V12 Jag / Daimler engine questions...

hello all the will be my first post on the forum. i just purchased a 87 he with trans for 50 bones. I plan to install it in my 49 dodge coronet (it's actaully a dodge custom cdn built). I want to run a three two barrel setup or something similar. On the off chance that this will impossible has anyone tried a Mega squirt setup for fuelly? or does someone out there have a fuelly harness i have the ECU.


thanks in advance
levi

 

I did a Megasquirt on a HE V12 once but in the end it was not really worth it. You can clean up a lot on the stock Jag EFI. You only need 1 fuel pressure regulator, not two. I also removed the AIR tubes, sealing the holes in the intake with 1" nail anchors and the stock air tube orings. Then I split the fuel rail and mounted it where each air rail was. Now you have 12 short and symmetrical rubber hoses going to the injectors, and it looks mint.

Jag wires the injectors in four sets of three. You can rewire the triplets so that you can hide the wires underneath and without criss-crossing over the motor.

Then, you relocate the alternator to the top of the vee. A/C compressor goes where the alternator/air pump used to be. Air pump goes into the dumpster.

Next you get rid of the idler pulleys as you want an electric fan or 2 anyway.

Get rid of the speed control.

Drill lightening holes in the throttle tower to make it look cool and also make it easier to access in the vee.

Run your plug wires really really neatly.

You end up with a pretty open vee and a nice look to the motor. You can hide or streamline just about everything atop the motor. Thermotime switch, vacuum delay switches; everything gets the heave-ho.

And it works. Quite well.

Given the dizzy in the valley and the plugs on the inside of the heads, a three-two manifold is not going to look good.

You could pick up multiple SU manifolds from an early, pre-HE motor.

Make sure you install slightly stouter springs under that 49, and a good anitroll bar, and relo the upper shock mounts to the frame. Or, just swap in a Jag IFS and for that matter, the Jag IRS, cage and all. That would be one kick-ass, fast, and smooth handling 49 Dodge.

 

all i know from my past is that they are my least favorite clyinder head in the world to rebuild.. make that anything jag. they do have a habbit of dropping seats if overheated too. also if you really want to put some money into it you can (with some welding required get 2 6 cyl jag heads and get them to mate up and work on a v12 resulting in a quad cam v12.
my 2 cents would be very expensive on the rebuild and depending on the car can look like too much motor for the car (ruin proportions)
also they are english which doesnt rate in my oppinion

 

plym 49 would you happen to have a pin out diagram for the stock ECU? i have an ECU but the guy hacked to engine out of the car.

 

also curious if running 2 2bbls mounted on the stock efi intakes. i would have to machine a mount on top of the intake, but that isnt a problem . any idea's?

 

That is a Jag urban legend. If you use the XJ motor heads there is not enough room inside the vee and the motor is top-heavy as all get-out. The factory did this once for the XJ13 but with special castings to make the angles work. If you were to try the AJ6 heads, cutting one and flipping it back to front, you run into other problems.

The fact is that no one can point to anyone who has ever done this except perhaps a one-off somewhere as a science experiment. You can read all about these urban legends on the various Jag forums.

The dropped seat problem was due to the factory listing and using an incorrect spec for the seat inserts. They were a little too loose. If you really cook your V12, crank it over on the starter for a second every 5 minutes until temperatures come down as the dropped seats are caused by a closed valve seizing to the seat under severely overheating conditions. Then the motor cools and you crank the motor and you drop a seat. This is really the only circumstance you can drop a seat, and hopefully gearheads like us would not permit their motor to overheat to that extent. Re-builders commonly use standard clearances for the seats, and then even that problem goes away

You are correct that the Jag V12 HE motor is limited in breathing by the May heads. That's just what it is. Do you remember in an earlier reply I posted pix of my friend's twin-Whipple supercharged HE motor? That car made a good deal of power.

These are very good motors. Not the best, certainly not in the breathing department, but in the strength area they are pretty darn good. I agree that you can make more HP more inexpensively with a BBC. However, there is nothing like a 12 and these motors are the most affordable 12 cylinder motors out there.

 

I don't have one handy any more but suggest you download the Kirby Palm book as it might be in there. Also check Roger Bywater's AJ6 engineering site as he might have one there. He sells exchange ECUs with modest performance upgrades that improve midrange power.

 

Run, Run, Run away!! Great motor if your a rich tinkerer. Start with 20,000 for a rebuild and Ad 5000.00 for every upgrade. And once it's a high performance motor it will get real cranky. And your mechanic will own your house to keep it running and not over heating.

A shop I worked in did a 1976 ( I think ) E-Type Jag. that a customer wanted worked up and a 6 speed transmission. The Engine Tech got it done ($60,000 Engine, Tranny, suspension and rear end upgrade.) Car was a rocket and worked but would over heat in traffic and was forever being tinkered with to keep it in tune.

Like I said, Run, Run, Run away. Aluminum scrap price is up!!!

The Old Tinbasher

 

Disagree. First of all these motors usually don't need rebuilds. The lower end is bulletproof - the crank is so hard it is tough to regrind it - good thing you never need to do that. Pistons/liners/rings also last a long time. There is no way you would spend 20K rebuilding one unless maybe you were paying list to have the dealer do it for you.

There is no reason for these motors overheat, or cost 60K for a total package. Well, of course there are folks willing to pay a lot for almost anything.

 

Tom Walkinshaw could make these v12 Jags sing.

 

I have/drive a '77 Jag, XJ6C Coupe, and an '88 Jag, Hess and Eisenhart XJ12 Convertible. Both cars run like watches. They do NOT have exotic, poorly engineered engines. When I bought the V-12 I knew absolutely nothing about an injected 12 cylinder Jag engine..other than when you opened the hood, it was packed solid with stuff I had no idea did what. Couldn't even see where the spark plug wires went. When I got a price on a tune-up of $1,500 plus parts, I educated myself in a big hurry. 10 hours later, it was done and ran like new. While I was in there, I tore down the distributor, and fixed the sticking (not quite siezed) centrifugal advance, which cured the slight running real warm problem. Sent the fuel rail/injecters out to a guy that cleaned/rebuilt/balanced them and that was the icing on the cake. So smooth at a stop light, you'd think it stalled. All told, about $300, plus my labor. As for the I-6 carbureted engine in the Coupe, although it too is put together different than "good 'ol American iron", when you get down to it it's just an engine. Neither the V-12 or the I-6 is anything that's other worldly in opinion...nothing any self respecting Hot Rodder can't fix/work on. In MY opinion they're both very well engineered engines...just not what we're use to working on.

 

well i got the engine today. looked at it pretty good i think i can machine out the stock efi intake manifolds and install 4 1 bbl carbs. now if that will work i don't know.

 

Wait a minute. Is that an HE engine? If so, I don't know if anyone has gotten one to run with carbs. High compression, lean-burn. Perhaps check the Jag forums to see if anyone has successfully run an HE on carbs.

I used to wonder if a plain-vanilla GM V6 EFI assembly could not fire those 12 injectors. Anyone could burn you a chip. I never got as far to see if the GM ECU would drive twice as many injectors or if an in-between driver circuit would need to be added.

 

i suppose it could, all you would to do is spec out the output transistors for the fuel injectors if they won't hold enough current replace them with units that will. i was hoping that by running 4 carbs that i could tune the engine a lil better also i could stack head gaskets if i had to , to lower compression.

 

I'm thinking that they better be reeeal big 1-bbl. Why not Webers?

.

 

It'll end up being a pretty expensive "free engine"!

 

I don't understand your comment-I'm under the impression that mistresses ARE dangerous and expensive. Mine was.

 

the engine is only 326 ci 500 - 600 cfm worth of carburetion is all you need. webers are too expensive for me.

 

As far as I can work out 1 computer isn't up to it. But 2 computers definitely are, and they are sooo cheap that you might as well
http://www.kalmaker.com.au/page2.html

 

I ran an XJ12C for a couple of years, It had, without a doubt, the finest running engine I have ever owned (when it was running). But one time I stopped the car and found the "V" full of raw fuel (from a leaky injector hose) I knew it was time to move it on. Back in the late 70 and early 80s, you would see a lot of V12 cars with burned hoods for this reason.

That said, once you get one of these motors dialed in, you will be very impressed with the smoothness and power surge. I loved the way it would move a 2 ton car down the road...

Good luck!

 

engine is cool ! might look neat with some trick looking, through the hood, air cleaners. I have a GMC v12 that i've been looking for a car to stuff it in.If you think the jag is big take a look at one of them.

 

That's not gonna work. Stick with the EFI, it's easier.

 

Yes until you fogure out that you need twice as many sensors, too. No easy way to multiplex them. Much easier to set up a driver for twice as many injectors. Given the advances we have seen in injector design in the last 20 years, I would not be surprised if you could not find 12 new ones that draw the same current as 6 old ones. Also remember that the Jag has ballast resistors in the mix - I would not doubt that you could not find a way for a modern 6 cylinder setup to fire 12. Heck if it is not a sequential EFI then you could use a V8 setup to fire 12, right?

 

-------------------
Actually, not quite true. The TH400 used by
Jaguar had a the so-called "GM universal
case" that originally was used for Buick
nailhead applications. After GM dropped the
nailhead engine, they offered the TH400 with
nailhead case pattern to several other non-GM
manufactures who used it - with or without
an adapter plate - to fit their various engines.
Besides Daimler and Jag, among others, the
"universal case" TH400 was used by Jeep
(with the 225 Buick V6 and and the 327 AMC
V8) and Rolls Royce with their own V8s.

Mart3406
--------------------
P.S. Here's an 'oddball' use for a Jag V12!
www.corvaircorsa.com/V-12-01.html
==========================

 

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-----------------------
If you want to stay with EFI and are willing to
build your own controller, the D.I.Y. 'Megasquirt'
unit can handle 12 cylinders.

Mart3406
============================

 

Interesting, I had never heard that. That certainly should make it easy for a nailhead owner to put a TH400 in their rod, since the Jag flavor of the TH400s can usually be gotten for free. Does this mean you can also put a Dynaflow behind your V12?

One thing I do know is that the dowel pins on the Jag V12 are in the exact same spot as the dowel pins on a Chevy, although the diameter is different.

How does this GM 'universal case' scenario map to the ability to use certain E-Type components to use Jag parts to put a manual behind the V12? Did every Jag V12 use the same bolt pattern? Did they not use Borg-warner autos in the early days?

 

yeah I've decided tonight that fuelly is the only way to go now i just have to figure out if the stock computer or megasquirt is for my project.

 

plym49 provide a link to Mr Eitel's Jag powered Corvair.Mr Eitel also has built a mid engined V8-60 powered roadster styled somewhat afterr the '40 Ford. Mr Eitel is in his mid-80s or above!

 

---------------------
I built a megasquirt controller - and
then fabbed the rest of the f.I. system
from mostly boneyard-sourced bits and
pieces - for a buddy's homebrew
'2.3 turbo-EFI-Pinto' engine build and it
worked and ran great. (420hp@5000rpm
on 20 lbs. boost from a 144 cubic inch
4-banger - and still very street drivable
too!) The nice thing about the megasquirt,
besides it being very low cost, is that there
are a lot of them out there and a lot of guys
building and running them - on just about
anything you can think of too - so there's a
fairly huge online support network for them.
Any problems in building, setting up, running
or tuning a megasquirt system and the solution
is usually only a couple of mouse clicks away.
If your Jag still has most or all of the OEM F.I
system intact, you're already way ahead of
the game for doing a conversion too, as most
of your existing parts will be usable with a
megasquirt system.

Mart3406
==================

 

well i have a small side problem here no one that i can find online sells gaskets for this engine anybody here that can help a brother out ?