6 Bolt Vs 7 Bolt Specs

[1993-Talon-TSI]

What are the main differences between the bottom end of a 1g 6 bolt and 1g 7bolt.

1g 6bolt:
same comp. pistons
stronger rods
same block?


1g 7bolt:
same comp. pistons
weaker rods
same block?


As for the crank, is the only difference the 7 bolt part or is it weaker?? i have been looking for some direct real answers on this subject and i cannot find them.

i have 1 93 7 bolt and wonder if i replace the rods and pistons would i be in the same boat as doing it to a 6 bolt?
Thanks

 

[alexg1323]

cant be done, the journals on the 7 bolt are narrorer then the 6. there not interchangable.

 

[drivemusicnow]

cant be done, the journals on the 7 bolt are narrorer then the 6. there not interchangable.

Huh? i was pretty sure you could put the 6bolt rods in any of the 7 bolts.. however, the 2g 7bolts have higher comp pistons... but i do think theres more difference between the motors than just the rods.. are you saying the crank cannot be interchanged?

 

[95AWD_TSI_TALON]

He thought The same thing I did from your post. I also thought you were asking if you could swap a 6 bolt CRANK into a 7 bolt motor. Which you can't do.

 

[1993-Talon-TSI]

Again back to the first question, does anyone have a list of the differences between the two engines. 1g 6bolt and 1g 7bolt.

 

[95AWD_TSI_TALON]

6 bolt motor
-12mm head studs
-stronger rods
-individual main girdal's
-beefier block (more mass)

7 bolt 1g
-11mm head studs
-weaker rods
-1pc main girdal
-and dont forget crankwalk

 

[1fast97gsx]

yep and:

1g-

7.8:1 compression pistons


2g-

8.5:1 compression pistons


As far as swapping 6 bolt rods into a 7 bolt block / crank ... it can be done but they have to be machined to fit. That costs around $90.

 

[Stapl3]

7 bolt 1g

-and dont forget crankwalk

Be serious.

 

[DSMX1]

so whats better? a 6bolt or a 7bolt and what years do these show up in?

 

[Steve93Talon]

If you siphon through all the BS, you'll find that 1G 7 bolts don't crankwalk any more than 6 bolts do, they've made about the same WHP on stock internals, the main cap/girdle design is better, and because the rods are smaller, you have less rotational mass. The bottom line is if you're shooting for up to 450-500whp, either will work fine stock and if you want more, you'd have to do pistons/rods in either to hold up.

 

[98spyderboost]

If you siphon through all the BS, you'll find that 1G 7 bolts don't crankwalk any more than 6 bolts do, they've made about the same WHP on stock internals, the main cap/girdle design is better, and because the rods are smaller, you have less rotational mass. The bottom line is if you're shooting for up to 450-500whp, either will work fine stock and if you want more, you'd have to do pistons/rods in either to hold up.

Just jumped time and had to rebuild the whole timing system. Didn't damage anything else. Did a leak down and compression check no leaks and 55-60 on all cylinders.
Checked for crankwalk while i was under there. Cant even move the crank with a crowbar As for overall "mass" i personally havent read that anywhere before. The fact is that 6 bolts were made for 3 years, 7's for all the other years. Do some simple ratio calculations. No one really knows what causes crank walk. Lots speculate and there are many theorys and the truth is if there was something inherently wrong with the 7 bolt then someone would have come up with an undisputed reasoning for it by now considering they are over 12 years old. None so far.

Back to original question.
These are the main best of both worlds, in my opinion
1. 7/6 Bolt, doesnt matter IMHO but that's up to you. but the cranks are NOT interchangable.
2. 2g pistons are quite high compression compared to 1g pistons.
3. 1g rods are more durrable, but must be mahined for 2g pistons.
4. all 1g intake, and TBs are larger and will not fit on a 2 g head without seriously hogging out the intake ports. The good news is FLOW bad news is the 2g head is designed with a more efficient valve angle. Hogging one out to fit a 1g mani will defeat that and effectively make it a 1g head. Also 1g studs are bigger. So they will fit on a 2g with tapping but not vise versa.
5. Main cap journal is better quality on 2g.

From year to year there are other minor changes and I may be off on some of my info but mostly accurate.

My personal desire is a 7b block, 7b crank, 2G pistons,1G rods (machined to fit), 2g head, portmatched to a sheetmetal intake. BTJM

 

[norice4me]

hey i just got a new eclipse how can itell if it is a 6 or a 7 bolt.

 

[xXDSMSoonXx]

hey i just got a new eclipse how can itell if it is a 6 or a 7 bolt.

If you have a 90-91 you are guaranteed to have a 6-bolt (unless the previous owner swapped it ) also there are a few 92's with six bolt the ones made before June (correct me if wrong) the rest are the 7 bolt motors

 

[norice4me]

what will let me know its a six bolt and not a 7 thanx. or the other way around

 

[gsx951]

Did a leak down and compression check no leaks and 55-60 on all cylinders.
Checked for crankwalk while i was under there. Cant even move the crank with a crowbar

You have done something wrong. If your compression is really 55 to 60 psi, then your top end is shot. What method did you used to check axial playin your crank? We're talking about numbers here that for people who are unfamilliar with machine work, appear to be tiny and without consequence. If you have more that .010" (ten one thousandths of one inch) you are crankwalking.

 

[gsx951]

If you siphon through all the BS, you'll find that 1G 7 bolts don't crankwalk any more than 6 bolts do, they've made about the same WHP on stock internals, the main cap/girdle design is better, and because the rods are smaller, you have less rotational mass. The bottom line is if you're shooting for up to 450-500whp, either will work fine stock and if you want more, you'd have to do pistons/rods in either to hold up.

Steve, your 7 bolt and the 7 bolt in 2G cars are different.
The 2G motor used a rotor plate and pick up on the crank as a crank angle sensor and this sensor becomes damaged when the crank shifts in the block: the ignition dies long before the bottom end but the result is the same.

 

[Tort9320g]

Be serious.

EXACTLY !!! 93 TSI AWD Stock 7-Bolt, Stock head, 264/272's, 20gtd05h, VPC GCC, Full 3"

11.05 @122.93 God only knows how many passes !

134,000 Miles

 

[Steve93Talon]

Steve, your 7 bolt and the 7 bolt in 2G cars are different.
The 2G motor used a rotor plate and pick up on the crank as a crank angle sensor and this sensor becomes damaged when the crank shifts in the block: the ignition dies long before the bottom end but the result is the same.

Your point? I was answering the posted topic which compares 1G 6 bolts and 1G 7 bolts.

 

[xteekayx]

hey i just got a new eclipse how can itell if it is a 6 or a 7 bolt.

if the car engine (if still the original) was made before 5/92 it's 6 bolt....