rod bearings and crankshaft drag
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rod bearings and crankshaft drag
Hey guys, 2 different questions...
has anyone measured how much torque it requres to spin the crank once it, bearings and timing belt are assembled? My 4.25" stroke crank, takes about 5 ft-lbs....Trying to figure out if there is any binding or main bearing are too tight....I can NOT spint it by hand from the sount....
Also, does Clevite make oversize rod bearings? Coming up with .0018 clearance, I would like to be in the .0025 area or so.
Thank you.
has anyone measured how much torque it requres to spin the crank once it, bearings and timing belt are assembled? My 4.25" stroke crank, takes about 5 ft-lbs....Trying to figure out if there is any binding or main bearing are too tight....I can NOT spint it by hand from the sount....
Also, does Clevite make oversize rod bearings? Coming up with .0018 clearance, I would like to be in the .0025 area or so.
Thank you.
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Re: rod bearings and crankshaft drag
JohnJOHNZ wrote:Hey guys, 2 different questions...
has anyone measured how much torque it requres to spin the crank once it, bearings and timing belt are assembled? My 4.25" stroke crank, takes about 5 ft-lbs....Trying to figure out if there is any binding or main bearing are too tight....I can NOT spint it by hand from the sount....
Also, does Clevite make oversize rod bearings? Coming up with .0018 clearance, I would like to be in the .0025 area or so.
Thank you.
Make sure the crank is straight number one and we seem to have to line hone alot of big blocks from other shops due to when they install the crank they seem to bind a little and we line hone the block and it seems to take care of the problem. And Clevite makes X bearings for extra .001 clearance except in the P series. Even at .0018 clearance it should spin easy.
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Hi Carl,
the block was honed at my machine shop....I can turn the crank no problem pusing on the rod journals et cetera (rods are not installed yet) and also turns easily with a wrench and crank socket on the front of the crank snout....takes 5 ft-lbs to turn it this way...just a final check to make sure main bearing are not too tight, et cetera...
Just wondering if I should be able to spin the crank by hand from the front snout....timing belt is installed so that adds some drag.
My rods are at .0018...I thought that the Clevite H series were made undersize for less clearance, I need some more clearance...
Thanks for your help once again..
the block was honed at my machine shop....I can turn the crank no problem pusing on the rod journals et cetera (rods are not installed yet) and also turns easily with a wrench and crank socket on the front of the crank snout....takes 5 ft-lbs to turn it this way...just a final check to make sure main bearing are not too tight, et cetera...
Just wondering if I should be able to spin the crank by hand from the front snout....timing belt is installed so that adds some drag.
My rods are at .0018...I thought that the Clevite H series were made undersize for less clearance, I need some more clearance...
Thanks for your help once again..
Last edited by JOHNZ on Sun Nov 28, 2004 12:21 pm, edited 1 time in total.
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Re: rod bearings and crankshaft drag
My opinion, if you can't spin it by hand something is too tight, not round or bent.JOHNZ wrote:Hey guys, 2 different questions...
has anyone measured how much torque it requres to spin the crank once it, bearings and timing belt are assembled? My 4.25" stroke crank, takes about 5 ft-lbs....Trying to figure out if there is any binding or main bearing are too tight....I can NOT spint it by hand from the sount....
Also, does Clevite make oversize rod bearings? Coming up with .0018 clearance, I would like to be in the .0025 area or so.
Thank you.
5 ft lbs is way too much for just the crank & cam.
Never bothered to measure how much it takes to turn it but it would be in in lbs not ft lbs
What happens without the belt? that will tell you what is tight.
What engine is this?
I have no problem with .0018 on the rods on a small block, I have run them to 9000+ there without problem in both road race & circle track applications.
Yes Clevite makes an oversize, it is the -1X series
Fed Mog makes them also.
Mike
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- Wolfplace
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I see Carl had already posted an answer so I was a bit redundant
For a BB I would like another half thou for a minimum on the rods.
For a BB I would like another half thou for a minimum on the rods.
Mike
Lewis Racing Engines
4axis CNC block machining
A few of the cars I have driven & owned
A tour of my shop
The Dyno
And a few pics of the gang
"Life is tough. Life is even tougher if you're stupid"
John Wayne
Lewis Racing Engines
4axis CNC block machining
A few of the cars I have driven & owned
A tour of my shop
The Dyno
And a few pics of the gang
"Life is tough. Life is even tougher if you're stupid"
John Wayne
Carl and Mike,
crank by itself turns at 22 in-lbs, crank and cam with belt on turns at 27 in-lbs....but belt is lose....once I put the belt tensioner on, then that adds all the drag....
can turn crank itself by hand, can turn crank and cam by hand with little effort, but once the tensioner goes on things get tight...I wonder if I need a larger belt, it has enough slack though once the tensioner is on..
I want to be at about .0026 or so on the rod clearance so I will need to check if I can get .001 oversize, they will bring me from .0018 to .0028!
Thanks guys..
crank by itself turns at 22 in-lbs, crank and cam with belt on turns at 27 in-lbs....but belt is lose....once I put the belt tensioner on, then that adds all the drag....
can turn crank itself by hand, can turn crank and cam by hand with little effort, but once the tensioner goes on things get tight...I wonder if I need a larger belt, it has enough slack though once the tensioner is on..
I want to be at about .0026 or so on the rod clearance so I will need to check if I can get .001 oversize, they will bring me from .0018 to .0028!
Thanks guys..
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John check and see what you thrust clearance is mabe its tight.
Website is up and running
http://hinksonautomotive-cncblocks.com/
Machine shop tour
http://hinksonautomotive-cncblocks.com/shop-tour/
Monthly Specials
http://hinksonautomotive-cncblocks.com/specials/
55MM babbit cam bearings with 1 hole
http://hinksonautomotive-cncblocks.com/
Machine shop tour
http://hinksonautomotive-cncblocks.com/shop-tour/
Monthly Specials
http://hinksonautomotive-cncblocks.com/specials/
55MM babbit cam bearings with 1 hole
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Bill,
there are 2 tensioners that came with the belt drive....I am using the smaller one and it does what I described....it is not adjustable as the postion of the tensioner on the cover is fixed...
Looks like finding a larger belt would be my only option at this point....doesn't the crank moving by .002 messes up my bearing clearances?
Thank you.
there are 2 tensioners that came with the belt drive....I am using the smaller one and it does what I described....it is not adjustable as the postion of the tensioner on the cover is fixed...
Looks like finding a larger belt would be my only option at this point....doesn't the crank moving by .002 messes up my bearing clearances?
Thank you.