Replace or Keep Crank

[fastclip]

Okay I am doing a Winter Rebuild on my 95 Gst 7 bolt 4g63. The current engine had about 130k on it. I will be taking the lower block to the machine shop to have the honing, redeck, hot tank and balancing done. I will be running wiseco 8.3:1 with Eagle rods. Arp studs all throughout the block. I don't want to bore it unless I have to for maintenance reasons, but from an observation of the block doesn't look like I will have to though. The top of the head will have BC 272 intake and exhaust cams, new valves, BC racing springs w/ TI retainers, then new water and oil pump. Also, eliminating the balance shafts. I will be running an act 2600 clutch with street disc and act lighten flywheel.

Now yes I know I have a 7 bolt....etc. Now what should I do with the crank.. All I really want to do is replace the bearing on it, and possibly do the mod to the bearings
http://www.dsmtuners.com/forums/show...ighlight=crank

Now should I replace the crank or just do the mod?
And no I do not want to do a 6bolt swap

 

[28-psi]

In my experience with polishing the crank...I would say leave it alone or replace it. What condition is it in? With 130k on that engine I would lean toward replacing or upgrading it. And why 8.3:1? Why are you hesitant on going .020 over?

 

[iwannagofast89]

How much of a difference is it to bore it in the HP and TQ

 

[zero97tsi]

If you have the money to do it, why not? It wouldnt hurt anything, but I don't think you NEED to.

If your going too, if possible drop the cash for a butcher crank from FFWD or equivalent. Youll cut down on a little rotating mass while your replacing it.

 

[tqmx1]

Unless you buy a brand new crank you have no idea what you are getting. (some one elses junk) You have some idea on the history of your crank I would stick with it.

 

[turbolover10]

If you've had good luck with it this far I'd stick with it.

 

[zero97tsi]

Unless you buy a brand new crank you have no idea what you are getting. (some one elses junk) You have some idea on the history of your crank I would stick with it.

I doubt the guys at FFWD, or any other reputable shop, will grab just any crap and turn it out to customers.

Like I said, it all depends on finances. If you have money to blow on getting things, why not get the best?

 

[fastclip]

In my experience with polishing the crank...I would say leave it alone or replace it. What condition is it in? With 130k on that engine I would lean toward replacing or upgrading it. And why 8.3:1? Why are you hesitant on going .020 over?

Well the reason i am not wanting to bore it unless i have to is because there really isn't truely a huge benefit to cost for our engines.

its the option on the piston, well you can get i think 9.0:1 or something towards that but i would like to keep the compression a little low for the safe side

as for the crank, it looks to be in good condition, no movement at all

 

[fastclip]

If you have the money to do it, why not? It wouldnt hurt anything, but I don't think you NEED to.

If your going too, if possible drop the cash for a butcher crank from FFWD or equivalent. Youll cut down on a little rotating mass while your replacing it.

Okay that is what i was thinking, like i wish i had the extra 900 to upgrade, but i am already going beyond what i really need. I have no intentions of running the engine to the max, I have had good experience with building a car and only running it to like 85% to 90% of its limits.

Kinda like injectors 660 do what you want but you are going to be running them at 99% then you need to get 800+ you know

And from what i have read, my .02 cents on CW, is just like your chances of throwing a rod, or an oil/water pump going bad.....Just because it happen to one engine doesnt mean it will get yours...You push your engine/car you ARE/WILL break something

 

[zero97tsi]

If your going to be shooting for a "good street manners" setup, maybe ~300HP, i see no reason to spend the extra money if you dont have it "laying around". Save it for other, better things that will help out in the long run.

 

[fastclip]

Yea, I mean I know i won't but after this engine is done. I really only want to be changing parts that are typical maintenance, or things that break. Becuase I already have full 3in exhaust, upgraded fuel with all SS lines from tank to rail, rewired 190 FP, regulator, Big Evo 16G, GT manifold, evoIII o2 housing, Greddy Big front mount w/ hard pipes and type-s blowoff. And waiting for all the engine to get done to send off for DSMlink

Don't you think this setup will push more then 300 though, i was hoping about 375+whp

 

[zero97tsi]

350 or less id say with a 16g. Go to "members" on the top red bar and look at dyno sheets. ~350 is where Evo III 16g's start to come in, and big 16's. There is one person with a 16 in the 400's, and Ill bet he has one hell of a tune going on. I don't want to be a downer, anything is possible.

Spend the money on revised lifters, or put it in a "when my car breaks" fund.

 

[fastclip]

oh yea, i forgot I am getting revised lifters from extremepsi. Yea that is what i heard about the 16G, so i might be going to a bigger turbo in about 6 months or after the engine is broke in. So you think that since the crank is still in good condition just to have it polished and all the bearings replaced.

 

[tqmx1]

I doubt the guys at FFWD, or any other reputable shop, will grab just any crap and turn it out to customers.

What I was meaning was don't go to your local chain auto parts store and get a crank kit. With that you are taking a major crap shoot.

The DSM venders thats another story and I was not meaning them.

 

[zero97tsi]

I doubt the guys at FFWD, or any other reputable shop, will grab just any crap and turn it out to customers.

What I was meaning was don't go to your local chain auto parts store and get a crank kit. With that you are taking a major crap shoot.

The DSM venders thats another story and I was not meaning them.

Ahh, understood.

 

[28-psi]

Well the reason i am not wanting to bore it unless i have to is because there really isn't truely a huge benefit to cost for our engines.

its the option on the piston, well you can get i think 9.0:1 or something towards that but i would like to keep the compression a little low for the safe side

as for the crank, it looks to be in good condition, no movement at all

The reason I was asking about the bore is that you are running Weisco's that need tighter tolerances between the piston and the wall. If you throw a factory size piston in a worn out bore that has now been re-honed you might slap and or cause premature wear. That was the benefit for me at a minimal price.
I used to manage GT Motorports in Rancho and had my block bored and honed in their million dollar machine shop. Instead of smooth strokes with the hone, they left it in one place for too long which resulted in barrel shaped and tapered bore's. I figured it out while fitting the pistons. So make sure you triple check clearances and have the machine shop "fit" them and number them when they bore or hone the block. My Weisco's were all off a couple thousandths when I pulled them out of the box.
As for the compression ratio...why not? Factory was 8.5:1...you might end up at that depending on how much they resurface and gasket thickness.

 

[fastclip]

The reason I was asking about the bore is that you are running Weisco's that need tighter tolerances between the piston and the wall. If you throw a factory size piston in a worn out bore that has now been re-honed you might slap and or cause premature wear. That was the benefit for me at a minimal price.
I used to manage GT Motorports in Rancho and had my block bored and honed in their million dollar machine shop. Instead of smooth strokes with the hone, they left it in one place for too long which resulted in barrel shaped and tapered bore's. I figured it out while fitting the pistons. So make sure you triple check clearances and have the machine shop "fit" them and number them when they bore or hone the block. My Weisco's were all off a couple thousandths when I pulled them out of the box.
As for the compression ratio...why not? Factory was 8.5:1...you might end up at that depending on how much they resurface and gasket thickness.

Yea i mean i figured i would have to bore the engine atleast .20, because of wear on the block, but the block has never been really pushed, and everything looks good, but of course that is from the eye and thus why i am taking it too the machine shop to get measured. So I am waiting to see, but i will probably bore it. Now the compression I just am kinda afraid to run the higher compression, as this will be a street car running on pump gas and i want to run about 22 lbs. But the biggest issue is finding a good legit maching here. But i was asking about the crank mainly. Also i might just go with this block from slowbo http://www.slowboyracing.com/estore/product.php?productid=1031&cat=50&page=1y with the wiseco and eagle setup

 

[28-psi]

If money is not an object...and your looking at a $2600 short block why not go 6 bolt? I bought my engine for $900 complete (throttlebody to the turbo). Then invested about $1250 in parts and a few hundred in machine work. You dont need anything extra that an imported 6 bolt wont already have except a cam sensor harness for the conversion and a map sensor relocator from dsmparts. Is someone doing the work, or are you doing this yourself? PS...I have a "street car" that I drive every day with 9.0:1's and 22psi on 91 octane California shit gas and guess what, my car runs pig rich. Don't sweat the compression thing...you want to have a fast street car right? The important thing is to make sure you assemble the engine correctly.

 

[fastclip]

Y, is it almost everyone is afraid of the 7bolt. Considering even evo's are running 7 bolt engines. I mean seriously you look on here and about the same number of people have thrown rods, seized up engines, and so on. With anything with this engine or even a matter of any High Performance engines people break T , its going to happen. Now yes, 6 bolts have their benefits, I use to have a 92 eagle AWD with a JDM cyclone engine. But 7 bolts have theirs too. I mean just because this person throws a rod doesn't mean this other guy is going to throw one too that has the same rod. Sometimes there is a 1000 X factors. I also have noticed that a lot of people who claimed CW and had the under-drive crank pulley.hmmmmmmmmm. Also, gee do you think that it is the matter of how well you treat and take care of your engine too. Now, yes some people do everything right and just get bad luck. T happens. Then, to top it off these cars became the cracker box image of Imports due to that great documentation on street racing aka "The fast and furious" ,and ,so, a lot of people went out and bought these cars, unhooked the BOV hose to vent to the atmosphere, put on pulley kits because it gave them 50 HP. And drove the car everyday like Michael Andretti and wondered why these damn things broke. So, come on planes crash, people drown, people get shot, and buildings blow up. So, what are you going to do, lock yourself into a padded room too?

Now, yes I do know that these cranks have had known issues, but its like anything else that is massed produced and are allowed a "tolerance of error".

Thank you for the recommendation, though that is what this site is for.....I just wish every time a person mentions about building a 7 bolt engine the first thing out of the block is well use a 6 bolt.

Now for the compression ratio of the 9.0:1, I might consider that...And is a good thing to know that it works out. As I was afraid that raising compression in our engines won't allow us to boost as hard. And with a FWD, boost always helps and I am trying to get this engine to get some more RPM's out of it to be in gear longer after hook up. Thus why I am redoing everything in the head to help out, running all ARP studs, and modding everything related to the suspension. And in that case a 6 bolt can help because it does have bigger studs, but I don't want to run a 6 bolt.

So sorry about the novel, and to anyone I probably just pissed off

 

[28-psi]

All we are trying to do is help
But when you are running "22 psi" with any decent size turbo and you are scared to run an ACT 2600 because of the pressure your putting on that tiny little thrust bearing, you will understand why.
My crank walk issue wasn't due to neglect...look at my profile, you could eat off that engine but it happened and I learned my lesson. As for a "tolerance of error" I dont think that Mitsu had 2600 pound pressure plates in mind when they designed that engine. All I know is that I sleep much better at night knowing that the money and effort that I put into my car paid off and statistically won't have the problem that my 7 bolt did. Most of us have been there and done that a few times and can't understand replacing a problem with a problem, I think that's why your sick of hearing the same advise. But good luck with your project and any questions that should arrise feel free to ask...I've done this too many times to mention.

 

[1gDSM4g63]

Unless you plan on doing a stroker replacement you crank with a new one will make little difference. And I don't about butchering the crank. It shaving the crank will make it weaker. Just make it knife edge crank by polishing it so it will cut through oil faster. It's best to save you money on transmission rebuilt upgrade. With a 130,000 your transmission will definitely have problems. And it you're going to stay with a 16g turbo, 272/272 cams are not a good idea. 272/272 are used for big turbo that are late spooling for high rpms. Go with 264/264 cam for early spooling turbo.

 

[fastclip]

Oh, I know about the tranny. I had a brand new one stuck in the car at 104k. So, its fairly new. The crank i didn't want to have it touched besides having it polished and any required touch on it and then that mod that the guy came out with. Then with the turbo I will upgraded it eventually. I don't plan to stay Big E16g, for more than a year

 

[fastclip]

All we are trying to do is help
But when you are running "22 psi" with any decent size turbo and you are scared to run an ACT 2600 because of the pressure your putting on that tiny little thrust bearing, you will understand why.
My crank walk issue wasn't due to neglect...look at my profile, you could eat off that engine but it happened and I learned my lesson. As for a "tolerance of error" I dont think that Mitsu had 2600 pound pressure plates in mind when they designed that engine. All I know is that I sleep much better at night knowing that the money and effort that I put into my car paid off and statistically won't have the problem that my 7 bolt did. Most of us have been there and done that a few times and can't understand replacing a problem with a problem, I think that's why your sick of hearing the same advise. But good luck with your project and any questions that should arrise feel free to ask...I've done this too many times to mention.

Thank you, also i noticed 97 7 bolts had more of them. But none the less it is the chance I am going to take, now in 6 months will i get I told you so then so be it. Hopefully not though.
I will give you props though your car looks extremely clean and nice man. I love how black looks but as long as you keep it clean. I use to have a black car, but it sucked keeping it clean

 

[93blueGS]

If you do get it polished, I'd get it re-nitrided for safety reasons.. I've heard bad things about polishing/turning a crank and it spins a bearing not long after..

 

[fastclip]

okay, so now i am in a a funny sit. Guy is screwed financially, selling 6 bolt lower block with 5k miles on it, wiseco pistons 8.5:1 with eagle rods, bored .20 over really cheap. but just lower block with oil pump and pan on it