NewbVetteGuy

I could use some CF assistance locating an appropriate set of Crank/Mains bearings and Rod big-end bearings for my ultra-low mileage SBC "mini-rebuild".

I already purchased Cam Bearings: Durabond CHP-8T coated bearings.

I am waiting to hear back from the Machine Shop about the OD of my crank after polishing and the ID of my rods' big ends to see if I need over-sized or under-sized bearings so I won't actually order until after then (Wednesday), but I'm looking to narrow down my options dramatically by then.
-I want "Good" bearings and I think a modern Bi-Metal bearing with an anti-friction coating is about right. I'd love to keep the tolerances slightly tighter than they were in 1979 to be able to run a grade or two thinner oil; it seems that the "performance" bearings generally come with increased clearances to run at higher RPMs; my intake is a 19" long, long-runner design so I will NOT have a high RPM motor and don't need, nor want the extra clearance...



I read a few articles about bearings this weekend and now I'm going to go start trying to narrow down my options, but I'll refresh this page here every once in a while.

Adam

NewbVetteGuy

Mains Bearings:
King Bearings:

• SI Recommended for OE applications. Recommended for performance engines with factory crank shafts? MB557SI $24
• Seems like they have their "HP" Series that's a "Performance" bearing but much of the description talks about blow, turbo charged, NOS or high RPM usage- sound like it's designed for high loading with probably larger clearances than I really need or want (to use a thinner oil); say that they have increased eccentricity. Don't seem to offer a coated version for increased protection against starts with low oil.
• XP "Extreme Performance" Series seem to be for pure racing. Definitely not right.
• XP Coated

Clevite Bearings:

• H-Series Say they're "Performance" bearings, developed for NASCAR. Tri-Metal with Moly/Graphite Tri-Armor coating. (I like this feature!) Especially good for "medium-to-high REVs". $120 -holy moly!!
• P-Series Seem closer to OEM-style bearings. Tri-metal only, though? "1/2 groove"? $32.99

Rod Bearings:
Clevite Bearings:

• P-Series Again seem to be Clevite's entry-level bearings, but even then Tri-Metal and performance focused including higher eccentricity and crush factor vs oem bearings.
• H-Series "Performance, developed for Nascar; medium to high RPM again. Tri-metal only.
• H-Series Coated: Same as previous but now coated with Moly/Graphite for protection against very short term oil loss
• M-Series Special-purpose rod bearings for severe crank deflections.

Adam
-What does a 1/2 groove do? (Sounds like increased oiling for high RPM applications.)

TimAT

I just did my BBC- used all Clevite bearings per the machine shop- H series bearings and fitted them to get the clearances I wanted. And measured with a micrometer bot ID and OD and calculated the clearances. The upper half of the bearings is grooved, but to keep oil supply to the rods.

427Hotrod

If it's not making mega power or RPM you can use P's just fine...BUT...make sure your crank doesn't have a big fillet as you need the chamfer on one side to clear it like the H's have. If it's a cast crank I wouldn't put H's on it.

Not sure about closing clearances much. Old adage is true....if you have a little extra ...YOU know it...if you have a little too little...EVERYONE will know it when it comes apart. Don't get hung up on trying to use a mega thin oil and tight clearances. Not a recipe for long life. Put it together with what it needs and stick close to the .001" per inch of journal diameter.

Not sure the coated is necessary either unless you want some extra protection in case something goes bad. I've run H's for years at 8000+ RPM and they always look like I took them out of the box when I open the motor- non coated.


JIM

NewbVetteGuy

Thanks Jim. I have no idea what is meant by a crank "Fillet" or what a "Big fillet" is on a crank. It's the stock, forged L82 crank...

My thought on coated is that after the engine sits for a while most of the oil will be drained out of where it should be and while you're cranking the engine around you may have metal on metal contact (this is why all the new cars with the start/stop technology come with coated bearings). -Seems like a tech that should be in even the entry-level bearings but it doesn't seem to be.


Adam

gkull

Most aftermarket forged cranks are radiased in the throws. so you have to use chamfered bearing to clear the rounded edges.

TimAT

The fillet is the point where the journal and the main part of the crank come together. That little radius between the machined surface and the side of the counterweight. Aftermarket cranks seems to be ground with a larger radius than the factory stuff. This explains the radius thing:
https://help.summitracing.com/app/an...row-bearing%3F

As far as the coating and oil retention, my thinking is once it has oil on the bearing, the film might get a little thin after it sets, but nothing to worry about. How many engines set for years, someone comes along and primes the system, and fires it up? I had one set for 22 years and never did anything but hook up a battery and add fresh gas. Fired off and ran great with good oil pressure. And as Jim noted, maybe some extra protection if something goes bad. MY luck is if something goes bad, the only thing left is to walk away.

bmans vette

Do you know how to measure clearances with Plastiguage? Or do you have a large micrometer?

Btw...good reading here on the tight clearances/bearing subject.

Good luck with your build.
If its the original crank, I'd want to know if it is round on all journals, otherwise false readings.

http://www.enginebuildermag.com/2018...t-cant-see-it/

NewbVetteGuy

Yea, I'm going the Plastigauge route.

Adam

TimAT

Impossible to check the journals for taper or out of round with plastigage with any accuracy. Sure, it'll mash more at one end than the other, but was it because the cap didn't go on exactly straight? You can get a dial bore gauge for $108.00, and a 2-3 inch micrometer is about the same money. Tools you can use over and over.
Not a big fan of plastigage when it's got to be accurate. And IMHO, building an engine needs to be pretty accurate if you only want to do it once and have it live a long time.
And what's a couple hundred bucks compared to the cost of a spun bearing?

bmans vette

Plastigauge is good for measuring newly created parts fit where a recent bore was just done.
I was not implying that it is as accurate as a good set of mics. But not everyone wants to invest a couple hundred on a good set of 3" mics.
A decent set of calipers would work for an out-of-round check.

NewbVetteGuy

bmans vette

If you order it and they are reputable.
Dont assume.
There are great machine shops and crappy machine shops.
Dont know anything about yours so not trying to judge.
It pays to be specific with them.
Good luck with your build.

TimAT

IT's tough to find a machine shop that is on the money. I'd guess 90% of them are cranking out stuff that's "Close enough". They machine shop that I used for my 496 has a stellar reputation for being right- and I still checked everything short of the balancing. And it was as advertised. Some of that may have come from being an aircraft inspector for 30 years too. Trust but verify.

Metalhead140

Trust but verify, I agree! Buy or borrow the mics, do it properly.

I used King Hp main and rod bearings, and I bought a set of standard, a set of .001" larger, and a set of .002" larger, then mixed and matched shells to get my clearances spot on. ~30,000 street and track miles later and it's still going strong. I run a 10w40 race (plenty of zddp) synthetic oil.

Jebbysan

I recommend the King SI up to about 6500 rpm and the HP series for anything over that or Blown/Nitrous. Coated bearing are a pain in the *** because they do not machine the bearing accordingly to account for the .0005 plus the coating adds......stay away from coated....not needed, don't try to reinvent the wheel. If you are that concerned about dry fire use an Accusump.
Pay special attention to clearances across the journal too......front to back......very few check this.
Use ONLY a dial indicator and micrometer and mic EVERY rod and crank journal as well as check the clearance of the rod on the vice BEFORE you knock the pistons in.

Jebby

NewbVetteGuy

I might be able to borrow a set of MICs from a local guy...

I'm not going to buy yet another $100 tool that I'm going to use once in my life.

I asked a similar question on SpeedTalk and although there was a variety of opinions, Mark O'Neal (the former owner of Probe Pistons) recommended the King SI or HP bearings. A few other folks said CleviteP and not H series.

Specifically CB663P and MS909P Clevite P main and rod bearings were recommended. Anyone disagree?


Adam

Jebbysan

NewbVetteGuy

That's both interesting and confusing.

I'm not running an aftermarket crank. The stock L82 forged crank and stock "Pink" "X" rods.

-Are the Clevite P bearings ok now? ;-)


Adam

Jebbysan