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2G Rebuilding a crank walk engine tips

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1kick

5+ Year Contributor
84
17
Mar 27, 2018
Santa fe, New_Mexico
I don't know how many people saw my last post but I recently rebuilt my 4g63t and in less than 2k miles it developed crank walk so I have to rebuild it again I'm looking for some tips to prevent it from happening again and what I should look for when pulling it apart that I may need to replace

1 I noticed when I pulled it apart the first time the crank bearings were worn more that the rod bearings which tells me they were getting less oil does any one know how to fix this

2 is it true that having a crank with different clearances for the mains and rods will cause crank walk my machine shops sucks and will charge me an arm and a leg to get them to match

3 I used clevite bearings on my rebuild as I do plan to get a mild tune and didn't want to go with race bearings and have to replace them often as this car sees 100 miles a day is there a better bearing to go with

4 will I have to buy a new crank I know the bearings are the parts that wear but the crank has to wear a little right ?

5 a rebuild should fix this problem if the bearings aren't worn out completely?

Any tips you think will help me make my next rebuild successful will help me and maybe someone else
 
1 - Clutch adjustment is critical on the 2g, check it often and learn exactly how to check it and adjust it, it will change.
2 - Not true.
3 - Clevites are fine, as long as they are name brand you should be fine, many people use them with no problems.
4 - You would be well advised to get a new crankshaft at this point.
5 - Correct.
 
1- @motomattx is right
2- you need a new machine shop. Your clearances should be within the specifications defined by the manufacturer.
3- personally I don't use name-brand Clevites much more, I had two bad sets come in a row. I usually use King or ACL race bearings.
4- the crank will need to be checked for tolerances and finish, but most of the time I see cranks in your situation needing to be replaced.
5- yes, just make sure things are done correctly and CLEANLY.

Other things you can do are disconnect the clutch switch so you can crank the car without having to press the clutch. Use good quality oil. Ensure you have proper oil pressure. Avoid extremely high poundage pressure plates if it's a daily driver especially.

Good luck and keep a log so we can see how it goes!
 
the machine shops around here suck ass. Every time i have complained about bad machining, at any of the shops, i have always been told "Its good enough". The last time i have a head resurfaced, it was way to rough for a MLS gasket and the asshole told me to hand sand it with a piece of sand paper and block of wood.
I won't even deal with any of them anymore (my best friend works at one of them).

If i were you, i would hit up Jack's Transmission in Colorado Springs. They specialize in all things DSM.
See HERE
and HERE

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Agreed with the others.

You should also check the condition of your oil pump and gears. Check their tolerances and the shaft bore (oil pump drive gear). If you have balance shafts, check their bearings and whether they are rotated correctly, whether the shafts are worn or are eliminated etc. Eliminated shafts will cause an increased dynamic oil pressure. If you do the teardrop oil port mod, that will allow even more oil volume to flow to the head. Sometimes, at high RPMs, this can lead to oil starvation of the rotating assembly since it's pushing a lot more oil towards the head.

On a late '97-'99 7 bolt block the thrust bearing is split and there is a specific recommended way of installing the split thrust and applying the preload. If it's not installed correctly it could lead to premature thrust wear.

Another thing to look out for again related to the clutch system is the very important two aligning dowel pins between the block and trans, as well as the smaller M8 bolt that threads from the block towards the trans and goes through one of the dowels. It's an essential bolt to have. Check that you have it. They don't call it the crankwalk bolt for no reason.
 
the machine shops around here suck ass. Every time i have complained about bad machining, at any of the shops, i have always been told "Its good enough". The last time i have a head resurfaced, it was way to rough for a MLS gasket and the asshole told me to hand sand it with a piece of sand paper and block of wood.
I won't even deal with any of them anymore (my best friend works at one of them).

If i were you, i would hit up Jack's Transmission in Colorado Springs. They specialize in all things DSM.
See HERE
and HERE

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That's a bummer. I'm noticing it more around here as well, unfortunately. My long time machinist, some of who's college courses I attended, closed up shop this last year, so now I'm down to 3-4 "eh" shops and 1 specific racing shop. Makes me wish I'd become a machinist instead kinda.
 
If you’re running forged 2618 aluminum pistons, I’d remove and weld the tips of the oil squirters and reinstall them, or buy new ones from extreme psi.

Look, the crankshafts in 2g’s are throw aways.
They’re supposedly not nitrided from mitsu so the thrust surfaces are not as hard as they should be.
The only way to reuse a crankshaft in a 2g is to send it to Mile High crankshaft in Colorado and have them fully dial it in, pull the sludge traps to fully clean out the oil galleys, tap and plug sludge traps, plasma nitride the crankshaft, then give it a final polish and ship it back to you.
The shipping both ways and work done at mile high will cost you what a brand new eagle crankshaft will cost you shipped from extreme psi.
But give them a call and find out.
http://www.milehighcranks.com/
 
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heres the specs of my 300,000 km crank tolerances are written near the top.
out of roundness spec is .0006 although this is for a 1g 6 bolt

Connecting Rod specs are 1.7709-1.7715
Crank journals are 2.2433-2.2439

Pulled these specs from jafro .
Idk if this will help you or not for the crank but worth a post,


I'd recommend blue printing your crank this time around and finding out your oil clearances
 
Thanks for all the info guys Im gonna pull it this weekend as far as the clearance for the bearings I used plastigage to measure the crank bearings using red I got .002 inch - .003 my oil pressure was a little higher than half on the factory gauge and slowly started going down the more miles I put on it probably due to the fact that the bearings are wearing from all the shavings it's gonna be a pita to clean all that junk out of the oil passages
 
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Here's a few pics I haven't had time to pull the crank from the bearing wear could I have tightened one side more than the other or is there something else going on and yes the crank walk bolt is missing
 
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As you can see the thrust bearing on the block is not nearly as worn #2 rod bearing is worn unlike the rest of the rod bearings it also seems to have shrunk as you can see. it was stuck to the crank when it came off any ideas there
 
It's the only one like that the others are still snug against the rods and caps this is the only one with lots of wear what would cause it to deform like that
 
I think they are steel back they are clevite oe replacements I'm starting to think it was the work done on the crank that's the only thing that changed when I pulled the crank the first time with 158k miles on it the bearings were worn but it didn't have problems like this
 
I guess I put too much trust in the machine shop I should have checked all the clearances I only check the mains and they were good
 
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