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

 

[chanley talon]

You can tell a 6 bolt from a 7 bolt buy looking at the oil pan behind the harmonic balancer .
If it dips in it is a seven bolt . If it is round with no dips in it is a six bolt.
Just in case someone replaced yours with a six bolt.

 

[GreddyGst]

hi guys

i have a 97 gsx and i m trying to found out do i have a 7 blot or 6 bolt and which is better or they are the same!!!
please give me some tips!!!

I think crankwalk is soo overated. Many people blow their headgasket or have 0 compression one of their cylinders etc etc so many other problems occur before crankwalk even starts but thats just my opinion. I'm still running strong with 404whp on a 7bolt stock motor with 113,xxx mileage.

One way you can tell a 6bolt from a 7bolt is checking if flywheel has 6bolts or 7bolts.

 

[CFTDSMMANIAC]

i would say 6 bolt is way much better and reliable 6 bolt has better head it flows way much CFM's and the block is way much stronger, the advantage of the 7 bolt is only on the pistons they are a little way more high on compresion that is why sometimes you se people with 1g's install 2g pistons.

 

[daveyfx]

i would say 6 bolt is way much better and reliable 6 bolt has better head it flows way much CFM's

It does flow more but it is poorly designed compared to the 2G head.

and the block is way much stronger,

The 6 bolt rods are better, yes. That's about it.

the advantage of the 7 bolt is only on the pistons they are a little way more high on compresion that is why sometimes you se people with 1g's install 2g pistons.

That and the 2G pistons are physically more solid.

 

[CFTDSMMANIAC]

2G better in design?????? are you nuts how can a Head That flows way much less CFM'S be better than a one that flow much farther? can you tell me the logic on that? the valve springs and retainers are the same, the intake manifold is way much smaller, and the ports smaller with cams with less lift and duration. better design?

It's true 2G pistons are way better but there is nothing wrong with 1G pistons in my last car i had 1G pistons with stock engine internals and made 464HP to the wheels with no problem at all and it was my daily driver, i build up a 7bolt for a friend of mine and the car coulnd't handle that same amount of power and also in order to make more HP we made a head swap and forged internals 7bolt stock block is crap no offense but crank and rods suck!

 

[98eclipseRS]

2G better in design?????? are you nuts how can a Head That flows way much less CFM'S be better than a one that flow much farther? can you tell me the logic on that? the valve springs and retainers are the same, the intake manifold is way much smaller, and the ports smaller with cams with less lift and duration. better design?

It's true 2G pistons are way better but there is nothing wrong with 1G pistons in my last car i had 1G pistons with stock engine internals and made 464HP to the wheels with no problem at all and it was my daily driver, i build up a 7bolt for a friend of mine and the car coulnd't handle that same amount of power and also in order to make more HP we made a head swap and forged internals 7bolt stock block is crap no offense but crank and rods suck!

You are a ####ing idoit, please turn off your computer and do not post your misinformed garbage on this site anymore. Thank you!

 

[fallenauthority]

2G better in design?????? are you nuts how can a Head That flows way much less CFM'S be better than a one that flow much farther? can you tell me the logic on that? the valve springs and retainers are the same, the intake manifold is way much smaller, and the ports smaller with cams with less lift and duration. better design?

It's true 2G pistons are way better but there is nothing wrong with 1G pistons in my last car i had 1G pistons with stock engine internals and made 464HP to the wheels with no problem at all and it was my daily driver, i build up a 7bolt for a friend of mine and the car coulnd't handle that same amount of power and also in order to make more HP we made a head swap and forged internals 7bolt stock block is crap no offense but crank and rods suck!

Get a better grasp at the English language and of the 7bolts and 6 bolts and come back to us.

 

[ericbev]

2G better in design?????? are you nuts how can a Head That flows way much less CFM'S be better than a one that flow much farther? can you tell me the logic on that? the valve springs and retainers are the same, the intake manifold is way much smaller, and the ports smaller with cams with less lift and duration. better design?

What makes you think that you will gain HP with a 1G head over a 2G head just because the intake runners are larger?

When comming to cylinder head engineering, airflow is not the No. 1 criterion (much to everyones dismay seeing as all these compaines rate their CNC ported heads in CFM of airflow). Bigger is not always better. Port volume, runner shape, mixture velocity and cross-sectional area are extremely important.

This straight shot design (utilizing a high dive angle) allows for a line of sight from the inlet directly to the front opening of the intake valve. This typically gives a lower flow value but because it is straight, it attains higher velocity of fuel/air entering chamber. It also creates a turbulent spin or swirling in the combustion chamber, yielding a more efficient and more complete burn

A head design with an intake port shape that compromises flow in favor of creating more combustion chamber swirl and redirecting incoming fuel droplets away from the cylinder walls, allows a nice balance between flow and combustion, and typically makes more power than just having "more flow". The single biggest factor affecting flow quality, is flow velocity.

The HP increase from a 2g head to a 1g head is from the cams and the intake manifold. If your using aftermarket cams and plan on buying a SMIM don't put on a 1g head because you'll end up with no gain and a head that has an inferior port design. Also, the castings on 2g heads are far superior to 1g castings. They have more alluminum in the lifter bulkhead to reduce flexing and less problems with casting shifts than 1g heads.

It's true 2G pistons are way better but there is nothing wrong with 1G pistons in my last car i had 1G pistons with stock engine internals and made 464HP to the wheels with no problem at all and it was my daily driver, i build up a 7bolt for a friend of mine and the car coulnd't handle that same amount of power and also in order to make more HP we made a head swap and forged internals 7bolt stock block is crap no offense but crank and rods suck!

You did not have swap heads as a last resort to make more power. The 7-bolt blocks only downfall (if you consider it that) is the infamous crankwalk which is enormously overhyped and often misdiagnosed.


At Zach.

 

[98eclipseRS]

All this other tech mumbo jumbo


At Zach.

Ah its good to be back.

 

[CFTDSMMANIAC]

Jajajajajaja what is the problem of you guys did't know at the time you bought your cars that the 1 motor is way much better and reliable? it is not my fault that 2g motors are not that good as a 1g motor, but as i can see mi bad for destroying your hopes with your little 2g rods and motors my bad i apologize.

p.s. been there done that!
Why it's that everybody just swaps there 2g's to 6 bolt?
when you answer me this question just let me know.

 

[fallenauthority]

Jajajajajaja what is the problem of you guys did't know at the time you bought your cars that the 1 motor is way much better and reliable? it is not my fault that 2g motors are not that good as a 1g motor, but as i can see mi bad for destroying your hopes with your little 2g rods and motors my bad i apologize.

p.s. been there done that!
Why it's that everybody just swaps there 2g's to 6 bolt?
when you answer me this question just let me know.

Cause the 6 bolt is a better motor, and you are an ass who missed the whole point of this thread. Want a cookie?

 

[jepherz]

Just because you read one article on how the 1g head is larger, and flows more air up top (if it even does) doesn't mean it is "better". "better" is a term that must be defined during every use as what one person sees as better, another may see as totally worthless.

I don't know much about the heads on the 1g vs. 2g, but from what I think, the 2g head has much better mid range. If you're driving your car on the street, and you don't plan on revving to 8 grand between lights, I fail to see why top end would be much more of a deciding factor in your description of "better".

With that said, although all of these designs are serve only a fraction of importance when compared to NA motors, they still matter. Header design in an NA motor involves intense calculations concerning the resonant frequencies of the air entering the motor and isn't just limited to the overall area of the openings in each runner.

The 6 bolt vs. 7 bolt argument will go on forever as the 6 bolt guys say the motors are stronger/more reliable, and the 7 bolt guys will say that crankwalk is way over-rated. Try to add more intelligence into your posts, and you will get a lot more respect. Your personal biases don't answer anyones questions.....

Ohh yeah, nice staying on topic too...

 

[xlMcMlx DsM]

on machv.com, it says that there is no distinction between the 6 and 7 bolts on the 95-99 420A, and also the 1.8 SOHC. So, since i have a 1.8, how would i know whether to say 6 or 7 bolt when ordering parts? like say, a crank pulley? or clutch and flywheel? thanks

 

[reeper]

the bolt deal is in terms son how many bolts hold the flywheel to the crank

 

[timloomis]

6 and 7 bolts usually go with the 4g63,not the 4g37 or the 420a.i dont know if an aftermarket flywheel is made for the 1.8.

 

[GSEclipse620]

If you have to say wether it is a 6 or 7 bolt when your ordering it, then your looking at a part that most likely will not fit your engine at all. 6 and 7 bolt terms are assosiated with the 2.0l 4g63.

 

[xlMcMlx DsM]

the bolt deal is in terms son how many bolts hold the flywheel to the crank

yeah i kno,, but is there a place that specializes in 1.8 parts or something? but i was just wondering that b/c i might order a few things from machv.com, so ill just figure it out from there
thanks

 

[1badturbo]

Before everyone says do a search, I did. I just went through 387 post of crap about people not being able to tell a 6bolt from a 7bolt, and found nothing related to my topic If someone knows where I can find my answer please post the answer and not do a search.

I have a 95 gst, and somehow managed locked up the motor on my way to work. So I'm in need of a new motor, my question is should I stick with the 7bolt and go after market pistons, and rods or should I just swap a 6bolt into it, and if the 6bolt is the way to go how much whp would I be able to get out of a stock 6bolt, and will the aftermarket things I have now work on it.

 

[GreddyGst]

I would built the 7bolt motor with Eagle rods, weisco pistons, ARP studs and port the head to match the intake manifold and ex manifold. Rather than a stock 6bolt with some xx,xxx mileage.

 

[erebusknight]

the only real difference in the 6/7 bolt motors is the 7 bolt had a manufacturing defect where the main bearings surface on the crank was not machined correctly. Almost all newer ones these days are either remaned correctly or the 6 bolt. Many companies sell with a warranty. I think most of them did their research or have heard enough to be sure on what they sell

 

[keymaster]

After recently experiencing crankwalk on my 2G, hands down get the 6-bolt. They've been proven time and again to push 450whp all day long. Several have pushed 550whp+ on STOCK internals. I wouldn't risk the 7-bolt, especially if you ever put an aftermarket clutch in. Just a little peace of mind at night.

 

[Bo0O0ostedDSM]

If I were you, I would swap in a 6 bolt... it really is the safer way to go. Rebuilding a blown 7 bolt just isn't a great idea imo.

 

[GreddyGst]

After recently experiencing crankwalk on my 2G, hands down get the 6-bolt. They've been proven time and again to push 450whp all day long. Several have pushed 550whp+ on STOCK internals. I wouldn't risk the 7-bolt, especially if you ever put an aftermarket clutch in. Just a little peace of mind at night.

Chances are you will blow the engine or have tranny problems or have low compression on one cylinder etc before you crankwalk. Over here in the west coast crankwalk is not very common on dsm. I haven't heard one crankwalk story yet, most of my dsm buddies have other issues and when they rebuild is for different reasons not crankwalk. Now, I'm not saying crankwalk never happens but I wouldn't be paranoid. I have a stock 7bolt motor that is nearly 10 years old with 115k miles pushing 400+whp over 450+whp on dynojet so this can be done on 7bolts. *More power if the engine is built*

There is a guy here in dsmtuners that was pushing 550-600whp on stock 7bolt motor till his motor blew but not crankwalk related. If you plan to have serious whp then I recommend getting LSD for future traction problems.

Good luck with whichever motor you pick.

 

[jtxtrmboost]

Don't blow the money on a 6 bolt, it may be piece of mind to some and if your worried about walking your new motor then go 6 bolt or find a 99 short block and build that. I have a built 7 bolt with forged internals and have had great success. Its really up to you and piece of mind, if you need a 6 bolt to make you feel all good then thats up to you. I'm not saying a built 7 bolt will not walk, but the odds that a fresh 7 bolt 4g63 is going to walk is less likely than another issue that could arise.

 

[Fabian972]

After recently experiencing crankwalk on my 2G, hands down get the 6-bolt. They've been proven time and again to push 450whp all day long. Several have pushed 550whp+ on STOCK internals. I wouldn't risk the 7-bolt, especially if you ever put an aftermarket clutch in. Just a little peace of mind at night.

So your saying an after market clutch increase the chance of crankwalk?