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

 

[bmwisthekey]

sorry for the thread hijack but im curious to know the opposite of your question
"will a 1g 6bolt tranny will bolt up to a 2g 7bolt engine?" i know the tranny mount is different, if it is possible is there any problems ( starter, axles etc...im assuming u need the corresponding shifter cables and shifter as well)

 

[Gamble97]

The mount needs to be modified, and from what I've read it's more work than it's worth

 

[halik008]

6 bolt trans will bolt up to 7 bolt motor......and 7 bolt trans will bolt up to a 6 bolt motor......it's not about tran/motor fitment.....it's about the mouting points locations differences between 1g and 2g chassis....

1g- three mounts on the motor....1 mount on the trans
2g- one mount on the motor. ......3 mounts on the trans

You can use 2g trans in a 1g but not the motor, you can use 1g motor in a 2g chassis but not the trans.

 

[jorge4g63]

Hey i was wondering if the same can be said for a 2g trans in a 92 fwd,i heard 2G trannys are stronger than 1g trannys,correct me if i'm wrong. thanx

 

[halik008]

Hey i was wondering if the same can be said for a 2g trans in a 92 fwd,i heard 2G trannys are stronger than 1g trannys,correct me if i'm wrong. thanx

yes and yes......all 1g's are the same

 

[Gamble97]

can you take a 1g tranny and just switch all the mounts/brackets to fit in a 2g?

 

[RotaryRyan]

can you take a 1g tranny and just switch all the mounts/brackets to fit in a 2g?

No, it won't bolt up.

1g trannies go in 1gs. 2g trannies go in 2gs. Unless you want to fabricate your own mounts.

 

[nightspeed87]

how about a
90'S 6 bolt motor fitted with a
93 7 bolt tranny?

(Both tranny and engine are 1g just tranny is 7bolt and motor is 6bolt.)
Will that cause any problems, will it need to be fabricated or will it work fine?

 

[Spln_Hrd]

No, it won't bolt up.

1g trannies go in 1gs. 2g trannies go in 2gs. Unless you want to fabricate your own mounts.

1g trannies go in 1gs. 2g trannies go in 2gs and 1gs.

 

[halik008]

can you take a 1g tranny and just switch all the mounts/brackets to fit in a 2g?

nope the castings are not the same.

 

[halik008]

how about a
90'S 6 bolt motor fitted with a
93 7 bolt tranny?

(Both tranny and engine are 1g just tranny is 7bolt and motor is 6bolt.)
Will that cause any problems, will it need to be fabricated or will it work fine?

no problems......they are both 1g after all

 

[nightspeed87]

no problems......they are both 1g after all

Oh sorry I forgot to include that the 7 bolt tranny is a n/t tranny with stage 2 centerforce dual friction clutch in it..... Isnt like the flywheels different or something from 7 to 6 bolt, and what differs about 6 bolt trannies to 7s in 1st gens.... I have a feeling theres something different.?

 

[halik008]

Oh sorry I forgot to include that the 7 bolt tranny is a n/t tranny with stage 2 centerforce dual friction clutch in it..... Isnt like the flywheels different or something from 7 to 6 bolt, and what differs about 6 bolt trannies to 7s in 1st gens.... I have a feeling theres something different.?

there are no 6 bolt and 7 bolt trannies.....they are the exact same.....

as for n/t 1g trans.....well it will bolt up to turbo motor since n/t and turbo blocks are same in that respect but if they are the same gear ratio wise i'm not sure.....probably not.

 

[nightspeed87]

ive read somewhere that the n/t tranny has a lower gear ratio
in other words better for 1/4 mile times, but not as good for all out top speed ( beyond 100mph type ) pulls....
( Which im not so concerned about top speed, as long as I can reach at least 130 which Id probably never do )

Can anyone confirm this...... And besides the ratio difference, would one think the n/t tranny is pretty much the
same as a turbo tranny ( just with a weaker clutch and flywheel stock set up )
because venders sell n/t and gst clutches seperately because I believe they are of a
different design or something. So I couldnt put gst clutches or flywheels into a n/t tranny from my knowledge...

But suppose I drop in the most powerful and durable n/t clutch and flywheel for that
n/t 7bolt tranny, and suppose the clutch and flywheel I drop in is capable of handling 300 + whp, would you assume that the tranny itself will be able to handle 300 + hp to the wheels??? ( Because even if it does work I dont want to blow up that n/t tranny farther down the line when Im making more power .)

 

[jorge4g63]

Thanks for clearing that halik008,but how do you go about making th e2g tranny fit in a 1g chassis? thanx

 

[98evoIIIpwr]

Get an evo III motor and be done. I found mine for 1k and it was a direct bolt up. Plus the extra 80hp is good. This debate has been beaten with four sticks already but if you can get a good deal its the way to go. Plus it can handle more power.

 

[jayman77]

6 bolt

 

[nightspeed87]

its not a 2nd g tranny if you tlking to me.... Its a 7bolt 1g n/t tranny..... 6 bolt stopped after 92, my car is a 93... Most ppl think all 1gs are 6bolt.... With the proper clutch setup would one think that a n/t tranny would be just as durable as a gst tranny?
I mean i dont see, or know any differences other than the flywheels have a locating pin on the gst tranny and n/t doesnt.

 

[halik008]

Thanks for clearing that halik008,but how do you go about making th e2g tranny fit in a 1g chassis? thanx

1g trans have only one mount.....2g's have 3......but they both share the same mounting point...so all ya gotta do is remove the other 2 unnecessary mounts and drop it in like a 1g trans.

 

[nightspeed87]

I have a 1997 2.4 spyder as well. Can someone answer this question?

you have to do some fabrication on the head to get all the bolts to line up and etc, but its been done before and if you have the money to do it then i say go for it...
It would be more than your average 4g63, because it would have a 2.4 displament..
And to be honest I dont even think they sell stroker kits that go past a 2.3 displament... Maybe Im wrong but you would definily have some power if you turbo charged, but like i said that would be money....

 

[nightspeed87]

Yeah 7 bolts walk... so what. If you build it then most of the parts are aftermarket and its much less likely to walk. So build it. a built 7 bolt I would take over a stock 6 bolt anyday. #### it they are both 4G's and can produce power. IMO its a car. Build it, make it fast, smoke some people and call it a day. A friend of mine around town has a 500+ awhp eclipse and drives it like 150 miles a week and hasnt had a problem for 2 yearz. Do what suits you and you shouldnt be dissapointed. my .02 cents.

Also I aggree on getting the 6 bolt ( like i just built and am dropping in gst ) because others may not think so but a 6 bolt motor runs much stronger than a 7 bolt, longer rods over shorter,
on my n/t 1st gen i had a 7bolt and I had a friend with a n/t 6 bolt and mines had full exhaust, header, intake and performance clutch and his car was completely stock and it was always faster on top end... And his motor just ran stronger and we had about the same compression, and he even had more milage. Even when I drove his his clutch felt better than mines and I had a performance clutch, something about the 7bolt crank just doesnt have the same feeling as the sixes....

If your on a budget then just stick with a 7 and build it up and hope your not one of the final destination motors, beause yea that would suck to build a 7 and have it walk on you after all your hard work, but if you can get a 6 I see it as, do it once do it right the first time, and most guys telling you to get a 7 in a besides money factor scenerio are just saying that because they have 7s and it hasnt walked on them and there trying to defend their engines, but they knew if they had a 6bolt in their car theyd be telling you how great a 6 was... but most ppl on this site will tell you 6 is better anyway, and those are ppl whove experienced both.

 

[rabenne]

I stripped the already heli-coiled exhaust manifold holes, not studs. I will be swapping on a refreshed 7 bolt head, but I was wondering if the only machiene work was on the stud holes? I know you must ream them 1mm oversize from 11mm to 12mm, but is that the only thing I would have to do? It is a complete head, and I have all the 7 bolt parts like intake manifold, throttle body and thermo housing.
help!

 

[redg1clipse]

well. i tried my 6 bolt block with a 7 bolt head, and it didnt work for me. my motor mounts kept on rubbing on the head. i'm not sure what it was, but there was something else that wasnt working for it too. but thats all i can say man. sorry. hope ya get it on there.


cody

 

[rabenne]

Just to clarify, I currently have a 7 bolt head on a 6 bolt block. I was just trying to figure out if there is additional machiene work that I didnt know about. But thats a ton for everybodies help on this question so far!

 

[dave99gst]

That should be it -
Is the head from a 95 ? (same CAS style as stock) or is it newer ?
You will be using a 1g CAS and will have to accomidate it if the head is not a
97-99 style.