasket and the time I’ll more than likely pull it and get it machined and eliminate that part of the equation! Thanks again! 

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What is the source of the oil???  There is no oil in the head, and there is no oil passage between the block and head.  How much oil are you talking about?

 

  Measure both heads from the flat spot under a head bolt to the bottom of the head directly below, stock head should measure 2 inches give or take a couple of thousandths. Previously milled heads will measure short of that. My 56 head milled .050, along with 230 block decked .010 works great, runs fine on 87 octane with initial timing of 5° before TDC, fired off by a 54 dodge truck distributor.

Machinist estimated 8.7 to 1 cr with that work and .030 over pistons.

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Sorry guys last question for tonight! Can pretty much any machine shop handle this work? Or should I search for someone knowledgeable about these old motors? I’m in NC happy to travel if it means someone that knows what there doing! And willing to pay for quality! Thanks 

Edited by Jschrift

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42 minutes ago, Jschrift said:

 

Sorry guys last question for tonight! Can pretty much any machine shop handle this work? Or should I search for someone knowledgeable about these old motors? I’m in NC happy to travel if it means someone that knows what there doing! And willing to pay for quality! Thanks 

If it were me,I would only take it to an automotive machine shop.

 

There is no shortage of automotive machine shops in the Winston-Salem area. Let your fingers do the walking through your local yellow pages and contact the ones that have been in business for a decade or more. There has to be car clubs/restoration clubs in your area,contact them and ask who they get to do their machine work.

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Hey Guys so I grabbed my 230 head this afternoon and I realized I was wrong it does have the bump (I think) I didn't realize it was so small. So I will pull the 218 head and use it but in the meantime I measured this one and it appears to be around 1-13/16" is it way shaved down? See photos is it odd that the chamber is way smaller than the gasket? seems odd? I've never seen one from below. Thanks guys this has been real helpful!

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