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Cat Whisker

Should I shave??

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I've been working on this 52 Dodge 230 engine for over a month now and have just about finished. She's got new valves,  guides,  seats, springs, new .030 over pistons, new bearings, seals, gaskets, etc, new oil pump and starter. After cleaning the head, I found someone had stamped the head underside (gasket side) with .023 so I guessing it was already milled/shaved. It does seem like an odd amount to remove but I have no way to know how much, if any was milled off. Checking with my very old Starrett straight edge, it's in great shape with no more than .003 gaps anywhere.

 

I would like to shave more off (around .045-.050 more) After placing a new head gasket in position and setting the head on with putty in 3 chambers and head bolts very snug, I get readings from .204 to .216 of head to valve clearance at the thinnest places after 2 complete revolutions.

In the past, working on other engines, I tried to keep the head to piston clearance somewhere around .090-.100 so I'm guessing this wouldn't be any different for valve to head space.

 

I was able to finally get the engine back where it belongs. See pics.

 

Does anyone see why I shouldn't go ahead and shave .050 off the head??

Many thanks in advance...

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Edited by Cat Whisker

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I did .010 off my block, and 040 off the head, plus running a single sheet copper head gasket from the Marine parts bin.  My machinest calculated a 8.2 to1 cr on my 56 230. Think stock was in the 7 to 1 area. This with .030 over pistons also. Runs great on 87 octane, lots of reserve umph when needed.

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I thought this was a personal grooming thread at first glance.  When I first read it my thought was. Marijuana is now legal and haircuts are against the law.  It took 50 years but the hippies won after all.   Peace!

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4 minutes ago, greg g said:

I did .010 off my block, and 040 off the head, plus running a single sheet copper head gasket from the Marine parts bin.  My machinest calculated a 8.2 to1 cr on my 56 230. Think stock was in the 7 to 1 area. This with .030 over pistons also. Runs great on 87 octane, lots of reserve umph when needed.

I forgot to mention that I did take some of the top of the block to deglaze it. I removed no more than .002 at the most. The head gasket I plan on using is a Fel-Pro with copper on one side. With the numbers you have on yours, they sound great. I'll bet it's a real pleasure to drive. If I can reach something close to 8 to 1, I'll be a happy camper. Thanks and take care.

 

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1 hour ago, Plymouthy Adams said:

the little increase in CR will not be so great that you need to sacrifice metal for future clean up as needed....at least that is my thinking....you can do either way....your money your project...

If I can get something close to 8 to 1, I think that will wake it up just a bit. My husband left me this project which has become more of an obsession than a project to finish it. As for the money, I have a J2 mill and with this stay at home stuff, I have plenty of time. I was just hoping that someone would have some experience with the head to valve clearances on a flathead Dodge 6. Thanks and take care.

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Well - to really find out what you have, measure the CC's (using a buret) in the head and add the compressed thickness of the head gasket to get your head's combustion chamber volume. Don't forget to add in volume from the cylinder assuming the pistons might be below deck at TDC. Once you know these pieces of info you can calculate your CR, and figure out how much to cut. I dont think you have to be as concerned about valve to head clearance as it's not as big a problem as with an over head valve engine where piston to valve clearance is an issue.

 

Most of these flat heads are around 7:1, with the later engines having increased CR of around 8:1. Increasing the CR will increase the HP and torque as you know.

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50 thou is a nothing cut in terms of interference fit with the valves...GIVEN you are certain no other cuts have been done prior....the only way to determine this is to do a CR check and modeling clay on the head and cycle the valves...read the specs....

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3 minutes ago, Plymouthy Adams said:

50 thou is a nothing cut in terms of interference fit with the valves...GIVEN you are certain no other cuts have been done prior....the only way to determine this is to do a CR check and modeling clay on the head and cycle the valves...read the specs....

I did the clay (Play-Doh) in 3 cylinders. That's how I got the measurements of .204 to .216 of head to valve clearance at the edges of the domes (thinnest area). Thanks again and take care.

 

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Look at the specs for the 218 from 42 through 54.  Each bump in hp and torque was accompanied by a bump in compression ratio, the same with the 230.  We're other things involved like ignition advance curves, maybe slight tinkering with camshaft profiles sure but most of the gain came from increased compression.  Intakes changed little, exhaust even less, carburetors basically the same, combustion chamber design and valve sizes nearly identical, port sizes and flow patterns pretty much standardized. More squeeze more bang simple as that.

 

http://carnut.com/specs/gen/ply40.html

 

http://carnut.com/specs/gen/ply50.html

 

http://carnut.com/specs/gen/dodge40.html

 

 

http://carnut.com/specs/gen/dodge50.html

 

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21 minutes ago, greg g said:

Look at the specs for the 218 from 42 through 54.  Each bump in hp and torque was accompanied by a bump in compression ratio, the same with the 230.  We're other things involved like ignition advance curves, maybe slight tinkering with camshaft profiles sure but most of the gain came from increased compression.  Intakes changed little, exhaust even less, carburetors basically the same, combustion chamber design and valve sizes nearly identical, port sizes and flow patterns pretty much standardized. More squeeze more bang simple as that.

 

http://carnut.com/specs/gen/ply40.html

 

http://carnut.com/specs/gen/ply50.html

 

http://carnut.com/specs/gen/dodge40.html

 

 

http://carnut.com/specs/gen/dodge50.html

 

Great reference info. Many thanks for sharing. I'm going to get the head mounted on the mill table this evening and let the chips fly. Thanks and take care.

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8 hours ago, greg g said:

I thought this was a personal grooming thread at first glance.  When I first read it my thought was. Marijuana is now legal and haircuts are against the law.  It took 50 years but the hippies won after all.   Peace!

And now we are all Bald.....

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Don't be shy take the full .050" off you will like it. I did .070 once it got to full clean-up. 

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I did my '56 to .060.  Not running yet, but assembled.  Seems fine.  After the head mill and some chamber grinding, I think it's at about 8.5CR.  checked it with a big syringe to measure out the diesel and did the math.

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6 hours ago, Veemoney said:

Don't be shy take the full .050" off you will like it. I did .070 once it got to full clean-up. 

That's what I did. It cleaned it up real nice. I was going by the stamp of .023 that was already on the head so I guessing/hoping that I'm at .070 plus the .002-.003 I took off at first to deglaze it. Thanks for the vote of confidence. 

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4 hours ago, kencombs said:

I did my '56 to .060.  Not running yet, but assembled.  Seems fine.  After the head mill and some chamber grinding, I think it's at about 8.5CR.  checked it with a big syringe to measure out the diesel and did the math.

I would like to get this puppy together but I am going to cc it just to have an idea. If I can reach something around 8 to 1, I'll be a happy camper. Thanks for the info and take care.

 

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With those valve clearances you could shave another .080 off and be safe.  On the OHV engines I build I try to keep the valve to head clearances to no less than .125.

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35 minutes ago, Adam H P15 D30 said:

With those valve clearances you could shave another .080 off and be safe.  On the OHV engines I build I try to keep the valve to head clearances to no less than .125.

Thanks for the info Adam. This is the 1st OHV engine that I have done. Play-Doh is my friend. I did take .050 more for a total of .083 off the head and .008 off the top of the block. The top of the pistons are still below the deck, but just barely. I just finished the head yesterday.  I also took about .007 off the top of the head to square it up at the bolt holes and the water gasket surface. The mill marks look rough in the picture but the surfaces are really smooth. I should have this puppy started in a few days. Thanks again and take care.

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1 hour ago, Cat Whisker said:

Thanks for the info Adam. This is the 1st OHV engine that I have done. Play-Doh is my friend. I did take .050 more for a total of .083 off the head and .008 off the top of the block. The top of the pistons are still below the deck, but just barely. I just finished the head yesterday.  I also took about .007 off the top of the head to square it up at the bolt holes and the water gasket surface. The mill marks look rough in the picture but the surfaces are really smooth. I should have this puppy started in a few days. Thanks again and take care.

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Looks good.  Take a carbide bit and knock the sharp edge off where it transitions to your combustion chambers before you install.

I've said it a lot, if I were to ever go through my 230 again, I would install 218 rods and buy pistons that came to 0 deck.  Pistons below the deck are a quench-killer but if you're a few thousandths below it will be fine.

Edited by Adam H P15 D30

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23 hours ago, Adam H P15 D30 said:

Looks good.  Take a carbide bit and knock the sharp edge off where it transitions to your combustion chambers before you install.

I've said it a lot, if I were to ever go through my 230 again, I would install 218 rods and buy pistons that came to 0 deck.  Pistons below the deck are a quench-killer but if you're a few thousandths below it will be fine.

I'm sure glad someone is out there to keep me honest. Of the heads/blocks I've done in the past, I have chamfered around the sharp edges. I had forgotten this time. Many thanks for the reminder. I cleaned the head again and give her a good coat. I got it mounted and torqued down yesterdy. I was able to add some of the goodies now the head is on. Many thanks again and take care.

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I took .070 off my head and .012 off my block and liked the results. The only thing I regret is now if I change can I really have to watch the lift of the new grind. I would record the new valve clearance and write it down for future reference.

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Unless I missed something, you don't have the heat shield that goes between the exhaust manifold and the fuel pump.  Should be one there. It's made from light sheet metal. The down loads section of this site has a pattern. It's a good thing to have in hot weather.  Tell us about the carb and distributor, they don't appear stock. Nice looking engine.  With you increased cr, it's going to want a bit of timing advance from stock.  Are you familiar with using a vacuum gauge to set timing?  It is a good process that will take your mods into account and do a real time, real conditions setting.  What are you running for spark plugs?

 

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