Thrust bearing modification (crankwalk prevention)

[sschambers]

DSM Jeff:

Like I said, if you plan on using ARP studs, you MUST get the block align honed with these studs or else you're going to run into problems. ARP even warns about getting the block align honed when using their main studs. Also, you may want to consider the MBCAD kit (MachV sells it). It's a main-dowel kit to be used in conjunction with ARP main studs. It ensures there is no end to end movement within the main girdle (caps). Though, I questioned this when I was assembling my motor because even without the dowels in place, there was no movement whatsoever within the main caps but I used them anyway. When I aligned the thrust bearing, I waited until the engine was in the car, un-bolted the finger-tight oil pan bolts and main studs, and had a buddy push the clutch in while i pryed the main caps toward the rear. I felt this was the best way to ensure a perfectly aligned thrust bearing.

Steve

 

[sschambers]

Since it seems like more people are curious about this, I went ahead and inverted the colors of the photos I took of my bearing when I filed it down some; in hope to make the modification stick out a little better. I wish I would have had a better camera at the time to take these pics instead of my phone.

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Not sure if this will make it worse to see, or better. The original pics are still at the top, I won't be taking them down any time soon.


Steve

 

[DSM Jeff]

DSM Jeff:

Like I said, if you plan on using ARP studs, you MUST get the block align honed with these studs or else you're going to run into problems. ARP even warns about getting the block align honed when using their main studs. Also, you may want to consider the MBCAD kit (MachV sells it). It's a main-dowel kit to be used in conjunction with ARP main studs. It ensures there is no end to end movement within the main girdle (caps). Though, I questioned this when I was assembling my motor because even without the dowels in place, there was no movement whatsoever within the main caps but I used them anyway. When I aligned the thrust bearing, I waited until the engine was in the car, un-bolted the finger-tight oil pan bolts and main studs, and had a buddy push the clutch in while i pryed the main caps toward the rear. I felt this was the best way to ensure a perfectly aligned thrust bearing.

Steve

Ok, maybe I won't be using arp's as honing isn't an option right now. This is just a bandaid fix to hopefully get a bit more life of this engine. So if I replace stock bolts would I need to go through with a hone or do you think I'd be ok in just replacing. I'm just getting ideas because the manual says to just replace the thrust bearing if you're out of spec which this one almost is. I guess I'll be doing some more homework before I go any further. Thanks for the heads up.

 

[sschambers]

Ok, maybe I won't be using arp's as honing isn't an option right now. This is just a bandaid fix to hopefully get a bit more life of this engine. So if I replace stock bolts would I need to go through with a hone or do you think I'd be ok in just replacing. I'm just getting ideas because the manual says to just replace the thrust bearing if you're out of spec which this one almost is. I guess I'll be doing some more homework before I go any further. Thanks for the heads up.

I don't see any problem in just replacing stock main bolts with stock bolts (or re-using them if they're fine). If you did an align hone every single time you re-used or replaced main bolts, on any motor, people like us would have a VIP card for our favorite machine shop....Or a "after every 5 hones, get 1 free" card

 

[Artago]

I'm going to have to replace the thrust and main bearings soon too. Would you mind doing a quick write up to help me out? I've never done it before.

Tom

 

[DSM Jeff]

I don't see any problem in just replacing stock main bolts with stock bolts (or re-using them if they're fine). If you did an align hone every single time you re-used or replaced main bolts, on any motor, people like us would have a VIP card for our favorite machine shop....Or a "after every 5 hones, get 1 free" card

I figured that but had to ask the dumb question, . I'll price out some bolts when I'm down at JNZ and see what they run. I just want to try this and see how it goes, only thing, not my engine. Thanks for your help. I'll update if I do end up doing this.

 

[4g64fiero]

SSchambers,

Nice thread bro. I just rebuilt my 95 7 bolt but failed to align the girdle properly causing a thrust bearing failure within the first 1500 miles. I was wondering if you could delve more into the process of aligning the girdle properly. Is it just as simple as torqueing the girdle down while under load from the clutch being pressed? I assume it would be critical to have a properly adjusted clutch before persuing this process.

Thanks in advance.

 

[4g64fiero]

Any more details?

 

[MidShipCivic]

Hi all. I've had my motor rebuilt twice and it's walked twice.

Right now it's at 0.009" so time is ticking. What I would like to know is.... has this mod had any success? Basically, I want an update.

I've been reading everything I can about this issue including magnus' oil passage/squirter/lack of flow theory and it seems like that this mod could aid in getting more oil to the thrust bearing.

I'm going to be replacing my bearings soon and would like to know how this mod has held up in your car? Maybe I'll try it myself.

Thanks,

Tom

You then had someone build your motor the wrong way TWICE then.

Was this on the same motor and crankshaft?

7 bolt 4g64 I didn't do any of these procedures and my motor perfect...

 

[Artago]

You then had someone build your motor the wrong way TWICE then.

Was this on the same motor and crankshaft?

7 bolt 4g64 I didn't do any of these procedures and my motor perfect...

That's what I'm thinking. I need to replace the bearings but i don't want to remove and disassemble the whole motor. I'm looking for a good write up on how to do it with the motor in the car. Any advice / links?

Tom

 

[MidShipCivic]

That's what I'm thinking. I need to replace the bearings but i don't want to remove and disassemble the whole motor. I'm looking for a good write up on how to do it with the motor in the car. Any advice / links?

Tom

If you have excessive end play you don't reuse that crankshaft the thrust surfaces are uneven/rippled.

You'll have to remove the motor for that issue.

 

[sschambers]

Hey guys sorry I haven't been around lately. Was in SoCal for a month then went to Cancun with my girlfriend. Now I'm back to the terrific Pennsylvania sunshine (aka clouds, rain, snow, cold)

Anyway if you're looking to just replace the main bearings due to excessive end play, I would recommend pulling the whole motor and doing a complete rebuild.

Like mentioned, if the end play is out of spec there is an extremely good chance that the crank's thrust surface is in bad shape (uneven, fine lines cut into it, etc).

If you replace only the main bearings with a not-so-perfect crank thrust then you're going to run into the same problem again very soon down the road.

BUT if you still don't care; here you go...

Jack the car up high enough to comfortably get under it (or if you have a lift then that would be perfect).

Drain the oil.

Remove the downpipe

Remove all of the 10mm bolts that hold the oil pan to the bottom of the block.

Usually the oil pan won't come right off, so take a rubber mallet and lightly smack all around it to loosen it up (and make 100% sure you have all of the bolts out). I don't recommend prying the pan from the block as you risk re-sealing issues.

Once the oil pan is off, you will see the internals (crank, rods, bottom of the pistons).

Loosen all of the main bolts. I do this by following the torque sequence in reverse, little by little. Keep track as to which main bolt/stud went where (at least I do).

Once they're all out, remove the bed plate/girldle. This can sometimes be a PITA also. Just work at it gently, it will loosen up.

Once you have the girdle out, you'll have the bottom halves and the top halves of the bearings to remove. From my experience the bottom halves like to stick to the crank when the girdle is removed. These are easy to remove, just pull them off.

As for the top halves, this can be tricky. Get a feeler gauge to push the one side of the bearing up and over the crank until it slides all the way to the bottom, then remove. Repeat for the others. Sometimes they're a PITA to make slide all the way around. Just BE CAREFUL to not scrape or mark up the crank.

Take the new bearings, install the bottom halves into the bed plate; do not lubricate the bottom sides, only the side that make contact with the crank.

The the other new halves, push them up into the the motor; kind of the same way you took the old ones out, just in reverse this time. Again, only lubricate the side that make contact with the crank before installation.

Now that you're probably covered in oil, you can probably guess how the rest of this task goes.

Ensure all of the new bearings are properly installed (pay attention to the locating tabs).

Slip the girdle back up in there.

Follow correct torque sequence along with the method I use on the first page of this thread (to align the thrust bearing).

Make sure there are no metal shavings or junk in your oil pan. Either way, I always clean the entire pan out anyway but that's just me.

Use a NEW oil pan gasket. They're a few bucks for a cork gasket at Auto Zone. Use this gasket paired with RTV sealant. Don't go overboard with the RTV, you don't want that shit spreading out so far that chunks get into the oil pan.

Bolt everything back up.

Enjoy the ride for the next week until you have to do it again


Once again, make sure to note the condition the crank's thrust surface is in. I wouldn't even bother replacing just bearings. Get a new crank and get everything machined.



Steve

 

[LocknessMonster]

Whats the difference from the 97-99 redesigned 7 bolt thrust bearing compared to the evos thrust bearing design? If its different could the block be machined to accept these changes.

 

[WhiteEclipse]

Here are a few pictures of my own thrust bearing that I did the modification to. I'm sorry that some are so blurry, they were taken with my camera phone. If you're wondering why my main bearings are black, it's from the graphite coating that was applied to them.

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Rear Thrust Face

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Closer shot of the mod

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Showing the chamfer from the parting line

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Another shot of the rear thrust face

I know this is an old post but I will definitely be giving this a shot on the engine I'm building right now