The Build "89 Jacobra"
#21
Wow, this project needs a reality check. Way too much material was taken out of that front sub-frame. That;s a accident waiting to happen. The 460 is one of the few domestic V8's that weighs more than a Jag v12.
https://www.stang-aholics.com/i-2418...k-engines.html
Could have just bought this and set the engine a bit higher. Not a good idea to have your sump lower than the cross member. Anyone who has driven an XJS hard knows the front subframe can scrape when pushed hard. Having the sump even lower than that... real bad idea.
"650+ HP" was mentioned in an early post.... From a 460?.... no way on this low budget build.
https://www.summitracing.com/parts/f...EaAmRqEALw_wcB
This is what a 650 HP big block ford costs and looks like,
The metal cut away on the trans tunnel is very important for the structure of the car. It needs to be there somewhat perpendicular to the rails as it was.
The trans is sitting way to low. The pan will scrape unless the car is jacked up considerably. Also the pinion angle looks far off too.
You could have swapped the exhaust manifolds side to side and had them exit froward then cross over and loop down and back. That solves the clearance and steering shaft issues.
I'm all for engine swaps but this one is a bridge too far becasue of the poor engineering choices that have been made. I seriously doubt this car will move more than a few miles under it's own power. It's 4th down and your on you own 1 yard line. punt. I'm not being discouraging...I'm just encouraging you to start over with a different approach.
https://www.stang-aholics.com/i-2418...k-engines.html
Could have just bought this and set the engine a bit higher. Not a good idea to have your sump lower than the cross member. Anyone who has driven an XJS hard knows the front subframe can scrape when pushed hard. Having the sump even lower than that... real bad idea.
"650+ HP" was mentioned in an early post.... From a 460?.... no way on this low budget build.
https://www.summitracing.com/parts/f...EaAmRqEALw_wcB
This is what a 650 HP big block ford costs and looks like,
The metal cut away on the trans tunnel is very important for the structure of the car. It needs to be there somewhat perpendicular to the rails as it was.
The trans is sitting way to low. The pan will scrape unless the car is jacked up considerably. Also the pinion angle looks far off too.
You could have swapped the exhaust manifolds side to side and had them exit froward then cross over and loop down and back. That solves the clearance and steering shaft issues.
I'm all for engine swaps but this one is a bridge too far becasue of the poor engineering choices that have been made. I seriously doubt this car will move more than a few miles under it's own power. It's 4th down and your on you own 1 yard line. punt. I'm not being discouraging...I'm just encouraging you to start over with a different approach.
PS. Oh by the way the 460 is only 20 pounds heavier then the V12 and it sets a full foot or better back. So it shouldn't be an issue.
Jack
The following users liked this post:
Greg in France (12-07-2018)
#22
I went back and studied the links you added and. I'll give you some specifics. The oil pan you pointed out, is the exact same pan, as the one on my motor. I don't want my carbs sticking out of the hood, so I cut a notch in the pan to clear the rack. It's got to fit first.
I will also rebuild the front crossmember roughly 2 + inches lower then it was originally and triangulate it to act as a skid plate, to protect the oil pan.
The engine you describe is a stock A460 block with a stroker kit. It has 10 to 1 Compression. Mine is factory stock with 10.5 to 1. I have the DOVE heads, and my valves are the same size. I will have to port my heads especially on the exhaust side to get some more flow, and Ive already made one header 2" head pipes with 3 " collectors, and know how I'm going to make the second one to clear the steering. It will also have 2"head pipes, and 3" collectors
As for carburetion they list 870 CFM. I'm building a dual 2 barrel manifold which will mount one 500 CFM 2 barrel directly over the front 4 cylinders, and another 500CFM 2 barrel directly over the rear 4 cylinders. Giving me 1000 CFM, and near perfect fuel distribution. This with the ported heads, and a very similar cam, and valve train as they have listed in their build. The numbers should be in the same ballpark. I have used the Comp Cams Cam Quest, which should give a reasonable expectation of what is possible. With the basic things I have listed. It came up with between 647 to 693 HP. depending on how "radical" a cam I chose. So I'm in the Ballpark.
Just a little deeper explanation of the method behind the madness.
If you remember, my cousin "Carroll" stuffed a 260 Ford V8 where a 4 cylinder used to be, and came up with a Cobra!
I'm just moving up to the next level.
Jack
I will also rebuild the front crossmember roughly 2 + inches lower then it was originally and triangulate it to act as a skid plate, to protect the oil pan.
The engine you describe is a stock A460 block with a stroker kit. It has 10 to 1 Compression. Mine is factory stock with 10.5 to 1. I have the DOVE heads, and my valves are the same size. I will have to port my heads especially on the exhaust side to get some more flow, and Ive already made one header 2" head pipes with 3 " collectors, and know how I'm going to make the second one to clear the steering. It will also have 2"head pipes, and 3" collectors
As for carburetion they list 870 CFM. I'm building a dual 2 barrel manifold which will mount one 500 CFM 2 barrel directly over the front 4 cylinders, and another 500CFM 2 barrel directly over the rear 4 cylinders. Giving me 1000 CFM, and near perfect fuel distribution. This with the ported heads, and a very similar cam, and valve train as they have listed in their build. The numbers should be in the same ballpark. I have used the Comp Cams Cam Quest, which should give a reasonable expectation of what is possible. With the basic things I have listed. It came up with between 647 to 693 HP. depending on how "radical" a cam I chose. So I'm in the Ballpark.
Just a little deeper explanation of the method behind the madness.
If you remember, my cousin "Carroll" stuffed a 260 Ford V8 where a 4 cylinder used to be, and came up with a Cobra!
I'm just moving up to the next level.
Jack
The following users liked this post:
Greg in France (12-07-2018)
#23
im ok with the firewall hacking by the time its put back together and closed in it will be just fine. the sub frame will defiantly be needing some beef added back into it. i think a aftermarket or customized sheet metal oil pan would be beneficial. you could shorten it and then add some boxes to the sides of the pan to regain the lost oil sump capacity, things generally look pretty rough and scary when there still in the hack and fit stage.
The following users liked this post:
89 Jacobra (12-07-2018)
#24
im ok with the firewall hacking by the time its put back together and closed in it will be just fine. the sub frame will defiantly be needing some beef added back into it. i think a aftermarket or customized sheet metal oil pan would be beneficial. you could shorten it and then add some boxes to the sides of the pan to regain the lost oil sump capacity, things generally look pretty rough and scary when there still in the hack and fit stage.
This is what it looked like before I cut the bubble out all I did was remove the bubble and cut it flush with the frame rail.
#25
the sub frame i was referring to was the front suspension sub frame/ cross member /engine cradle area that was cut for clearance, i would say that is going to need to have some strength added back into it for sure. i don't see anything in the firewall/foot well area that raises any concern to me. iv cut entire firewalls and trans tunnels out of car before and they went back together and were fine. cutting a bit out of the lower corners of the firewall / footwell wouldn't bother me at all. i can see that you left the uni-body "frame" rails in place.
Last edited by Ezrider; 12-08-2018 at 12:40 AM.
#26
Oh Sorry,
I am going to box in the area cut out in the front crossmember, and extend it downward about 2 to 2 1/2 inches below the crossmember its self, and then make wings from the outer portion at the outboard edges of the crossmember to the part extended down, and create another crossmember simply 2+ inches lower then it is now, and weld it all solid, and closed in. Kind of like making one under the other, and welding them together to create one 4+ inch thick crossmember. Which will provide lots of strength, and some protection for the oil pan, kind of like a skid plate??? It's a work in progress so everything is subject to change or adjustment at this point. But that's the intent at this moment.
jack
I am going to box in the area cut out in the front crossmember, and extend it downward about 2 to 2 1/2 inches below the crossmember its self, and then make wings from the outer portion at the outboard edges of the crossmember to the part extended down, and create another crossmember simply 2+ inches lower then it is now, and weld it all solid, and closed in. Kind of like making one under the other, and welding them together to create one 4+ inch thick crossmember. Which will provide lots of strength, and some protection for the oil pan, kind of like a skid plate??? It's a work in progress so everything is subject to change or adjustment at this point. But that's the intent at this moment.
jack
#27
#29
Yeah I've got to grind off some of the spot welds, and pull them apart to be able to clean them up, and smooth everything out inside. Then I'll have to finish the welding, and dimple them so the bolts will all fit. But they will fit and clear everything. So that is a major milestone conquered. I'm thinking I'm going to wrap them with header wrap. This will make them look a lot better and keep the heat down under the hood a little bit. I've never used header wrap. The only reservation I have is that it would slip out of place, and end up at the bottom of the pipe? But with everything it took to construct them, they definitely ain't pretty, but at least they'll be functional, and are one heck of a lot bigger then the best stock manifold Ford ever created. Now on to the dash, heater assembly and the wiring.
#30
#31
The following users liked this post:
89 Jacobra (01-15-2019)
#32
Yeah Fiberglass can be a real pain! ERRRRR I mean an itch! LOL! I'd say a "Seven Year Itch" but I've been married for 36 years!!! LOL!
Yeah, we know it fits, and we have workable headers. Now on to repairing the fire damage. Then I can make it run for real. Anyone ever removed the entire wiring from under the hood and dash at the same time??? How are they connected together? Most US cars have a junction block on the firewall somewhere, but I'm not seeing one??? Any Help would be appreciated. Thanks Jack
Yeah, we know it fits, and we have workable headers. Now on to repairing the fire damage. Then I can make it run for real. Anyone ever removed the entire wiring from under the hood and dash at the same time??? How are they connected together? Most US cars have a junction block on the firewall somewhere, but I'm not seeing one??? Any Help would be appreciated. Thanks Jack
#33
The cabin has two connectors, one each side, down by where the driver/passenger ankles are, on the bottom of the A post under the trim. These unplug each side and are accessible on the outside by removing the wheelarch baffles. The main loom from the OEM ECU in the boot (trunk) also goes though the firewall on the US passenger side (at least on UK cars) and has no plug, it goes through a grommet. This can probably be left in place, or if you are not using it at all, removed by pulling it through from the engine bay where it plugs via connectors into various engine looms.
The dash and interior wiring all unplugs all over the place, and requires the dashboard and centre console to be removed to get at it. There are two large positive posts from the battery under the inside of the dash as well as the ones on the other side in the engine bay (it is the same post each side that feeds the cabin one side and the engine bay the other). There are also important earth connectors under the dash. If you are going to use the OEM aircon, be very careful to note the vac lines that are all over it, as they are easily displaced.
I have a few pics of the dash underneath if you need any help. My advice is to actually remove as little as you can get away with, consistent with the welding requirements, but to separate and thoroughly clean every single connector and earth under there!
Great fun the project, and thanks for posting about it so regularly. There is plenty of exhaust wrap that is non fibreglass, by the way.
The dash and interior wiring all unplugs all over the place, and requires the dashboard and centre console to be removed to get at it. There are two large positive posts from the battery under the inside of the dash as well as the ones on the other side in the engine bay (it is the same post each side that feeds the cabin one side and the engine bay the other). There are also important earth connectors under the dash. If you are going to use the OEM aircon, be very careful to note the vac lines that are all over it, as they are easily displaced.
I have a few pics of the dash underneath if you need any help. My advice is to actually remove as little as you can get away with, consistent with the welding requirements, but to separate and thoroughly clean every single connector and earth under there!
Great fun the project, and thanks for posting about it so regularly. There is plenty of exhaust wrap that is non fibreglass, by the way.
#34
Hey Greg, Thanks for the great info, as I'm at a little bit of a loss. I'm learning a lot about the different approach to engineering, US vs UK. I'm gonna pull everything form my car, and see what I find before I attempt to remove all the good stuff from my parts car. Yes I'm going back with all the original heat, and A/C components. So I'll have to clean all the connections, and be careful as you suggested. I appreciate the heads up about the vacuum lines, do they make a hose diagram for the vacuum lines. Kinda like a wiring diagram? Sounds to me like I've opened a real can of worms. Oh well a little at a time. Dad always said, If it's difficult, we'll do it right away. If it's impossible, it'll take just a little bit longer! Thanks Again, I may well need more of your guidance, and knowledge as this progresses.
Jack
Jack
#35
Well a little update to the Build. I've completed the DS header. All it needs is finish welding around the header flange, and a little cleanup. I've decided to cover them with header wrap, that will hold down the underhood temps a little, and hide the "Ugly" As long as they function, and clear everything we're good. You can see on the rear 2 tubes have been dimpled in to clear the Jaguar steering shaft. So that is one hurdle successfully cleared. The only drawback is I'll have to remove the steering shaft to remove the header.
Jack
Jack
The following users liked this post:
Don B (02-11-2019)
#36
#37
Update, Got lucky, and have been able to put a couple days in on the Jacobra! God I love the sound of that. Jacobra!!! Here's a few pics of the heat, and ac unit after I tore it out of the dash. "Toasty" The dash removal took about 4 to 6 hours, then another couple hours for the heat, and ac, along with the wiring harness. I'm glad I wasn't the guy at the Jag factory, installing that harness, as it was a major PIA!!! But it's all out. Now to close up the holes. and repair the rust around the trans tunnel as heated metal rusts, much worse then even bare steel. It's quite obvious this thing got damn hot, in several areas as noted by the pictures. You can also see where the wiring burnt. Most of it was on the passenger side of the heat ac unit. I still don't know what kept it from burning to the ground??? All I can figure was they just absolutely flooded it with water, which could also be what attributed to the rusted spots, in the floor boards. Oh well, I've definitely seen worse, and repaired worse. Just thought I'd catch everyone up. Now I've got to weld it all shut.
Jack
Jack
The following users liked this post:
Ezrider (09-02-2019)
#38
#40
Hey Steve, When I bought her a little over 3 years ago. I had no Idea she had burnt under the dash. It had an engine fire. But the dash is perfect, not warped or melted, carpet's ok, no smoke on the windshield. All the telltale signs weren't there. I found no indication it had gone that far. Once I started pulling the interior, and cutting into the firewall area to make room for the 460. I found burnt wires inside the car, and until I pulled the dash and everything yesterday. I wasn't sure of the full extent, of the damage. And yeah it's a little worse then I hoped it was but, that's why I bought a parts car.
Jack