I cant believe it! Fully built, $7500, 700 miles, and CRANKWALK!!

[Blue97GST]

oh stupid me... I meant "CRANK ANGLE SENSOR!" Now I'm sure that no 1g's have a CRANK angle sensor right?

 

[Blue97GST]

Here this is copied directly off the pages of TURBO4WD.COM. Sorry it's so long but it is interesting to those who want to learn about crankwalk:

Brief History:
On August 4th 2001 on my way home from the track I developed Rod Knock. - See Rod Knock Videos and Raw Pictures -
I had to decide what to do... go 6 bolt 1st gen short block, rebuild my short block, or go with replacement 7 bolt short block? I toyed with this for a few weeks talking to many different people and shops. Needless to say, I got different answers from each person.

I realized that I needed to do some self evaluations (The same thing I tell many people who e-mail me regarding parts for their cars) It was time for me to follow some of my own advice.

I first needed to decide on a 7 bolt or 6 bolt motor. In the DSM tech. world, when we talk about 6 bolt verses 7 bolt, we are referring to the number of bolt holes for the flywheel in the crank. 6 bolt motors are found in 90-early 92 turbo cars, and 7 bolt motors are found in the late 92-99 turbo cars.

So what are some Pros and Cons to the 6 and 7 bolt motors in a 98 GSX ?
6 bolt:
Pro: 6 bolt motors have a larger journal on the crank to accept a larger rod. This makes them more forgiving if minor detonation occurs. Major detonation will hammer any rod bearing. Hmmmm... Larger rod... Spun bearing! The 6 bolt are felt to be a stronger bottom end, but this is in stock trim.
Con: The 6 bolt motor has a lot of structural differences to the 7 bolt motor. The 6 bolt motor doesn't have a crank angle sensor which is on the 7 bolt motor. (there is a work around using a 1G crank angle sensor. http://www.magnusmotorsports.com/ ) There have been a few people who have been having some problems with the 1G cam angle sensors and stock 2G ECUs. They get a random misfire, check engine light RMCEL. This occurs when the stock ecu detects the crank angle sensor (which is not there anymore) out of sync with the cam angle sensor. This RMCEL causes the car to go into a limp home mode until reset with the gas pedal. It was designed into the OBDII specs. In order to get the 6 bolt motor to work in a second gen, there is a long laundry list of parts you need in addition to just the short block. They are listed on Magnus's web site. Also the 6 bolt motor would require a 6 bolt AWD flywheel. Remember I already have a 7 bolt aluminum dual disk clutch and flywheel assembly!

7 bolt:
Pro: The 7 bolt has a lighter rotating assembly. That means less mass for the motor to spin in order to transfer power to the wheels. It also creates faster revs. Also the 7 bolt short block is a direct replacement for my 7 bolt with a spun bearing.
Con: The 7 bolts can spin rod bearings easier. Due to the differences in rod bearings. 95-99 model year cars are known to get crankwalk. That is where the crank wears out the Thrust bearing also known as the crank bearing. This bearing is on the drivers side with the pulleys. As the bearing wears out, it allows the crank to move outward. (Remember the 2nd gen Eclipses have the crank angle sensor) The crank has what is called a key on the crank, two different sized plates. When the crank starts to move outwards, the key will eventually make contact with the crank angle sensor and the car dies!

So now I have a few of the Pro's and Con's of both set ups. Trust me there are a lot more, but I don't have the time to get into all of them.

But wait... What about Race Short block verses Stock Short Block!?

I thought this Pro's and Con's list was supposed to make things easier!

Ok, race verses stock... how much HP do I want to make?
Answer: 450-500 HP - for now ;-)
Well, I know my Frank II turbo is only good for about 450 HP, so there is no need to go beyond that without my 3rd turbo upgrade. Again, I started talking to the experts to get their opinions. I was told that the stock bottom ends are unpredictable. Some will hold 500 HP others will let go at 300 HP. It is the luck of the draw. The consensus is that the stock 6 bolt short blocks seem to be more stout because of the larger crank and rods.

Time for some self evaluation... At the HP levels I want, and want to run reliable, I will need to go with a built motor. At this point I will have to start addressing the $$$. I keep telling myself, if I am going to do it, I need to do it right the first time.

I have to decide, am I going to go 6 bolt or 7 bolt race short block? My answer will probably shock you so I will explain...

I am going with a 7 bolt race short block... Yes, that is correct, and it isn't a typo! 7 bolt race block!
There is a catch... I am going with a 1993 1st gen 7 bolt short block. Since you are scratching your head, I will explain why I am doing what I am doing.

The number one concern people are thinking... What about crankwalk? It is a 7 bolt motor, you are wasting your money!

Here is my "PERSONAL" feelings on the matter of crankwalk. 1st generation motors get it too! Both 6 bolt and 7 bolt short blocks can get crankwalk. I am sure there are more then a few 6 bolt motors with crank play that is out of spec, but the owners don't know it because the cars don't have crank angle sensors to kill the motor. After looking at my short block in the car, I had 7 thousandths play in the crank. At 9 thousandths the thrust bearing needs to be replaced. I also noticed that the crank was also very close to hitting the collars. I was not able to measure the amount of play before contact with the collars but it was very, very small. I believe that not only in mid 98 and 99 did Mitsu put in different thrust bearings, they also limited the space between the crank and the collars. That way they could catch crankwalk before it did severe damage. So would my car have gotten crankwalk? I don't know and will never know. But I would be very curious to hear from some 1st gen 6 bolt owners, how much crank play they have measured with their oil pans off!
Now please keep in mind that this is my personal opinion. There are others that believe that crankwalk is caused by bad cranks, bad blocks, bad machining, bad bearings, bad oil passages... the list goes on. But I do find it interesting that crankwalk magically appeared once Mitsu started installing crank angle sensor on the cars...

If my theories are correct (not saying they are) then the best choice for me is to go with a built 7 bolt race short block. If I get one that is built to withstand 600+ HP, I should be able to run 450 HP all day long with no worries. Plus by going with a built race short block, I will be replacing all of the weak stock parts with stronger ones. Including the rods and rod bearings!

So now the bigger question... Who is going to build my 7 bolt race short block for me???

 

[larryd]

Originally posted by HighPsi91
I was told the same BS by likely the same people. The CM2500 clutch is a POS. If the cranks thrust bearing surface was prepared right and the bearing was aligned properly it should not have walked. The clutch was installed by extreme so if walk was due to improperly adjusted cluth then thats on them. The 95 style thrust bearing should have no problem handling an ACT 2600. the late 2G's are a different story. I think you should think about taking it somewhere else. I can suggest where but I dont think I can do that here. Ask LarryD.

I couldnt agree more..

1) you measured the play in the crank and its off the scales which makes me wonder if they ever even bothered to measure it which you think a well known shop would do before they took your 7500.00 to build you an engine

2) 7500??? come on people.. I dont care if its the pope building your engine.. for 7500 you can buy a whole new car, infact several of them..

3) If you do decide not to have Extreme do your work I can definitely give you some advice on who to talk to to get it done right.

the simple fact is even if its not extreme's fault that the motor walked which I find hard to believe, The fact that the best there offering is to put in the 6 bolt for 2gs is rediculous, they should offer him this repair for cost of parts and thats all.. they sound as bad as SATAN to me right now

 

[rdrkt]

Originally posted by MustGoFaster020
Well, I notice a lot of people are saying $7500 . If you break it down it's actually not that bad.

Vendors love guys like you. I got a Magnus built 6bolt 4g64 with Ross Pistons, Crower Rods, all the factory pieces and gaskets, full balanced etc for $3600 shipped. If all I wanted was a 4g63 with the same internals then it would have been several hundred less. There are many vendors that could build you a comparable motor for that price.

GSX4LIFE: My current motor is a 6bolt 91 rod overbored 95 piston motor. My total to have the motor built including core charge and assembly was a little more that 1k. Larry is having a similar motor built for about the same price. I understand your position but I would not throw ANOTHER 2k at a 7bolt block it just doesn’t make a lot of sense.

 

[Tevenor]

Originally posted by Blue97GST
oh stupid me... I meant "CRANK ANGLE SENSOR!" Now I'm sure that no 1g's have a CRANK angle sensor right?

You aren't very smart are you?

This is for everyone to read, not just you:
ALL DSM's HAVE NEED A CRANK POSITION SIGNAL AND A CAM POSITION SIGNAL

The 1G's don't have a crank sensor mounted in the front case like a 2G. The sensor that bolts into the head is a both a cam position AND crank positions sensor. It sends out 2 distinct signals to the ecu.

I just wanted to clear that up since there seems to be some confusion out there. And if you doubt my information:

www.magnusmotorsports.com/1g2g.htm

I wrote that page, that is my engine that Marco used as the prototype, and it was my 2G that has been running this swap for over a year now.

 

[BrnOutKing]

An owner of a shop around here just had his 1G completed with as built as you could get motor that went on him also in less then 700 miles.

-Brian
ps: 2G's aren't the only one's that get crankwalk.

Here in MN.... I know 3 - 1g's that got it and 1 - 2G that got it.

out of my group. and I know more 2G guys then 1G guys.

 

[rdrkt]

Originally posted by BrnOutKing
An owner of a shop around here just had his 1G completed with as built as you could get motor that went on him also in less then 700 miles.

If a motor goes out that quick you know its a builder error.

 

[Tevenor]

Originally posted by rdrkt

If a motor goes out that quick you know its a builder error.

Bingo! Give that man a cupie doll!

 

[BrnOutKing]

The question is though will a shop cover it?Saying it's there fault and getting them to pay might be pretty hard since they know it was ment for racing... and usually nothing is warrantied.

The owner figures that with as much business as he throws at them they should cover it....but who knows.

Kind of like my Friend Andy who broke a tranny still under warranty.
they replaced it and it broke again in less then 10 days....

The dealership said it's driver error not there fault.

-brian

 

[GRNDSM]

I am sorry to hear about this… I also had a race motor come down with crankwak in just 300 miles. In my case, I think that was related to oil pressure. That is why I am now running two oil pressure sensors (one the block and one in the head).

>His offering is that the ACT2600 was the cause.

The only way that a clutch can take out .060” of thrust play in only 700miles is if it was grossly misadjusted AND there was already some other condition which would have caused crankwalk. Ether way, it should be shop’s responsibility. There are literally hundreds of 2G’s out there with ACT 2600 clutched which have not crankwalked in thousands of miles. THERE IS SOMETHING ELSE WRONG WITH YOUR ENGINE!!!

>because he offered to put the CM2500 in instead, Extreme is not responsible.

How convenient… Tell you what, why don’t you call around and ask real DSM experts if that is possible…

>"You'll Deffinately be in business. You wont have any more problems
>after this, Im sure of it"

I find this absolutely amazing…If he is this positive that ACT 2600 causes crankwalk in such short time, why would he let you leave his shop with that clutch behind one of his motors and risk redoing the job? I know I wouldn’t have…

>So Im gonna trust his word on this. What else can I do?

Get it in writing… If he is not willing to do it. Take your losses and go to someone else.

BTW we have a couple of New England Club DSM members who do 1G in 2G conversions for around ~$800 in labor (+ parts). They are probably too far away for you to use, but you should be able to find someone more local to you.

Good luck!

Leon
RR

 

[Blue97GST]

Originally posted by Tevenor


You aren't very smart are you?

Your mom isn't very smart for not using a condom the night you were concieved. F*ck you man, go to hell.

 

[Tevenor]

Originally posted by Blue97GST


Your mom isn't very smart for not using a condom the night you were concieved. F*ck you man, go to hell.

Actually, the night I was conceived, the bed was covered in peanut butter, but that is another story....

Take a deep breath and realize this is the focking internet. Didn't you say 'oh stupid me'? Weren't you the one that posted the wrong information not once but twice? Maybe I should have added a ' ' to make it a 'ha-ha' thing so I didn't offend your sensitive side.

Damn someone got up on the wrong side of the bed this morning....

 

[Blue97GST]

I don't appreciate being insulted but I'm not gonna come up to NY and beat you up or anything. Knowing that Kodak is polluting the hell out your area and your children will be born with three eyes is revenge enough for me hehe... Anyway, I was pretty sure that that Turbo4WD guy knew his sh*t pretty well, after all, he's got pictures of himself taking apart the head tranny and stuff. So I was sure that since he said 1g's didn't have a crank sensor and 2g's do that it was true. He did have an early 1g 6-bolt, too. Oh well

 

[boostineklipz]

I would have thought Extreme Motorsports would have paid to fix any problems since you paid that huge some to build your motor. I know they over charge and all but geez. I am shocked that they are not going to offer to fix the engine. I mean they do good work from what I have seen and they def know their sh!t about DSM's. I hope everything works out and all.

Blue97GST- Chill out man. Tevenor is one of the more knowledgible people on the site, so show a little respect. You were wrong twice!

 

[ProjectDSM]

Ahh jeezzzz all this talk about Crankwalk has me kinda worried. I've had a ticking noise coming from my motor for quite some time. A few people Ive talked who have heard it in person say its my lifters. I think Ive listened to them just to kinda hope its exactly that. Im at 57000 on my motor now and think I need to have something done before waranty is gone. What can you guys suggest?

May just start a new thread on this one...

 

[HighPsi91]

Crankwalk on 99's is extremely rare. The late 98 and 99's have a different style thrust bearing than previous 4g63's. If I were you I wouldnt lose too much sleep over it.

 

[Violater101]

Yeah, prolly just lifter tick ..do you hear a louder tick when you press in on the clutch and does the clutch stick when you depress it? I guess I have a either a late or mid 98 ..mine was Jan 98 ..is that late or early?

 

[MustGoFaster020]

Originally posted by rdrkt

Vendors love guys like you. I got a Magnus built 6bolt 4g64 with Ross Pistons, Crower Rods, all the factory pieces and gaskets, full balanced etc for $3600 shipped. If all I wanted was a 4g63 with the same internals then it would have been several hundred less. There are many vendors that could build you a comparable motor for that price.

I wasn't saying I would pay it, but I am just saying that He didn't have to lift a finger for a built motor to be in his car. When you think about it half that was mostlikely labor charges.

 

[ImportModder]

For $7500 I thought you'd be their best friend. All this talk about CW gives me the bejeebers. If you have the money to spend $7500 on an engine, whats $2k more? Wow. I wish I had that sorta money lying around.

 

[696]

Are 97's prone (more or less) to crankwalk as well? I plan on building mine next year. I saw that someone said that there was a conversion that had to be done to drop a 1G into a 2G? What needs to be done? I would like to stay with my 7bolt to keep the cost down but, if getting a 1G motor will (more or less; I know nothing is 100%) eliminate I might. Lastly if I decide to rebuild the 7 bolt what should I do to the motor to try and reduce the chance of crankwalk? What clutch to use, port oil passages, ect.....
696

 

[Beemer]

OK guys, a moment of silence in the flame wars please...now then. Lets consider the obvious. The 2G has a deficiency, as they are MORE prone to crank walk. Now let us consider why. (i have 2 90 gsx's and just sold my eagle talon tsi awd, '97 vintage, with 24k on it...stock and IT had some crank walk).. When you put a stiffer clutch in a 2g or a 1g for that matter, what are you pushing on when you push in your clutch? Duh, the throwout bearing right? OK. Where is that force being transferred to? The fingers of the pressure plate, right? What is the pressure plate attached to? the flywheel... What is the flywheel attached to? The crankshaft.. I have found that not only does the THRUST BEARING on a 2g not take that load very well, the CRANK is made out of a softer material than the 1G. If you look, the surface that rides on the thrust bearing also wears..when it shouldn't. Also, the 2g has all the main bearing caps in a single web. Folks, that is a cool thing to do from a financial standpoint, but not a longivity standpoint. If you look at the dual webs on the 1G, you will see they are WAY thicker than each individual web on a 2G.. you may think cast iron is strong, but any machinist worth anything can take an inside micrometer in a dsm bore , lock it in and drop it by squeezing the bore with both hands. I have actually gone to the trouble of checking main web flex with an atc 2600. Mounted a dial indicator to the block, and centered it on the main web above the thrust bearing (car was up on a rack) and measured a consistent .003 to .005 movement of the main bearing web when the clutch was pushed in inside the car. The 2g main web actually transfers the flex, being one piece. On the 1g, the main caps on cyl 3 and 4 flex a bit, but that's where it stops, although the crank will still move. but the 1G crank is made of a bit harder steel, so it wears less, and flexes less. Buscher uses a chevy powerglide (2 speed automatic from the 60's) because there is no way he will lose a motor to crank walk! (I'm sure there are many other reasons as well, but i am sure that is one of them, since he is running rwd, he could use ANY manual or automatic he wants to)

So YES the 2g has a lighter bottom end. YES it will rev quicker due to less rotating mass. And YES, you can equal it out by using an aluminum flywheel on a 1g and aftermarket rods (bill miller makes aluminum ones i think...damned memory)

What I think would fix the crankwalk problem for good is finding a way to get a torrington thrust bearing on either side of the crank, like small block chevy guys do with their camshafts. (Anyone who has ever torn down an automatic trans has seen one of these bearings). Only problem is that torringtons are one piece, and look like a front wheel bearing out of a mustang, only flat. How you could mount one on either side of the crank is a mystery, although i have my ideas about cutting one in half and pinning it to the thrust bearing after shaving the thrust bearing down...

Just something to think about. I really don't think clutch adjustment has anything to do with it though.

Just some food for thought guys

 

[NDgsx]

Like I said, cfdf pressure plate, act street disc:
http://www.roadraceengineering.com/clutchpressure.htm

 

[Tevenor]

Originally posted by Blue97GST
I don't appreciate being insulted but I'm not gonna come up to NY and beat you up or anything.

Feel free. I will give you my address if you would like. It won't solve anything but if that's the way you resolve stuff.

Originally posted by Blue97GST
Knowing that Kodak is polluting the hell out your area and your children will be born with three eyes is revenge enough for me hehe...

Thanks. I appreciate the sentiment.

Originally posted by Blue97GST
Anyway, I was pretty sure that that Turbo4WD guy knew his sh*t pretty well, after all, he's got pictures of himself taking apart the head tranny and stuff. So I was sure that since he said 1g's didn't have a crank sensor and 2g's do that it was true. He did have an early 1g 6-bolt, too. Oh well

Being 'pretty sure' is like 'almost focking the prom queen'. It doesn't count.

I am over this. Hopefully you are too, so we can go back to topic.

 

[Tevenor]

There are lots of theories. I don't think any of them are necessarily wrong. And I don't think all engines walk for the same reasons which is why no 1 reason can be to blame.

Take for example 3 engines: 1 completely stock with stock clutch (like my first engine), 1 stock block with an ACT 2600 clutch assembly, and one recently rebuilt engine with an ACT 2600 clutch assembly.

Now all three walk. Engine 1 walks not because of extreme clutch pressure but because lack of oiling along the thrust surface resulting in contact between the crank and bearing and voila! Dead thrust bearing. Engine 2 dies with plenty of oil volume across the surface of the thrust but because of undo lateral pressure from the clutch assembly (per Beemers POV above). Now engine 3 dies not because of the clutch and not because of oiling, but rather because the thrust bearing was misaligned at rebuild and consequently wears rather fast.

Now all you read or know is that all 3 walked. But what you don't realize is that each for a different reason.

It's similar to the common cold. There are many viruses that cause the same symptoms which is why we have no cure for the common cold. Because there is no single thing to target.

 

[GRNDSM]

Beemer,

I know what you are saying about the extra force from pressure plate, but is not quite this simple. Higher spring rate pressure plate will make an engine already prone to crankwalk loose its thrust sooner, but it along, will not do it! I have seen a thrust bearing on my friend’s ’95 AWD with 125k miles on it. He went through 3 ACT 2600s since he got the car at 40k miles. And his thrust was PERFECT. And let me tell you, those were very hard miles as he AutoXs a couple of times/month.

>Buscher uses a chevy powerglide (2 speed automatic from the 60's)
>because there is no way he will lose a motor to crank walk!

I thought that automatic trannys can cause crankwalk when torque converter gets too much oil pressure.

But David went to a Powerglide tranny because he was sick of AWD drive train failures and not because of high clutch forces (there were no crankwalk problems back in those days ). And John Shephard is using 3100-3200lbs pressure plate with out a single crankwalking incident. Granted John is using 6 bolt motor, but those also have crankwalk issues (be it not as common).

>What I think would fix the crankwalk problem for good is finding a
>way to get a torrington thrust bearing on either side of the crank, like
>small block chevy guys do with their camshafts. (Anyone who has
>ever torn down an automatic trans has seen one of these bearings).
>Only problem is that torringtons are one piece, and look like a front
>wheel bearing out of a mustang, only flat. How you could mount one
>on either side of the crank is a mystery, although i have my ideas
>about cutting one in half and pinning it to the thrust bearing after
>shaving the thrust bearing down...

That is possible with a lot of R&D work. I know that many have looked into it but decided to just go with 6 bolt motors as they are much less prone to this problem.

>I really don't think clutch adjustment has anything to do with it though.

Misadjusted clutch can put slight continuous load to the thrust bearing. It is like driving around with your foot always on the clutch pedal. So just apply your thrust force theory but use ~10% of full engagement force at 100% of time.

I stand by my conviction that high pressure-plate force accelerates the thrust wear, but it, in itself is not the root cause of it. So if you have an engine which would crankwalk at 70k miles on a stock clutch, it might crankwalk at 50k miles with ACT2600 (numbers used as an example)…. or 10k miles with musadjusted ACT2600 .

Leon
RR