Mid Engine Ecotec 2.2 Conversion in a GT

[baz]

think its looking good just worry about the front not having the weight and pushing all the time if you look at the pic of rons gt in
http://www.opelgt.com/forums/attachm...achmentid=4288
on the pic you can see how high it sits with no engine

[GTJIM]

Just a wee note of caution! While removing the rust and body solder from the rear end of my GT the section of sheet metal behind the rear screen that has the fuel filler in it was removed. It graphically showed how "floppy" the body became without this strengthening element and why Opel did away with any idea of a rear trunk lid. We had to run a temporary brace across the lower edge of the rear screen hole just to hold things square.

As long as the entire rear floor pan/rear motor & suspension area was made nicely rigid in your proposed layout it would probably work OK but all the rear sheet metal on the standard GT is part of the structural integrity of the whole body. BTW: Love the way the rear section of the whole body pivots in your drawing!

Here is a picture of another inovative way that an opening hatch has been incorporated by hinging the rear screen and leaving the sheet metal intact.

[Tire Fryin GT]

Originally Posted by baz think its looking good just worry about the front not having the weight and pushing all the time if you look at the pic of rons gt in http://www.opelgt.com/forums/attachm...achmentid=4288 on the pic you can see how high it sits with no engine

With the flip hatch in the rear, I will have to move the gas tank to the front. I am also going to mount the battery, radiator, spare tire, coolant resivour and tranny cooler in the front. I plan on lightening the front spring also. And if necessary I will add weight to the front. I don't think there will be a problem with push when I get done.

[Tire Fryin GT]

Originally Posted by GTJIM Just a wee note of caution! ...... .......BTW: Love the way the rear section of the whole body pivots in your drawing! Here is a picture of another inovative way that an opening hatch has been incorporated by hinging the rear screen and leaving the sheet metal intact.

For strength I was thinking about a roll bar/rear roll cage that would stiffen the floor pan and tie into the frame/engine mount.

I hope I can make a real GT rear section pivot just as well as the drawing... that is the real trick.

I thought about the rear window opening but in the car I want to build it really doesn't give you the kind of access you would want to the motor and rear drive. With the flip rear it will give lots of access to the engine compartment. The rear will also be easily detachable so that it can be removed for more complicated work. And having it removed will make fabricating the new engine compartment and suspention ALOT more accessable and a whole lot easier to weld.

The GT in the pic is sweet looking. It looks like the rear fenders were widened ... another idea I had considered if the outside width (tire to tire) was too wide for the for the body.

[baz]

georges if your lay up skills are up to it have you thought of doing the back end in fiber glass ?

it would be lighter and if you are putting a cage in to stiffen the rear end you could hinge it upwards to give full access and a handy rain cover
it would also mean you can do the shock mounts/engine mounts/gearbox mounts all to the cage and have it as an integral subframe for more strenth

[Tire Fryin GT]

Originally Posted by baz georges if your lay up skills are up to it have you thought of doing the back end in fiber glass ? it would be lighter and if you are putting a cage in to stiffen the rear end you could hinge it upwards to give full access and a handy rain cover it would also mean you can do the shock mounts/engine mounts/gearbox mounts all to the cage and have it as an integral subframe for more strenth

I really don't like fiberglass, I think there is just something about a Steel body. After looking at a photo posted by Mike Siegel and seeing in detail the inside of the rear I dont think the roll cage will be necessary. I think the rear end with be stiff enough. Check attachment for example. Hope mike doesn't mind me using his photo for example as it is the best view of the inside rear I can find. Thanks in advance Mike.

Note the cuts would conveniently be placed in the center of the supports. When all channeled in for the seal it should be pretty strong .. I dont think it will even effect the frame in the rear as most of the structure would be left in place.

[baz]

georges the gt is a veryflexable shell [early unibody](if you jack up 1 corner you can hardly open a door )so a cage is needed if you do any structural stuff especialy to put the drive in the back

[RallyBob]

The moment you cut out that rear floor pan and the associated 'box' sections that tie the differential area to the tranny tunnel, the car gets very weak. You will have to add some structural tubing, especially if you are trying to modify the bodyshell to open for accessibility. But most of that could be tied into the strut mounts and suspension crossmember, improving the handling at the same time.

Bob

[Tire Fryin GT]

I found out today that a co-worker has a 2003 Pontiac Grand Am with a 2.2 Ecotec engine in it. That is the same setup virtually as the Cavalier has with a slightly wider suspension. He said I could spend some time with his car and a measuring tape. Soon I will post some dimensions and maybe someone out there with a GT could get me a few dimensions to compare with. I got a glance at it today and it looks like the strut towers are fairly low and would fit in the GT nicely.

[jeff denton]

Hey, TFGT, look up the thread Rollcage Progress where Travis and I were comparing his rollcage to Speedway GT's. Where mine was stressing brutal strength and safety with straight runs not caring about interfering with interior space, his was more painstakingly curved to very closely fit the GT interior metal. You'll want his style rollcage with my style rear hoop setup. And I do recommend basing this on my style rocker panels, in fact this will be a must on your car. On Speedway GT the original Opel is all gone from the "shock mount crossmember" back. Yours will be cut about two feet forward of mine. Replaced with tubing trussed and braced to laugh at rear impact, in your car this all becomes nice solid motor/transaxle mounts.
Regardless of where I put the floor jack under my car, when it lifts, either one whole side or one whole end goes up. That is what we call a stiff chassis. Only a rollcage can do that for you!
You've certainly got an interested audience here... Isn't it great?
And I'm sure you know all about using a chassis jig before any cutting starts, be sure you start with that or you'll have a mess!

[Tire Fryin GT]

I am hoping someone in GT land can take a few measurements for me. It seems like alot but it really isn't that bad. Measurements in Inches would be ideal but CM's would be ok to as I can convert it. Any help would be GREATLY APPRECIATED !!!

Ok here goes, hope I can explain this clearly.

1) In the pic of the Rear of the GT. I am looking for the distance from the top of the fender well, center to the same spot on the other side. Including the flair, this should be the widest point of the rear.

2) Same pic, the distance from the rear point of the side window to the other side window. Measured from inside the GT.

3) In the pic of the passenger rear. The distance from the center of the wheel hub to the center top of the wheel well at the fender, (A) in the pic.

4) Same pic, from the center of the wheel hub to Aproximately where the rear fender "flattens" out. Aproximately 3-4 inches from the out side edge of the fender. (B) in the pic.

5) In the pic of the inside. From the point of the rear side window to the center of the top wheel well (D) in pic. (C) being the center of the top of the wheel well.

6) Same pic, from the point of the window to the rear of the seat at aproximately the same height, with the seat adjusted all the way back. (E) in the pic.

With these measurements, I can put together a pretty good representation of the "engine compartment" in the rear of the GT. Then I can measure my friends engine, transmission and strut height.

[Tire Fryin GT]

Originally Posted by jeff denton Hey, TFGT, look up the thread Rollcage Progress where Travis and I were comparing his rollcage to Speedway GT's. ...... You've certainly got an interested audience here... Isn't it great? And I'm sure you know all about using a chassis jig before any cutting starts, be sure you start with that or you'll have a mess!

Yes, I will check out those threads. I think that I will have to build some sort of frame, but I don't want a roll cage. I might put a roll bar behind the seats and tie it into the rear and frame but it won't go to the windshield and down the front roof supports like most roll cages do. I dont think that I will have to do much to the frontend since it shouldn't be susceptible to the frame twist you get with a forward mounted engine and a rearend. With the mid engine transaxle there should be no twist in the body at all. Whatever I add I want to keep it to a minimum. My target is a 2100lbs or less. The ecotec weights 60lbs less then the iron block 2.2 and I would bet you save more than 60lbs over the 1.9 Opel engine.

I don't have a chassis jig, I will have to improvise.

And YES it is great. When I had all my GT's I was the only one I knew that was a GT finatic.

[Tire Fryin GT]

Originally Posted by jeff denton ...look up the thread Rollcage Progress where Travis and I were comparing his rollcage to Speedway GT's. Where mine was stressing brutal strength and safety with straight runs not caring about interfering with interior space, his was more painstakingly curved to very closely fit the GT interior metal....

Can't seem to find them ... can you point me in the right direction?

[jeff denton]

It's in the Racers Forum, called Rollcage Progress, there are actually more than a few great examples of rollcages.
You are gonna need something to hold the car together, just a rollbar isn't gonna do it. You need something that works like a truss holding the roof up on your house. Six points minimum.
I don't think you'll have any trouble meeting your 2100 pound goal, but it will be interesting to see how your front/rear weights compare.

[RallyBob]

Originally Posted by Tire Fryin GT The ecotec weights 60lbs less then the iron block 2.2 and I would bet you save more than 60lbs over the 1.9 Opel engine.

The 1.9 engine weighs about 35 lbs less than an Ecotec. But I'm not sure if the published Ecotec weight is with or without accessories. Of course, you'll effectively eliminate the complete rear axle weight from the car (transaxle probably weighs a bit more than a 4-speed Opel tranny and driveshaft)

[Tire Fryin GT]

Originally Posted by RallyBob The 1.9 engine weighs about 35 lbs less than an Ecotec. But I'm not sure if the published Ecotec weight is with or without accessories. Of course, you'll effectively eliminate the complete rear axle weight from the car (transaxle probably weighs a bit more than a 4-speed Opel tranny and driveshaft)

I found a weight of 275lbs for the ecotec and I couldn't find anything on the 1.9. But 240lbs sounds light for a Cast Iron block w/cast iron head vs. Aluminum block w/aluminum head, Although it does have 2 balance shafts in the motor that weight 20lbs each I believe.

[RallyBob]

I'm not debating you, I only found one reference (perhaps incorrect) to the Ecotec's weight, and it was probably with all accessories intact (305 lbs). I've weighed a 1.9 at 265 lbs.

Bob

[Tire Fryin GT]

Originally Posted by RallyBob I'm not debating you, I only found one reference (perhaps incorrect) to the Ecotec's weight, and it was probably with all accessories intact (305 lbs). I've weighed a 1.9 at 265 lbs. Bob

No debate here... you peaked my curiosity. I am trying to reduce the overall weight of the GT, so I was suprized when you you said it was lighter. The 275 spec I found mentioned that it was without accessories.

I would like to find specs on weight of all drivetrain componants but I don't think that will happen. Maybe after I have some of these peices in hand I can supply the specs for anyone else that is interested.

I appreciate yours and everyone elses interest in this project. Keep the suggestions, facts, concerns and specs coming, they're all welcome information.

[Tire Fryin GT]

In about 9 hours I will be checking out a 71 GT 1.9, auto, AC, 88k and original paint. The car is about an hours drive away. With any luck it won't be rusted out. He said on the phone that he has replaced many parts and that its a good running GT with little rust.