CA Rocker Arm Alignment
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=197240
Printed Date: 25 Sep 2024 at 5:35am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: CA Rocker Arm Alignment
Posted By: dfwallis
Subject: CA Rocker Arm Alignment
Date Posted: 17 Sep 2023 at 8:55pm
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Nearing assembly stage for rebuilt 1952 CA engine (Crankshaft had to be returned for additional end play work). I noticed that the rocker arms don't align very well with the valve stems. They are too WIDE. There are no shims/washers. The rocker arm bushings themselves would have to be ground to achieve narrower spacing. Some are misaligned by as much as 1/2 of the "button". Apparently it's been that way for some time as there was considerable button wear which I've cleaned up. I don't have the setup to grind these bushings "true". Since it ran that way for 50 years (probably), should I worry or do I need to take it in for more head work (head was rebuilt, new valves, seats, springs). If I have to take it back to the machine shop, I'll have to suspend work until next May, probably, since I have to return home. The rocker arm bushings extend beyond each side by between 1/16 and 1/8 inch (varies as they're not all pressed in identically or evenly). I thought that maybe somebody assembled them in the wrong order, but that does not seem to be the case as none matched other valve positions. |
Replies:
Posted By: steve(ill)
Date Posted: 17 Sep 2023 at 10:59pm
I had a "B" with the same engine. Had a freeze plug failure.. Here is a photo of the rocker arm area.... You can see that the rockers do NOT fit the valves very good.. That is common on this engine. ------------- Like them all, but love the "B"s. |
Posted By: Alberta Phil
Date Posted: 18 Sep 2023 at 9:00am
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I've been building engines for years and rocker arm bushings were always faced off flush with the rocker arm. Never seen them left protruding past the edge of the rocker. |
Posted By: steve(ill)
Date Posted: 18 Sep 2023 at 9:05am
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Im not sure what you are going to "face off"... look at the FIRST rocker arm on the left. it obviously sets about 1/8 inch to the LEFT of the valve stem center... the second rocker sets to the RIGHT of the valve stem center.... compare the rocker arm end to the spring cover and you can see the offset.
one thing to remember... AN auto engine puts out about 1 HP per cubic inch.... this engine puts out about 25 HP for 125 cubic inches... I agree it is not the BEST design... but seems to work for 75 years.. ------------- Like them all, but love the "B"s. |
Posted By: steve(ill)
Date Posted: 18 Sep 2023 at 9:12am
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The rocker arm bushings extend beyond each side by between 1/16 and 1/8 inch (varies as they're not all pressed in identically or evenly OK.. i understand what your saying.. Are the BUSHINGS original ? ... Thats my point.. Many are FLUSH and still the arms do not align to the stem. ------------- Like them all, but love the "B"s. |
Posted By: steve(ill)
Date Posted: 18 Sep 2023 at 9:42am
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look about the 13 minute mark.......... https://www.youtube.com/watch?v=_YH4dY1Hg5U" rel="nofollow - https://www.youtube.com/watch?v=_YH4dY1Hg5U ------------- Like them all, but love the "B"s. |