how "tight" should the crankshaft be with new bearings?
Chuck Bremer
went through the process of installing a reconditioned crank with new main
bearings (crank journals were turned down .010", and .010" undersize
bearings were used). I followed the FSM recommended bearing clearances-
.001"-.0025". all bearings Plastigaged out to anywhere between
.001"-.0015". The block was checked by a machine shop and found to be
within spec as far as the mains are concerned. the cylinders and deck
needed machining, but i wouldn't imagine that would impact the mains. (i may
be wrong!!)
after cleaning the mains and bearings, applying copious amounts of assembly
lube and tightening the main caps, the crank was impossible to turn. i
tried so much as using a 2' breaker bar on the flexplate mounting bolts to
try to move it and it would hardly budge. is this normal? I wouldn't
imagine it is...
what am i doing wrong? the clearances are a little on the tight side, but
if i use stock size bearings, clearance will be waaay big, correct? any
suggestons?
thanks in advance-
Chuck
Bulletsnbrains
plastic hammer to set the bearings and remove pinch on the thrust bearing
caps.
Brian
"Chuck Bremer" <cbremer@hotmail*.*com> wrote in message
news:k58ac.7190$Dv2....@newsread2.news.pas.earthlink.net...
Steve Grammer
just one of them binding then check for problems in that area.
"Chuck Bremer" <cbremer@hotmail*.*com> wrote in message
news:k58ac.7190$Dv2....@newsread2.news.pas.earthlink.net...
Will Honea
It would be really nice if the crank would turn <g>. Seriously, I did
the same thing last time I replaced a crank. Turned out that one of
the rod bearings was in backwards so that the lock tab was not seated
in the notch. That made the bearing squeeze the journal enough to
freeze the crank. My son was helping - he must have done the
reversing since I would never do such a stupid thing...
I would back off all the bearings and re-torque them checking the
rotation between each bolt just to see where it was binding. Snug is
one thing, tight is good, but frozen??
--
Will Honea <who...@codenet.net>
Mike Romain
journal.
The caps and connecting rods are all numbered. I would double check the
numbers to make sure they are right and are both/all on the same side of
the crank. When they numbered them, they stamped the numbers on the
halfs on the same side close to each other so you can tell if one is
flipped.
Someone told me that I should see a couple ft lb of torque extra on the
crank bolt for each bearing tightened.
The finished engine will turn freely though and you don't need a 2'
power bar to do it.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Rex B
Did the machine shop check the main journals for alignment?
Rex in Fort Worth
c
"Chuck Bremer" <cbremer@hotmail*.*com> wrote in message
news:k58ac.7190$Dv2....@newsread2.news.pas.earthlink.net...
There are several things that could cause this, but until you find the
problem, DO NOT try to force the crank to turn or you will more than likely
ruin something. Like the other posters said, loosen one bearing at a time
and see if it frees the crank. With the seal installed, it should not take
more than about 25ft-lbs. of torque to turn the crank. Personally if the
crank is locked up tight, then I would remove all the caps, the crank and
the bearing inserts and start again. Check all of the bearings to see if any
have been damaged from forcing the crank to turn. Check all of the bearing
saddles in the block and the bearing seating surfaces on the caps for burrs,
dirt and metal chips. The backs of the bearings and the saddles should be
dry when installing them. This will allow the bearings to seat properly, as
well as give them a good contact surface with the block to transfer heat
away from the bearings. Check the crank for burrs on the journals,
especially around the oil holes.
After everything is checked out, reinstall the bearing halves in the block
and lay the crank in place without lube. Do not rotate it. Now check for
crank endplay by placing a dial indicator on the flywheel flange surface and
moving the crank back and forth toward the front and rear of the engine. You
should have about .008 endplay, but check your service manual for the exact
specs. When this clearance is verified, install the cap with the thrust
bearing and lightly snug it down. Give the crank a good smack with a large
plastic or rubber mallet to properly position the cap. Now torque the cap to
specs and recheck the endplay. If it is in spec, then just turn the crank a
few degrees to ensure that it rotates freely. If it doesn't. then there is a
problem with the thrust clearance or that journal on the crank. If it does
rotate and the clearances are ok, then do another journal and repeat the
procedure until they are all done.
There is also a remote chance that the crank saddles in the block are
misaligned, and if that is the case the block will need to be align honed or
bored, but this is not real likely. Also be sure that you are putting the
main caps on the right way. They only go on one way and also have to go back
in the original position they were removed from.
As far as your clearances go, they are a bit tight . If you are worried
about this, the bearing companies make bearing sets for most engines which
will give an extra .001 oil clearance. If I recall right, Clevite just added
an X to the part number, but you would have to check with your parts
supplier to be sure.
HTH
Chris
mic canic
the rule of thumb is replace a crank, line bore the block
i have seen guys go through 3 cranks to get one that spins good without a line
bore
check the bearing clearance using plastigage with new bearing's
throw away the ones used and use new since the bearing have been squished and
retorqing distorts them even more
Brian
"mic canic" <dbr...@cac.net> wrote in message
news:406A405F...@cac.net...
> if all the assemble procedures were good
> the rule of thumb is replace a crank, line bore the block
> i have seen guys go through 3 cranks to get one that spins good without a
line
> bore
> check the bearing clearance using plastigage with new bearing's
> throw away the ones used and use new since the bearing have been
squished and
> retorqing distorts them even more
Bad advice here, I think. If you line-bore every time you change a crank,
the bores move up, the timing chain get's loose, timing gears lose their
lash, etc. I grant that every time the block is bare you need to measure to
see if the bores are the right size and in the right place, but you don't
just line bore by default in every case. If you are building high end
engines then when you prep a block for the first time, you re-machine
everything, including the main bearing bores, to get the block square, but
you don't re-do that every time to swap out a crankshaft.
If you need to try three cranks to get one that works, then either your
block is bad, or the cranks are bad, end of story. If the crank is on size
and not bent, it will spin. If the block main bores are on size and
straight, the crank will spin. If the bearing clearance is right, it will
spin. If the crank that came out was straight and the journals were good,
then 99% of the time the block is good to go. You need to measure each
journal on the crank and compare it to each journal in the block with the
bearings installed and the cap torqued to full spec. Plastigage only works
if you take a lot of care and torque to full spec. When you dry build the
bottom end, you need to install each main cap one at a time and spin the
crank, so that you know that each one is perfect, as a final step.
BTW, I agree with changing the bearings out even if they look good if the
have been used, but not because the get "squished". The bearings get
squished at least three times in building up a motor, because you need to
install them to measure the clearances, to dry build to measure deck height,
to re-measure after the block cmes back from machining, etc.
The OP probably has one or more main caps reversed, that's all. Or he had
the block line bored and it came out wrong - that has happened to me more
than once. If I have to have a block line bored, then I also have it line
honed afterwards. The line-hone process has a lot less room for error.
Brian
Mike Romain
any good.
Grinding a block to try and make up for a shitty crank job is just plain
foolish.
Man no wonder the places you work for go under.
Throw away the bearings after plastigauging them. LOL! Fool, the next
set need to be checked too.
Mike
TranSurgeon
of the counterweights and turn it easily, a really good one will go for a
half-turn or more with a flick of the pinky
c
"TranSurgeon" <nobul...@mchsi.com> wrote in message
news:l4Eac.147026$1p.1870509@attbi_s54...
One other thing I just thought about on this one. Some crankshaft grinding
shops leave a large fillet radius where the edge of the journal meets the
counterweight. This is commonly done for cranks intended for hi performance
or racing applications. Depending on the engine, this may require narrowed
bearing inserts. It is not usually an issue on the mains, but it is
something you might want to check out.
Chris
shiden_Kai
"TranSurgeon" wrote
Agreed. When I'm replacing pistons in 3100 engines,
I can turn the crank by hand with the pistons and new
rings in place, con rods torqued up, no heads on the
engine, engine bolted to the torque convertor and trans.
Ian
TranSurgeon
"shiden_Kai" <violet-lighte...@hotmail.com> wrote in message
news:WGJac.1882$Pk3.1398@pd7tw1no...
somehow, I juest KNEW you'd appreciate that high-tech definition............
Bob
turning a little harder but it's probably been 10 or 15 years since I've
rebuilt one of them.
Bob
Refinish King
They're asking for a crack to happen. Read the manual, for every crank,
there is a specified fillet radius!
Refinish King
"c" <c...@me.org> wrote in message
news:3BGac.17220$z%1.1...@twister.rdc-kc.rr.com...
Refinish King
Sounds like he either:
1: Got a bent crank.
2: Got a crank cut 00.9
3: Even better, the machine operator was on crack and left the machine on a
1/2' stroke when doing the mains?
LOL
Refinish King
"shiden_Kai" <violet-lighte...@hotmail.com> wrote in message
news:WGJac.1882$Pk3.1398@pd7tw1no...
>
Bob
applications.
Bob
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:%zNac.8164$Hs1....@fe03.usenetserver.com...
Brian
the time, for formula ford cranks. Very common. I have no idea what the
new radius, I just ask John at Canada Chrome to do it and he does it. he's
been grinding cranks probably longer than I've been alive.
Brian
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:%zNac.8164$Hs1....@fe03.usenetserver.com...
mic canic
better than measuring with the correct tools.if you want a good solid motor redo
how many times have you heard of someone complaining of a rod knock after a rebuild
you can bet it's from retorqing a rod bearing twice
and line boring a block doesn't necessarily mean machining the block but maybe a .001
or so to make sure that new crank runs true as posssible because it's bearing quite a
load esp. if the engine has been bored and the cam is stiffer and the heads been
ported for some real horsepower.
any new timing chain tensoner can take care of any slack
from a line bore
TranSurgeon
> any good engine builder knows that plastic gauge is just a quick reference
and not
> better than measuring with the correct tools.if you want a good solid
motor redo
> how many times have you heard of someone complaining of a rod knock after
a rebuild
> you can bet it's from retorqing a rod bearing twice
bull crap
youo can torque 'em as many times as you want, and it still won't make it
too loose..........
> and line boring a block doesn't necessarily mean machining the block but
maybe a .001
> or so to make sure that new crank runs true as posssible because it's
bearing quite a
> load esp. if the engine has been bored and the cam is stiffer and the
heads been
> ported for some real horsepower.
> any new timing chain tensoner can take care of any slack
> from a line bore
yeah, those chain tensioners on small-block Chevies sure work
good.............
Will Honea
me, Mr Numbnuts, how torqing a bearing that is supposed to have a
small but finite amout of clearance is affected by re-torqing. I know
that some engines required new BOLTS after being torqed once but
that's because of bolt stretch and necking. If the bearing doesn't
fit right the first time and is damaged then it shouldn't have been in
there in the first place but replacing the bearing after torqing?
Only if you are on commission - and never check the clearance of the
torqed assembly.
--
Will Honea <who...@codenet.net>
Mike Romain
>
> "mic canic" <dbr...@cac.net> wrote in message
> news:406F552A...@cac.net...
> > any good engine builder knows that plastic gauge is just a quick reference
> and not
> > better than measuring with the correct tools.if you want a good solid
> motor redo
> > how many times have you heard of someone complaining of a rod knock after
> a rebuild
> > you can bet it's from retorqing a rod bearing twice
>
> bull crap
Ditto! It's from 'not' using plastigauge to double check things.
>
> youo can torque 'em as many times as you want, and it still won't make it
> too loose..........
>
> > and line boring a block doesn't necessarily mean machining the block but
> maybe a .001
> > or so to make sure that new crank runs true as posssible because it's
> bearing quite a
> > load esp. if the engine has been bored and the cam is stiffer and the
> heads been
> > ported for some real horsepower.
> > any new timing chain tensoner can take care of any slack
> > from a line bore
>
> yeah, those chain tensioners on small-block Chevies sure work
> good.............
And the one that the Jeep engine in question 'doesn't' have works really
good too.
I wish this fool would go away with all his BS. He 'might' know
something, but it certainly isn't Jeep engines and he keeps telling
people to do things that will cost them big bucks or are just plain
wrong.
A timing chain tensioner on a Jeep 4.0. LOL!
Mike
HLS
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:%zNac.8164$Hs1....@fe03.usenetserver.com...
>
> They're asking for a crack to happen. Read the manual, for every crank,
> there is a specified fillet radius!
>
> Refinish King
A radiused fillet is less likely to crack than a sharply ground one, re the
stress raiser
phenomenon we have discussed before.. I think that more often than not, the
fillet
is not intented to be left overly large...it is probably a result of less
than precise machining.
It can interfere with the edge of the bearing, just as "c" said.
I never heard of anyone using narrower bearings, but they do 'relieve' the
edge of the
bearing where it might contact the fillet.
Seems I have seen a special tool to do this, but don't have one myself.
Refinish King
But, if you have an excessively large fillet radius, especially in a cast
iron crankshaft. that is the perfect place for a radial crack to begin.
The fillet radius should be ground with the stone dressed to the propper
radius for the crankshaft in the machine.
Refinish King
"HLS" <Sorry@nospam> wrote in message
news:10719qs...@corp.supernews.com...
c
been doing it wrong all these years.
http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECCS/CSGenInfo.html
It is common knowledge that a radius reduces the chance for a stress crack
by ditributing the stresses evenly across the radius. The bigger the radius,
the more area to absorbs stresses.
Chris
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:SK4cc.4262$Em4....@fe03.usenetserver.com...
Refinish King
not a regrind.
So like I said, go look in the book that crankshaft grinders use. You'll be
surprised, and more surprised at what they use for gauges to check the
stones when they dress them.
Refinish King
"c" <c...@me.org> wrote in message
news:T%4cc.13442$YC5....@twister.rdc-kc.rr.com...
Bob
> I guess Lunati and all of the other aftermarket crank manufacturers have
> been doing it wrong all these years.
>
> http://www.holley.com/HiOctn/ProdLine/Products/IEC/IECCS/CSGenInfo.html
>
> It is common knowledge that a radius reduces the chance for a stress crack
> by ditributing the stresses evenly across the radius. The bigger the
radius,
> the more area to absorbs stresses.
>
> Chris
>
knows what he's talking about or not.
Bob
c
a racing engine shop, or do you have a specific one in mind?
Chris
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:ak5cc.4342$Em4....@fe03.usenetserver.com...
Refinish King
Racing engine shops use different tollerances, I've been there!
Refinish King
"c" <c...@me.org> wrote in message
news:lr6cc.13450$YC5....@twister.rdc-kc.rr.com...
mic canic
33003440
c
do with a small fillet increasing strength, it has to do with providing
clearance for the sides of the bearings. It is common sense (maybe this is
why you don't get it?) that a larger fillet increases strength. 'nuff said.
Chris
"Refinish King" <noneofyou...@neveryoumind.nospam.com> wrote in
message news:Y3gcc.5641$Em4....@fe03.usenetserver.com...
Del Rawlins
> Yeah they do, but you are dead wrong as to why they do it. It has
> nothing to do with a small fillet increasing strength, it has to do
> with providing clearance for the sides of the bearings. It is common
> sense (maybe this is why you don't get it?) that a larger fillet
> increases strength. 'nuff said.
The fillet radius doesn't so much increase strength as it spreads out
the stresses on the crank. Without it, all of those stresses would
concentrate at the sharp corner leading to eventual fatigue failure.
This is why aircraft engine crankshafts have radiused journals.
----------------------------------------------------
Del Rawlins- del@_kills_spammers_rawlinsbrothers.org
Remove _kills_spammers_ to reply via email.
Unofficial Bearhawk FAQ website:
http://www.rawlinsbrothers.org/bhfaq/
Refinish King
A regrind, is not a performance crank, and the OP said he was looking for
narrower bearings to clear the filler.
So put that in your pipe and smoke it.
He wasn't building a nitro funny car engine.
Next time, learn to read context, and not hammer your one sided point to
make yourself deeman, kid!
Refinish King
"c" <c...@me.org> wrote in message
news:jvocc.45753$z%1.2...@twister.rdc-kc.rr.com...
Refinish King
news group. He wanted his point known, disregarding the original post saying
he required narrower bearings. But, there would have to have been some
submerge arc welding on that crank to make the fillet narrower?
Grinding makes the fillet area wider, does it not?
Refinish King
"Del Rawlins" <del@_kills_spammers_rawlinsbrothers.org> wrote in message
news:20040405204...@enews.newsguy.com...
ooda...@gmail.com
Paul in Houston TX
> I'm rebuilding a 41 packerd 6cyl and it had a rope on the rear cap and wood for the
> sides and win I tighten that cap down it is real real hard to spin is this normal ?
http://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=5449&viewmode=compact&order=DESC&type=&mode=0&start=10&menumode=2
>>>Ashton Crusher
>I'm rebuilding a 41 packerd 6cyl and it had a rope on the rear cap and wood for the sides and win I tighten that cap down it is real real hard to spin is this normal ?
that it's real real hard to spin. But IDK.