Cracked exhaust manifold blues

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   I recently purchased a 65 Classic 660.  Had a tick once warmed up.  Disassembled the intake and exhaust manifolds and found multiple cracks around the heat riser on the exhaust manifold.  Curious if the '69-'80 manifold would fit?  I can find those easily.  Currently attempting to braze the cracks, assuming these engines don't run too hot.  Does anyone know of an alternate year manifold that fits, or a salvage yard that may have a replacement?

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ramblingsolo Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Fan Joined: Jun/26/2019 Location: michigan Status: Offline Points: 10	Post Options Post Reply Quote ramblingsolo Report Post Thanks(0) Quote Reply Topic: Cracked exhaust manifold blues Posted: Jun/26/2019 at 8:59pm
	I recently purchased a 65 Classic 660. Had a tick once warmed up. Disassembled the intake and exhaust manifolds and found multiple cracks around the heat riser on the exhaust manifold. Curious if the '69-'80 manifold would fit? I can find those easily. Currently attempting to braze the cracks, assuming these engines don't run too hot. Does anyone know of an alternate year manifold that fits, or a salvage yard that may have a replacement?

mixed up Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jun/16/2015 Location: Monroe mich Status: Online Points: 2178	Post Options Post Reply Quote mixed up Report Post Thanks(1) Quote Reply Posted: Jun/26/2019 at 11:12pm
	what size motor. your in Michigan try ken havakost out of Monroe he is in to nash and has lots of older model ramblers on is property he has a web site not Shure what it is
	69 amx 290 auto 65 220 290 4spd 80 ford fairmont

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19692	Post Options Post Reply Quote farna Report Post Thanks(1) Quote Reply Posted: Jun/27/2019 at 7:00am
	65 should be a 232. You can use a later exhaust manifold, but must change the intake as well. Any 65-79 exhaust manifold should bolt up, I don't think there were any changes that would keep it from bolting to the intake. Both manifolds were changed in 1980 when the six went through a weight reduction program (and lost about 80 pounds!). The change occurred in calendar year 1980, in January, so early 1980 models will have the old design manifolds and heavier engine. You can use the 80+ intake and exhaust manifolds as well, but must change both. Not a bad thing if you don't have a 2V carb. The BBD carb isn't bad, but you don't want the electronic version that will be found on at least 82+ engines, maybe 81 (would have to check TSMs). CARS had the electronic version, Jeeps still had a non-electronic BBD for a few more years. I'd find a smaller Motorcraft 2100 though. You do need an adapter to use it, but a lot of Jeepers do this and the adapter is readily available (Rochester to Holley adapter). The 1.08 venturi model delivers 287 cfm and is a good fit, but you can run a good bit smaller if you find one. The 1.08 is in a circle on the float bowl. Here are the other sizes: 0.098 - 190 cfm, 1.01 - 240 cfm, 1.02 - 245 cfm, 1.08 - 287 cfm, 1.14 - 300 cfm, 1.21 - 351 cfm, 1.23 - 356 cfm, 1.33 - 424 cfm Here's a good write-up of the conversion: https://forums.off-road.com/jeep-short-wheelbase/50151-how-install-motorcraft-2100-258-jeep-detail.html The BBD as used by AMC on the sixes is rated at 195 cfm. Any of the 0.098-1.08 carbs will be a good fit for a stock engine. I wouldn't go over 1.08 without a much better cam though, and the 1.01 or 1.02 would be the best for a stock motor IMHO -- the 1.08 is easier to find and not too big though. This is the best technical page I've found for the Motorcraft 2100, but he doesn't have the venturi size/cfm chart on it... which I found odd since he has everything else you could think of! https://www.carburetor-parts.com/Motorcraft-2100-Technical_ep_422.html Edited by farna - Jun/27/2019 at 7:05am
	Frank Swygert

ramblingsolo Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Fan Joined: Jun/26/2019 Location: michigan Status: Offline Points: 10	Post Options Post Reply Quote ramblingsolo Report Post Thanks(0) Quote Reply Posted: Jun/28/2019 at 7:26am
	That is good info, thanks Frank. I see a few later model manifolds on ebay with air ports. I think I'll just pick one of those up so I can continue to use my intake and holley 1931. She ran good before I pulled it apart. Side note: I opened up the valve cover last night and I see that all of my valve seals are in little pieces stockpiled around the springs in the valley. Looks like I'm going to pull the pan to check the pump pick-up for shrapnel. Does anyone know if people have issues with the valve seats in these heads when running unleaded fuel? In my experience, old castings are hit or miss on the seat hardness.

vinny Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 2837	Post Options Post Reply Quote vinny Report Post Thanks(1) Quote Reply Posted: Jun/28/2019 at 9:24am
	Well if you had a slant 6 Chrysler you could buy one from Dorman but I don't see a listing for the AMC.

ramblingsolo Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Fan Joined: Jun/26/2019 Location: michigan Status: Offline Points: 10	Post Options Post Reply Quote ramblingsolo Report Post Thanks(0) Quote Reply Posted: Jun/28/2019 at 10:57am
	Vinny, are they actually different manifolds? The one posted here looks identical to what I have. https://www.ebay.com/itm/4-2L-AMC-Jeep-International-New-Exhaust-Manifold-199-232-258-Inline-6-cyl/123795494719?hash=item1cd2c9573f:g:SsQAAOSwnFZXUcYi#vi-ilComp

vinny Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 2837	Post Options Post Reply Quote vinny Report Post Thanks(1) Quote Reply Posted: Jun/28/2019 at 4:14pm
	Oh, maybe they do make them new. I guess if it looks the same as yours it probably will fit. When I dumped my car off I had a look at the manifolds on the SBC I am working on. It must be contagious, cracked manifold there too.

vinny Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/05/2012 Location: Calgary Status: Offline Points: 2837	Post Options Post Reply Quote vinny Report Post Thanks(1) Quote Reply Posted: Jun/28/2019 at 4:25pm
	I've seen that before with those black umbrella seals,even in a head rebuild from a shop, but that goes back some years. The umbrella seals I just used in a SBC look good, kind of like orange silicone rubber with a spring around them. Edited by vinny - Jun/28/2019 at 4:40pm

billd Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Forum Administrator Joined: Jun/27/2007 Location: Iowa Status: Offline Points: 30894	Post Options Post Reply Quote billd Report Post Thanks(1) Quote Reply Posted: Jun/28/2019 at 5:05pm
	AMC changed from the rubber to a sort of plastic valve seal in later years. There's a bulletin about them and V8 head sets include both styles. Early Chevy used a square cut o-ring in the valve to form an umbrella seal using the metal spring cap. Those were nice as when they went - no chunks floating around the engine as the dried crispy seal parts were sort of trapped until you took things apart. Do check for chunks and bits and pieces of those old valve seals - they can sort of gunk things up in there. I'd use the newer style seals and shy away from the rubber - teflon is good. Iv'e seen exhaust manifolds new - and I've seen good ones for sale on eBay - and even bought NOS manifolds from eBay in the past. There's a bunch of those engines laying around the country, don't give up hope. I have a 1980 258 here and some other AMC 6 cyl parts like heads and such but without digging am not sure exactly what I do have.
	http://theamcpages.com http://antique-engines.com

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7555	Post Options Post Reply Quote tomj Report Post Thanks(1) Quote Reply Posted: Jun/28/2019 at 11:56pm
	the leaded gas/valve seat thing is not the big deal it was made out to be int he scare days of no-lead. one of the big magazines back in that time did a real test and found something like 5% shorter valve seat life vs. leaded gas. i put 200,000 miles on a '70 232ci head that ran propane only, when i did a valve job the valves were badly recessed, but cleanly and it all worked out fine. no lead at all there!
	1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com