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Discussion Starter · #1 ·
:disco: For all the engine builders...What bearing do you typically use in a blown app? I have used Clevite77 'P' series (not happy) and I am trying ACL (have not disassembled yet). What should I be using. Since not all bearings are created equally I am not interested in what works on "Joe's" turbo motor or "Buddy's" n/a motor. I want to know what takes the punishment and heat of a roots blown engine the best.
 

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Blown,
Clevite 'P' series bearings are designed for OE replacement and are not at all suitable for maximum performance, ESPECIALLY a blown application.

You need to use a performance bearing such as Clevite 'H' or 'V' series bearings. There is a huge difference between Clevite 'P' bearings and the high performance, one of the most important of which is the steel strap material used for the bearing's back.
Virtually all NHRA and IHRA Top Fuel and Fuel Funny are teams are using Clevite 'H' or 'V' bearings exclusively, as are most of the Pro Stock and alcohol teams.
 

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Discussion Starter · #3 ·
I have heard the 'V' bearings are the better choice to use (I was also told the ACL's are almost identical which is why I used them the second time) assuming the material is the same between the 'H' & 'V' is it just the eccentric of the 2 that is slightly different? Or is it just a different way to market the same bearing. Anything I have read on these bearings is 'use this for that, and that for this'...not exactly a very good explanation. What other options are there besides clevite?
 

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Which ACL are you referring to?
I use the Clevite H or V & also the ACL H which is an excellent bearing too.
We used to use the M series in the AFD because they were very soft & forgiving but had to change them every weekend, sometimes every run.
these are "softer" on the surface & designed to be "sacrificial' in very high HP deals where you are going to get crank deflection

Some use the Sealed Power performance bearings & swear by them, some use C&A,,, they all seem perform very well.

Any of the performance bearings should be fine but my preference is the Clevite H & the ACL H series.
There is also the Clevite P series that is a performance bearing & it is the same basic bearing as the H with more eccentricity if you are distorting the rod
What is it you are trying to accomplish?
 

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Discussion Starter · #5 ·
Which ACL are you referring to?
I use the Clevite H or V & also the ACL H which is an excellent bearing too.
We used to use the M series in the AFD because they were very soft & forgiving but had to change them every weekend, sometimes every run.
these are "softer" on the surface & designed to be "sacrificial' in very high HP deals where you are going to get crank deflection

Some use the Sealed Power performance bearings & swear by them, some use C&A,,, they all seem perform very well.

Any of the performance bearings should be fine but my preference is the Clevite H & the ACL H series.
There is also the Clevite P series that is a performance bearing & it is the same basic bearing as the H with more eccentricity if you are distorting the rod
What is it you are trying to accomplish?
It's not so much that I want to accomplish anything...I just want to make sure I am running the proper bearing for my application. Everyone has an opinion and I was wanting someone (like yourself) who has the experience building many different combinations of blower/cent/turbo/na motors could say. 'Yup good thing you asked cause...these work fine for na enignes but they just don't seem to stand up in a boosted engine.' or 'Stop being paranoid just slap in anything and make sure to change the oil after a million miles'

In answer to your other question I don't think I used the ACL 'H' I think they were just their "premium" bearing not the "race series"

Thanx
 

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Modified Mains

Hi Travis (just caught your name in the post)

As for the bearings, about a year ago we started testing more units in the dyno room with the "King" line of bearings. They seem to be able to sustain more load than any other brands we've used. Upon removal from some combined SB's and BB's, they've managed to keep the "press" fit in the bores for a much longer period of time. These were all fairly high HP units. Some N/A SB's were in the range of 900+ HP. The BB's ranged much higher.

Let me add this here specific to "Blown" units. We modify ALL main bearings used in these units by installing some "lateral-feed" oil grooves on the upper shells. These grooves force the oil towards the outer area of the insert where the loads are much higher. In some cases they've actually solved some front main "loading", on the upper shell, from an overly tightened blower belt. I have the shells still here as a reminder that this modification does work!

I follow one unit in particular here, a blown 540" '56 Chev running 9.30's on street tires and hitting the scales around 3900#/4000# with the driver. The mains have been inside there some 5 years now with not a single issue.

(Add) Hi Paul, good call on the "Kings"!

Thanks, Gary in N.Y.

P.S. I'll place a photo here of a set of modified mains to give you an idea of the procedure.
 

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Hi guys,We use the King bearings but have also used the Clevite Race series.Another thing to mention is that we run a .001 under bearing for added bearing clearance,which seems to help on a moderate boosted application(28-34 lbs).I don't know if this applies to a low (6-15 lbs.),but I thought it was worth mentioning.
Also,we never run a crank that has been turned down.I feel that a $20,000 engine, deserves a new crank,if it's hurt bad enough to need machining.
We check and replace Main bearings every 15 to 20 ,1/8 mile passes,and have the crank magnufluxed while we are at it.It seems that the center main will tell you more about what the engine is experiencing,so that one is the first to get checked. ALWAYS.
 

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Hi guys,We use the King bearings but have also used the Clevite Race series.Another thing to mention is that we run a .001 under bearing for added bearing clearance,which seems to help on a moderate boosted application(28-34 lbs).I don't know if this applies to a low (6-15 lbs.),but I thought it was worth mentioning.
Also,we never run a crank that has been turned down.I feel that a $20,000 engine, deserves a new crank,if it's hurt bad enough to need machining.
We check and replace Main bearings every 15 to 20 ,1/8 mile passes,and have the crank magnufluxed while we are at it.It seems that the center main will tell you more about what the engine is experiencing,so that one is the first to get checked. ALWAYS.
=
Just to be clear, the .001 under bearing loses a thou it does not gain a thou of clearance.
The 1X bearings have extra clearance.

And the King performance bearings also have an excellent reputation, I just normally prefer the H series of bearings.
I really haven't seen any big differences between any of these bearings as far as staying put, they all have the better backing.

The biggest contributor to loose bearings in the bore is detonation assuming you didn't run it out of oil in which case the condition of the bearing is probably a mute point.
If you detonate it, blown or not things tend to move around. ;)

I don't think you are going to go wrong with any of the performance bearings mentioned.
I would use the one's that are the easiest for you to get.
 

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Discussion Starter · #12 ·
Thanx for all the info...This is the kind of "bearing experience" I'm looking for.

GOFAST Gary. The bearing modification I assume has no bearing :)sad: sorry no pun intended) or effect on the oil preasure?How would one go about explaining this to a machine shop to modify it? (measurements,depth ect)
OK so I can run a Clevite 'H' bearing or ACL 'H' (I assume is the "race series") or King bearings...The King confuse me a little they offer "King Silicon Bi-Metal Bearings" and "King "Pro Series" Performance Bearings". Which of those 2 are the better? If it helps here is the web site for the outfit that carries all 3. http://www.competitionproducts.com/departments.asp?dept=179

Thanx again...now we're gettin' somewhere!:hurray:
 

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Like Mike mentioned in a previous post, Clevite has the 'M' series bearings for blown drag race engines that experience high levels of crankshaft deflection. These bearings are referred to as "micro-babbitt" bearings, as they have a thin overlay of babbitt material. These work well in blown maximum effort engines but the life span is much shorter than 'H' or 'V' series, and they must be checked frequently, making them suitable for race engines only.
Both 'H' and 'V' series Clevite bearings are performance bearings, based upon the high strength steel base material. The only difference is the face material, which is lead-indium on the 'V' series. The 'V' bearings were originally developed in Europe by Glacier-Vandervell (now a division of Clevite) for Forumla One and other max-performance applications.
 

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Discussion Starter · #15 ·
Thanx for all the info...This is the kind of "bearing experience" I'm looking for.

GOFAST Gary. The bearing modification I assume has no bearing :)sad: sorry no pun intended) or effect on the oil preasure?How would one go about explaining this to a machine shop to modify it? (measurements,depth ect)
OK so I can run a Clevite 'H' bearing or ACL 'H' (I assume is the "race series") or King bearings...The King confuse me a little they offer "King Silicon Bi-Metal Bearings" and "King "Pro Series" Performance Bearings". Which of those 2 are the better? If it helps here is the web site for the outfit that carries all 3. http://www.competitionproducts.com/departments.asp?dept=179

Thanx again...now we're gettin' somewhere!:hurray:

:boring:
 

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I had beleived the only difference between a Clevite P and H bearing was the greater camfer for clearance on the H bearing for aftermarket cranks with a larger radius on the edges.
 

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I had beleived the only difference between a Clevite P and H bearing was the greater camfer for clearance on the H bearing for aftermarket cranks with a larger radius on the edges.
=

Not so ;)
There is the standard "P" series that is a very good bearing for everyday use in mild performance engines & even some higher HP ones depending on what you refer to as high HP.
They have a thicker Babbitt top & are less sensitive to dirt.

The Performance "P" & the "H" series bearing have a different backing that is stronger & is not plated
The bearing material itself is somewhat the same but the top layer is thinner for heavy loading, & both have more "crush" for a given bore.
The "P" performance series also does not have the chamfer of the "H" & has more eccentricity.

I Can't tell you much about the King bearing as I don't normally use it simply because I have no issues with either the Clevite or ACL so no reason to change.

Easiest to just go read about the bearings here, excellent info
http://www.engineparts.com/motorhead/techstuff/brgselec.html

http://www.aclperformance.com.au/us/prod_e_bearingsus.htm


And a different perspective with some general information from someone not trying to sell you something or convince you of who's is best on the merits of the different bearings
http://www.aa1car.com/library/ar797.htm
 
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