Stupid Cobra II - An extremely NON EURO build thread

[GingerBeef]

Hello Eurodrivers.. Me again.. This time I have no excuse. This just straight up isnt a euro build, BUT Mr. President Railton gave me the green light so here we are. This is my 1978 Ford Mustang Cobra II. He did reccomend that I post this build somewhere else for more exposure but meh. I dont care for that internet "clout", and would rather share this build with the local Eurodrivers community. Hope yall dont mind [emoji14]

Actually, this car does have a very small tie to this club... Some of you might remember this car back from Into the Rockies 2014 where it drove for the very last time. We limped it home that day, and its just been sitting at various locations ever since...







After a year or two of planning my build, and gathering parts. I finally felt confident to start making some progress on this car. So I aired up the tires, and moved it into my tiny garage.







So, not 100% sure whats broken in the 302 Ford small block engine, but it overboosted/leaned out/whatever and it's now low on compression.. Another bad sign was when I pulled the oil drain plug, coolant came out. Also, my brother wants the Paxton supercharger kit, and the Tremec TKO 500R transmission for his 67 Mustang, so that means the old V8s gotta go.



As with any other engine pull, I started off with pulling all the accesories, plumbing, heavy brass radiator and (very few) wires. While pulling stuff off, I discovered a funny looking (what I believe to be) a DIY torque reaction mount haha






On the inside of the car, the guy who built this thing in the 80s made a crude a switch panel. These switches have the electric fans, fuel pump, foglights, and I believe ignition power (if I remember correctly?) wired on seperate circuits. This is perfect for what im planning to do with this car... However, this needed to be discnnected to get the shifter out for the engine pull. So, I labeled everything, and started unplugging. The panel itself is steel and heavy, the switches are hot glued to the back of it, and above all, im not a fan of the extremely loose spade connectors connecting everything together. Ill definitely be making a new one down the road, with some cooler looking switches and hopefully better wiring.







Now, it was time to yank out this old 302... It feels kinda wrong "un-V8ing" a clasic muscle car... But you guys know me. I dont do normal.
I pushed the front end out of the garage for more height clearance, and of course it started to blizzard immedietly... But after another 20 minutes or so.. It was done.. This Cobra will officially never be V8 powered again.








Hmm.. So much room for activities... The bay looks even bigger due to the fact that this cars prehistoric suspension design means that theres no front strut towers... I was about 90% sure that the engine I planned to drop in would fit without modifications to the unibody.. But after seeing the bay, I had no doubt it would.

Last thing to do with this V8 was to split the trans for easier transport, and haul the lump over to my brothers so I could make room for the Cobras new heart...







Thatll be all for now... The new engine is in my garage already, but ill save that for the next post.

Cheers!

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[stefan]

Re: Stupid Cobra II - An extremely NON EURO build thread

I remember the car from the cruise! Cool to see a couple build threads going at the same time. Love the engine-riding pic.

[Canadian Turbo]

Re: Stupid Cobra II - An extremely NON EURO build thread

Thanks for sharing Jason, your build threads are always so much fun, and make me wonder why I don't get more done with my own time

[GingerBeef]

Re: Stupid Cobra II - An extremely NON EURO build thread

Thanks for sharing Jason, your build threads are always so much fun, and make me wonder why I don't get more done with my own time

Thanks Blair! What can I say... I love making more trouble for myself that kills way too much of my time haha.

I remember the car from the cruise! Cool to see a couple build threads going at the same time. Love the engine-riding pic.

I had no idea you were on that cruise! What were you driving at the time?



So, some of you who follow me on Instagram might already know that I've been planning to throw an RB25DET into the Cobra to replace the old V8. The idea is definitely inspired from the Fast and Furious Tokyo Drift Mustang.. Only with the shittier classic Mustang and the shittier RB engine haha. The Fast and the Shittier anyone? But for those of you who are out of the loop, I'll take you through the whole (sort of complicated) story on how I obtained the new powertrain.

This journey started pretty much exactly a year ago when I found a crusty abandoned 1990 HCR32 Skyline project on Kijiji (thats an R32 GT-ST for those unfamiliar with Skylines).







The R32s originally came with a RWD RB20DET (2 liter inline 6 turbo) but this one was in the process of being RB25DET (2.5 liter inline 6 turbo) swapped from what I was told was a later model R33 Skyline GT-ST (more on that later). Besides missing most of its interior, and being in a million pieces, for unknown reasons this chassis has been deemed by the Alberta government to be no longer roadworthy, and unrepairable. So this means I got the whole lot for a pretty good deal. Anyways, I stripped and sold whatever I could from the rest of the Skyline that I didnt need to regain some cost and then sold the rest of the shell to Boost Factory so they could chop it up and use its sheetmetal to fix an R32 GT-R with some terminal frame rust. At the end of the day I managed to get the drivetrain, wiring and ECU for about $1000. Not bad at all.. As you can see from the earlier pic, the engine was already removed from the car when I purchased it, and its accesories/wiring was crammed into a big tupperware box so unfortunately alot of stuff was missing.. But I had most of the important bits.















Now this is where things get interesting/ terrible for me... Like I said earlier, I was told from the seller that the powertrain was an RB25DET Series 2 from a manual R33 Skyline... But after some thorough inspection of my motor only last week I discovered that it was in fact an RB25DET NEO engine from an automatic 2001 WC34 Stagea 2500T (essentially a wagon version of an R34 Skyline GT-T).

Now.. This is both good and bad news for me. The good news is its overall a better powerplant. The NEO has a larger turbo that runs higher boost pressure, has higher compression, variable valve timing, and it has much stronger internals (the same rods as a GT-R's RB26DETT). Long story short, it makes about 280hp and 250 ft lb of torque stock, 30ish hp, and 40ish ft lb more than the standard RB25DET. This should be plenty of fun in the tiny Cobra II that weighs in at around 2800lbs.
The bad news is, it is a much bigger pain in the ass to wire in. And all my wiring pinout collecting and research done over the last year is now worthless... OH and speaking of wiring, after taking a closer look at my engine harness I discovered that whoever removed the wiring of this Stagea engine was an absolute bell end, and cut a bunch of wires.



For example, the wires for all 6 of the fuel injectors were snipped off instead of unplugged. Sure, theyre in a tight spot and are kinda a pain in the ass to remove.. BUT if they had spent even 2 seconds looking, or had half a brain they would have discovered that the wiring harness just simply unplugs from a main connector...







So, thats it for now, this project will be on hold for a week or two while I do some more wiring research, and try to track down ECU pinouts. Its probably also a wise idea to catalogue what I have... And more importantly what im missing so I dont get held up by something stupid down the road. Thanks for following everyone, and please, if you have any questions dont hesitate to ask!


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[Thor]

Re: Stupid Cobra II - An extremely NON EURO build thread

So excited to see this thing come to life again!

[witchcraftz]

Re: Stupid Cobra II - An extremely NON EURO build thread

Wow crazy, looking forward to following the build.

[GingerBeef]

Re: Stupid Cobra II - An extremely NON EURO build thread

Finally back working on this project! I originally wanted to have this thing ready to drive for my graduation, however with this whole COVID19 situation all my iron ring and graduation ceremonies/ banquets got cancelled. All in all, this has been a really crappy situation for all of us, so I lost motivation for a few weeks. (I was also struggling to adjust to the online classes for these last few weeks of my degree). Furthermore, it doesnt help that I also bought a Mk2 Supra to play around with... Every day I tell myself i need to downsize my fleet, yet the exact opposite happens. Whoops.



But anyways, enough with the excuses. Its safe to say that after todays work on the Cobra... My motivation is back! Im so stoked with how this is turning out. As you can imagine, one can expect that alot of fab work and modification would be needed to install an engine thats a completely different layout, into a chassis thats from a different manufacturer, AND is almost 2 decades older. But everything went better than expected.
Today I mated the RB20 trans to the RB25 engine, and decided to drop it into the bay for the first time to see what modifications to the engine/chassis would be needed to situate this drivetrain into the Mustang. Luckily, it popped right in!







Not only was the drop in process smooth and easy... But almost everything miraculously just fit?? Its almost like Nissan designed this engine to fit into a 1978 Mustang. Before this test fit, I did take some measurements, just to make sure that this idea wasnt completely unrealistic. (I was concerned that the fact this was a very small car, combined with an inline 6 being a longer setup than a V8, I wouldnt have room for a radiator.) The lengths ended up being in the same ballpark as the V8 originally had a huge chunky mechanical fan that took up alot of space. The RB25 has an 8" wide dip in its oil pan, designed to clear the Skyline/Stagea's subframe. The Mustang has a 13" hole between the steering rack and front sway bar to clear the V8 oil pan.. So even from the initial measurements, this was a good sign as I had a few inches to play with. But how everything lined up in the end was just so much better than I could have ever hoped. Ill shut up now and just let the pictures do the talking.





As you can see from the above pictures. That lump in the RB25 oil pan fit within the Mustang's subframe with no issues. It is worth noting that in the picture the engines just simply resting on the subframe, so its sitting an inch or two lower than it will when its actually mounted. In its final position, there will be even more clearance between the front sway bar. Firewall clearance is also acceptable. Theres enough room to connect/disconnect heater core hoses, and look for leaks etc. At the front of the engine there is ample room for a radiator too.





The most incredible part is that after I made sure everything looked good in the bay I went inside the cabin to see where the Nissan shifter was... To my surprise it just lined up perfectly, dead center in the Mustangs OEM center console. Just amazing.



I also test fitted the Nissan engine cover... Whats your guys' opinion on this? Im pretty torn. I do think the engine without a cover is cleaner and looks more serious. But, on the other hand I love the look of the "Turbo" script and the whole "Nissan 2500 Neo 6" stuff. Its just so JDM looking. Either way its not a huge deal I guess. I can always just take the cover on and off depending on how I feel that day.



There was one (fairly major) hiccup tho. But I cant complain seeing how well everything else worked out. The turbo has some major clearance issues. As in it just straight up doesnt fit. The downpipe will also be terrible to try to fit, but thats a future me problem.







Like I said though, im really not upset about this revelation, nor am I too concerned haha. I was honestly expecting so much more work to get this engine to fit right, like modifying the oil pan, or cross member, and even cutting a new hole in the trans tunnel and potentially fabricating a new center console. As far as the turbo fitment goes, im not worried as I have a few solutions to this that I can think of.. Im just trying to decide whats the best option.

A. Sourcing an aftermarket RB exhaust manifold (top mount maybe) that will move the turbo forward, and higher. Im gonna have to consult the Skyline guys on this to see whats available on the market.

Pros: if there is a solution, its just bolt on, quick and easy
Cons: id imagine a manifold like that would be quite expensive... Stock turbo oil and coolant lines will no longer bolt on, so ill have to fab new lines.

B. Make an intermediate pipe between the turbo and the stock exhaust manifold. It appears that theres enough space that a sharp 90° bend off the exhaust manifold and straight towards the front of the car with a little S bend in it or something to move the turbo forward will fit.

Pros: I can move the turbo to the most optimal, and aesthetically pleasing location possible. Also sounds like a fun project. Also, alot more cost effective than an aftermarket manifold.
Cons: like A, the oil and coolant lines will have to be made from scratch. Additionally, this will make the downpipe even more terrible to try to make and fit properly.

C. Theres enough clearance to the front tire (like alooootttt) that I can cut out that section of the unibody, and then box in the nagative space back to restore strength. Essentially just cutting it until the turbo fits.

Pros: Quickest and cheapest option. This will keep the turbo in the stock position, and thus retain all OEM Nissan parts, saving more time down the road.
Cons: "Jankiest" option. It feels a little too Roadkill for my liking... Although I am confident I can make it look clean, im not 100% sure how I feel about cutting into the car.

Im gonna have to think my options over in the coming weeks. Either way, I can get started on other parts of the build like the engine mounts, trans cross member, wiring etc. while I ponder..

[witchcraftz]

Re: Stupid Cobra II - An extremely NON EURO build thread

I like the cover, without it, it's just another engine, with it on it screams custom mashup.

[fbatwork]

Re: Stupid Cobra II - An extremely NON EURO build thread

I agree - engine cover required

[GingerBeef]

Re: Stupid Cobra II - An extremely NON EURO build thread

Exciting progress: Engine mount fabrication! This was a super tedious, but fun, and a very rewarding process! The first step was locating the engine into its final position. Centering the engine was fairly simple, I measured the frame rail to crank pulley distance on both rails, and then also measured the rear of the trans to other frame rails. As far as rotation goes, I decided to slant the engine left/right to Nissans OEM specification of 10 degrees towards the drivers side (passenger side in the Cobras case). Nissan also specified a 2 degree tilt towards to rear of the engine in order to optimize the driveshaft angle due to the position if the rear differential, but I believe in my application something closer to level will work. With the engine in place I laid out all the stock Nissan and Ford engine mount components to see what would be the best to start with. On top are the OEM Ford mounts, with the Nissan ones below them.





Ideally, the goal was to utilize as many of the Nissan parts as possible. Nissan spent alot of money paying somebody much smarter than me who spent hours designing these engine mounts for this specific engine. Additionally, using the stock Nissan mounts means that if anything were to wear out down the road, I can simply buy more Skyline engine mount inserts, meanwhile the Ford Mustang II mounts are discontinued. With the engine mocked into the final position it was clear that I could use the stock mounts with a simple adapter bracket to the Cobra chassis. So with that in mind, I started the process of making cardboard templates.









After the cardboard templates were test fitted and everything looked good, I started cutting the pieces of the final engine mounts out of 3/16" mild steel with an angle grinder and used my new drill press to drill some holes.















With the components cut out, I used the piece that bolts to the frame rail as a template to mark and drill holes to make sure everything will bolt in together smoothly in the future. My friend Kyle's slick little 90° drill made this go way faster. Without this tool the engine would have needed to be removed again for this step.







Also, heres a top tip if you need to cut a bunch of bolts to the exact same length. Use nuts to space them out properly, and clamp them inline in a bench vice. After that, go to town with your cutting tool of choice. The nut also has the added benefit of cleaning up the cut threads.





Now with these fresh holes drilled into my frame rail I could bolt one side of the mounts to the rail, and the other side to the engine. After confirming the placement and angle of the engine one last time and sanding the mill scale off, I quickly tack welded the bracket together in the car with a MIG welder and added a brace out of 0.035" wall thickness 1/2" tube. Welding the bracket in place in the car with the engine in the correct position ensured that the brackets would be at the perfect angle, and saved me alot of time calculating and measuring the angle needed on this glorified L bracket.









After all the positioning was confirmed with the tack welded mounts, I brought them over to Kyles shop to TIG weld the mounts completely. I could have done this with my MIG, but the TIG in theory provides a prettier end product. This theory was shattered immedietly as im not a professional welder and I was having some new issues with this welder that ive never experienced before. Some weird sparky, bubbly crap. Oh well, it still turned out pretty decent, and with a coat of "New Ford Grey" engine enamel they look pretty dang good in my opinion. Like, I wouldnt be disappointed if I had bought these on the internet. Of course, a 1978 Mustang to RB25 engine mount does not exist on the internet, trust me, ive looked. Anyways, im extremely proud to present to you guys the worlds first RB Cobra adapter mounts!













Once the paint dried, I could finally bolt my engine into my car and start confirming my measurements... As I said earlier, my aim was a 10° slant towards the passenger side. This angle can be measured off the side of the block, off of 2 machined bosses in the block. Ive also read, that when the engine is rotated 10°, the top of the cam cover should be level. Also, I forgot to take a picture, but I did confirm that the car is sitting perfectly level in both directions, so the values you see are what they are in relation to the car.







Bingo. Nailed the left/right rotation... Lets see if its level longitudinally...






Not bad at all considering that I still need to make the transmission crossmember. I'll take less than 1° off any day... actually, I had set my expectations to be within like 2° of my targets as I didnt think this was too too important in the grand scheme of things... With that being said, let me make this clear that the engine sitting pretty much exactly where I planned it to does not reflect my skills as a fabricator, but instead my great luck of how things ended up haha. But there we have it... An RB25DET NEO sitting quite happily in the engine bay of a 1978 Cobra II.





Overall, im quite happy with how this project came out. I cant complain about the results, and I think aesthetically (which obviously is the most important aspect of an engine mount) the dont exactly catch your attention, but they look cool of you do happen to notice it.

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[stefan]

Re: Stupid Cobra II - An extremely NON EURO build thread

Just finally reading this last post. Nice work. Mounts turned out great, by the looks of it.