6 bolt vs. 7 bolt [merged] 6bolt 7bolt 6-bolt 7-bolt six bolt seven bolt

[asdfzxc]

All 6 bolt vs. 7 bolt threads are merged here.
How do I tell if I have a 6 bolt or a 7 bolt?
Will x part from a 6 bolt fit a 7 bolt?
Will x part from a 7 bolt fit a 6 bolt?
Which one is better?
How do I swap my x bolt for an x bolt?

What is the difference between 6-bolt and 7-bolt engines (aside from the obvious - 6 vs. 7 bolts connecting the flywheel )

Is there an advantage over either of the two engines?

Thanks,

-Mike

 

[daveyfx]

I'm not so sure this swap would be worth it, I would probably advise differently. This is somewhat the opposite direction most people normally go. Since the 1g rods are better and the 2g pistons are better you would be essentially taking the worst parts of the two motors and creating one. The CR would be lower though(7.8:1 instead of 8.5:1).

Maybe he's trying to create the world's most unreliable DSM.

On a serious note, however, the 2G pistons are much stronger than the 1G pieces (will handle detonation better, higher compression, etc.)

 

[aspekt9]

How can I find out if my car is a 6 bolt or 7 bolt?

 

[brodiedehass]

Go here and read. It will tell you what you need to know. http://www.vfaq.com/mods/early-late-engine.html

 

[adrian2627]

ok, i already bought the whole nine yards of parts, je pistons, eagle rods, fidanza flywheel, centerforce clutch all for my 7 bolt ### i was planning on doing a complete rebuild. but now things have kinda changed. i started to hear knock kinda behind the block maybe under or by the head, sounds like a rattling sound at 3000rpm. its not crankwalk and i just drained the oil and put fresh mobil1 10-30 and oil that came out was clean. i am thinking of doing a 6 bolt swap but i dont want to just throw all the parts i bought since it already cost me money. i was wondering if my pistons and rods fit a 6 bolt? i know its not going to be a direct fit but has anyone done it before? i have to drive this car 900 miles back to fort riley and i am worried. any help would be appreciated.

 

[MrBoxx]

Umm... is this for the 96 Eclipse N/T that your profile says you have?

 

[partyplace69]

the pistons will fit on a 6 bolt rod with some work but the rods wont work

 

[adrian2627]

no, i have a 97 gst now. sorry havent updated my profile. just got back from iraq anyways, what do you mean the rods wont fit? are you serious? how do i fit the pistons?

 

[project_tsi]

Rod's won't work b/c the big end width is smaller than 6 bolt rods. The 7 bolt rods would walk on the 6 bolt crank.

7 bolt pistons will fit 6 bolt rods but not without machining the rods to fit pin of the 7 bolt piston. The 6 bolts have a 21mm pin, whereas the 7 bolts have a 22mm wrist pin.

A common 500hp safe setup is to take 1g 6 bolt big rods, add in ARP rod bolts, and machine the rods to fit 2g 7 bolt 8.5:1 CR pistons.

 

[adrian2627]

ok, so my question for everybody here is do you guys think its worth doing this or just rebuild my 7 bolt and bulletproof it, double check all clearances and all the good stuff? thanks again

 

[DGK215]

I've searched for about an hour on this and I cant seem to find this. How do you tell if a 2nd gen has a six bolt swap other than the the bolts that hold the flywheel to the crank? Maybe I just havn't looked hard enough but i just cant seem to find the answer I'm looking for.

 

[brute]

http://www.vfaq.com/mods/early-late-engine.html

 

[DGK215]

Thanks for the link. I must have been an idiot to not have found that on VFAQ.

 

[90gst]

Hello, I' writing because I bought a 90 gsx...I went to change the clutch and found out its a 7bolt crank but the block and everything else apear to be a 6bolt...I checked out the pan and its a 6bolt..... how it this possible? I had to get a flywheel and the rest of the stuff for a 7bolt.

 

[wolf20043]

Hello, I' writing because I bought a 90 gsx...I went to change the clutch and found out its a 7bolt crank but the block and everything else apear to be a 6bolt...I checked out the pan and its a 6bolt..... how it this possible? I had to get a flywheel and the rest of the stuff for a 7bolt.

That cant be good .WTF

 

[98eclipseRS]

Its possible because the cranks are interchangable. You NEED to contact the person you bought it from and ask him wtf is going on with the car. It obviously needed an engine rebuild at some point in its life and the last owner decided to buy a cheaper more readily available 7bolt crank over trying to source up a 6bolt crank.

 

[98eclipseRS]

I would also like to add that if the crank bearings are sized correctly to the crank itself you won't have to worry about crankwalk if that is your concern. Having one less bolt for flywheel attachment doesn't make the crank magical and crankwalk proof. The LATE 7bolts are just more known for it because mitsu had some machining/bearing issues that they obviously did not want to deal with.

 

[MoparTurbo]

Hey, I just recently totaled my car and am wanting to part it out, I would like to get the most out of it as I can. The engine was swapped for a low milage one before I got the car. I want to know how I can figure out which type of motor is it, and how much should a long block with about 70k on it go for before shipping?

 

[luvmygst]

It is a 7 bolt. Do a compresion test that will tell you the condition of the motor.(assuming it still starts) do you have proof of the low milagage swap?, and does it have any mods. Im looking for one right now ill pm you.

 

[DOHCeclipse]

Im planning on putting a turbo on my 91 eclipse gs with 4g63, and i figured i could take all the turbo stuff off of a 92 turbo 7 bolt motor and put it on my motor, but i was wondering if i could take the pistons out of the the 7 bolt and put them on my 6 bolt connecting rods without modification so i could run more boost than what i could on my n/t pistons?

 

[95blackGsTurbo]

You have to machine the rods to get the pistons to fit.

 

[sandman7000]

http://www.vfaq.com/mods/early-late-engine.html
theres a link how to tell if its a 6 bolt or 7 bolt. more then likely you will have a 7 bolt chillin in there.

 

[Carter97GSX]

If you're parting it out why don't you just take it out and count the bolts?

 

[TaloNKiD505]

Hey, my new car came with an extra crankshaft. I was wondering how i would be able to tell if its a 6 or 7bolt, or if there is even a difference, so i could sell the thing already .

Thanks
Matt

 

[kspharris]

WTF Seriously? Ok well look at the end and there will be either..... 6 holes or 7 holes in a circular pattern.

 

[wolf20043]

6 bolt holes for theflywheel=6 bolt
7bolt holes for flywheel=7 bolt
Dowel pin with 6 bolt= turbo
no pin with 6 bolt=non turbo.
Mike