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Unread 01-11-2010, 04:16 PM   #1
SoleilJeep
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304 V8 1972 - Need Help !!!

Hi,

This is my first day as a member. Need some help. I have been working on a CJ7 project Got an engine that was machined (304 V8 1972) and to my surprise the valve train is completely different than my current engine (304 as well but 79') the set up for this is as independent valve train, pivot ball is half a circle, rock arms are smaller and there are no bridges, and instead of bolt inn assembly has a stud out pattern of assembly.

The problem or doubts:
1) I have used rock arms and pivot balls, in good shape. Should I use those or get new ones.
2) when rocker arm and ball are inn and tighten by the nut (not a bolt, this setup is w/ studs were you slide the rocker arm first, then pivot ball and then the nut) at 23lbs of torque the rocker arm has still a movement side to side (some rocker arms move more than others), which I do not know if normal.

Thanks for any help that can be given. Kind Regards

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Unread 01-12-2010, 09:22 AM   #2
h2ojeep
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The nut is a self locking nut and even though you may hve 23fp on it does not mean that it is seated.

As the nut is tightened it will push against the valve stem (stem held up by the spring) on one end of the rocker arm and will , at the same time, push against the other end of the rocker which seats against the push rod. The other end of the rod is seated against the lifter which in turn is seated against the a lobe on the cam shaft. (may be too basic here, and a lot of this you may know)

When you say some of the rockers are loose, that would be normal in that the lifter is on the flat part of the cam lobe (assuming the rocker was properly adjusted) With that same logic, the arms that are tight (tighter) indicate the lifter is on some part of the lobe up to the "peak" of the lobe (tightest) and thus pushing down on the spring and opening the valve.

As the engine heats, the arms will tighten to some extent.

Adjusting valves:
each engine has some standards as to how to adjust and tighten. Different ways to adjust solid lifters as opposed to hydraulic lifters. As well there are different methods of tightening, some will a cold engine not running and some with a warm engine running. Check your (a) service manual. There is a better explanation than I can give you here.

Using different arms:
There are different lengths in the arm (different ratios) which may not be noticeable to the naked eye, so mixing would not necessary be a good idea, although it is probable that they are all stock.

I hope this helps you. Welcome to the forum.
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Unread 01-12-2010, 11:53 PM   #3
SoleilJeep
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Thanks so much it gives me a better idea. On the manual I have purchased, none walk me over the 304 v8 1972. My concern was/is that on the companion pistons the discrepancy of tightness is to big at the same torque. If you do not mind me asking, up to what point would you tighten these (cold set up)?
Thanks so much, for your time and explanation.
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Unread 01-13-2010, 06:54 AM   #4
cj5752
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I'm going to guess here that someone has converted the heads to adjustable rocker arms. He may have to set the "lash" or preload on the lifter for each individual cylynder. I believe on the AMC heads when tou do this you need guide plates to hold the pushrod so the rocker arms stay centered on the valve.
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Unread 01-13-2010, 09:00 AM   #5
SST4530
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I'm going out on a limb here so someone correct me if I'm wrong. AMC V8's came factory with non adjustable rockers with pivots and connecting bridge between intake and exhaust valves for each coresponding cylinder. Having studs in the heads and individual rockers leads me to believe these have been modified so each valve can be adjusted. Having said that, if your running a Hydraulic lifter cam shaft??? You can adjust the lifter preload cold by rotating the engine until the lifter is at the base of the cam lobe for each valve or fully closed position. Turn nut to zero rocker lash and then 1/2 to 3/4turn to put plunger in center of lifter bore. Repeat this for each valve. Upon start up you should have break in period for the cam of at least 15 to 20 minutes at around 2000 to 2500 RPM. Be sure engine is ready to run when you get ready to crank it. No cooling or oil leaks and be sure you have oil pressure. h20jeep gives good advice as well, Hope this is helpful.
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Unread 01-13-2010, 10:17 AM   #6
SoleilJeep
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Quote:
Originally Posted by SST4530 View Post
I'm going out on a limb here so someone correct me if I'm wrong. AMC V8's came factory with non adjustable rockers with pivots and connecting bridge between intake and exhaust valves for each coresponding cylinder. Having studs in the heads and individual rockers leads me to believe these have been modified so each valve can be adjusted. .
Not to my surprise, cause these things always happen to me, the AMC 1972 304 v8 was the only motor to have a stud out, semi-circled pivot ball and no bridges. On the re-builder's and maintenance manuals they do not go into this particular year. I will keep researching, thank you very much for the info, I will give it a try, I am doing a P.O.R treatment to all the tin, so hopefully by the end of the weekend I will try to have the motor back in place.
Thank you all so much!!!
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Unread 01-13-2010, 11:00 AM   #7
CSP
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There are two castings of factory AMC V8 heads that have adjustable rockers sitting on studs.

amc heads

SoleilJeep you might want to google the Bulltear forums. Lots of AMC V8 specific knowledge there.
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Unread 01-13-2010, 12:08 PM   #8
SST4530
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That's good news then, and means these haeds have the prefered adjustable valve train. So if you follow my suggestions above then it should come out OK.
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Unread 01-18-2010, 01:27 AM   #9
SoleilJeep
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Thank you so much for the help. You have made me truly appreciate this place. Hopefully I will be able to return the favor some day. I will let you know as soon as this thing is running.

Have a great week!!!
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Unread 01-18-2010, 07:51 AM   #10
cj5752
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Great info on the AMC heads. I was not aware these heads existed. Anybody got a set they want to sell?
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