How to select main bearings?

GoldenEagle91

Active Member
Dec 25, 2012
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Hi guys, I'm getting ready to order some main bearings but I have a couple questions regarding which ones to pick up. The bearings are to be used on a new crank from Eagle. The variables for selecting which bearings to purchase are groove style and if there is a certain material that you guys recommend more than another.

Thanks in Advance,
Andrew
 
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Thank you for the reply. What about in regards to groove style? There was three different options that included 1/2, 3/4 and full. Which one is the correct one to use?
 
Imho, clevite 77 bearings will get the job done, no need for something fancy, coatings, etc.

I have to disagree coated bearing can save your motor in the unlikely event that say a piece a debris takes out your oil filter. trust me ive seen it on a very nice boss mustang a customer of mine built.

as fare as the grove i think the 3/4 is correct but im not 100%
 
^ if something large enough passes your oil filter no coating on earth is going to save the bearings surfaces and you now have way bigger problems.
on a second note, i have run motorcraft filters for years and just recently switched to wix after a long conversation with one of there tech guys at a trade show.
 
^ if something large enough passes your oil filter no coating on earth is going to save the bearings surfaces and you now have way bigger problems.
on a second note, i have run motorcraft filters for years and just recently switched to wix after a long conversation with one of there tech guys at a trade show.

I'm not talking about passing through a filter what I said was " in the unlikely event that say a piece a debris takes out your oil filter." as in road debris like rocks and metal because lets be honest the oil filter location on a SBF is not ideal for protection in this way. Also the bearing coatings are there to protect from heat and lack of lubrication on the crank or whatever but your right the bearings will likely be done if that does happen but what about the crank shaft?

Also I too use only wix filters and will continue too even after i do my remote oil filter.


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Coated Bearings
The latest news in performance bearings is the availability of coated performance bearings from two of the leading bearing manufacturers: Dana/Clevite and Federal Mogul/Speed Pro. Both companies unveiled their new coated bearings at the recent Performance Racing Industry Show in Indianapolis.
Though coated performance bearings have been available for many years from such companies as Swain Coatings, Calico Coatings, Polydyne and others, the entry of Clevite and Speed Pro into this realm has brought coating technology into the main stream.
Various types of coatings have been used to reduce friction, improve wear resistance and heat management. But the primary purpose of today's bearing coatings is to protect the bearings against dry starts and damage if oil pressure is lost. In other words, it adds an extra layer of protection should the oil film go away.
Barry Rabotnek of Federal Mogul said the "Duroshield" Competition Series coated bearings feature a unique molybdenum disulfide (MoS2) coating in a polymer base that is applied over an H-14 alloy copper/lead bearing. Coated main and rod bearings are currently available for small block and big block Chevy, small block Ford, and for Honda rod journals.
"We will be adding more coverage as we go forward with this new product line," said Rabotnek.
The coating, which is only .0003? thick, has a "hydrophilic" matrix which bonds to the bearing surface and absorbs oil to improve lubricity and reduce friction. Rabotnek said the new bearing line has been tested and proven under brutal operating conditions, including running in a 3,000 hp twin-turbo drag engine at nearly 240 mph, and a record-setting Camaro at the Bonneville salt flats.
Don Sitter of Dana Corporation said Clevite's new "TriArmor" high performance coated bearings use a proprietary moly/graphite coating in a PTFE polymer base to reduce friction and provide extra insurance against oil starvation and abuse.
"In a perfect world, you don't need a coated bearing. But in the real world, a coating provides an extra measure of forgiveness and protection. So we now have coated bearings for those who want this kind of protection and are willing to pay for a premium product."
The TriArmor coating, which is only .0003? thick, is applied over a standard Clevite 77 H-Series or V-Series bearing. There are no other modifications to the bearings and the bearings can be installed with the same fit as before.
Sitter said the standard rule of thumb for bearing fit is to allow .001? of oil clearance per inch of journal diameter, plus an additional .0005? fudge factor. But with the coated bearings, you don't need the additional fudge factor. In fact, the coating provides additional conformability.
Sitter cautions against using bearings with coated parting lines because bearing crush is vital to a proper fit and bearing longevity. For this reason, the parting lines on Clevite's Triarmor bearings are not coated. "In a racing engine, a .0003? coating on the parting line can increase the total crush effect by .0012? (.0003? x 4). Initially, this causes the bore to become distorted. Then, as the coating extrudes from the parting line faces, the bearing loses its tight fit in the housing causing additional problems."
Coatings Work
One of the best stories about the benefits of using coated engine bearings came from Dan Swain of Swain Coatings, Scottsville, NY. "Back in 1993, we started coating engine parts for a number of NASCAR teams. We coated a set of bearings for Alan Kulwicki, who was running in a NASCAR race at Martinsville. Part way through the race, Alan's motor threw the belt for the oil pump drive and he lost all oil pressure. But he kept going and ran another four or five laps. When a caution flag came out, he went into the pits and had his crew replace the oil pump belt. The engine was still running great and he went on to finish the race. The coating on the bearings saved the engine and helped him win the championship later that year."
Swain said coated bearings are a great insurance policy against oil starvation and dry starts on any engine application, not just racing engines.
"We also do tons of coated bearings for heavy-duty diesel engines. Many of these engines are typically rebuilt after 500,000 miles. Uncoated bearings typically develop a timing mark wear pattern at 2 and 10 o'clock that eventually leads to bearing failure. But when we replace these with coated bearings, the bearings will often go a million miles without a problem."
Swain said coatings are not as easy to develop or apply as one might think. If not done correctly, the coating may flake off. Molybdenum disulfide and tungsten disulfide are both extremely tough coating materials that can withstand pressures of up to 350,000 psi without deforming or galling. They also hold oil rather than repel it to improve lubricity. But either material alone won't stick to a bearing surface. The active ingredients must be held in a polymer matrix that has a pseudo-metallurgical bond with the bearing.
"We activate the bearing surface so the coating will adhere to it, and spray on the coating with a robot. The coating is heated as it is applied, which crosslinks the matrix and bonds it to the metal. The coating we apply is only .0002? thick, so it isn't necessary to compensate for the thickness of the coating when select fitting the bearings. You can run tighter tolerances with the coated bearings," said Swain.
Jerry Ehlert of Calico Coatings, Denver, NC, offers similar advice. "We apply a .00025? to .0003? coating of moly and teflon, which allows a slightly tighter fit than normal. In our experience, the coating extends bearing life anywhere from two times to 10 times over that of an uncoated bearing in racing applications. We've heard numerous stories from racers who have lost oil pressure and continued to run several laps without wiping out their engine thanks to coated bearings and pistons. It really can make a difference."
Ehlert said Calico offers coated bearings for both domestic and import applications, including many sport compact engines such as Honda, Mazda, Mitsubishi, Subaru and Toyota. "We buy bearings from other manufacturers and coat them with our proprietary material. We've been doing this for 20 years and have had great results."
Whether coated bearings are right for you or not depends on the kind of engines you're building (stock or performance) and how much your customers are willing to spend for the added protection afforded by coated bearings. For most applications, a coating adds less than $100 to the cost of the bearing set. That's cheap insurance considering what a warranty claim due to a dry start or loss of oil pressure might cost."

full article here: http://www.enginebuildermag.com/Article/1084/engine_bearings_stock__performance.aspx
 
The most important thing that has not been asked is...what material is the crank? Cast or forged, what rod, street or race?

Eagle forged stroker cranks use a narrow Chevy v6 rod bearing and a standard size ford small block main.

I prefer King bearings personally and I am also a true believer in coated bearings, I use them in all my race stuff

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In years as a counter person, I was Never asked about the groove length. I think it is time to ask a good builder or machine shop.
Wix are well made. It is easy to see the difference at a display where they and the others are cut open. I still run conventional oil and a Fram filter. It is shocking how cheap some filters are made - hot glue cardboard caps on the skimpy media folds. They are not made for 5000 + mile oil changes. But if I go with synthetic oil and for sure on my next build, Wix it will be.