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232 rebuild questions

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kronik View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kronik Quote  Post ReplyReply Direct Link To This Post Posted: Nov/19/2017 at 9:07pm
Thanks for all the replies...

Questions concerning the pistons / compression:
1) what is factory compression?
2) can I just deck the head to raise compression? If so how much?
3) What is my current piston compression height, 1.581? And does the compression height change with the later model 232’s?
4) the 258 and 304 pistons fit? Are there anymore that cross over?

Edited by kronik - Nov/19/2017 at 9:35pm
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tomj View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Nov/19/2017 at 9:08pm
i would find a good machine shop and spend enough to get solidly good work done. in my experience even decent shops tend towards the "its only an old car" and dont do the best work they can do. it really matters, at any power level, and you'll get "free" (expensive, free :-) power from an ordinary engine that is balanced, has all new valve springs all measured and fit (do not trust package markings).  if it's not right it's wasting or not making power.  i bought NEW valve springs, correctly specified (still ahve the invoice) and they shipped the wrong springs; same dimension different rates.

pay extra attention to everything in or on the head. buy a NEW oil pump, pump bodies wear, not just gears. dont need high volume or pressure. in my somewhat foolish experimentation with oil pumps even .001" changes in pump internal clearances makes a measurable difference. it doesnt add power -- it adds reliability in the form of longer life and lower wear.

check everything, assume nothing. weigh each and every rod, check each for straightness. this costs, but all that stuff is 50 years old, you cant know whats been done to it. (there exist at least for the 195.6 rods that are visually identical, with the SAME CASTING NUMBER, that weigh 100 grams more than the other set. eg. six of one weight, six of another.)

some stuff you can "do later" (carb, alternator, etc) somethings are a huge PITA to do later. i wouldn't over-cam it. personally i would buy a Foredom grinder, a big box of abrasive rolls, and clean up the flashing etc in the head you have, then give it to someone who will cut very good multi-angle seats, undercut the stems, and make what you have flow. it will probably cost less than all the 4.0 stuff. the 4.0 head is certainly superior. but most of the "low hanging fruit" you can get with good, solid machine work on parts you know to fit absolutely and first time.

quality work always pays in the long run.

1960 Rambler Super two-door wagon, OHV auto
1961 Roadster American, 195.6 OHV, T5
http://www.ramblerLore.com

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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 5:51am
65-71 sixes were 8.5:1 compression, 72-78 8.0:1.
Compression height was the same for all IIRC... there are 2-3 different rod lengths though, and piston dish sizes change over the years. I wouldn't be concerned with "what other pistons fit" -- you can find just about anything you want for the six.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 7:28am
One thing to keep in mind is that replacement head gaskets are thicker then the stock steel shim head gasket; thus lowering your compression ratio. Getting a custom made head gasket will prevent this and/or having the block decked to make up for the replacement head gasket's thickness will keep compression ratio where it originally was (8.5:1 if accurate) or you can increase it slightly.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CDNragtop Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 7:37pm
Hey Guys,

This is a great thread as I'm in a similar spot with a 232 auto in a 66 American convertible I bought two years ago. I've yet to get it on the road, dealing with numerous restoration activities and not enough time to get them done. In my youth I had numerous AMC cars with V8s but am going to stick with the six for now. It seems healthy enough for a mild upgrade without pulling it out for a rebuild. My exhaust is rusted out so I need to make a few decisions first

I didnt think that there were any viable options for upgrading the earlier generation(pre-72?) 232 with a better intake, carburation and headers while keeping the original cylinder head. I also heard about header clearance issues with starters too. Replies on this thread don't even mention these issues and that concerns me.

I started getting interested in the various 4.0 FI discussions but after reading all the posts, I am realistically not willing to deal with the numerous conversion issues. I even thought about just getting a 4.0 head and going with a carburetor but again, now I see issues with oiling, closing un-needed cloolant passages, pushrod length, etc.

I checked Clifford Engineering previously and saw they listed some pre-72 performance parts but feedback I've seen from club members is poor regarding the quality of their products. True?

So, what intake and exhaust manifold upgrade options are available to bolt onto a 1966 232 head? If I need to replace the head to do these things, what is recommended, outside of a 4.0 head and all the modifications it seems to need? Please remember the starter clearance issues...

Thanks guys!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaemonForce Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 9:37pm
Most of the intake options for the earlier engines exist because of the continued production run and evolution of the L6 across manufacturing periods in AMC and VAM. When you find a 1980ish intake with something other than the single barrel Carter and start finding twin barrel optioned heated intakes with passages for coolant to run through it and get things warm during the dead of Winter, you have something. Offenhauser and Clifford made a run of single plenum 4bbl intakes but good luck finding them.

Despite being intake orphans in each generation, the one and only genuine issue with these engines are the heads. Namely the junk head used on the widely popular 258. Poor airflow, a plastic valve cover that leaks and never seals, a critical hot spot on the siamesed #3-#4 exhaust ports that makes the head and exhaust manifold prone to cracking. If I had a 232, especially the early one, I would keep the 232 head for experimental use before production. Tear it off for cleaning, porting, polishing, new valves and then test fit the later intakes with a Carter 2bbl or Motorcraft 2100. The stock exhaust should be fine, or at least as fine as the woes you get with the starter being on the same side as the exhaust. I didn't know there were headers still available for the 232/258. Must be as rare as teh 4bbl intake. Ermm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Nov/20/2017 at 10:11pm
LOL - here we go - you must have the worst luck of anyone out there calling the 258 head junk and stating it is prone to cracking. Odd, I've owned several, and took one all over the country and put over 80K on it with NO issues at all, none. And the 258 valve cover wasn't plastic in all years - only certain years. For example, the 1980 and prior 258 had steel valve cover. 
The 4bbl intake can be had all over the place - OFFY has a decent one, you can get them to this day on ebay and craigslist. 
I had headers on my 68 232 - and I'd never recommend it to anyone who lives in a place other than a warm climate - constant throttle freezing as you give up the ability of the exhaust manifold to warm the carb and intake. 
The water heating wasn't an option. It was a necessity, and not for the "dead of winter". Carburetor icing can start in even with temps in the 40s. Been there.
That water heated intake by Offy was to replace the intake on the 1981+ cars and/or to make up for lack of exhaust heating the intake if used on prior years. The stock 258 beginning after 1980 had a ceramic heater under the carb that warmed the intake until the coolant reached 165 degrees, then the electric heater kicked out and the coolant kept the intake warm. That was necessary as AMC divorced the intake and exhaust and streamlined and lightened the exhaust manifold making it more of a "free-flow" exhaust manifold. The intake was aluminum to save a lot of weight. They were all 2bbl in the states as I recall. I've never seen a 1980 or later with a 1bbl and not so sure they didn't make that change earlier. 
AMC also had to move to an all-electric choke when they divorced the manifolds as there was no longer a tube through the exhaust manifolds to heat the choke stat. 
I did put a stock 2bbl intake on that car but didn't see much difference other than top end. 
I love the 232 and 258 and frankly never had troubles with either, and can't complain about either except their rocker arm setups. I've put hundreds of thousands of miles on 'em over the years and have owned several of each.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2017 at 1:32am
Yes. Intake manifold heating is very important on these inline sixes. The intake manifolds literally hang off the side of the engine, exposed to the cold air blowing over them as the car drives down the road. Cold manifolds don't vaporize fuel, and non-vaporized liquid fuel does not distribute evenly to all six cylinders nor does it burn well. It just dribbles into the bottom of the manifold and runs into the lowest cylinder, so that cylinder has a bunch of liquid fuel to try and burn while the others are lean. It's not good. 

Intake manifolds refrigerate themselves. The liquid fuel changing phase from liquid to gas inside the manifold absorbs heat from the manifold. The manifold will get colder and colder unless heat is introduced from an outside source. Even engines that are running at operating temperature need a little manifold heating. 

An air cleaner funneling cold air into the carburetor doesn't help. 

Thermostatically controlled heating on the carburetor intake air and manifold heating are good. Just enough heat, but not too much. 
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Post Options Post Options   Thanks (1) Thanks(1)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2017 at 6:32am
Replacement head gaskets are a little thicker -- but not that much. You might lose 0.1 compression, but will never notice it.

The 4.0L head isn't a hard swap. Filling the triangular ports on the passenger side (US vehicles) is easy -- brake cleaner to clean them first, then stuff with toilet paper until you have about a 1/8" deep hole, then fill with a good epoxy (JB Weld is what I've used three times...). Let cure a couple hours then trim level with a razor blade if required, and add some more epoxy to the center where it will likely sag. Another couple hours and trim again, then let cure over night. Turn over and spend 15-30 minutes with a water hose washing the TP out. Don't worry about getting all of it, it will dissolve -- won't clog anything. I still get most of it out.

No oiling issues. The head and/or gasket blocks the oiling port on the old block. New lifters will have an oiling hole for the pushrods. You will need new hollow pushrods -- and that is the only catch. Someone on here actually did this, and I think they ended up using Ford 351 Cleveland pushrods... but I'm not certain. You will need to get at least one adjustable length check pushrod and set up one cylinder. Not real hard to do -- see http://www.compcams.com/Technical/Instructions/Files/Verifying%20Pushrod%20Length%20And%20Rocker%20Arm%20Geometry.pdf. I'd start by doing that with the stock 232 pushrods, just turning engine over by hand. If thye check out you just need to find a hollow pushrod that length. I'm not sure if they will work, as there are some geometry changes in the valve train of shaft vs. pedestal rockers. For one thing the rocker arm ratio is different -- 1.5:1 for shaft, 1.6:1 for pedestal -- so you get a little higher lift with a stock cam. This (pushrod length) is the only difficult part. You will have to clock the starter to clear the exhaust (twist it in the casing so the solenoid clear the header), but the left hand starter will otherwise just clear the 4.0L exhaust.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote AMXRWB Quote  Post ReplyReply Direct Link To This Post Posted: Nov/21/2017 at 10:02am
The 258 head is not crack prone.The 4 liter head is crack prone.Do a net search and you will get many pages of information on the topic.Nothing wrong with the plastic cover.It was never designed to last 10 years.Today many items under the hood are plastic. The last 258 heads had a aluminum cover from the factory.Remember the small block chevy years with the metal valve covers with no gaskets and rtv to seal them?They lasted a few months out on the street before they leaked.
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