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What causes thrust on the crank to go? #932334 02/19/11 03:35 PM 02/19/11 03:35 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge OP master
TheOtherDodge OP master Joined: Feb 2003 Posts: 4,953 Houston, Texas	If the thrust was set when assembling motor and the converter is not ballooning, what else could cause the thrust to go? A bent crank could..what else?

Re: What causes thrust on the crank to go? [Re: TheOtherDodge] #932335 02/19/11 03:39 PM 02/19/11 03:39 PM
A Anonymous Unregistered
Anonymous Unregistered A	not enough clearance on the converter to the flexplate or if your converter bolts came loose a few times causing the converter to bang the flexplate shocking the crankshaft.

Re: What causes thrust on the crank to go? #932336 02/19/11 04:19 PM 02/19/11 04:19 PM
Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY HEMIFRED master
HEMIFRED master Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY	staying on the converter or trans brake too long home of the Sox and Martin Hemi Duster

Re: What causes thrust on the crank to go? [Re: HEMIFRED] #932337 02/19/11 06:23 PM 02/19/11 06:23 PM
Joined: Nov 2004 Posts: 6,890 North Alabama M Monte_Smith master
Monte_Smith master M Joined: Nov 2004 Posts: 6,890 North Alabama	Quote: staying on the converter or trans brake too long Ding, Ding, Ding...winner winner, chicken dinner..lol.......Fluid pressure, is trying to blow the converter out of the front of EVERY trans. Does not matter if the converter is ballooning or not, it IS pushing on the crank. Turbo combos are notoriously hard on thrust surfaces. Monte

Re: What causes thrust on the crank to go? [Re: Monte_Smith] #932338 02/19/11 06:36 PM 02/19/11 06:36 PM
Joined: Jan 2003 Posts: 6,150 Melbourne , Australia LA360 master
LA360 master Joined: Jan 2003 Posts: 6,150 Melbourne , Australia	That is good to know! Alan Jones

Re: What causes thrust on the crank to go? [Re: Monte_Smith] #932339 02/19/11 06:38 PM 02/19/11 06:38 PM
A Anonymous Unregistered
Anonymous Unregistered A	Quote: Quote: staying on the converter or trans brake too long Ding, Ding, Ding...winner winner, chicken dinner..lol.......Fluid pressure, is trying to blow the converter out of the front of EVERY trans. Does not matter if the converter is ballooning or not, it IS pushing on the crank. Turbo combos are notoriously hard on thrust surfaces. Monte There's more than 1 reason for thrust bearings to go south. Yes thats one of them but you need to look at different avenues to cause the problem.

Re: What causes thrust on the crank to go? [Re: HEMIFRED] #932340 02/19/11 06:45 PM 02/19/11 06:45 PM
Joined: Dec 2008 Posts: 1,200 UK 6 602heavy pro stock
602heavy pro stock 6 Joined: Dec 2008 Posts: 1,200 UK	Quote: staying on the converter or trans brake too long This is the reason i chamfer parting line of thrust bearing , puts pressurised oil to rear thrust face , might not help in all cases but it helps.

Re: What causes thrust on the crank to go? #932341 02/19/11 07:24 PM 02/19/11 07:24 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge OP master
TheOtherDodge OP master Joined: Feb 2003 Posts: 4,953 Houston, Texas	"There's more than 1 reason for thrust bearings to go south. Yes thats one of them but you need to look at different avenues to cause the problem." like????? Im not on the converter very long... On a bracket tree, I get on it as soon as he final stages, if I final stage before him... So that is really only about 2 seconds at the longest.

Re: What causes thrust on the crank to go? [Re: TheOtherDodge] #932342 02/19/11 07:32 PM 02/19/11 07:32 PM
Joined: Oct 2004 Posts: 1,752 detroit area M moderncylinder top fuel
moderncylinder top fuel M Joined: Oct 2004 Posts: 1,752 detroit area	crank flex,,,, by heavy bob weights or too much power for the material of the crank... what clearance did you run? you may want to open it up .005 or more,, usual is .004-.010 but ihra type pro stock motors have to run .025 or more because of flex you may need to be at .015,, id try to open it up .005-.007

Re: What causes thrust on the crank to go? [Re: moderncylinder] #932343 02/19/11 07:37 PM 02/19/11 07:37 PM
Joined: Feb 2003 Posts: 4,953 Houston, Texas TheOtherDodge OP master
TheOtherDodge OP master Joined: Feb 2003 Posts: 4,953 Houston, Texas	I was discussing this with a friend.. Let's say I had "x" amount (doesnt matter what it is). If nothing was wrong with converter, etc, even if it is too small, wouldn't the thrust "naturally seat itself"? How would this cause it to totally kill all the thrust?

Re: What causes thrust on the crank to go? [Re: TheOtherDodge] #932344 02/19/11 07:53 PM 02/19/11 07:53 PM
Joined: Feb 2004 Posts: 4,501 Gainesville,FL G goldmember master
goldmember master G Joined: Feb 2004 Posts: 4,501 Gainesville,FL	Quote: I was discussing this with a friend.. Let's say I had "x" amount (doesnt matter what it is). If nothing was wrong with converter, etc, even if it is too small, wouldn't the thrust "naturally seat itself"? NO! How would this cause it to totally kill all the thrust? Restricted oiling to the thrust bearing. Are both bearing halves worn evenly?

Re: What causes thrust on the crank to go? [Re: goldmember] #932345 02/19/11 08:40 PM 02/19/11 08:40 PM
Joined: Jun 2007 Posts: 2,646 Plymouth Meeting, PA bigtimeauto Trophy Winner
bigtimeauto Trophy Winner Joined: Jun 2007 Posts: 2,646 Plymouth Meeting, PA	what did the journal side of the bearing look like? that will tell you if the problem is from something else besides the converter / TB pressure. BB, TT5,Procharged 3300lb Street Car 4.79/154

Re: What causes thrust on the crank to go? [Re: bigtimeauto] #932346 02/19/11 11:32 PM 02/19/11 11:32 PM
Joined: Feb 2005 Posts: 20,203 PA. pittsburghracer "Little"John
pittsburghracer "Little"John Joined: Feb 2005 Posts: 20,203 PA.	Under the don't ask me how I know engine build my engine builder (me)forgot to check the converter to crankshaft hub clearance the first time I used a K1 crank. Instead if having clearance to float in the hub it thrusted the crank forward taking out the thrust. When I discussed this with another local Mopar builder he had this happen to him with an Eagle crank. Make sure it float in the hub. 1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27 Livin and lovin life one day at a time

Re: What causes thrust on the crank to go? [Re: pittsburghracer] #932347 02/19/11 11:59 PM 02/19/11 11:59 PM
Joined: Jan 2003 Posts: 1,807 Mopar Country, Mi ccdave The Ultimate
ccdave The Ultimate Joined: Jan 2003 Posts: 1,807 Mopar Country, Mi	Somtimes if main studs replace the stock main bolts,the thrust surface can get offset due the studs having a tad larger O.D. The result is the bearing offset scrapes the oil off the thrust surface and destroys the thrust surface of the crank. I've had to drill out a few #3 caps in my day to fix this problem.

Re: What causes thrust on the crank to go? [Re: HEMIFRED] #932348 02/20/11 12:04 AM 02/20/11 12:04 AM
Joined: May 2007 Posts: 446 oregon S savoyracer mopar
savoyracer mopar S Joined: May 2007 Posts: 446 oregon	Quote: staying on the converter or trans brake too long ... ....i am dealing with this very same issue right now. What amount of time would you consider staying on the convertor, or brake to be to long?

Re: What causes thrust on the crank to go? [Re: pittsburghracer] #932349 02/20/11 12:06 AM 02/20/11 12:06 AM
Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont Twostick Still wishing...
Twostick Still wishing... Joined: May 2003 Posts: 6,571 Downtown Roebuck Ont	Quote: Under the don't ask me how I know engine build my engine builder (me)forgot to check the converter to crankshaft hub clearance the first time I used a K1 crank. Instead if having clearance to float in the hub it thrusted the crank forward taking out the thrust. When I discussed this with another local Mopar builder he had this happen to him with an Eagle crank. Make sure it float in the hub. I've seen this happen on a Hemi. Kevin

Re: What causes thrust on the crank to go? [Re: ccdave] #932350 02/20/11 12:09 AM 02/20/11 12:09 AM
Joined: Nov 2004 Posts: 4,330 Lynchburg, VA Leon441 master
Leon441 master Joined: Nov 2004 Posts: 4,330 Lynchburg, VA	I know a guy who bought a Valve body used. Turns out some holes in the seperator plate (powerglide) were blocked off. His line pressure was extreme and ruined two cranks before he realized what was causing it. Check the line pressure of the transmission. Career best 8.02 @ 169 at 3050# and 10" tires small block power.

Re: What causes thrust on the crank to go? [Re: savoyracer] #932351 02/20/11 12:49 AM 02/20/11 12:49 AM
Joined: Jun 2003 Posts: 52,972 Romeo MI MR_P_BODY Master
MR_P_BODY Master Joined: Jun 2003 Posts: 52,972 Romeo MI	Quote: Quote: staying on the converter or trans brake too long ... ....i am dealing with this very same issue right now. What amount of time would you consider staying on the convertor, or brake to be to long? I would think bigger torque would build heat easier so the question might be somewhat hard to answer... but on my SB I can stand right on the converter from the top bulb to the last and it hasnt hurt the engine or trans in 5 +years... I run right up on the stall... 5600

Re: What causes thrust on the crank to go? [Re: Monte_Smith] #932352 02/20/11 01:53 AM 02/20/11 01:53 AM
Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY HEMIFRED master
HEMIFRED master Joined: Jul 2010 Posts: 3,502 SOUTH JERSEY	Quote: Quote: staying on the converter or trans brake too long Ding, Ding, Ding...winner winner, chicken dinner..lol.......Fluid pressure, is trying to blow the converter out of the front of EVERY trans. Does not matter if the converter is ballooning or not, it IS pushing on the crank. Turbo combos are notoriously hard on thrust surfaces. Monte Seeing that I was right proves "EVEN A BLIND SQUIRREL FINDS A NUT SOMETIMES" home of the Sox and Martin Hemi Duster

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