Just bought a gsx with a 6-bolt rebuilt by K Watanabe (in Van Nuys, I'd stay away) about 3000 miles ago. Head gasket blew, I tore it down completely last weekend, and this is what I found:

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As you can see there's a huge .058" gap (almost 1.5mm) between the crank and the bearing, and you can see the grooves the crank and bearing ate into eachother on the thrust side. The crank was ready to get down with the block.

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The bearings themselves look a bit like a train wreck, definitely not what I would like to see at 3000 miles. Dirt's gone through them plus there's been pretty serious contact with the crank. There were tons of shavings in the oil pan, some long strips that probably came off the thrust bearing. Unfortunately I didn't take a pic cause I figured it's normal break-in shavings.

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And the best part of all is the nice clean block they built up from. Looks like a block that was sitting bare in the rain for years. I went at it with a hone till I was green in the face but there's still a good groove where the rust ate a ridge into the walls. It was a last-ditch effort, it definitely needs reboring. I don't even know how the rings didn't tear up in a bore like that, the motor had pretty good compression, just over 150 across.

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The reason for this thread (other than ragging on idiotic "engine builders") is to find out what would cause crank walk on a 6-bolt, and how do I avoid it this time? Is it from out-of-spec thrust bearing clearance to begin with? I kinda doubt that.

I'm leaning towards oil starvation (although the dash gauge has showed decent oil pressure while I was driving it). It seems the front balance shaft bearing wasn't rotated, but the shaft was removed. It lines up with the little hex plug on the front of the block. I'm not sure, but I assume that means it lines up with the oil gallery hole. I'm gonna have to turn it.

The oil pump may be worn too. I think I saw in some manual how to check the oil pump clearances, but if someone wants to reiterate or add to it, I'd appreciate it. I also asked in another thread: does the case need to be replaced too, or just the gears in order to rebuild the oil pump?

It had an ACT 2100 pressure plate, which is way lighter than my old 2600, so I'm pretty sure the clutch wasn't the cause.

I'd like any input on how to put this together right this time. I have a decent idea, but I always appreciate more insight.

I'm building a 2.3 stroker with

-karking unturned crank,
-eagle rods
-wiseco 40-over, probably going with .004 clearance measured at the bottom of the skirt
-calico coated bearings
-arp everything
-crco main bearing dowel kit (www.crco.com)
-kiggly main girdle (http://www.kigglyracing.com/Main_Girdle.htm)
-align hone mains (I think that will be necessary with the three changes above)
-bore, hone cylinders
-deck block and head
-polish crank
-maybe balance (I think this is pretty much unnecessary, all the parts are balanced to begin with). Should the weight of the counterweights change when you go with a lighter piston and rod?
-maybe magnaflux the block if it doesn't cost too much
-RRE's probably gonna do all the machine work since I can't find anyone else trustworthy in the area.
-clean squirters
-I have a dial bore gauge, plastigage, feeler gauges, gonna triple-check the shop's work too

I wanna build this thing to be bulletproof and last a long time on the street. That's why I'm going all out on the mains, I don't want this funky bearing wear anymore. Not going for huge power, just a fun, reliable 400hp street motor. Please reply to as many questions as you have the answer to... I have a looot of questions in this post Thanks in advance, and better luck with your own engines!

Just had a thought, could the corrosion come from the coolant from the blown headgasket sitting in the cylinders for a couple of weeks after I took the head off?

I would not use that block since it walked so far. Its best to get a complete oil pump/front cover and pack the gears with assembly lube and vasolene. I would stay away from the dowel kit and the main girdle you wont need it. spend your money on what you need (you will run out).
There are better machined/quality rods than eagle there garbage in my oppinion. Look at the manley's or the scat rods. You will need to have the small end of the rods honed for the piston pin so keet that in mind. The pistons and rods (I know scats are already balanced sets so all you will need is have the crank balanced. Also look in to the new fluid damener (crank pulley) to replace that old stocker or a new oem will work also)
As far as the cause of the issue with the block you dissasembled it could be a few things. First is was that crank turned if so was it done correctly? Was the thrust bearnings aligned when it was assembled? Was it alighed honed straight? Was the engine prelubed? was the clutch freeplay adjusted correctly? Also make sure what ever machine shop you use make sure they have a deck plate for that engine when they machine and hone it. Use the search with any questions you have this site is full of everything for the 4g63.

Well I don't see the problem with using this block since the crank never actually contacted it. It was close, as you can see from the pics, but there was material left on the thrust bearing. Anything I'm missing?

I asked SBR about the rods and they said they're very similar, so I went with Eagles since everyone seems to be running them. Haven't seen any horror stories, though I haven't searched for it specifically. I would think they'll work fine for my application.

I've never heard of having to hone the small end of the rods. Can you give me any details/references on this?

As for the rebuild, I'm pretty sure they screwed up everything they could manage, did as little as possible and didn't try to do anything right. I'll check if the crank was turned. I plastigaged it for shits and giggles, and the clearances did come out good at around .0015

Question: what do you mean by "aligning the thrust bearing"?

Aligning the thrust bearing involves just loose assembling the mains and tapping the crank with a dead-blow hammer in both thrust directions. This makes sure the front/rear thrust faces are aligned on the top and bottom thrust bearing halves.

I doubt you need to coat the bearings with your power goals. I also wouldn't bother magnafluxing the block.

I would avoid a 0.040" over block in a high power application though. If your goal is only 400whp, then I wouldn't worry about it. If you're going for broke, cylinder wall thickness is your friend. The block I split a wall in was bored 0.040" over.

From your pictures - those main bearings are showing a lot of wear for any mileage. It is fairly normal, smoooth looking wearing (aside from the debris marks). That is just too much wear though, which indicates a lack of oil pressure or quality.

Counterweights - I haven't done any analysis to prove this yet, but I'm fairly certain the 4g64 crank is severely lacking counterweight. You definitely don't want to decrease the amount of counterweight. The 4g63 has about the same size counterweights as the 4g64 crank. The '63 doesn't have any problems at high rpm, but the '64 will kill main bearings in a heartbeat if taken past 8500rpm. The longer stoke '64 should need more counterweight than the '63, and considering it overloads the mains at high revs, I think this is a very strong indicator the '64 lacks counterweight. My advice - don't remove any counterweight.

Kevin

Thanks a lot for your insight, Kevin! (Nice car you got there, by the way)

The calico bearings are the same price as clevites from SBR, so I figured they can't hurt, expecially in oil starved situations (which I'm trying to avoid this time). I'm pretty sure all the problems were caused by the front balance shaft bearing not being turned around. Too bad I don't have a pic so you guys can verify, but I'm pretty sure it's open to the oil gallery.

What do you guys think about doing this mod to the thust bearing, to feed it extra oil?

<img src = "http://www.4secondsflat.com/bearing1.jpg">
from this link http://www.4secondsflat.com/Thrust_bearing_failures.html

Again, I probably don't need it in a 6-bolt with good oiling, but it's another one of those cheap insurance things that seems like it can't hurt.

Has anyone talked to CRCO lately? They don't return my emails and their voicemail box is full. Does anyone else sell them?

If I can't obtain them I guess I'll go with stock bolts. I just don't like them cause they seem to have yielded and stretched while I was playing around with plastigaging the old crank. I followed the haynes manual procedure of 18lb/ft and an additional 90 degrees, which felt like a lot of torque. I'm afraid new ones will stretch too after all the tightening and loosening throughout the build.

Does the machv mbcad dowel kit work the same as crco?
http://www.machv.com/conracmbcadk.html

I fail to see how you'd be able to align the thrust bearing if the dowels held the cap perfectly tight Do they align that perfect with the factory machining?

Does the mbcad kit require machining? The machv description leads me to believe it doesn't, but from what I've read about the crco kit, that required machining.

Why do you think you need this? Maybe Kevin can offer his insite for your aplication. Yes I do beleive that the block and caps need maching and causes more problems than good if not done corectly.There are many guys putting down over 600 HP with just ARP studs. Kevins main girdles look like nice pieces for a 600 HP motor but 400HP those caps arnt going anywere with studs and a line hone.
If your going to go with the eagles have your macineist make sure the big ends are all 100% perfectly round and the same sizes also have them balanced.

I have a bore gauge, been playing with it last night, looks like it's accurate enough. Actually it might be too big to measure the rods, I'll have to check.

The reason I'm going nuts on the mains is basically just to make myself feel better And because I believe there's more load on them with a stroker, and I wanna keep it reliable. It's one of those things that while I'm doing studs I might as well do the alignment kit, and for 150 bucks extra the girdle can't hurt. It's a chain of might as well's. But at the end of the day I know that shit ain't moving anywhere. I'm still under the illusion that if I do this right, I'll only have to do it once We'll see...

Some people seem to advise against using the arp's without dowels, not sure how much substance there is to that, but some actually cite signs of rubbing between the caps and block. I'll have to ask RRE if they can do this correctly and have my thrust bearing line up.

How should the wrist pin fit in the rod? Slide in easily, right, can't be tight? If the small end needs to be opened up, can I do it with a small brake cylinder hone?

I'd bet the house on not lineboring (or not doing it correctly) when installing ARP mains.

What exactly are you betting on? If you mean the cause of the failure in the pics, it was a stock rebuild, no ARPs.

steel_3d said:

What exactly are you betting on? If you mean the cause of the failure in the pics, it was a stock rebuild, no ARPs.

Click to expand...

Ah I was looking at your future mods list. It is a good thing I do not own a house.

Well, I've done a lot of reading (thanks guys, for pointing me in the right directions), and decided not to dowel the mains. I'm much more comfortable leaving wiggle room to align the thrust bearing, than to hope it just lines up perfectly after it's machined. According to Kevin, the girdles stop the caps from walking anyway. I might just go a bit tighter on the ARP's, maybe 50lbft.

I'm in the same boat as you and while I considered using the dowel kit, the machinist felt a little wiggle room would be better as well. While I'll be building a 7 bolt, it makes me feel better to know that my trashed bearings were not the result of walk. With the pan off, we yanked on the crank with a crowbar and it wouldn't move. At least that was still good.

All the best on your build and keep us posted when she's up and running.

Andy

steel_3d said:

Well, I've done a lot of reading (thanks guys, for pointing me in the right directions), and decided not to dowel the mains. I'm much more comfortable leaving wiggle room to align the thrust bearing, than to hope it just lines up perfectly after it's machined. According to Kevin, the girdles stop the caps from walking anyway. I might just go a bit tighter on the ARP's, maybe 50lbft.

Click to expand...

Just another note I wanted to add for you is that when alighning the thrust bearings the cap is not nessasaraly what is moving its the bearings that are lighning up with the back of the cap and block straight.
What happens is if you dont alighn the bearings you have 1 side (bearing) sticking out farther than the other bearing causing an uneven load on the side of the bearing. When you have both sides straight with each other more load can be placed on them with out failure and the oil film is also more consistant.
The main girdle is a great idea but I dont like having no thread stock left over the top of the nut after you get done torqing them down. Its always a good Idea to leave 1/4 to 1/2" above the nut for strength. You can see it in his pics. Not bashing it should have extra long studs with it.

Interesting, it seemed to me like the thrust bearing fit tight on the cap and block, but I've never installed a new one so we'll see.

Also, I can definitely see the issue with bad alignment. I think it's much worse than just uneven loading. The protruding lip will act as a scraper, destroying the oil film, effectively running half of the bearing dry, metal to metal contact, yadda yadda, done.

This is one of the reasons why I want my mains to stay put, cause I feel even a small amount of walking might cause this type of scraping effect.

Again, this is just me theorizing, and trying to avoid all the potential sources of failure that I can think of. Is it all necessary? Maybe, maybe not. I just know I'd wish I had thought things through more if it failed.

Like the thrust bearing mod I referenced in an earlier post: filing an extra oil channel into the bearing. Has anyone tried it? Only person I've found doing this is ShapeGSX. One problem I just thought of with this is that you're sacrificing oil pressure in the main bearing for the thrust surface. Is it a significant loss? Is it worth it? I was just thinking "why wouldn't the manufacturer make that simple design change?" Well, that seems like a good reason not to. But then why would a document put together by automotive engineers offer the idea? I'm thoroughly confused. Maybe filing a really thin channel would be ok?... Maybe drilling out the oiling hole in the crank would offset the loss from the channel? That's probably going too far for me, just food for thought... Then again, if it was this simple, why wouldn't all thrust bearings/cranks be manufactured this way?

By the way, what's the ideal weight oil to run in an engine like this?

And my other question still remains: How should the wrist pin fit in the rod? Slide in easily, right, can't be tight? If the small end needs to be opened up, can I do it with a small brake cylinder hone, or is it something that must be done by the machine shop? Do I need to go for a specific tolerance number?

Once the main bearing cap is torqued the bearing doesnt move. Also all the oil pressure coming out of the main bearing area lubes the thrust surfases. Oil is forced on to the bearing then forced out by pressure lubeing the thrust another way of puting it. I dont think its a good Idea to file the thrust bearing ends like you posted because you will loose a little oil pressure going to the rods (the main bearing oil feeds the rod bearings as well) I would just use the ARPs and call it a day.
As far as the small end on the rods yes you need to have it professionally machined (honed) to proper size. Its called a floating pin fit. Make sure you put a good asssembley lube on the pin before installing it.
Proper oil is 10/30 in the summer and 5/30 in the winter.

Filing a channel into the bearing should not cause any oil pressure loss because the oil is still contained by the thrust surface.

Anyway, my engine has been running like this for ~50,000mi.

What oil were you running, prior to "the walk" ?
How is your harmonic balancer holding up ?

-Jaraxle

definite oil starvation.your almost down to the copper on the bearings.since the cylinders where rusted up like that,the guy that built it probably didnt clean out the block,and goo stopped the oil.my block looked like yours,but i tanked it and cleaned the hell out of it first.

Yeah, the block's definitely getting the full treatment.

Not sure what oil was in the car, cause I barely drove it after I bought it and it was relatively clear. The engine never ran more than 2-3000 miles I'd say, so I doubt the type of oil would have made a difference.

The crank pulley is still good. It's a relatively new one actually. I'm gonna get everything balanced this time, can't hurt with a stroker.