RezinTexas

Iron block 383.
11.3 CR street motor. No boost. No nitrous.
K1 4" crankshaft
Clevite MS-2199 H Bearings
Block was line honed at HKE with ARP studs.

I am using a mitutoyo dial bore gauge with an outside micrometer to come up with the following clearances. Measurements were taken at 90-deg from the parting line.

Some of what I have read leads me to believe #3 and #5 are too tight. A few others lead me to believe it will be ok. I tried removing the #3 cap, cleaning, and re-assembling with proper torque procedure. Dimensions did not change.

Should I get .001" undersized bearings for #3 and #5? Any help is appreciated!

No.____Min______Max_
#1___0.0024___0.0026
#2___0.0024___0.0026
#3___0.0017___0.0019
#4___0.0023___0.0025
#5___0.0019___0.0020

KCS

iTrader: (20)

#3 is always tight with Clevite bearings. You could use a combination of STD and X bearings for those two and get clearance closer to the others.

chrisfrost

iTrader: (8)

Under sized bearings are smaller inner diameter and they don't make bearings that have larger inner diameter ( oversized ) . So You measured the main journals on the crank and measured the bearing with caps tqed without the crank ?

chrisfrost

iTrader: (8)

Have You mocked it up with the crank and either assembly lube or engine oil to see if the crank spins freely ?

Gray86hatch

iTrader: (83)

With iron you want them at .0025

Is the crank or the bore dimension what is making them tight

Tim

RezinTexas

Thanks for the replies.

Main caps and bearings were assembled without crank for checking the dimensions.

The main journals on the crank are all within .0002 of each other (2.5584-2.5586), these were measured at 4 points each. This tells me that the tight clearance is a result of the bearings.

RezinTexas

no, I have not done this.

KCS

iTrader: (20)

They have X bearings that have a .001" larger ID for more clearance. I have half a set in my engine too.

Old Geezer

iTrader: (3)

^^^
http://www.cnc-motorsports.com/engin...-full-set.html

KCS

iTrader: (20)

Those are for less bearing clearance.

wildcamaro

iTrader: (15)

make sure if you use an under/over sized bearing shell that you make it the top shell especially on rod bearings...

RezinTexas

can you explain the reason for this?

RezinTexas

I found them in the Clevite catalog as MS-2199HX. It specifies each bearing as .0005 thinner, for .001 more total clearance.

If I understand you correctly, you assembled your engine with 1 side regular, and 1 side "X" bearing for an increase of .0005 in clearance? If so, that sounds like a good solution for me on #3 and #5, as adding .001 seems too much.

Did you install the undersized half on the upper or lower?

KCS

iTrader: (20)

Yep, you got it. I used ACL's because I knew that the Clevites are tight on the thrust, but I ended up with half STD size bearings and the other half X's for a little extra clearance.

I don't remember which side they went in, I personally don't think it matters in 99.9% of the builds. The idea here is that the side with less load gets the thinner bearing and the side with more load gets the thicker bearing. We're only talking .0005", so unless it's on a BIG shot of nitrous or there is nitro in the fuel, I don't think it matters.

quik95lt1

iTrader: (7)

run the "x" .001 under bearings on 3 and 5 that is too tight....