CA Valve Tappets Pitted
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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=129962
Printed Date: 23 Oct 2025 at 7:18pm
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Topic: CA Valve Tappets Pitted
Posted By: BlackFatbob
Subject: CA Valve Tappets Pitted
Date Posted: 13 Oct 2016 at 9:05am
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Hello, this is my first post at AC. So thanks in advance for all the good technical content I have found here. I'm in the middle of an tear down and overhaul of a 1951 CA that used to belong to my Uncle and have found that the valve tappets have some pitting on the face. It looks to me like these these faces are hard chrome plated and I'm in a bit of a quandry as to how to proceed. Any opinions on grinding the faces on a surface grinder to clean them up and/or resurfacing them on a valve grinder. Or should I just punt and look a better set of tappets. I'll post some pics tomorrow. Thanks
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Replies:
Posted By: CAL(KS)
Date Posted: 13 Oct 2016 at 9:11am
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a camshaft grinding service can surface your tappets unless they are just terrible. this is usually done when a camshaft is reground anyway ------------- Me -C,U,UC,WC,WD45,190XT,TL-12,145T,HD6G,HD16,HD20 Dad- WD, D17D, D19D, RT100A, 7020, 7080,7580, 2-8550's, 2-S77, HD15 |
Posted By: BlackFatbob
Date Posted: 13 Oct 2016 at 9:14am
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Thanks CAL, Yes, my concern is that these will be through the hard chrome to clean up. If indeed these are hard chromed as they appear.
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Posted By: Dick L
Date Posted: 13 Oct 2016 at 11:13am
| I have resurfaced a bunch of them and have never noticed any hard chrome. |
Posted By: BlackFatbob
Date Posted: 13 Oct 2016 at 11:28am
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Hi Dick, I was hoping you would pick up on this. Maybe I'm being fooled by the surface finish. Here's a pic or two
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Posted By: BlackFatbob
Date Posted: 13 Oct 2016 at 11:32am
Here's another
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Posted By: steve(ill)
Date Posted: 13 Oct 2016 at 12:31pm
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couple of them are a little deep.. Might be cheaper to buy a used set and pick out the best ones as compared to grinding $$. ------------- Like them all, but love the "B"s. |
Posted By: LeonR2013
Date Posted: 13 Oct 2016 at 1:49pm
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Posted By: Dick L
Date Posted: 13 Oct 2016 at 7:07pm
I would pitch those. It sure looks like a coating on them. You can never say never but there was no coating on any I have removed from old engines. I have some around here someplace that are wore concave. Those that I have resurfaced polished up like new. I wouldn't think you would want a hard chrome surface rubbing on a cast iron camshaft. I have never seen any rusted that bad either. Take a grinder and lightly remove a small part of the area that looks like a coating and see if it changes look. Hard chrome would not be very thick. Hard chrome will chip after it is thick at some point. I have had mold cores hard chromed but don't remember how thick it can be before it is in danger of chipping. I had some mold cavities re-hard cored to thin the part and the build up was nickel with a flash hard chrome.
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BlackFatbob wrote:Posted By: steve(ill)
Date Posted: 13 Oct 2016 at 8:00pm
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http://www.ebay.com/itm/Allis-Chalmers-b-rocker-arm-lifters-and-rods-/172357628005?hash=item282150b065:g:jccAAOSwH3NXnVn4" rel="nofollow - http://www.ebay.com/itm/Allis-Chalmers-b-rocker-arm-lifters-and-rods-/172357628005?hash=item282150b065:g:jccAAOSwH3NXnVn4 ------------- Like them all, but love the "B"s. |
Posted By: BlackFatbob
Date Posted: 14 Oct 2016 at 7:15am
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Thanks Dick, Maybe somewhere in the middle of 1951 the factory tried some hard coated tappets. I'll put one on the surface grinder and take light cuts and pics along the way and post them. I guess the coating stress cracked over the years and when the engine was left open to humidity the rust got after the soft steel underneath. Really strange though.
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Posted By: BlackFatbob
Date Posted: 14 Oct 2016 at 7:16am
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Thanks Steve, I grabbed em. I needed one pushrod too so that's a heck of a price. Many thanks Dennis
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Posted By: SteveM C/IL
Date Posted: 14 Oct 2016 at 12:44pm
| For you guys resurfacing lifters,don't they have a slight convex surface to aid in spinning? |
Posted By: BlackFatbob
Date Posted: 14 Oct 2016 at 1:24pm
| I was curious of that, too. These appear to be flat and no wear signs of spinning. |
Posted By: Dick L
Date Posted: 14 Oct 2016 at 6:39pm
That is correct. Most are flat or slightly concave when they come out of a old tractor.
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Posted By: Tracy Martin TN
Date Posted: 14 Oct 2016 at 7:41pm
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What aids them to spin is most are off center to lobe of camshaft. HTH Tracy ------------- No greater gift than healthy grandkids! |
Posted By: SteveM C/IL
Date Posted: 14 Oct 2016 at 11:35pm
True.I'd bet they all are offset but I thought I read in performance mags that they were slightly convex.I think Dick concurred? |
Posted By: cranky
Date Posted: 15 Oct 2016 at 7:49am
| most tappets under 1" in diameter have a convex radius.the engine manufacturers list this info and any good cam shop will have a tappet grinder. tappet grinders can easily be adjusted to produce the desired radius. |