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196 Retorque with 2 barrel carb

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al1630 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote al1630 Quote  Post ReplyReply Direct Link To This Post Topic: 196 Retorque with 2 barrel carb
    Posted: Feb/03/2019 at 11:43am
I need to do a head retorque on my 63 American, the TSM says to do it with the engine at operating temperature. Problem is, I have the Carter WCD 2 barrel, and a torque wrench won't fit onto the head bolts that are right next to it. Do I have to take off the carb and torque it cold, or is there another way?
1963 Rambler American 440H
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pacerman Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2019 at 11:57am
I torque them cold, adding either 2 or 3 thousandths' to the factory specs for both intake and exhaust valves.  Here's the thing about torquing a "warm" engine.  The definition of warm as I have come to understand it, means that the engine had been run vigorously for ten minutes or more (like with actual driving, not idling) and then the re-torquing is accomplished very soon after it is shut off.  So most of us just don't do it that way, either because the car is down for other maintenance at the time and/or is not safe for a road test when we need to re-torque the heads.  I suppose I have removed the carb to get to the bolts (with a two-barrel carb) but I don't specifically remember doing that.  Joe
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2019 at 9:54pm
what joe sez.

the AMC TSM for the 195./6 ohv does say to torque the head hot, which is apparently very odd advice, according to my engine builder. the point of torquing is to give the bolts the correct stretch, and usually done cold.

we know today that AMCs advice for this particular engine was to deal with side effects of it's head cooling engineering fault. at issue is the head bolts backing out from crazy thermal spikes at startup.

you're checking for loose bolts, not so much worrying if one is 55 ft/lbs instead of 60 ft/lbs or whatever. i'd just do it cold. set the wrench to 60 (i think it is) and pull slowly til it clicks (or whatever ytours does to indicate). if it's 60, it's fine. one junk engine i checked some of the bolts were *loose*!

i do recall that the WCD blocks the two bolts adjacent to the carb flange. but i dont recall what i did to deal with it!


1961 roadster american
195.6 OHV, modded
T5z, 3.42:1 mustang axle
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farna View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2019 at 6:55am
Have to remove the carb to get those two bolts. The alternative is to use a crow's foot "socket", but there is a little math in dealing with the offset to get the correct torque. Might be worth getting one, as it isn't much. Just keep a note with it on how much to torque using it, once you figure it out.

Here is some good reading! Note that if the crow's foot is set 90 degrees to the wrench handle it doesn't affect torque, just if it's in-line.

Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote al1630 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/11/2019 at 5:28pm
Thanks for the tip. I might have to pick one of those up. It's probably easier than taking off the carb every few thousand miles.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2019 at 6:05am
Since the head gasket has been replaced over the last 20 years (I'm assuming...), you can get by with retorquing every 10-12K miles or every third year if you don't drive much. I retorqued mine every other year when I was driving daily (drove one for 14 years, 5-7K a year). Adjusted valves at the same time. The better material in the newer head gasket just works better. The gasket used to have "no retorque required" on it (or the package, don't recall which), but that was in reference to the fact that in the 60s and earlier you installed a new head gasket, ran it a couple hundred miles at most, then retorqued (due to the material used). Some assume that means they no longer have to check the torque of the head bolts any more, but expansion/contraction issues are present in the 196 OHV due to the nature of the conversion from a flat-head (small sealing surfaces and a rather massive iron head). 

In theory you can eliminate the retorque requirement by using studs instead of bolts to hold the head on. Makes it a little harder to remove the head, but reduces maintenance to adjusting the valves every 10K or so. TomJ has done this to his engine and has reported that no retorque has been needed (he does check it every so often). I'd still check it every couple years just as insurance (set click torque wrench to 60 and see if it clicks on 3-4 random bolts -- the ends should work loose before the others). Good 196 heads are hard to find now since they are old and have been run hot several times, making them crack rather easily. The first sign of a loose head gasket is running hot, not a loss in power as you'd suspect.
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tomj Quote  Post ReplyReply Direct Link To This Post Posted: Feb/12/2019 at 11:08pm
i'm fairly sure that the end-to-retorques was solving the chronic head cooling problem -- simply drilling a hole in the edge of the thermostat suffices.

i actually measured this: if you have a thermostat that actually closes seals tight, and doesn't leak any coolant, at cold engine warmup, i measured .024" growth in the length of the head, while the block was still cold (warm to the touch). when the thermstat opens, the temperature plummets in seconds -- this rocks the head bolts back and forth each cycle, and backs them out.

many thermostats "naturally" leak; some have a hole, or a hole with a jiggler. very many 195.6 OHVs never have this problem; i suspect, but cannot test, that those had a more normal thermal startup.

studs are "better" than bolts in well documented ways, but i'm not sure they're necessary here. but after using them i'll probably switch every project motor over to studs. they're not even expensive.


1961 roadster american
195.6 OHV, modded
T5z, 3.42:1 mustang axle
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farna View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/13/2019 at 6:31am
I forgot about the hole in the T-stat!! I always drilled a 1/8" hole in mine mainly to prevent air entrapment. A 3/16" is more like what the 196 needs for the head, and I don't think a 1/4" would hurt. Might be why I never experienced much head bolt loosening, but I did check torque every other year (10-14K miles) anyway. I don't recall more than 2-3 each time being just a little under the 60 lb spec, never enough to allow a leak of any kind, but that was a long time ago. You have to adjust the valves anyway, so no harm in taking 15 minutes to check head bolt torque (and a lot of good if there is a couple loose!).


Edited by farna - Feb/13/2019 at 6:33am
Frank Swygert
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Post Options Post Options   Thanks (0) Thanks(0)   Quote pacerman Quote  Post ReplyReply Direct Link To This Post Posted: Feb/13/2019 at 1:17pm
One more note about torque.   We learned in Physics 101 that starting friction is always more than running friction so if you just check the torque by setting a torque wrench to, say, 60 pound-feet and twisting a fastener, you are not really detecting the "running" torque of that fastener.  The actual "running" torque could be somewhat less.  Therefore, isn't the proper procedure to loosen the fastener and retorque it to the proper setting.  It might make no difference in the the whole scheme of things but on something like a racing engine or a nuclear reactor (LOL) , I think that would be the proper procedure.  Joe
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Post Options Post Options   Thanks (0) Thanks(0)   Quote farna Quote  Post ReplyReply Direct Link To This Post Posted: Feb/14/2019 at 5:54am
You are correct Joe, and that's what I usually did when retorquing.

I checked the head bolts a few times by just setting the wrench and pulling though. They might have been a little under torqued that way, but apparently not enough to be an issue. If one or two moved a little at 60 I backed it up half a turn or so then torqued on down. 

I guess if checking by just setting and pulling you should set it a few pounds over what they should be, like maybe 62-65. It does take a little more effort to get the bolt moving.

I tell people all the time that axle nuts may take 400-500 ft/lbs to loosen though they are torqued to 250 ft/lbs, but they get stuck, unlike those more "mobile" 196 head bolts!!
Frank Swygert
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