Rebuilding a 230

[meadowbrook]

Hi guys, my '50 Meadowbrook's original unrebuilt 230 still runs reliable, does not smoke and pretty much keeps on soldiering, the only issues being a very light tapping noise as it warms up and borderline compression, 100 psi on cylinders 1-4, counting from the firewall end, about 95 on #5 and 85 on #6.

 

If I were to rebuild it, would there be a noticeable seat of the pans felt change if I were to do so per the specs of a 1958 engine? If I remember correctly, by then the 230 had higher compression (8:1?), a more aggressive cam and a 2 barrel carb, going from 103 to 138HP (I'm sure it's gross HP).

 

Are the 2 barrel carbs used on those hard to find? I assume I would need a new manifold. Any changes on the exhaust side of things?

 

Just thinking out loud. 

[deathbound]

No big deal, just FYI.....cylinders are #1-#6, starting at the front of the engine. If you rebuild, may as well take take some off the block/head, regrind the cam, dual carbs/exhaust......an expensive snowball.

[dpollo]

The two barrels used from 55 to 59 are quite rare. I have one on a 218 in my 35 Plymouth

and it works quite well.  The intake  is different but it fits the same exhaust manifold as the single barrel.

 

I have not tried it but it looks like the two barrel from a 273 would fit.  Maybe too much carb for my 218.

 

An easy way to identify the head used from 57 to 59 is the small hole for the temp gauge sender,

although a parts book would be better.  

[meadowbrook]

Cant I just the same head and just shave it as needed?

[dpollo]

Sure you can, but if you are looking for more compression start with one which gives you

the best ratio to begin with.  However, a very effective way to raise compression is to use a 218

head on a 230.   The 218 chamber is smaller.

 

At this late date many engines have been through the rebuilding process, some more than once so it 

might be important to identify your starting point.

 

You can measure the overall thickness of the head from the gasket surface to the bolt bosses and this could reveal

how many times the head has been resurfaced already.  I believed the starting point was 2  inches but  going out to measure several before I wrote this I found some variation + and -  .040.

[greg g]

engines benefit from better breathing and more compression.  Conventional wisdom suggests that .090 can be milled from a stock head and still run on regular grade gas. I'm sure that most of those would have been used for some sort of competition and not put on a street engine.  And most rebuild shops would only mill what was necessary to achieve a flat and true sealing surface.  So with that in mind you are probably safe taking .040 of a normal head.  I did that on mine, plus took .010 off the block.  The machinist who did it also checked, using some clay, that there was sufficient valve clearence.  Remember the thickness of the gasket will put some material back in the equation when bolted back together.  My guy estimated my final CR at about 8.8 to 1.  If you need to bore the cylinders that will figure into the final squeeze figure also.  My engine (from a 56 Plymouth) with the above mods and .030 over pistons, stock cam, single exhaust and dual carbs puts 127 HP to the rear wheels at 3300 rpm (about 63 mph) I also run 2 inch ID exhaust through a dynomax low restriction muffler.  This set up gives me 19/20 mpg on regular on road trips.  Stock HP for the engine was 125 at the flywheel at 3600 rpm.

 

You might want to look at carb adapter single to 2bbl (available from most hot rod shops) and a 2bbl from a 6 cylinder 258Jeep engine. 

 

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Edited March 3, 2016 by greg g

[timkingsbury]

Hi guys, my '50 Meadowbrook's original unrebuilt 230 still runs reliable, does not smoke and pretty much keeps on soldiering, the only issues being a very light tapping noise as it warms up and borderline compression, 100 psi on cylinders 1-4, counting from the firewall end, about 95 on #5 and 85 on #6.

 

If I were to rebuild it, would there be a noticeable seat of the pans felt change if I were to do so per the specs of a 1958 engine? If I remember correctly, by then the 230 had higher compression (8:1?), a more aggressive cam and a 2 barrel carb, going from 103 to 138HP (I'm sure it's gross HP).

 

Are the 2 barrel carbs used on those hard to find? I assume I would need a new manifold. Any changes on the exhaust side of things?

 

Just thinking out loud. 

The 2 barrel is a red herring.  Go get a dodge truck carter ball and ball from a big block 265 ci motor and you have more cfm.   That being

said you have 3 Siamese intake ports feeding 6 cylinders.  You naturally are getting more fuel into the middle port feeding cylinders 3 and 4 and you have too

much back pressure on the exhaust side on the exact same 2 cylinders that have the least amount  of fuel going into them.

 

The answer is easy. Get dual exhaust to let the overall breathing of the exhaust improve and balance the fuel going into each of the 3 intake ports with

dual carbs.  Chrysler knew it was the way to go and showed their hand with dual carbs and dual exhaust from the factory in 1952 on the 265 ci trucks.

 

There are a few schools of thought on why you didn't see that translate to the cars later, but I truly believe raising the compression and the advent of the v8

and hemi took away the need for the dual carbs and dual exhaust in the six cyl flathead. 

 

In your case, freshen it up, bore it out as there is no replacement for displacement, shave the head, put on dual carbs and dual exhaust  and  cam and you will exceed the hp and torque of any 230 coming from the factory.

 

Tim