JL ws-6

iTrader: (50)

Understood. dry sump, maybe someday, but not in the forseeable future. I think adding a vacum pump will come first, and if the motor survives long enough without any huge rebuild expenses, a dry sump afterwards... but again, I don't think I'll be that lucky.

helicoil

iTrader: (104)

Yes, it was interesting to see the FM 152M #3 thrust which fit loose in the housing bore had about .0028"-.0029" for oil clearance compared to .0024"-.0026" like the other mains (1-2-4-5).

The Clevite .001" under set went the other way on the mains and were much tighter than the FM set. Compared to what was previously mentioned, my actual numbers were .0015"-.0016" on mains 1-2-4-5- and .0012 on the thrust (#3). I was going from memory and didn't have my notes in front of me when I posted earlier. The Eagle shaft is nice and round measuring 2.5582"

I am going to try a few more sets of main bearings in here for my own knowledge. A set of Clevite MS2199H (std.) and another set of 152M1 FM's that are both on the way.

I have to say I like the way the Clevite thrust fits the housing bore, except the oil clearance it gives is too tight for me and I just don't feel comfortable with the FM thrust fit on the OD, maybe some other sets will be different. I have a feeling I will end up using the Clevite std. #3 thrust (top and bottom) and halfing the std. and .001" under Clevite set on the rest of the mains to get what I like.

Monte4ever

iTrader: (2)

I know this thread is old but I have CLevite MS-22199h main bearings which gave me .0014 - .0016 clearance. I ordered their MS-2199h1 main and it gave me .0006 clearance. This bearing suppose to be .001 undersize but was actually .001 over. What's up with that? I ordered another set today in hopes that maybe the set was defective or mismarked. I have an iron block and want .002 - .0022 of clearance. Does anybody have any recommendations on which bearing would work best if these don't?

427

iTrader: (3)

You want MS-2199X.
The bearings you have reduce clearance by .001, the X adds .001 over std.

Kurt

Monte4ever

iTrader: (2)

Thank you VERY much. I sat on the phone with Summit Racing and they gave me that number. However, to correct it they are sending UPS to pickup the order and hopefully they are sending me the correct bearings. Thanks again.

racer7088

Monte4ever

iTrader: (2)

Thank you. I called them and made sure they were sending MS-2199X.

OneQuickCoupe

iTrader: (1)

Gents,

What are you engine building experts running for clearance on the LSX Iron Block?

This thread is adressing the aluminum block.

My engine builder, (by son) tells me he's seeing .0022 main clearance using ACL coated bearings.

While I see in this thread people running the above clearance with an aluminum block, is it acceptable to run this clearance with a LSX Iron?

This is our first go round with this new block so it would be appreciated if any of you gents have secrets to making one of these life.

Thanks in advance,

LSX Nova

racer7088

No you should run more clearance in the iron block in general. We run about .0025-.0030 and could be even more depending on application and crankshaft.

JL ws-6

iTrader: (50)

What oil thickness you plan to run also effects the clearance, and what you can deal with/tolerate.

Better to be a little loose then too tight, you can always swap to a thicker oil to compensate, if it's too tight, you're stuck/probably going to hurt something.

OneQuickCoupe

iTrader: (1)

The crank is a Callies Magnum and the rods are Oliver. The bearings are Calico coated ACL's.

LSX Nova

racer7088

how much power total?

OneQuickCoupe

iTrader: (1)

I wouldn't think much more than 600 at the crank.

LSX Nova

racer7088

For an iron block I would run .0025-.0030 and you should be fine.

JBM

iTrader: (15)

How bout an LSx block, with a 3.90 center counter wt crank, Honda journals, and aluminum rods? Hoping for 1050+ and plan to spin it to 9500 or so.

novaflash2002

iTrader: (51)

as far as what can be done for clearances, i dont like to run over .002 on rods or mains at any rpm or hp. it is just that much easier to let the oil squish out of and off of surfaces. put a drop of water between two pieces of glass, push down on it. at first it is easy, but when you get down to that last bit it is very hard to squeez it out. same princable with bearings, the tigher the more oil it holds. thats why a crank is radiused and fillet; it will oil better with tighter clearances. as far as the rumor of the oil cooling the crank i call bs. it moves so fast it realistically has little time to cool the journals. im called crazy and unrealistic, but it is funny how i have built and seen built many high hp sbc, and ls series engines running as tight as .001 clearance with no problems. main key, make sure that the bearing surfaces are prepped correctly, and the journals like wise. a couple of my dads nascar engine building buddys have stated they are starting to run tigher clearances again. no loss in power, and less engine failures.

OneQuickCoupe

iTrader: (1)

Gents,

Thanks for the feedback on this bearing issue.

I have one of the first versions of the LSX block and have some concerns going forward with this build.

If anyone has data on what to do to one of these to make it live I would appreciate the input.

Thanks,

LSX Nova

KCS

iTrader: (20)

Unlike you pressing on a piece of glass, the combustion pressure can get up around 100bar, which is a lot more load than what you or I can exert. At some point, that thin film of oil just isn't enough and metal surfaces meet. If it doesn't wipe out a bearing, it will cause frictional losses to go up big time.

How are radius fillets on a crank for oiling? I was under the impression that the radius was for durability purposes, to prevent sharp corners where a crack could start under high loads.

Yes, oil cools the crankshaft. The crank journals are in constant contact with oil, as long as the oil is cooler, it will absorb the heat from the journals. How fast it moves only means that it can carry that heat away faster.

NASCAR teams have the budget to experiment with tightening up oil clearances, the average guy buying a shortblock from a sponsor on here doesn't. I've heard of a local shop or two that used to run mains in the low, low .002" range, and went to .0025"-.003" when they got tired of spinning bearings.

What clearances to run are really a matter of application and the sum of the parts used. I have read of one example where a certain team had trouble with rod bearing failures. What they found is that the titanium rod would pull out and and arch away from the crank journal at peak inertial loads (TDC of exh. stroke), causing excessive clearance on the rod end of the cap. The oil would form vapor bubbles with this excessive clearance, and when the crank turned and the rod went under compression loads, the vapor bubbles collapsed, or cavitated, and destroyed the bearings. That was on an engine with super tight clearances as well.

racer7088

At that power (and rpm) you probably need a dry sump and I would still run about .0028-.0032 or so on mains there and .0023-.0027 on the rods.

I usually run coated as well with those clearances so if the parts move and touch they just knock off the coating and the crank doesn't grab the bearings and spin them.

The CCW crank is more stable though and will probably tolerate a little tighter clearances but I wouldn't go there.

JBM

iTrader: (15)

Thanks. I have the dry sump system as well. Good to have some notes to compare on a build like this. Also trying to estimate how thin I can go with the oil.