Installing a 6 bolt in a 7 bolt car

TurboSpider · Apr 4, 2016

I am looking at a 6 bolt complete engine that is for sale in Maryland to replace my 7 bolt. The car it would be going into is a 97 eclipse spyder gst. What modifications would have to be done to make this work. Does the clutch have to be swapped out or anything like that? After searching the forum, I see something about the crank sensor not being the same or something like that. Is there a lot of major mods to be done to get it to work. The engine is partially built with "weisco pistons stock rods. has bc springs and retainers and arp head studs motor is ready to be dropped into a car" 0 miles since it was built.

19Eclipse90 · Apr 6, 2016

1990TSIAWDTALON said:
FWD flywheel is larger than AWD (or visa versa, cant remember as all I have had apart is AWD) but that is the difference. 7 bolt head needs the head bolt holes reamed out for the larger head studs/bolts.

You have it right, Marty. FWD turbo flywheels are larger diameter and have 110 teeth compared to 106 for the AWD.

TurboSpider said:
so if you use the 2g head, you are able to use the 2g CAS and just plug it in like normal? I guess that would eliminate having to rewire a 1g CAS?

It would, but you still have the problem of the 1G combining the crank and cam position sensors into a single unit where the 2G had two dedicated sensors. If you use the 2G head on a 6-bolt block just to reuse the 2G CAS, the only plug-and-play solution is Kiggly's crank position sensor made just for this purpose but requires the balance shafts to be deleted.

TurboSpider said:
With ECM link I think I read in those other threads that you can make the computer ignore the minor misfires or something like that. I read about using the potentiometer to turn it until the misfires no longer happen.

ECMLink will be a much more robust solution.

TurboSpider · Apr 7, 2016

I have another question, the engine I am looking at has 9:1 compression with weisco pistons. If I drop the 6 bolt in as a complete engine, am I going to have to tune it just to get it running right, or is the tuning only needed if I upgrade turbo, or injectors or other upgrades.

laster969 · Apr 7, 2016

TurboSpider said:
I am looking at a 6 bolt complete engine that is for sale in Maryland to replace my 7 bolt. The car it would be going into is a 97 eclipse spyder gst. What modifications would have to be done to make this work. Does the clutch have to be swapped out or anything like that? After searching the forum, I see something about the crank sensor not being the same or something like that. Is there a lot of major mods to be done to get it to work. The engine is partially built with "weisco pistons stock rods. has bc springs and retainers and arp head studs motor is ready to be dropped into a car" 0 miles since it was built.

R you doing the 6 bolt because you are worried about crankwalk. If so I have had my 7 bolt and have never had crankwalk but it was built really good.

TurboSpider · Apr 7, 2016

I am doing it because my engine spun a bearing

hocka09 · Apr 7, 2016

TurboSpider said:
I am swapping because my engine spun a bearing. A pretty good deal came up on facebook for a built engine with 0 miles on it. It was built by a guy that builds these engines often. Most people are recommending I do a 6 bolt swap.

Is it easier to use the 6 bolt head, or put my 7 bolt head on the 6 bolt block? I am a little confused when it comes to that part.

Quick question; who are you buying it from? I might be interested in seeing if he can get me rebuilt/built long block.

TurboSpider · Apr 7, 2016

this is the guy that built it. https://www.facebook.com/brandon.cockran

TurboSpider · Apr 8, 2016

I am going to look at it tomorrow. Is there any thing in particular I should look for to make sure the engine is good. I mean it was never run since the rebuild so I can't pull the pan and look for metal shavings or anything. I guess I could take a socket to turn the engine by hand to make sure it wasn't seized. Any idea what size the crank bolt is to turn the engine with? Anything else to look for?

Hammer_Gaidin · Apr 8, 2016

Over the years, I did more than my share of swaps. The best advice I can give, is use the 6 bolt version of every part that is different. Assuming this, swaps are easy. Ill be it a bit pricey the more parts you need. Also, don't be afraid to pay for new parts over used ones. The last thing you want to do is skimp out to save a few bucks.

That being said, I believe I have used both 1g and 2g stock heads on 6 bolt blocks without issues.

Good luck on your build.

TurboSpider · Apr 11, 2016

Thanks for the advice guys, I am starting a new 6 bolt swap thread to chronicle the swap for others and hopefully receive more advice when needed. Thanks again

The Top DSM Community on the Web

Installing a 6 bolt in a 7 bolt car

TurboSpider

19Eclipse90

TurboSpider

laster969

TurboSpider

hocka09

TurboSpider

TurboSpider

Hammer_Gaidin

TurboSpider

Similar threads

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds