T-55

I bought a few months ago Lancer evolution 4. Nowi believe i have crankwalk problem . Symphtoms are : 1.Fast ticking noise when you push in the clutch 2. Shifting is hard when car isin't moving. My car is totally standard.


I am going to measure the free play, but how much is service limit? I have been surfing around net and i have been find different values .011-.009"



How to fix this problem. I have find several solutions on net:

1. Change the bearings. This may help a while but eventially the problem occurs again. This would be cheap, if you can do the work. Where to buy bearings? Is it recomended to use aftermarket bearings?


2. Change the bearings and crankshaft. Is it true that crank wear's out too? Is Evo 1-9 crank bolt on? Can you use other crank, in some other model?


3. Change the engine. So what i have been find information on net. Evo 5 -> have litle risk to have crankwalk problem. This is very expensive.

4. What about this http://www.dsmtuners.com/forums/cyli...crankwalk.html ? But how much to file to not loose oil preassure?


Yes, i have been using search but didin't really find all the information what i need. Sorry about my poor english, feel free to delete this if this all has been discussed or you don''t understand what i am saying

travman

iTrader: (26)

Does it look like this?

94AWDcoupe

iTrader: (125)

installing new bearings would be a complete waste of time. the best way to fix a crankwalk motor is to install new bearings and a good crank that has been nitrided. nitrided cranks are ten times more resistant to crankwalk AND spun rod bearings.

05ah8james

iTrader: (23)

Speaks the truth!! Nitriding isn't cheap because the metal expands, and has to be milled after nitration, but worth it. Honda's cranks come stock like this and is the reason they're almost impossible to kill.

What causes crank walk? I've never really heard much about the subject until I got an evo (honda kid at heart). Sounds like it would be ****ty thrust washers...

Jackson Machine

iTrader: (9)

It's usually caused by something pushing on the back of the crank, forcing the crank forward into the thrust surface making it wear, or poor lubrication. Worn clutch linkage will do it and it's fairly common in the older cars. A high base pressure clutch will do it too, but since yours is all stock that isn't it. Find out WHY it happened though and fix it otherwise it will just happen again with the new bearings.

A nitrided crank wont help you here. It's the bering thats wearing, not the crank. Hell, a hardened crank would make it worse.

T-55

I read the Evo 6 service manual and end play values are:

Standard value: 0.05 – 0.25 mm
Limit: 0.4 mm(it is 0,016 inch)


Can i use these values(end play bearing isin't same in Evo 4)?

94AWDcoupe

iTrader: (125)

You have got to be kidding. You build engines for a living? Wow.

Thats like saying you dont need nitrided cams in your motor. Maybe you should call any cam manufacture and ask what happens when you forget to nitride the cams before sending them out. Both Crower and Web learned this lesson the hard way. I am sure there are others.

Nitriding or other surface hardening is the single most important thing you can do to your crank. Its pointless to argue why there is friction between the crank and thrust surface. Whether it be from lack of sufficient oil pressure, excessive clutch pedal pressure, clutch safty switch, or whatever. The fact is there is periodic friction from the two surfaces rubbing each other. and thats why there is crankwalk. Just like with cams. Without the surface being hardened it doesnt have a chance. It eventully wears. Once the wear starts it cant be stopped.

I have seen about 50 spun rod bearings on 7 bolt engines (stock crank). Every single last one had to have the crank replaced from wear. The crank surface is soft from factory.

A couple years a go I started nitriding the cranks on all my motors I build. One customer changed his own oil. In doing so he lifted the car on the oil pan. This starved the engine of oil pressure for two weeks before he brought the car back. when he brought me the car it had a max of 30psi oil pressure and of course a rod knock. I installed new pan and replaced the bearings. I still have the pics of the trashed bearings. For the first time in my life I saw a 7 bolt crank survive spun bearings.

Do your self a favor. Ask your engine builder to nitride your crank. Or find one who will.

Jackson Machine

iTrader: (9)

Yeah.............right, Please enlighten me as to how surface hardening the crank will help this guy stop eating the thrust bearings. I'm all ears. Nitriding is good for adding extra strength but it wont stop you from wearing into the softer bearing material. The crank could be made out of Kryptonite but if you've got something removing the lubrication from the thrust surface it's going to cause excessive endplay (crankwalk).

Perfect example- A customer of ours has a 706 ci Chevy motor with a $3500 billet crank, harder than any nitrided crank out there. He's put a number of passes on it in the last few years with no problems. He decides to change out the torque converter, it's not installed properly and it pushes on the back of the crank causing the thrust to be worn almost immediately. The point I'm trying to make here is that hardening the crank isn't going to stop the original poster's problem.

T-55; Like I said earlier, try to find out what is causing your issue and don't just treat the symptoms. You must identify the root cause of your problem and fix it or you will continue to have thrust problems. If you have any questions as to what could be causing it and how to remedy the situation, feel free to give us a call at the shop, 410-859-3269 or shoot me a PM.

CandCPerformanc

Nitride treating the crank by no means will help solve a crank walk problem, all it will do is help the crank survive when the next set of bearings fails. JAM is 100% correct in the fact that you need to find the problem of why the thrust bearings are failing. I will explain 1 thing that is a downfall to nitriding of a crank is when you make the crank that much harder they are more prone to cracking when detonation occurs, a standard 4340 crank has a little flex in it that allows a small amount of twist and it will spring back. When you nitride the crank the journals are hardened now and it takes away from that flex. I know I will get reamed yet once again for bringing up V-8's but when you ask most of the big nitrous guys what type of crank they use they will say a standard 4340 and aluminum rods while most other types of power adder guys will use a billet that's been nitride treated, the reason behind the nitrous guys using the 4340 is because the combustion in a nitrous motor is violent and the 4340 along with the aid of the softer aluminum rods helps absorb the shock of the violent combustion. Now back to the thrust bearing issue on hand I found that allot of the 2G 7 bolt cranks had minor machining flaws in the surface of the crank between 1995-1997 on the thrust surface the other issue I find is that most motors I have had to tear down had balance shaft elimination kits and had over time made the oil pump unstable producing random oil pressure all over the board.

barneyb

As far as I am aware, no one knows the cause of crank walk in these engines. Well, Mitsu does, it seems to be fixed in the USA Evo engine. But, they aren’t saying, that would be admitting to the problem.

Some people have pointed to the oil squirters as a possible cause. They sometimes fail stuck open. That, combined with smaller oil galleries in your engine may cause insufficient oil pressure at low rpms (when the clutch is often depressed).

So, I’d suggest building the engine without oil squirters or go with an older design engine (6 bolt).

CO_VR4

iTrader: (83)

To the OP, crankwalk IS a bearing problem, but it is the THRUST BEARING, not the rods or mains. It usually requires a new crank, because there are not many shops that are equipped to weld and then properly grind the damage on the surface of the crank that is next to the thrust bearing. If it went long enough, the block will be damaged, too. There is some speculation about the cause, including the different oiling system on the 7 bolt motors of that era (as compared to the earlier 6 bolt motors), and also the issue of heavy duty clutches having an effect as well. Nobody has come up with conclusive proof of a "fix", but it is much less common on later motors, so that may be the way to go for you.

As I recall, the Evo IV up used the current configuration Evo motors (engine on passenger side, transmission on driver's side) so the "use a 6 bolt motor" isn't an option for you.

Here's an interesting read: http://www.magnusmotorsports.com/tech/crankwalk.htm

CandCPerformanc

we have a customer that had his Crank and bearings replaced at just under 40k by the mitsu dealer back in 1998 and the paperwork he got from them stated that the crankshaft was the cause of the thrust bearing failure due to improperly machined thrust surface. I guess it had a few thousandths taper to the thrust surface causing an uneven load on the bearing causing it to wear the outer edge of the thrust bearing to wear to the steal and it goes south from there. He now has 167k on the same engine and the bearings and crank they installed with no issues and he has had a 2600lb preasure plate for about 70k of them.

CBRicahrd

Jackson Machine

iTrader: (9)

That is so perfect! Thank you for this really impressive showing of Crank Walk!

You gotta love it!

94AWDcoupe

iTrader: (125)

You are dead wrong about only the softer bearing wearing with crankwalk. Both surfaces wear down. I have seen half dozen cranks with .050 worn off. Nitriding makes the crank surface slippery. It keeps both surfaces from eating each other.

Your torque converter example doesnt prove a thing. For the surface to wear that fast obviously the film strength of the thrust surface was completely overpowered. Crankwalk takes 50,000 miles to happen. Or more. And you give an example of a crankwalk on an improperly installed torque converter that happened almost immediately? This will be my last counter post with you.

Here is a description of nitriding off web camshafts site:
NITRIDING
Gas nitriding is a surface heat treatment which leaves a hard case on the surface of the cam. This hard case is typically twice the hardness of the core material up to .010" deep. This process is accomplished by placing the cam into a sealed chamber that is heated to approximately 950 degrees F and filled with ammonia gas. At this temperature a chemical reaction occurs between the ammonia and the cam metal to form ferrous nitride on the surface of the cam. During this reaction, diffusion of the ferrous-nitride into the cam occurs which leads to the approximate .010" case depth. The ferrous-nitride is a ceramic compound which accounts for its hardness. It also has some lubricity when sliding against other parts. The nitriding process raises and lowers the chamber temperature slowly so that the cam is not thermally shocked. Because of its low heat treat temperature no loss of core hardness is seen. Gas nitriding was originally conceived where sliding motion between two parts takes place repeatedly so is therefore directly applicable to solving camshaft wear problems.


I have found it also solves the thrust surface problem. Thats all I have to say on the subject. If you want to disagree , I DONT CARE.