XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

The Build "89 Jacobra"

 
  #21  
Old 12-06-2018, 09:42 PM
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Originally Posted by icsamerica View Post
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.
"Oh ye of little Faith". I've only begun, there is a lot of stuff to be addressed. I first have to make it fit. Then I will set about the task of restructuring the inner fenders, and firewall area. The areas cut open were simply dead space, so once closed back in, the structure will be nearly as strong, and with some additional bracing. It will be more then strong enough. Have a look at my trans mount, and crossmember, it's one heck of a lot tougher, then the pogo stick thing Jaguar made. I believe in overbuilding things, since I'm just as libel to throw it into a curve at 100 MPH, as I 'am to run 55, (sucks) So follow along, and you'll see I do know what I'm doing, and even though the fit, and finish isn't going to be "Show Car" worthy. I stated early on, I'm building a Hot Rod! not a show car!

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
 
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Greg in France (12-07-2018)
  #22  
Old 12-06-2018, 10:34 PM
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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
 
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Greg in France (12-07-2018)
  #23  
Old 12-07-2018, 12:09 AM
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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.
 
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  #24  
Old 12-07-2018, 11:26 PM
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Originally Posted by Ezrider View Post
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.
I have considered shortening the oil pan and extend it sideways, as you suggest. Just haven't got that far. The sub frame hasn't been touched, the big bulge that was part of the foot well is what's gone. It was just a bulge of metal, not sure what it was all about, becasue it didn't hurt the footwell size a bit? I'm gonna try to add a picture showing what it looked like before I removed it. The bubbles are behind the fiber heat shielding. and you can't see them very well, but the frame rail was not cut. what is cut is where the floor pan meets the frame rail it's also where the bubble attached. But yes I intend to add some bracing in that area as well.

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  
Old 12-08-2018, 12:33 AM
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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  
Old 12-08-2018, 01:47 PM
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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
 
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Old 01-13-2019, 10:11 PM
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Another update, I've pretty much finished the basic construction on my headers. A lot of cleanup trimming and finish welding yet to do to them. I hope the pictures come through this time as they will explain a lot.

Jack


 
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  #28  
Old 01-14-2019, 07:42 PM
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looks like a good start.
 
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Old 01-14-2019, 09:42 PM
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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.
 
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Old 01-15-2019, 01:05 AM
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yeah that's a lot of work getting everything all fitted up,header wrap will probably be a good idea, even my 2.5" rams horns put off a lot of heat. looks like your getting a lot of the big items checked off the list now.
 
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Old 01-15-2019, 03:25 AM
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Just be careful with header wrap, if its fibreglass wear some good gloves! Take it from me it cab become very uncomfortable!!
 
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  #32  
Old 01-15-2019, 05:10 PM
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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
 
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Old 01-16-2019, 01:38 AM
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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.
 
  #34  
Old 01-18-2019, 10:06 PM
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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
 
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Old 02-09-2019, 06:21 PM
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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





 
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Don B (02-11-2019)
  #36  
Old 03-03-2019, 06:04 PM
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Well I got my header wrap. Any ideas on keeping it tight? So it doesn't end up, wadded up, at the bottom of the pipe? Thanks in advance.

Jack
 
 

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