bearings.
Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC V8 Engine Repair and Modifications
Forum Description: AMC-made V8 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=105813
Printed Date: Apr/23/2024 at 10:38am
Software Version: Web Wiz Forums 12.03 - http://www.webwizforums.com
Topic: bearings.
Posted By: hacksaw1971
Subject: bearings.
Date Posted: May/20/2020 at 6:26pm
| ok .. since clevite 77 are junk on a hot build 401 .... what are yall using for rod and main bearings now?? i have always used 77's in the past and was sad to find out that thay be jap now and aluminum based and seem to flake apart under hard use when thay get warmed up .... never fails .... i guess if its a good strong part that is reliable .... ya ..... can't have that now can we??? lol |
Replies:
Posted By: Trader
Date Posted: May/20/2020 at 7:48pm
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Main bearings, I have been using King silicon/aluminum of late. Rod bearings: see this post: http://theamcforum.com/forum/401-rod-bearing-alternative_topic99248_page1.html?KW=pontiac" rel="nofollow - http://theamcforum.com/forum/401-rod-bearing-alternative_topic99248_page1.html?KW=pontiac Have not had any issues with 2 engines, mine has 8000 miles or more since posting. Still 5W30 and good oil pressure. Nice to be able to set all rod clearances within 0.0005" on just a re-polish of the crankshaft.
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Posted By: mramc
Date Posted: May/21/2020 at 6:59pm
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Clevite is a bearing name that been tossed around for a while. It use to be TRW Clevite and TRW went broke sticking the clevite name on bearings made by every body with no quality control. I got a bad set of main bearings in the early 1980 that wiped out a fresh 390 AMC V-8 I had done. Then after that it became Michigan Clevite 77 s main bearing. I'm not sure what happened with that company , but it went down too. My understanding now is that Clevite is owned by the MAHLE GmbH groups , as is I'm given to understand is Wiseco pistons and K1 rods. So, yes clevite as a name has had a recent history of putting out junk. But I expect better of the German's . King main bearings have a good reputation with AMC people. My understanding is they are made in England. They are reportedly a harder bearing then most , which what AMC seem to need. Last time I went though the old AMC Kenosha main factory , AMC was using Federal Mogul engine parts for the engines , particularly the V-8s. I saw pallets of Federal Mogul stuff back in the day. What to you use these days, well I'd look at the Federal Mogul stuff for any thing but maybe an all out race engine. Unless some one can tell me I'm wrong. Because I would like to know myself as I have delusions of rebuilding an AMC 360 V-8 in the near future. LRDaum
------------- LRDaum |
Posted By: Trader
Date Posted: May/21/2020 at 8:46pm
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I myself have built a 360 in a while, but have had issues with new Clevite 77's being too soft. You can actually take an old AMC original Clevite and a new one, take your finger nail to the edge and try and scratch it. The new ones will peal up soft metal while the old ones do not. The Pontiac bearing not only had sizes I wanted but also seem to be closer to the original AMC bearing as far as "softness". A purely unscientific qualification. The newer aluminum/silicon (AL/S) bearings are harder, bonded better and in use for almost all new engines. Could be engine oil has driven this or just cost - don't know. But today's engines and oil get many more miles before rebuild then back in the 60's and 70's. The 401 does not have an option for AL/S rod bearings in sizes I wanted, but the 360 has King Al/S available. Today, likely go with newer design Al/S bearings. The bonding bearing/backing process is completely different and I have not seen a bearing failure yet that was not do to poor assembly. But if the engine is not assembled with due diligence, AL/S bearings will take the crankshaft with them! Just my opinion, others please chime in.
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Posted By: FSJunkie
Date Posted: May/22/2020 at 2:50am
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Several types of bearings. 1. Microbabbit. Simply a steel bearing shell with a thick layer of Babbitt (lead-tin alloy) plated to it. Babbitt is the best bearing material there is except for being unable to handle high loads and being so soft that is scratches, deforms, and wears out easily. An overloaded Babbitt bearing will fatigue, crack, and fail. AMC phased out Microbabbitt bearings in the 1960's. As of 1966, the 199 and 232 were the only AMC engines still using Micobabbit bearings and only on the main bearings. V8's stopped using Microbabbit bearings long before that. 2. Tri-metal. A steel bearing shell plated in a thick layer of Copper alloy which is then overplated with a VERY thin layer of Babbitt. The load handing capabilities and fatigue resistance of Babbitt increases significantly if the Babbitt layer is kept thin. Tri-metal bearings have the highest load capacity and fatigue resistance of any bearing. The trouble is, the thin Babbitt layer wears through easily. Just a few seconds without oil will completely wipe out the Babbitt. 100,000 miles of easy driving is usually all it takes too. Once worn through, the journal will ride on the copper underlayer which is not a very good bearing material. Bearing temperatures increase and the bearing will start to dig into the journal. AMC switched to tri-metal bearings in the 1960's, with six cylinder engines being the last to adopt them. As of 1972, all AMC engines used tri-metal bearings throughout. 3. Bi-metal. Same as a Microbabbit bearing but replace the Babbitt with an Aluminum-Silicon alloy. Bi-metal bearings fit in between Microbabbit and tri-metal for load capacity and fatigue resistance but beat either type for service life. The bearing surface is Aluminum, which is much harder than Babbitt, so it lasts longer. It tends to polish the crankshaft, too, making bi-metal bearings significantly more forgiving of a rough crankshaft finish that would normally rub out a Babbitt bearing. They can operate with poor lubrication or at higher temperatures for longer than a tri-metal bearing can. The downside of bi-metal bearings is they hate dirt and grit. That's not normally a problem on a properly cared for "modern" (post 1950's) engine. AMC switched to bi-metal bearings in the mid-1970's, with all AMC engines using bi-metal bearings throughout by 1977. Most other manufacturers switched to bi-metal bearings around that same time. They are the modern standard. -------------- Clevite 77 is a tri-metal bearing. Great for high loads, not so great for imperfect machine work or long service life. Every AMC I've torn apart that had original tri-metal bearings was worn into the copper underayer before 100,000 miles. King makes all kinds of bearings, but the only bearings in their catalog for AMC V8's is their AM-series bi-metal bearing. Great for long service life and are very forgiving, but may not be up to the task for engines with exceptionally high bearing loads. However, they are more than up to the task for a stock to mild engine. I've torn apart AMC engines with their original bi-metal bearings at nearly 200,000 miles that still met OE clearance. King bearings are high quality and are made in Israel. King's head engineer, Dr. Kopeliovitch, is the leading engine bearing expert in the industry, and much of what I have posted here is information that I learned from him. I suggest reading some of his technical papers if you find bearing technology interesting. Though King doesn't catalog any other bearing for AMC engines, they might be able to match up something if you call them. There are many other manufacturers of both bi-metal and tri-metal bearings out there. King and Clevite are not the end to all. ------------- 1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |
Posted By: WesternRed
Date Posted: May/22/2020 at 5:49am
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Great post, FSJunkie. ------------- I've finally given up drinking for good...........now I only drink for evil. |
Posted By: cone
Date Posted: May/22/2020 at 6:14am
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I just bought a set of Clevite bearings for my 401 and didn't use them. The number 3 bearing top and bottom halves are both identical unlike the original. They also don't have the aligning tabs anymore. I call Clevite and was told they did that to save a step in production and the aligning tabs are not necessary. I figured that if AMC could have saved money in a safe way they would have done it first so I installed a set of Sealed Power bearings. They are made in Mexico but at least they look identical to the original bearings. ------------- 1987 J20, 87 Grand Wagoneer,70AMX, |
Posted By: bbgjc
Date Posted: May/22/2020 at 9:01am
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I've never had issues with the Clevite bearings for mild/stout engines. I don't know where made in Japan came from. I have in my hands s brand new set of CB-819-10 that were/are made in the USA. Michigan/Clevite 77 has been around a long time. To do also use plenty of King Bearing and their product are also great. It all depends on what the engine is for to dictate what style bearing you use. I've torn down and repaired plenty of street engines with race bearing in them after only 30/40 k and they are trashed and have worn the crank.
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Posted By: 6PakBee
Date Posted: May/22/2020 at 12:46pm
I read your earlier post with some interest. If crush is of concern, and it should be, why couldn't you just have an AMC rod ID sized to a Pontiac ID? ------------- Roger Gazur 1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach |
Trader wrote:Posted By: Trader
Date Posted: May/22/2020 at 8:16pm
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That's the the beauty of using the Pontiac bearings, the rods have the same big end. You do not have to have your factory rods resized, you can adjust by putting in bearings to get exactly the clearance you want. Rod resizing, can do a better job myself, then what seems local machine shops can do.
This is were personally, detail is extremely important and machine shops can be off 0.0005". Being able to adjust is significant. Also polish the journals myself, 800,1000,1500 and then 1700 grit final. Fitting and clearances are longevity. I'll spend 3 days minimum on a crankshaft measuring every diameter at many locations. Home made oiled Hemlock blocks to hold the crankshaft and 3 or 4 dial indicators. If I need to make a 0.0005" adjustment, that's important. A local machine shop that is supposed to be a high performance builder only measures each at 4 locations and 400 grit finish. Just not good enough! Call me @#&$ on this. That and what has to be done if the machine shops turn down 0.010" or 0.020". I have to request 0.009" or 0.019" so it can be made right. |
Posted By: FSJunkie
Date Posted: May/23/2020 at 2:48am
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King AM-series main bearings for AMC V8's are half groove bearings: grooved on the upper bearing shell, and smooth on the lower bearing shell. They have locating tabs on the uppers and the lowers. The thrust bearing faces are nicely finished rather than the splotchy mess seen on many competing bearings. King AM-series rod bearings for AMC V8's are of course smooth on both the upper and lower halves. Both halves are interchangeable and feature locking tabs and cut outs for the oil squirter holes. I'm not reading from a catalog on this. I built my latest 360 with these bearings. ------------- 1955 Packard 1966 Marlin 1972 Wagoneer 1973 Ambassador 1977 Hornet 1982 Concord D/L 1984 Eagle Limited |