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

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asdfzxc

Probationary Member
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Jul 7, 2002
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 :p )

Is there an advantage over either of the two engines?

Thanks,

-Mike
 
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would it work in my 96 gs-t
 

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My 7-bolt has crankwalk on it now.. :thumb: and now have to get a 6-bolt, i found one at the junk yard 1990 talon awd 185K miles on it, guy doesnt have title for car just gonna cut it in 1/2 and give me front end with motor and tranny for $400.00, good price? any suggestions on what to look for on if it is rebuildable shape? Or Things I need to look for on the car or take while im there?
 
well the only way your gonna know if it needs a rebuild is to take it apart or just put it in your car and see how it runs...and seriously if it had 185k on it i would tear it down and give it a fresh rebuild which isnt gonna be cheap. Hell if your getting the tranny you should sell it and use the money from that to get some parts for the rebuild ;)

the only thing i can think of that your gonna need to take off the car is the lower radiator hose, cam sensor plug and oil cooler...which the 90 air style cooler is a pain in the ass to mount on a 2g unless you do some custom lines and what not.

p.s. wrong forum for this post*
 
btracer said:
6bolt = 1st gen motor
7 bolt= 2nd gen motor

Correction:

6 Bolt = '89-'92½ (Anything around pre June '92)

7 bolt = '92½ + (there are still variations between the 1G and 2G 7 bolt motor).

Bolt # refering to number of bolts holding the flywheel to the crank.
 
A 6-bolt is pre mid '92 and lower motor with 6-bolts holding the flywheel to the crankshaft. 7-bolts were manufactured from mid 92 on up. The 1g 6-bolt motors have bigger stock rods and a stronger bottom end in general, but has lower compression compared to 2g 7-bolts. 7.8 v 8.5. The 2g 7-bolts have problems with crankwalk, whereas the 1gs are less prone to this. The best mix is 6-bolt block, crank, and rods, with 2g 7-bolt pistons.
 
Good explaination. I would like to add...
From what I understand.. Plz correct me if I'm wrong..
1g intake flows better than 2g. 1g JDM Cyclone flows a little better but I'm not sure why cause they look almost the same.

I have heard lots of cross feeback on heads.
Which head is the best to use in a 7/6 bolt combo?
 
98spyderboost said:
Good explaination. I would like to add...
From what I understand.. Plz correct me if I'm wrong..
1g intake flows better than 2g. 1g JDM Cyclone flows a little better but I'm not sure why cause they look almost the same.

I have heard lots of cross feeback on heads.
Which head is the best to use in a 7/6 bolt combo?

Correct, the 1g head flows better than a 2g, but there is a big debate between how much air gets through, and the velocity of the air. Although the biggest contributor to the 2gs responsiveness is due to the higher 8.5:1 compression, it may be attributed to the higher velocity of air going through a 2g head. A JDM Cyclone head is the same as a 1g head, but the intake manifold has dual runners per cylinder. An actuator opens and closes the second runners depending on airflow. Its supposed to keep low end responsiveness as well as cater to high flow high throttle situations. When I did my 6-bolt swap, I went with a 1g head with 1g MT cams (they are a little upgrade over 2g turbo cams)...but I have 9:1 pistons, so responsiveness was better because of that. In the end, the general consensus is to swap heads only if your 2g head dies, or you are replacing the headgasket, otherwise its not worth it.
 
wow thanks for all the info.now this cyclone?wats that like jdm version?also i am thinking of building a motor before i do anything so is like those 2.4 liter built blocks good?with a race head?and intake and exhaust manifold? im thinking of building all those so if thats done should i still have to worry about all this?
 
GreekPower said:
wow thanks for all the info.now this cyclone?wats that like jdm version?also i am thinking of building a motor before i do anything so is like those 2.4 liter built blocks good?with a race head?and intake and exhaust manifold? im thinking of building all those so if thats done should i still have to worry about all this?

The cyclone motor is JDM. Its a PITA to wire in the computer and all the motors for the intake manifold to work right, I don't think its worth the effort but obviously it has been done. 2.4 L motors are very good...they spool up the turbos alot quicker than the 2.0, but you can get 2.0s very potent as well. What car do you have now? I'd get to know how to tune and mod the motor you have now before you learn everything on a built 2.4 It would be a shame to destroy one of those.
 
right now i have a 93 3000gt vr4. i was just looking into getting a dsm or supra to mess around with on the weekends.kinda make it a sick dd/track car.
 
I heard that 1gen dsm 6bolt would have stronger connecting rods, and better cylinder head than the 1gen 7bolt engine. Is this true?

What else is better in the 6bolt engine assy ?
 
alexg1323 said:
the ability to maintain thrust bearing surfaces for a reasonable time if assembled properly, a bigger throttle body, and much more. Just try searching for it

I think he was comparing the 1g 6 bolt to the 1g 7-bolt. I think the 6-bolt rods are a little beefier, but the cr is 7.8:1 in all 1st gen turbo DSMs.
 
The difference between a 1G 6 bolt and 7 bolt are only the number of bolts that hols the flywheel to the crank, smaller main bearings, and thinner rods. They both have the same head design as well as the same CR 7.8:1. :thumb:
 
Syndicate13 said:
The difference between a 1G 6 bolt and 7 bolt are only the number of bolts that hols the flywheel to the crank, smaller main bearings, and thinner rods. They both have the same head design as well as the same CR 7.8:1. :thumb:

Can someone else also verify this ?
Guys here are telling that in the 7bolt engine cylinder head the intake "duct" (if that's the right word for it) would be smaller.
 
opps my bad.

ive actually heard 1g 7bolt heads are the best. They supposedly have alittle better casting on the exhaust side without as big a step before the valves. They also supposedly have better coolant passages. And if your using a 2g mani its always nice that they have the 2 10mm exhaust studs on the corners.
 
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