rod bearing clearance

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360duster

360duster

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Hi Guys, building a 512 for a friend with a 440 block and a 440source kit. I checked the crank and the rods, there´s only 0,0016" clearance - is this enough? As far as i know it should be 0.002 - 0.003" clearance at the rod bearings. Thanks for feedback!

Michael
 
360duster said:
Hi Guys, building a 512 for a friend with a 440 block and a 440source kit. I checked the crank and the rods, there´s only 0,0016" clearance - is this enough? As far as i know it should be 0.002 - 0.003" clearance at the rod bearings. Thanks for feedback!

Michael
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Use a GOOD 5W30 synthetic oil and send it.
 
street build, cruiser type....possibly a trip down the track from time to time, B-Body station wagon.
 
Myself I would not use a synthetic oil until a couple hundred
miles and I was absolutely sure ring were well seated. Not knowing
your ring and cylinder wall finish
 
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bore size is good from a previous rebuild, will do a dingle berry hone to get proper crosshatch. Piston clearance is good.
 
Maybe check for extra clearance bearings. If it is standard 440 rod journal size and you are measuring correctly, Clevite HXN bearings should get you there.
 
GTX JOHN said:
It is a bit on the tight side but it is still acceptable.
Race or StreetStrip?
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I agree. .002-.003 is where I'd like it but wouldn't lose sleep at .0015. Mains and rods measure the same? Good quality race oil and send it!!
 
Good Morning.....thanks for your feedback. I think they use chevy rods in this kits....so there should not be a problem getting different bearings. But as most of you suggested, i´ll run it as is. Thanks!

Michael
 
My 440-493 and later 495 ran fine with the oil clearance on the tight end.... .0015.
 
To tight for my liking but there are plenty out there running clearances like that. What did you use to check those clearances?
 
Running less than minimum clearance is asking for problems, why chance it?
I think a lot of failures happen from getting bad advice.
My question to you is, do you feel lucky?
 
If it's too tight, the whole world will know, if it's to loose only you will know. Think about it
 
replicaracer43 said:
If it's too tight, the whole world will know, if it's to loose only you will know. Think about it
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I use that quote all the time referring to ring gaps but it’s applicable here as well.
OP, I will run a stock build that tight, but anything I build to make HP I like em a little looser that that. Buy some extra clearance bearings and make the clearance what you want it to be.
 
i asked the guy the motor is for to get advice from 440source. At least they supplied the stuff, so they should give a feedback.
 
This is where I used to take a piece of crocus cloth, and a leather boot lace, a good stiff rum, doobies, and spend the evening making clearance . lol
 
360duster said:
i asked the guy the motor is for to get advice from 440source. At least they supplied the stuff, so they should give a feedback.
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I don't think I'd be using that clearance if it's someone else's motor.. If it ***** itself, your on the hook for the whole repair cost..
 
If it's too tight, I will only know, if it's too loose the whole town may know. lol
 
Feedback from 440source: "spec is .0015" to .003", i prefer .002" to .003"."

So even if it´s within spec, it seems a little tight. I´ll double check my measurements, and if still in doubt i´ll order the bearings with .001" extra clearance to be safe. hopefully these are not too loose then ;-)

Thanks at all for the Feedback!

Michael
 
Well an extra 001 bearing set would give you 0026. That’s not “too loose”. But if it concerns you at all use the upper shell from the extra clearance set and the lower shell from the standard set. That will give you an extra 0005 and you’ll be at 0021.
 
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