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232 rebuild questions |
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vinny
Supporter of TheAMCForum Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 2837 |
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I have a 66 and a 67 engine 232 both with 2 barrel WCD carbs. As I remember neither have water hoses going to the intake manifold and I assume they don't need it because the intake manifold is bolted directly to the exhaust manifold. I can see that any change in manifolds where the exhaust is not connected to the intake would require heating. I have had no issues with carb icing on the 232 but did occasionally when the 196 was in the car. That only happened in Vancouver with high humidity and at cold temperatures like in heavy fog. Possibly I did not have heater hoses connected to that manifold where a pipe might have run through the manifold.
Agreed the two barrel is no advantage at lower RPM but comes into its own at higher RPM. Also agreed that any way to get more fuel and air into it at lower RPM for more torque is what is needed. |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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I see Matt paid attention in science classes and didn't necessarily need to learn this in automotive sho classes. You'd have been very interested in my 232 experiments, junkie. I can recall the first morning the temps dropped below about 40 after I put the heaters on and chopped off part of the intake to clear the center tubes of the headers. I had converted to manual choke to overcome the issues there (lost that heat tube that went through the exhaust and heated the choke stat. I started the car, and had the choke out a bit and took off - got a ways and let up on the throttle and ........... it didn't return to idle, not even the fast idle for being slightly on choke. RATS, it was running about 2,000 RPM and the throttle didn't return. So I pulled over and opened the hood and looked at the carb and instantly knew the trouble - it was WHITE with ICE literally formed - not just frost, but ice on the throttle body of that carb. Of course the fan blowing cold air across meant that the natural warmth under the hood had no impact, wasn't any help at all. I operated that way for a bit -sticky throttle, poor driveability, then yanked the headers and put another intake and exhaust on it. Iowa has some VERY dry air in the cool days but also has very humid air on cool or cold days - and it was just too much trouble to deal with. If you have studied the later intake designs, for the later 258s, look into the intake under the carb and you see it's not flat there - they have nubs sticking up to warm not just that section of the intake, but the whole area - including carburetor, to prevent ICING in certain climates, improve cool weather driving, etc. - not just COLD, but COOL. When air is compressed you pack the molecules closer together and they have to give up that energy of their movement and it's given off as "heat". when you let the air expand, the molecules are farther apart and move more - and take energy away from whatever is in contact with the air - cooling the material because the air is stealing heat energy. So when the air expands as it leaves the venturi area it robs the heat energy from that area and since cold air can't hold as much water as warm air, the moisture is dumped out of the cooling air in the form of condensation and eventually water droplets, frost etc. - the more humid the air is, the more risk of carb icing. I worked on many many dozens of heat riser valves, 6s and 8s the complaint was always the same - poor cool weather driveability, or carb icing, choke not coming off all the way, etc. Usually that valve was just stuck, sometimes it was toast. |
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billd
Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894 |
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Agreed, and well said. I have actually seen 258s with the ORIGINAL "plastic" valve cover - and still sealed. The issue as I saw it personally was that if it did start to leak the owner or some young guy that didn't know squat would come out and gee, I bet it's just LOOSE......... and they'd tighten the nuts on top and spread that cover, squash it, deform it. then it was history. But I have seen them resealed and properly torqued and not leaking even to this day. And right, again, on the fact that not all later 258s had that valve cover. That was just for a time - started in 81 I think...... 80 still had the stamped steel cover, I know 82 had the plastic. Then later AMC cried uncle - seeing all the dopes out there who didn't know what they were doing destroying things and moved to the better cover. Hey - AMXRWB - I remember the Chevy small block valve covers WITH gaskets - they weren't much better! LOL Man, every one I pulled to repair/reseal I had to carefully hammer back to straight - yup, some feller came along and gee, simply tighten it and it will stop leaking. |
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purple72Gremlin
AMC Addicted Charter Member Joined: Jul/01/2007 Location: Illinois Status: Offline Points: 16591 |
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Never seen a cracked head on a 232-258. If you crack a head then you had to have it glowing red hot and poured cold water in it.
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farna
Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19611 |
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Only late 1999 and early 2000 4.0L heads are prone to cracking -- casting #0331. That was fixed -- look for "TUPY" cast in the center for those years. I ran a 2000 head without that for a long time, but I wasn't hard on the vehicle (83 J-10, 258 w/2000 4.0L head). Just a street truck with some light hauling, no off roading or anything like that.
The pre late 80 199/232/258 with a cast iron intake that bolted to the exhaust manifold was indeed heated by the exhaust and didn't need water to heat the carb. Even with a header and no exhaust bolted to the intake it fared well in cold weather, just a bit cold natured for the first 15 minutes or so. The cast iron intake would absorb and transmit a lot more heat than an aluminum intake. Without the exhaust bolted to it it just took longer, but would have to be a really cold, damp day to make it ice up after if got up to full operating temp. Not as bad as the aluminum intake... |
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Frank Swygert
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ramblin64sw
AMC Nut Joined: May/31/2012 Location: SoCal Status: Offline Points: 274 |
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The 4.0 head swap certainly isn't a simple bolt it on and run it, on the early blocks. If you are up for the challenge, I think it's worth it. A head that's more efficient is an en engine that's more efficient. The engineers at Jeep seemed to believe the upgrade was needed to bring the old 6 into the 21st century.
Pushrod's are a pretty minor problem. Even if you don't swap to the newer head, the pushrod length needs to be checked when rebuilding an engine. Milling the block and head, head gasket thickness, having the cam reground or replaced, replacing rocker arms, grinding valve seats and valves, they all have an effect on rocker arm geometry and pushrod length. Don't just assume your engine builder will get it right. Companies like Manton and Smith Bros can custom make you a pushrod to any length you need. Using a 4.0 head, .100" long sbc valves, and shiming the pedastals for the added .060" valve length allowed me to use a ford 351/400M pushrod. But please don"t assume this will work just right for you. Measure twice and cut once! Hope this helps, although, if you want less work, swapping a 4.0 and overdrive trans from a cherokee will give you the best bang for the effort and $'s. If I had to choose, I would start by upgrading the trans and rear end gear before upgrading the engine. Good luck!
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DaemonForce
AMC Addicted Joined: Jul/05/2012 Location: Olympia, WA Status: Offline Points: 1070 |
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Well I won't say you're wrong. It's been the constant case.
Might have everything to do with it. These engines will have 160-180K by the time I get them and the steel valve covers were only issued to CJs. Which is weird because some of the DJs had plastic valve covers and they didn't leak. They also used some RTV silicone equivalent and the bigger head bolts. Every 258 head I've pulled comes from a similar year AMC as my wagon and has been extremely prone to warping and cracking. Every time I've revisited this issue with magnaflux I've gotten a reported failure. This makes me wonder just how much damage my grandfather did to this car and to my knowledge it's the cooling system that would have failed in each case. I've had that on every V8 car and truck I've ever had but never on the L6.
This. It may be a daunting process but works and is minimal time compared to my port/polish jobs.
Also this. One thing about the adjustable pushrod length checker tool, I did NOT have or use this when I did my 4.0L but waited until I had rolling rockers before doing pushrod length checks. What I did was fitted a pair of the old stock pushrods to #1, measured it with an ordinary rule to SKU match it and looked for the next size down. Factoring in the excessive lash with a decked block and resurfaced head, I ended up getting a 9.660" Sealed Power SLP-RP-3275 set. You will likely need a set very different in spec if you go through with a head swap. You will also need to redo your pushrods if you go to a set of rolling rockers like I did, if you can. It was already in the works for me, so I planned for it. Keep in mind that you need to fit everything in a very specific order during this remanufacturing process if you want all of this geometry to be right. In my case that meant a lot of waiting for parts and a lot of time for working on other parts while I wait.
Again this. I bothered with the grand total of two hours of work in April 2012 before my 4.0L build ever started, to pull a nice 7120 head from a H.O. 4L Cherokee at half price from the local picking yard. Everyone agrees this is the superior head and is only prone to cracking if you're constantly wild with it and have cooling failures. The original intention of this job was to study the head design, combustion chambers, profile the valves for oversize refit and get the max port dimensions on the entire assembly for cleaning, reman and ultimately HEAD SWAP. So I definitely had some idea what I was doing with this back then but ended up pouring 2-3 weeks of my time during the last time I had it on the bench to clean, port, polish and paint this head for war. It is the top end of my stroker. The original Renix head on this engine did NOT appeal to me and looked like trouble. It is, so avoid it. |
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1971 Javelin SST
American 304 2v | FMX | AM20-3.31 1983 American Limited Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72 |
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Airdrie AMX
AMC Nut Joined: Aug/08/2010 Location: Alberta, Canada Status: Offline Points: 329 |
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Ok I have to ask, how do you go about measuring up for pushrod length without an adjustable pushrod? Don't say you used a ruler LOL
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72 amx javelin 401 4spd
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DaemonForce
AMC Addicted Joined: Jul/05/2012 Location: Olympia, WA Status: Offline Points: 1070 |
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No, it was a square. The point of this wasn't to get an accurate measurement but estimate the length to do a SKU match. I have no interest in custom pushrod length. I just needed an available replacement set that worked. I had the worst availability when it came to replacement parts for this engine. I've had all kinds of weird happenings like orders being cancelled due to zero inventory. I had a list of pushrods by length and SKU and have no idea where this came from but it works. This is the meat of it:
Jeep Push Rod Lengths Manufacturer Length Part Number Engine Year Sealed Power 9.641 RP 3275 4.0L 1987-96 “ “ 9.748 RP 3276 4.2L 1989-90 “ “ 9.695 RP 3235 4.2L 1983-88 “ “ 9.622 RP 3200 4.2L 1981-82 “ “ 9.594 RP 3171 4.2L 1980 Custom Length Push Rods Sealed Power 9.500 RP 3186 “ “ 9.513 RP 3190 “ “ 9.547 RP 3197 “ “ 9.620 RP 3172 “ “ 9.602 RP 3257 Manufacturer Length Part Number Engine Year Pioneer 9.639 PR-437 4.0L 1987-96 “ 9.728 PR-399 4.2L 1989-90 “ 9.700 PR-353 4.2L 1983-88 “ 9.622 PR-333 4.2L 1977-80 “ 9.594 PR-301 4.2L 1972-76 Stamped Rocker “ 9.656 PR-332 4.2L 1971-74 Cast Rocker Custom Length Push Rods Pioneer 9.500 PR-310 “ 9.547 PR-327 “ 9.560 PR-310A “ 9.668 PR-303 The specs are related only to the 4.0 and 4.2 engines so it's either part of someone's research notes for a stroker or a grab list for pulling a set from the junkyard. |
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1971 Javelin SST
American 304 2v | FMX | AM20-3.31 1983 American Limited Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72 |
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kronik
AMC Apprentice Joined: Jun/13/2011 Location: Oregon Status: Offline Points: 147 |
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Thanks for all the great info everyone.
I think I’m going keep the 232 head that I have. I thought I read something about an oiling issue due to a narrow passage which can be solved by modifying a head bolt? Can somebody please explain. How much should I remove from the head to achieve 9.5 CR? Considering I might use a cam with lift in the low .500s... I don’t want to take off too much. As far as intake goes, I think I will use an offy 4 barrel or an 80s aluminum 2 barrel at least. I can’t upgrade the cam without doing the intake and exhaust. Exhaust will be replaced with some type of header hopefully. Can’t seem to find much for the driver side starter though. |
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65 American
67 American |
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