Shortblock Assembly-Zero thrust clearance issues. Help
07-28-2014, 11:46 AM
#1
Shortblock Assembly-Zero thrust clearance issues. Help Hi fellas,
I've been slowly putting together my 408 iron block for my twin turbo build.
using the Summit Racing Iron block (with additional machining from my local shop to get the bore's within spec.
I'm using an Eagle 4" crank, polished std. journals. (Used in previous build with no issues)
This time around I decided to give the KING XP bearings a go. So far, Main bearing clearance is nice and tight at around .0026 - .0029 between the 5 journals.
I just finished tightening down the main caps. Using Lucas assembly lube on all bearing surfaces. Now, I'm not sure if this is the problem or not, but I also lubed the Thrust side of the #3 bearings as well as the thrust surface on the crank. Is this going to cause issues when checking the thrust?
I can spin the crank over with two fingers. But, I am getting ZERO thrust. Not even .001 of clearance. I've used a screw driver on each side of the crank and a dead blow to front/back with no difference in clearance.
I'm not sure what to do at this point. I'm thinking about throwing the KING bearings in the garbage and going back to the Clevite coated set in STD.
They sell the #3. thrust bearing in several brands separately. Is it okay to use a different brand bearing here if it spec's out correctly?
If anyone can help me, I would really appreciate it. Thanks in advance.
Edit: I did seat the thrust bearing by tapping crank front to back before torqueing the Caps down. Cleaned all bearing shells as well as block at point of bearing shell contact.
I've been slowly putting together my 408 iron block for my twin turbo build.
using the Summit Racing Iron block (with additional machining from my local shop to get the bore's within spec.
I'm using an Eagle 4" crank, polished std. journals. (Used in previous build with no issues)
This time around I decided to give the KING XP bearings a go. So far, Main bearing clearance is nice and tight at around .0026 - .0029 between the 5 journals.
I just finished tightening down the main caps. Using Lucas assembly lube on all bearing surfaces. Now, I'm not sure if this is the problem or not, but I also lubed the Thrust side of the #3 bearings as well as the thrust surface on the crank. Is this going to cause issues when checking the thrust?
I can spin the crank over with two fingers. But, I am getting ZERO thrust. Not even .001 of clearance. I've used a screw driver on each side of the crank and a dead blow to front/back with no difference in clearance.
I'm not sure what to do at this point. I'm thinking about throwing the KING bearings in the garbage and going back to the Clevite coated set in STD.
They sell the #3. thrust bearing in several brands separately. Is it okay to use a different brand bearing here if it spec's out correctly?
If anyone can help me, I would really appreciate it. Thanks in advance.
Edit: I did seat the thrust bearing by tapping crank front to back before torqueing the Caps down. Cleaned all bearing shells as well as block at point of bearing shell contact.
07-28-2014, 04:47 PM
#3
It said std. like all the others.
I'll try removing the #3. cap, check end play, remove assembly lube other than a light coat of oil on the journal surface and try again. But I'm not feeling confident this is going to solve the problem.
Has anyone used a different brand thrust bearing? Since they sell these individually, it might be worth a shot? I don't know. I'm getting tired of F'in with this engine. I should have bought a complete shortblock from a sponsor...
I'll try removing the #3. cap, check end play, remove assembly lube other than a light coat of oil on the journal surface and try again. But I'm not feeling confident this is going to solve the problem.
Has anyone used a different brand thrust bearing? Since they sell these individually, it might be worth a shot? I don't know. I'm getting tired of F'in with this engine. I should have bought a complete shortblock from a sponsor...
07-28-2014, 05:30 PM
#4
TECH Fanatic
you can open up the thrust clearance with a flat surface and some very fine sand paper. I've never done this personally, however I know of others that have done it successfully.
07-28-2014, 06:36 PM
#5
Don't get discouraged. Engine assembly is not difficult but you must be patient. There is a lot of checking that you need to do. Before you buy anything check what you have, post pics, and we'll help you. Then you can say that you built it instead of bought it.
07-29-2014, 10:38 AM
#7
Thanks guys, I appreciate the help.
Hopefully I just accidentally set the #3. cap offset a little or something. I'll give the above advice a go and report back.
I was under the impression that you wanted to smack the crank rearward first, then forward for setting Thrust. Does it matter which its' done before re torqueing it down?
Thanks again!
Dan
Hopefully I just accidentally set the #3. cap offset a little or something. I'll give the above advice a go and report back.
I was under the impression that you wanted to smack the crank rearward first, then forward for setting Thrust. Does it matter which its' done before re torqueing it down?
Thanks again!
Dan
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07-29-2014, 08:35 PM
#9
Okay,
I removed the #3. main cap. with just the cap removed and the top half of the thrust bearing still installed, I get approximately .005" of clearance. I removed the assembly lube and used regular motor oil for lubrication, rotated the crank 360 degrees, torqued the cap down to 15 lbs. I'm getting approximately .0025 of clearance. I imagine I'll lose even more clearance once I put more torque on it.
I very lightly de burred the edges of the cap just in case.
I'm not sure what to do. should I lightly sand down the bottom half of the bearing? Completely remove and measure both and then reinstall, or throw the engine away? lol.
Thanks.
I removed the #3. main cap. with just the cap removed and the top half of the thrust bearing still installed, I get approximately .005" of clearance. I removed the assembly lube and used regular motor oil for lubrication, rotated the crank 360 degrees, torqued the cap down to 15 lbs. I'm getting approximately .0025 of clearance. I imagine I'll lose even more clearance once I put more torque on it.
I very lightly de burred the edges of the cap just in case.
I'm not sure what to do. should I lightly sand down the bottom half of the bearing? Completely remove and measure both and then reinstall, or throw the engine away? lol.
Thanks.
07-30-2014, 11:06 AM
#14
Yeah, I used a dead blow several times on each end while slightly rotating the crank each time. As well as a flat head screw driver to slide it back and forth.
The readings were consistent at .0025".
But, I'm fairly confident that once I torque the cap back down to spec, I'm going to lose some clearance. I was aiming for a Bare minimum of .004 to .0055 max. I ran out of time yesterday to do these things. But I'll report back with any new findings.
Question: if I lightly sanded one side of both thrust bearings, would that cause any issue or would I be taking any chances? 600 grit on a 3/8" in. piece of glass and a finish sanding with 1000 grit? I'm just looking at taking off about .002" or so.
Thanks for the help guys!
The readings were consistent at .0025".
But, I'm fairly confident that once I torque the cap back down to spec, I'm going to lose some clearance. I was aiming for a Bare minimum of .004 to .0055 max. I ran out of time yesterday to do these things. But I'll report back with any new findings.
Question: if I lightly sanded one side of both thrust bearings, would that cause any issue or would I be taking any chances? 600 grit on a 3/8" in. piece of glass and a finish sanding with 1000 grit? I'm just looking at taking off about .002" or so.
Thanks for the help guys!
07-30-2014, 03:01 PM
#16
Before you start sanding, tweaking, or messing with anything you need to accurately assess what is going on. You must know what is wrong before you can fix it. You might find a burr pushing on the bearing. You may have an issue with tolerance stack up. Let's figure it out.
07-30-2014, 09:45 PM
#18
the issue is either the bearing in the #3. cap, or the cap itself.
I get .005 clearance with the top half still installed, but as soon as I slide the cap on and tap it down, clearance is back to .0025 at best. Even with the cap on without nuts, I can't get any more.
I'm noticing some scratches on the thrust surface of the crank from all of this. And the edges of the bearing show a little wear from this contact. So I'm going to take it apart, have the cap checked out and go back to the Clevite's. Hopefully the crank isn't scratched too bad.
I get .005 clearance with the top half still installed, but as soon as I slide the cap on and tap it down, clearance is back to .0025 at best. Even with the cap on without nuts, I can't get any more.
I'm noticing some scratches on the thrust surface of the crank from all of this. And the edges of the bearing show a little wear from this contact. So I'm going to take it apart, have the cap checked out and go back to the Clevite's. Hopefully the crank isn't scratched too bad.
07-30-2014, 10:09 PM
#19
Yeah, I used a dead blow several times on each end while slightly rotating the crank each time. As well as a flat head screw driver to slide it back and forth.
The readings were consistent at .0025".
But, I'm fairly confident that once I torque the cap back down to spec, I'm going to lose some clearance. I was aiming for a Bare minimum of .004 to .0055 max. I ran out of time yesterday to do these things. But I'll report back with any new findings.
Question: if I lightly sanded one side of both thrust bearings, would that cause any issue or would I be taking any chances? 600 grit on a 3/8" in. piece of glass and a finish sanding with 1000 grit? I'm just looking at taking off about .002" or so.
Thanks for the help guys!
The readings were consistent at .0025".
But, I'm fairly confident that once I torque the cap back down to spec, I'm going to lose some clearance. I was aiming for a Bare minimum of .004 to .0055 max. I ran out of time yesterday to do these things. But I'll report back with any new findings.
Question: if I lightly sanded one side of both thrust bearings, would that cause any issue or would I be taking any chances? 600 grit on a 3/8" in. piece of glass and a finish sanding with 1000 grit? I'm just looking at taking off about .002" or so.
Thanks for the help guys!
I didn't see what he had for a trans, but I'd like to see .005-.007". That kind of power will cause things to move and the drivetrain for it could put some serious force on the thrust.
The design of the reservoirs in the thrust face is also important.
07-31-2014, 11:31 AM
#20
Sanding it is probably your best bet. I've had it happen to me dozens of times and had to sand it on fine sandpaper to get the clearance where I wanted it. I put the shells together and sand them in a figure 8 on a granite block. Apply pressure evenly.
I didn't see what he had for a trans, but I'd like to see .005-.007". That kind of power will cause things to move and the drivetrain for it could put some serious force on the thrust.
The design of the reservoirs in the thrust face is also important.
I didn't see what he had for a trans, but I'd like to see .005-.007". That kind of power will cause things to move and the drivetrain for it could put some serious force on the thrust.
The design of the reservoirs in the thrust face is also important.
Should I sand both sides of the bearing's thrust surface, or carefully work one side only? I'm just afraid that sanding it might do more harm than good as far as the surface is concerned. I imagine I should use an outside Mic after taking off material, check and continue the process?
Also, I'll try and shoot for .005" minimum since you're an engine builder and I'm not.
Thanks again, guys. I appreciate all the help/support from this board!