Crankshaft upgrade

[StreetSleeper34]

Does anyone know where to purchase forged crankshafts for the 4g63 block? I have been using all the search engines I could think of, but wasn't really successful in finding a website that sold any. Any help or advice is greatly appreciated!

 

[talont3t4]

Why would you possibly want to upgrade your crankshaft?

 

[StreetSleeper34]

Why would you possibly want to upgrade your crankshaft?

Long story...but to dissipate heat better than a cast one and because I need one that can hold up to some pressure. I have gone through 2 stock cranks and one aftermarket Topline that was suppose to be better, but seemed to actually wear worse than the originals.

So now I am looking to see if a forged one is available and where I can find one.

 

[talont3t4]

I would look at your tunning all the fastest 4G63's in the world are using the stock crank!

 

[Tevenor]

Perhaps you could tell us what engine you are running. Year block? 6-bolt 7-bolt? Boost pressure? Gas? Etc. Throwing new parts at a problem is usually the last resort action, especially on cranks.

 

[StreetSleeper34]

Okay, the vehicle and engine in question is the one on my profile...a '94 7 bolt n/t that has had everything imaginable done to it. It might be a little over 10:1 compression after my lastest shaving of the deck. For a while I was running extremely lean and that raised the oil temp dramitically. When I opened it back up, the carbon deposits on the top of the pistons were flakey, indicating how hot it was running. I plan on putting an oil cooler on it to help as well. But the crank walked on me about a year ago, thus why I did all of my upgrades and mods. When I pulled it back apart last week to put in larger cams, new fuel system and remove the balance shafts, I wanted to replace all the bearings as well. I noticed the thrust bearing had quite a bit of wear and the crank seemed to have started to walk again. After only 14,000 miles! A machinist pointed out the differences in metal patterns with the Top Line crank and explained that the heat was actually more intense right where the Thrust bearing was and that may have some reasoning for the crank expanding and getting off line. He simply mentioned that if I could find a forged crank, it would dissipate the heat better and would last longer and I wouldn't have to worry about the concentrated wear and tear on the bearings. All of my problems could be a combination of running too lean, oil being too hot, and having the aftermarket crank with an aftermarket clutch. The lean issue is being fixed along with the oil temp, so I was just inquiring if I should upgrade the crank to forged steel as well or if fixing everything else will be enough. My biggest concern is having it walk on me again. The guy I spoke to assumed that having the stronger clutch was probably causing most of the wear, so getting a better crank that could handle it would be my best bet to prevent any future problems.

So this is why I started this thread. Before I went out and paid $600 on something, I wanted some advice and opinions of some DSMer's that may have had some prior experience with this type of situation. If my best bet is to get a stock crank and have it honed with my block, then I will do that. But I want to be sure. I am sick of ripping this apart and being worried about how far my limitations are. I want to have some fun with it and drive it like I stole it! ...with no worries about what is going to break next.

So that's my story. Hopefully someone has something good to add to this theory.

 

[tbTalonES94]

Well the fastests DSM's in the world run stock cranks man. So i don't even know if anyone has made a forged crank....it hasn't been needed. I would look into getting a new Mitsu crank and getting some bearings that fit perfect with your clearences. Maybe an extended slave rod and get rid of that UDP. Maybe it's your block. Maybe you should invest in a 6bolt...and hang a turbo on it Nah idk man just go with a stock Mitsu crank get some damn good bearings and hope for the best. Keep the oil clean and cool.

 

[huafist]

Did you have the mains align-honed last time you had the block in the shop? Also, high oil temps probably contributed to your thurst bearing wear. The higher the oil temp, the less lubrication oil provides. The general consensus is though, once a block walks, trash it and get a 6-bolt.

 

[StreetSleeper34]

Did you have the mains align-honed last time you had the block in the shop? Also, high oil temps probably contributed to your thurst bearing wear. The higher the oil temp, the less lubrication oil provides. The general consensus is though, once a block walks, trash it and get a 6-bolt.

No, and that is the thing. I wanted to do it this time and that is how all of this started. I would love to get a new block, but I have sooooo much invested into this one, it would cost me another fortune to have a 6 bolt bored out and redecked and then honed to the new crank. So I am trying to make do with what I have and come up with a "best case scenario" type of situation.

If resolving my other problems and getting this blocked honed with a factory crank will work, then so be it I will do that this weekend. But I definately want to be sure.

 

[tbTalonES94]

If you don't want to spend the money again to get a 6bolt bored out for those pistons you got and everything then make sure you 7bolt is perfect and get a new Mitsu crank. Have a machine shop check it for any inperfections and get your block perfect before settin that puppy in there. Good luck.....and with all this money invested you better be able to atleast keep up with me untill 3rd gear :laugh:

 

[StreetSleeper34]

If you don't want to spend the money again to get a 6bolt bored out for those pistons you got and everything then make sure you 7bolt is perfect and get a new Mitsu crank. Have a machine shop check it for any inperfections and get your block perfect before settin that puppy in there. Good luck.....and with all this money invested you better be able to atleast keep up with me untill 3rd gear :laugh:

Have faith! Otherwise I will get you after you run out of gas! :laugh: