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Cracked exhaust manifold blues
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vinny View Drop Down
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Points: 2837 		Post Options Post Options   Thanks (1) Thanks(1)   Quote vinny Quote  Post ReplyReply Direct Link To This Post Posted: Jun/30/2019 at 10:54pm
I'd say there is a good possibility that the 196 used narrower valve stems than the 232 so maybe the same as the GM's. Anybody got a head apart to measure one?
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ramblingsolo View Drop Down
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Points: 10 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ramblingsolo Quote  Post ReplyReply Direct Link To This Post Posted: Jul/02/2019 at 4:16pm
Yea, I went and brazed it shut. Should be good to about 600F, not a performance application by any means.
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Points: 10 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ramblingsolo Quote  Post ReplyReply Direct Link To This Post Posted: Jul/02/2019 at 4:21pm
Originally posted by purple72Gremlin purple72Gremlin wrote:

Originally posted by vinny vinny wrote:

Mine only had about 70000 on it. I've put on another 10000 since on the unleaded fuels. It's no big deal though to pull the head and have it redone when the time comes.
yep. It all comes down to how well it was taken care of to start with. Ive seen basic valve jobs last way beyond 13k. But then Ive seen them not. I had an engine that had a valve job done, and it was still going strong 90k later. And these heads had 200+ to start with.... if you want to just fix the valve train, pull the valve cover.. and have a look see. If its fairly clean, you might get by clean it and replace the valve seals, and do the head bolt mod.  One question I have is what is the oil pressure?


I haven't put a gauge on it yet. I've been an engine machinist for going on 13 years, so I understand what you guys are saying about the valve job. Sounds like these are soft seats, but can be made to last if they're cut right. The engine has just 30k original miles so environmental conditions resulted in the only wear on internals.
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Originally posted by billd billd wrote:




It's a judgement call as far as "replace the seals and move on" or go deeper. I've done literally hundreds of valve seal jobs - everything from basic to teflon seals (pull heads and machine guides) to valve jobs, you name it, every possible combo. If he feels he can clean things up by flushing it and cleaning up the gunk - well, been there and it's very doable. but he has to decide that.
I always told people watch the oil pressure and change the oil more frequently for a while. 
Granted, pulling the pan and cleaning things up would be ideal - and for a DIY'er without a lot of experience, I would suggest that.

Now why is it that I am running AMC engines with original valves/heads/seats and not having a problem? I've run AMCs for decades - 232, 258, 290, 343, 360, 390 -
my current 360 is a 73 with only a valve job as far as head work last rebuild.
My last 258 went 160,000 miles - unleaded, no issues other than eventually starting to drop oil pressure when warm. Valves - fine. 
My last 232 went over 120,000 miles - about half of that in the era of unleaded. 
Funny that I don't have these problems.........



Yep, not looking to sink a bunch of cash into this old engine when all I need is a ride to work and some groceries now and then.
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Originally posted by tomj tomj wrote:

if the car is a keeper, then a compromise might be a decent head rebuild. lots of shops have a tool that cuts the tops of the valve guide casting to accept a modern chevy type seal. my 195.6 ohv has that done, as does our '72 hornet.

if the bottom end poops out later, well, you have a good head. but bottom ends on 232s tend to wear out relatively predictbly.



Sure thing, do you guys put positive seals on the exhaust valves as well? The OEM strategy back then was to run the exhausts a bit loose and let some oil in there to keep things happy.
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Originally posted by farna farna wrote:

Consider rebuilding the head and having the positive seals (the "Chevy" type mentioned) installed. If you're pretty sure you want to rebuild in a few years you will already have the head done, just do the bottom end. Alternately, replace with stock type umbrella seals and rebuild all when ready. Doing the head now will spread costs out a bit. I've done several engines that way over the years. A good shop vac will get the pieces of seal out of the head.

It won't hurt to pull the oil pan and clean it out, but not really necessary. The plastic/rubber seal pieces break up easily, and aren't likely to get through the pick-up screen. Any that might will be ground up by the pump and aren't hard or big enough to do any damage. Damage or clogging is a remote possibiity... not likely, but not impossible either. The safe bet is to clean the pan. Your engine, your call.


Thanks for the advice. I don't worry about things making it through the screen, just clogging it. The gray mystery sludge can glue the valve seal pieces together pretty well in these old engines as they build a nest over the pick up screens.
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Points: 30894 		Post Options Post Options   Thanks (0) Thanks(0)   Quote billd Quote  Post ReplyReply Direct Link To This Post Posted: Jul/02/2019 at 5:56pm
Originally posted by ramblingsolo ramblingsolo wrote:

Originally posted by tomj tomj wrote:

if the car is a keeper, then a compromise might be a decent head rebuild. lots of shops have a tool that cuts the tops of the valve guide casting to accept a modern chevy type seal. my 195.6 ohv has that done, as does our '72 hornet.

if the bottom end poops out later, well, you have a good head. but bottom ends on 232s tend to wear out relatively predictbly.



Sure thing, do you guys put positive seals on the exhaust valves as well? The OEM strategy back then was to run the exhausts a bit loose and let some oil in there to keep things happy.


Yes. I put positive on both. Years ago the procedure was to knurl the guides, run them a bit more snug and use positive seals. The knurling kept oil against the valve stem the full length and allowed a tighter fit. 

I have positive seals on both intake and exhaust on my 70 390.
If the geometry is right - if the rocker pushes straight down, you won't have issues. 
Make sure the valve stem ends are cut perfectly straight, perpendicular to the valve, etc. 


http://theamcpages.com

http://antique-engines.com
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