7 bolt rebuild

[danny_l_2005]

ok after looking at the prices of a used 7 bolt motor around here seems to be alot. Prices i got were from 3 salvage yards that they had available:1800,1500,1300. For me its just way too much so im deciding to do my short block a rebuild. I would like to ask people who rebuild their 7 bolt motors to stock and what was their total cost. I spun a bearing recently so thats why im deciding to rebuild. Also what really happens to our cranks if we turn them, also why only 7 bolts? Hopefully i don't need to bore my cylinders because i wouldn't want to buy new pistons. I would like to know what do i need to rebuild my oil pump that might have the reason why all this happened and i don't want to risk that happening again. thanks

 

[morbidj]

I suppose some will tell you to swap it for a 1st gen 6 bolt bottom end. I wouldn't suggest turning that old crank as it more than likely wont hold up against crank walk in the future. My research here has lead me to believe that the nitriding process was shoddy to say the best to-wards the 7 bolt cranks, making them weaker over time in comparison.

BTW, I called the local Denver Mitsu dealer and was shocked $800 + for a new crank and that is minus the cost of bearings.

I myself am at a loss aswell. I purchased my car in a non running condition at a great price, the shop I bought it from atempted to repair a crank walked shaft by turning it and replacing the bearings, guess what they got? 300 miles later another crank walk and now a spun bearing on the #1 rod. So it looks like Im either going to order another 7 bolt engine from overbore.com or try pick up a 6bolt stage 1 bottom end from SBR.

Either way I will be watching your thread like a hawk best of luck.

 

[Jason84]

http://www.magnusmotorsports.com/crankwalktheory.htm

read this before you decide to "build" your 7 bolt...

dont waste your time or money

 

[Zmann42087]

http://www.magnusmotorsports.com/crankwalktheory.htm

read this before you decide to "build" your 7 bolt...

dont waste your time or money

Good call.

And while you're at it, read this too. Crank Walk 3 Times

Highly suggest you rebuild a 6-bolt.

 

[TurboDSM86]

Since you sound like you are planning on doing this yourself, i'll give you a couple options and a little advice. To start with, my car is on its 3rd motor. 2 7 bolts crank walked, Both were mitsuibishi motors. The second motor had 26K miles on it and took the walk. It's 3rd motor is a 6 bolt now which is completley problemless.

Prices -


6 bolt motor from classifieds 500 give or take a bit. Build it to how you want with what you want and youll still be under 2,000 dollars easily. You could be around 1000 if you just go with a stock rebuild and good machine shop work. These motors are a lot more durable and will probably never crank walk on you.

7 bolt motor - You can spend a good 1500 bucks for a 7 bolt motor that is bone stock and used from a junkyard. You could also maybe find one for cheaper in the classifieds, but its still a 7 bolt and who knows what you are going to get with that. It has a lot higher chance of crank walking and will be a lot less motor for the money.

My advice -


Do it once, Do it right. 6 bolt swap. Theres plenty of info floating around on this site and the internet in general. Build your motor to what you want, and cheaper.

 

[danny_l_2005]

to swap the 7 bolt bottem end to a 6 bolt do i actually need the kit from SBR or its just bolt on?

 

[morbidj]

Good question, it looks like it would make life a whole lot simpler as you would have it all there in a kit

BTW, I was thinking since we already have the 7bolt motor might as well try to salvage what we can from it. It would be nice to use the 2nd gen pistons on the the big first gen rods but what head would we want to use? For all I know the it seems to be an easier task to bore out the head stud holes and throw in some ARP studs on the 2nd gen head which will spool faster but will have slightly less top end power than that of the first gen head?

 

[danny_l_2005]

me and you have something different my budget is to spend 1500 max on rebuilding or change motor and i can't do the labor. and if buy a 6 bolt bottom end then rebuild and buy the kit well be over 1500 and that i can't do. Has anyone done a 6 bolt bottem end swap without spending more that 1500 and if so can you please tell us what parts you got and i would like to know how you did it. thanks

 

[jastermerrel]

My 7-bolt block is at the machine shop right now going for a stock rebuild. I'm having them install a BS eliminator kit while they are at it. About $900 is what it's going to cost me.

 

[TurboFever]

rebuilds for those prices? please tell me where u guys are shopping i call a few places locally, i forget the exact numbers but they were asking more than $2300 for as rebuild and $4000 for a used motor for my 95gst.

 

[danny_l_2005]

My 7-bolt block is at the machine shop right now going for a stock rebuild. I'm having them install a BS eliminator kit while they are at it. About $900 is what it's going to cost me.

What happen to your block? please explain on what things were needed and if crank is being turned. Aren't you afraid of get crankwalk?
Isn't automatics a little lets vulnerable to crankwalk than std because of the clutch being pressed often on std cars?

 

[danny_l_2005]

4000 for a used motor damn thats alot just buy another car for that price. Don't you think they must be ripping you off with that kind of a price unless its a new.

 

[Jason84]

i paid $2400 for a fully built bottom end... $1700 for a crazy head $600 for cams and then arp studs mitsu metal headgasket and then some...

and thats all out easily 600whp motor with the right turbo...

 

[danny_l_2005]

so what is actually need to swap a 6 bolt long block into a 2g.

 

[arash15]

so what is actually need to swap a 6 bolt long block into a 2g.

http://www.magnusmotorsports.com/article_1g2g.htm
theres ur answer. go to the bottom of the page.