Thread View: net.auto.tech
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Started by Adnan Yaqub
Thu, 02 Jan 1986 14:52
Valve Adjustment on 1975 Opel Manta (1900)
Author: Adnan Yaqub
Date: Thu, 02 Jan 1986 14:52
Date: Thu, 02 Jan 1986 14:52
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How do you adjust valves on this beast? The GM repair manual says to adjust them until there is no play between the rocker arm and the valve stem and the lifter. Then tighten down one full turn. Me and a friend did this, and on some of the cylinders we were afraid we would break the bolt. When we were finished we couldn't start the car. We backed off on all the cylinders and finally it was it's old noisy self. How do you really do it? This car's valves are really noisy. Adnan Yaqub @Allen-Bradley Co. ...!decvax!abic!acy
Re: Valve Adjustment on 1975 Opel Manta (1900)
Author: WILLIAMS
Date: Fri, 03 Jan 1986 13:17
Date: Fri, 03 Jan 1986 13:17
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>
> How do you adjust valves on this beast? The GM repair
> manual says to adjust them until there is no play between the
> rocker arm and the valve stem and the lifter. Then tighten down
> one full turn.
> Me and a friend did this, and on some of the cylinders we
> were afraid we would break the bolt. When we were finished we
> couldn't start the car. We backed off on all the cylinders
> and finally it was it's old noisy self.
I believe the engine should be running to do this! By tightening
down until there is no play(i.e., no valve chatter) and then an additional
turn you place the lifter's inner part about 1/2 way down its bore for
optimal operation. (What you did was tighten down so far that the valves
were probably never closing.)
Of course the lifters could actually be shot(siezed or excessive
leakdown) and adjustment won't solve the problem. Also, the stuff sold
in cans claiming to quiet noisy lifters probably won't help either.
1
1 1
1 2 1 Doug Williams
1 3 3 1 AT&T Bell Labs
1 4 6 4 1 Reading, PA
1 5 10 10 5 1 mhuxl!daw1
1 6 15 20 15 6 1
Re: Valve Adjustment on 1975 Opel Manta (1900)
Author: 0058
Date: Fri, 03 Jan 1986 17:07
Date: Fri, 03 Jan 1986 17:07
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> > How do you adjust valves on this beast? The GM repair > manual says to adjust them until there is no play between the > rocker arm and the valve stem and the lifter. Then tighten down > one full turn.... > ....How do you really do it? This car's valves are really > noisy. If I recall correctly from the last time I did my Opel's head, this sounds like the method that I used. It worked fine for me. If your valves are *that* noisy, please note that the car uses hydraulic lifters, so your valves should never get very noisy unless one or more of them has "popped". If this has occurred, the lifter no longer provides any tension on the rocker arm, so when you tightened it till there was no play, you had direct metal-to-metal contact. Attempting to tighten any distance beyond that point would be difficult indeed, and would probably result in the valve(s) being locked in the open position, i.e. car won't start. Another problem with the valve adjustment on these engines is that the adjusting nut on each rocker arm is a crimped nut, and they tend to loose their tightness with time and/or use. If I recall correctly, the factory manual said you should replace these with each adjustment. You might want to look into these as well.
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