Engine/Trans question -- using FWD engine in rear of Sterling/Sebring

[Flyer615]

So, a friend and I were discussing my Sebring. We were talking about the feasibility of installing a engine/trans combo from a mid-80's Dodge K-car. That is to say, taking a front wheel drive car and moving the whole shootin' match to the back end. I know that most of the conversations, thus far, have been about adapting a different engine to the VW transaxle (or something similar). I'm coming here to the experts to tell me why this would be a bad idea. I am aware of some of the issues. First, there's the axles. I'm wondering why I couldn't cut the axles, leaving the VW wheel and suspension assembly and graft the Dodge axles where the inboard part of the axles connect to the trans. I have access to an entire car and am enticed by heat and air and horsepower and automatic transmission and cake ... umm, nevermind about the cake.

I'm wondering about mounting the set-up using the existing trans mount in some way. Also, I've seen the roll cage style loop that encircles the engine and was wondering if there is a good way to install something of this nature and have it be structural.

Lastly (for now), with the Sebring, there is less room for this set-up. There is a shelf behind the seats that means the firewall is further back than the Sterling. I might be able to cut this, turn it over, and re-install, moving the firewall forward.

Okay, I have no trouble seeing the good stuff. Hit me with the bad.

Thanks,
Ken

 

[vpogv]

Honestly the biggest hurdle will not be the fiberglass body but the frame horns hanging off the back and the rest of the rear of the pan. You will more than likely need to cut a lot of that up and fabricate an entire rear end for the engine and trans set up if you don't use the stock VW trans and go with a mid engine-like set up.

Best way to do it is to get the engine (or at least measurements) and start figuring.

 

[letterman7]

It's actually been rolled around by quite a few people, just not the Sterling/Sebring owners. There's at least one car out there (a Sterling) with an Olds 455 rocking the Toronado transaxle.. not a conversion I would endorse, though! Structurally as well as weight distribution, you would need to find the donor car first, then start measuring and weighing. If you were serious about the conversion, lopping off the frame horns and fabricating a brace cage that joined with the perimeter floorpans and central tunnel would be a primary thing to do. It's been done in the past with the TransVair projects where the entire rear clip of a Corvair was welded to a VW Bus or even a Beetle floorpan - you simply eliminate the VW portions you don't need. Theoretically, you could set the entire FWD clip in place including the suspension so you wouldn't have to worry about mix and matching drive axles.

I had mulled this over years ago but didn't want to get into that much fabrication. I had considered the Geo Metro Turbo (I think - whatever the sub-compact was that was the three cylinder turbo) as it had a track width very close to the VW and the entire clip could have been placed under the body with a few modifications.

Personally I think it's a very valid idea if you can sort the logistics and don't mind cutting some fiberglass. Don't forget you'll need to figure out the cooling system as well - on a Sebring you have a little more room for that than a Sterling!

Rick

 

[Flyer615]

Okay, this is outstanding. You guys pretty much brought forward the issues that I was wondering about, which are frame horns and mounting and bracing the engine itself. I'm not afraid of the brackets and hardware. I own a small tool and die shop with CNC equipment. I'm more uncomfortable with the stresses put on the original pan and "quality" attach points. I don't worry too much about the plumbing of the cooling lines, but wiring with an ECM and the fiberglass work. Like, does the cutting of that back firewall cause a stress in the body that's gonna have me going down the road looking like Igor? I'm sure the wiring will work itself out if I mess with it long enough.

I read someones post about the area over the rear wheel wells being a negative pressure area. Will I be able to mount the radiator(s) in the rear? The existing radiator is very small ... or maybe two from a motorcycle (like someone suggested)?

A friend, my daughter, and I spent a Saturday a couple of weeks ago, measuring, taking notes, and just general scrounging for different possibilities. Looking at 4-cylinder possibilities, we took notes and measurements on about 40 different cars and their engines. I was a little discouraged until I got to the Dodge area of the yard. A Dodge Shadow had a 4-cylinder engine with a slight slant to the rear. This gives me about 14 - 15 inches from the CV joint to the front of the engine. The other brands measured anywhere from 15 to 19 inches. The 6-cylinder engines measured as much as 22 inches forward of the CV. Also, we figured that there could be one or two inches of set-back between the trans and the wheel assembly (misalignment). Is this possible?

My biggest concern with putting the entire sub-frame from the donor car back there is locking the wheels in the straight position and getting them aligned properly. Attachment also seems like it might be slightly outside my engineering capabilities. I am a sponge, gents. Water me. -confused* Thanks for all your help and input.

 

[letterman7]

Well, I'm certainly no engineer by any means, but if you place a tube frame under the existing chassis using, say, 2x3 box steel, 1/8 to 3/16 wall and weld it well to the perimeter frame, cross brace underneath to the tunnel and weld there (effectively eliminating your floorpans and giving you a flat floor), you should be able to cantilever off of that to provide support for a FWD platform. You'll probably still need to figure out some cross bracing in the rear somehow, but you could always fabricate a pseudo roll-bar behind the rear bulkhead for that as an attachment point.

As for locking the axles...once everything is in place you're going to have to do your best to set the wheels dead straight - and simply weld the pivot points. That's going to be your hardest thing to do correctly because any variance is going to send the car in weird directions with some serious tire wear.

Radiators: yes, behind the wheel well is a dead zone usually, but with a different engine configuration that might change. The general rule of thumb is to get a radiator bigger than you think you're going to need - getting air to flow correctly in these cars is tricky. Front mounts are always the best; side mounts a'la McLaren come in second. There are a couple people that have V6's in the backs of their Sebrings with small-ish front mounted radiators and they seem to have no issue. Look for the photos of the Carlisle show a few years back and the red Sebring and you'll see the setup.

As for cutting the rear bulkhead for clearance... you'll have to play that by ear. At worst you'll need to fab up subframes to support the body correctly, fastened to the new perimeter frame.

 

[vpogv]

As for locking the axles...once everything is in place you're going to have to do your best to set the wheels dead straight - and simply weld the pivot points. That's going to be your hardest thing to do correctly because any variance is going to send the car in weird directions with some serious tire wear.

Why make it so permanent where the wheels are welded straight? Should be pretty simple to fab up rear toe adjustment for those wheels so you have room to adjust.

 

[letterman7]

IRS rears (which this would be) generally don't have toe settings unless they are 4WD. Camber/caster yes. He'll need a way to lock the geometry or at a minimum tie the two spindles together and lock it with an adjustable link.

 

[vpogv]

IRS rears (which this would be) generally don't have toe settings unless they are 4WD. Camber/caster yes. He'll need a way to lock the geometry or at a minimum tie the two spindles together and lock it with an adjustable link.

Correct me if I mis-read but Flyer wants to take the entire front clip of the Dodge and place it in the back of the Sebring. Which means it would be already adjustable due to it being the steering parts in the Dodge. Which means the axles, tie-rods, hubs, etc. would be set up for adjustment alright, just have to create a solid point for the inner tie-rods to attach as the steering rack would be pulled.

 

[groundflyer]

The Dodge cars from the 80s had some turbos I had a Omni 4 door Called the glhs intercooled I think was 180 HP with a 5 speed and a 2500lb car and would go find v8 Mustangs *rock on*

 

[letterman7]

Correct me if I mis-read but Flyer wants to take the entire front clip of the Dodge and place it in the back of the Sebring. Which means it would be already adjustable due to it being the steering parts in the Dodge. Which means the axles, tie-rods, hubs, etc. would be set up for adjustment alright, just have to create a solid point for the inner tie-rods to attach as the steering rack would be pulled.

Correct. He'll need a way to tie the tie-rods in place or leave the steering rack in place and simply weld the pivot on the rack... which might be the easiest thing. It'll add a little weight, but it'll be closer to the centerline and low to the ground - good for dynamics. The only oddball in the whole equation is finding wheels that fit both a vintage VW and the new donor! Well... could always put custom rotors in the front, I suppose .

 

[Flyer615]

Correct. He'll need a way to tie the tie-rods in place or leave the steering rack in place and simply weld the pivot on the rack... which might be the easiest thing. It'll add a little weight, but it'll be closer to the centerline and low to the ground - good for dynamics. The only oddball in the whole equation is finding wheels that fit both a vintage VW and the new donor! Well... could always put custom rotors in the front, I suppose .

Actually, my original thought was to fab a mount for the engine/trans combo connected to the existing horns. Then, cut the driveshafts and use the VW outboard parts. My brain was thinking that since that portion was already there, locked in place, and aligned, I might not have to add a lot of extra engineering. This way, my only real concerns would be engine mounting, grafting inboard driveshafts (Dodge) to outboard (VW), cooling, and wiring. I have the wherewith to cut, weld, sleeve, and balance the driveshafts. I'm not sure if it would be strong enough, but I'm thinking that the 4 banger Dodge is not really a monster power producer, anyway. At 49, I'm not sure my constitution could take that much excitement anymore. *laugh*

Maybe I'm not giving enough consideration to the mechanics of mounting the engine without all that sub-frame? I don't know how sturdy those horns currently are that hold the existing transaxle. Also, until I get it all disassembled, I'm not sure of the weight difference between the Dodge 4-cyl and trans and the VW 4-cyl and trans. Power-wise, I think I may lose a little. The original builder of this car built the engine pretty heftily (I have the receipts). He advertised the car as having 120 HP, but I don't know if he actually tested or estimated it. The few times that I was able to shoehorn my big self into it, it seemed quite powerful. This time, I'm looking for reliable, peppy (but not a Corvette killer), comfortable (in a heat and air sort of way), and attention grabbing (which is a no-brainer with these cars).

Do y'all think the horns are stout enough to hold the engine/trans combo? Do you see any issues with the axle set-up I'm considering? Do you think there will be a tremendous difference in the weight between the two set-ups? If everything goes like I plan, I should have the donor car Friday or Monday. I guess I'll know more about mounting points after I actually get the Dodge.

Thanks for all the input. I really appreciate it.

 

[letterman7]

Just the fact that you'll retain the transmission will almost require the frame horns to go away. There simply isn't enough room to squeeze everything on top of and between the horns. The driveshafts any good machine shop can probably fab something up, or give these folks a call: The Driveshaft Shop | Home page
My feeling is that even if the combination does fit, it'll be too far to the rear and you'll be both out of room and the driveshafts will be at a ridiculous angle. Before you go spending any money I'd see if you can find just the drivetrain alone and measure and weigh it if possible. The frame horns are only meant to hold about 250 pounds max - though I've seen much larger engines hung off unsupported - but it's definitely not a good idea. The horns and subsequently the chassis will twist with the extra weight and torque - and I'm relatively sure that even a moderate watercooled 4 banger produces more horsepower than your "built" VW engine. I can't tell you how many engines I've seen that I've been told were built out and on disassembly have proven to be prettily painted bone stock motors.

If, in fact, your VW engine is what the seller said it is, you should easily have the torque to run an A/C compressor and not lose much response. In these cars simpler is better - if it drives well and you're happy with the performance why tie yourself up into a project that may quickly get over your head? Heater boxes in good shape and appropriate insulation will keep the cabin more than comfortable in the winter (and I'm working on an alternative heat source - stay tuned. Won't be viable much before years' end), and an A/C system can certainly be added. Again, it's figuring the logistics of where to place everything... search the forum for a/c threads and read on!

 

[Flyer615]

Okay, this is now an ongoing project. The automatic transmission is rebuilt. The engine is almost complete. Next, the VW engine/trans is coming out.
I bought a 1989 Dodge Aries with a 2.2 and automatic from the Sheriffs department in Chattanooga. Pulled the eng./trans and all the wiring. Scrapped the rest of the car. Purchase price for car - $400.00.
Scrap price after removing everything - $256.80. Net investment, so far - $143.20. As it happens, the sheriff's department couldn't get the trunk open. When I got the car home, I found out that the trunk was full from bottom to top with construction tools. I figure it worked out to be a wash.
Anyways, I'm going to make a luan form that replicates where the firewall currently is (to check for clearance). The frame horns will be cut off and a plate welded into place to hold the front motor mount, which, as best I can tell, is more of an anti-rotation mount to keep engine torque from turning the motor. The two side mounts will be incorporated into the existing shock towers (don't have that one designed just yet). I will be using the VW trailing arms. I know that I will have to fab the spindle/carrier (I'm not sure of the right term) that will attach the trailing arms of the VW to the Dodge spindle. Actually, it won't be the Dodge spindle. It will be a different part of my own manufacture. I figure the trailing arms was a pretty good set-up for Volkswagen, there's no need to re-invent something for that. Also, there is not room for the Dodge suspension. So, just to clarify, it will be a Dodge motor, trans, and axles. The hub/spindle/carrier will be machined at my business. The disc brakes and calipers will be from the Dodge. If the bolt pattern turns out to be odd, I'll turn the rotors 36 degrees and drill the needed pattern.
One advantage of the Dodge is that the exhaust and the intake are both on the back of the motor. This means that the oil dipstick and filter, trans dipstick, and water pump are the only things toward the firewall. I'm going to use an electric, inline water pump and make an aluminum elbow for each of the water inlets on the block. This way, I'll only have to have an access door on the firewall to check the oil and maybe for the filter.
Using an automatic trans clears up a huge issue that I was having with the three pedals on the floor. I just didn't have room for these two swim fins. Besides, while I realize that there is a company making AC that will work with the VW now, I still believe it will be a little easier to get heat and air with this setup.
I'll probably start a journal entry as soon as I can start getting some pictures. I'm not sure that the description by writing fully conveys what I'm trying to say. Pictures will definitely clear up a lot of things. Thanks for all the input.

 

[1/3RDOFF]

Dang, I'm a dollar short & a year late. But I'll ask anyways. Hope this build is coming together/got
started? The tie rods would be real simular to the fieros set up which allows for toe-in adjustments but also sets up some bump steer.

If I may add; a newer model engine package would provide more horse power, better mpg, & maybe some performance ad-ons. The Dodge Daytonas in the 90's had a 3.0 V-6, might work. Rick

 

[Flyer615]

Hey, Rick. The build is moving. Work and life in general have sort of moved things to a snail's pace. I have re-built the transmission and the engine from the Dodge, mostly sorted out the wiring, and accumulated all the stuff for the engine cooling. The stock radiator and condenser from the Aries is going to work just fine for the Sebring. It looks like it's going to need to be tilted about 20 degrees to fit vertically (the Sebring seems to have a bit more room vertically up front than the Sterling).
The biggest drawback, to this point, is the fact that I've been unable to determine if the trailing arms on the VW are going to interfere with the engine/trans so far. I was hoping not to have to make something new for that part of the suspension. I won't know for sure until I actually dry-fit the setup. I know that it's going to be close. I guess I need to start a build thread and start putting some pics up. With the wealth of knowledge that is here, I would be ahead of the game to start getting some other input. Thanks for asking.*hi-ya*

 

[1/3RDOFF]

Glad to hear your build is moving along. I'll be honest, I'm not a VW person, never have been. Just never got into them. So my Sterling is in sad shape. The back 1/3rd is burned off, up to the rr. window bail-the top main part. The rest of the car is in good shape though. I put a fiero k-frame & front end under it to move it around, but it all must be redone on a flat shop floor, squared, etc. Then frame up to the upper body section. I'll use a caddy drive train, got some 4.5's & 4.9s. My
picture posting skills r not too good, wife says she'll teach me. My computer skills r VERY limited. And the wife wants some other way to get in/out of the car--so I may fiberglass down the canopy & cut other style doors in, just not sure yet.

I have too many other projects: a4.9 for my fiero, finish the wifes fiero motor rebuild, redo my trike(add a complete new(er) drive train to the rear), got a chance to get a 1970 lotus Europa & then theirs the house. I'll let ya go-Rick

 

[Skorpiworm]

Did you start a build thread?

I would love to see this coming along.

I have a sebring body but no chassis and im planning on building a spaceframe for it and use it for the track.

To strenghen the welded driveshafts you can weld them and after put a tube on it as a sleve and then weld it to the shaft

 

[Flyer615]

Did you start a build thread?

I would love to see this coming along.

I have a sebring body but no chassis and im planning on building a spaceframe for it and use it for the track.

To strenghen the welded driveshafts you can weld them and after put a tube on it as a sleve and then weld it to the shaft

I did start a build thread. It's called Lucky 13 over in the build thread ... um, threads. I had to can my original idea about using the VW suspension, as the diagonal links were in the way of "sideways" engine/trans placement. Therefore, I am currently looking at using the rear subframe from a Fiero - though, I don't have this completely worked out either.

I would love to see this coming along, too. *laugh* Life and family issues have served to claim a lot of my time recently. It is about time to get back on track, though. I expect there to be some progress again in the coming weeks.

By the time I get it all worked out, I might have been better off to just build an entire frame, but it's not really in my nature to do things right the first time. I'm more of an "I-have-to-be-proven-wrong" kind of guy, before I go the common sense way.

As for the shaft welding, that was my intention. My biggest concern was balancing after the welding. Good luck with your build!

Ken

 

[Jay Laifman]

Don't know the status here. FYI, I am running an '87 Fiero GT V6 hanging off the back of the VW transaxle. Been pretty happy with it. But, now thinking of going back to an 1835 VW engine I picked up by chance.

When we put the engine on (in 1988), VW parts places had straps that would go around the tranny and the horns and give greater strength. And another couple straps that went around the forward part of the horns and tranny. I don't know if they are out there anymore. I actually never installed ours. The only issue we have had is that the front tranny mount tore apart once.

The only real issue has been that because the pipe from the exhaust manifold to the mufflers is so short, the heat build up regularly eats up the mufflers.

Engine is tired now and just blew up another muffler. That's why I'm thinking of putting the VW in. It would also be a project to do with my son.