V12 Jag / Daimler engine questions...

Her's a nearer pic of the engine bay of this car

 

Can you elaborate on the balance tube? Your reasoning and how you did it.

Untame

 

Has anyone found a header set for this engine?

Untame

 

The balance tube is just a 1" tube that connects the two plenums to help even out the intake pulses. I drilled and tapped the bottoms of the dual quad intakes and ran the tube in the valley around the bottom of the distributor.

 

I bought my headers from a guy named Chadbourn Bolles on this forum.

http://forums.jag-lovers.org/

 

Thank you MUCH for the pictures! BTW... I'm also getting ready to fire up a GMC V12 on the stand. Is that one yours?

Thanks, again!

Untame

 

No that GMC V12 is not mine, but I do have two of them. One is in my '50 GMC COE and I have a spare, just didn't have a good picture of the balance tube on mine.

Let me know how the V12 does.

 

Man, that is one clunky forum. I couldn't find any member list. I did try to post a wanted ad for headers, but I'm not sure it went through.

Untame

 

There is usually a delay in the new posts going up . That is mentioned somewhere there. Just go back after 1/2 an hour or so and see if it is up on the board.

 

Chad is the Real Deal.

 

Do you have a picture of your Jag motor with the intake/carbs installed?

Untame

 

Here ya go.

 

Thanks much!

Untame

 

I think i may look into that. the belt setup is driving me nuts trying to figure out how to get it to work.

 

You can also simplify the belts. You only need 2. Deep six the idler pulley and the air pump. Drive the alternator off one belt and the p/s off the other one. Mount the alternator where the aor pump was (needs to be offset a little) and replace the GM a/c compressor with a Sanden up in the vee.

For a cleaner look, mount the Sanden down on the lower right (instead of the alternator) and put the alt up in the vee.

Run an electric fan, too, obviously.

 

Jaguar V12's unlike most V8's Some 6 cylinders and a lot of 4 cylinder engines do not benefit from headers.. (It has to do with firing order, ask and I'll explain it but it's plenty boring)
Bottom line unless you have space for 12 primary pipes that are 31 inches long and collector pipes that are 20 inches long you don't have real headers, you have tubular exhaust manifolds..

The stock exhaust manifolds are not restrictive and really not as heavy as 12 pieces of 31 inch long primaries are.. In addition they are block huger type so you won't find a much more compact way to deal with exhaust.

 

OK I'd love to help.. I've probably built more Jaguar V12 engines than most people outside the factory.. a lot of them stone stock but many have been race motors so I know what makes horsepower and what is a waste of money..
First it's a remarkable motor.. All aluminum and will dazzle anyone who chooses to polish it.. If you take one apart (no metric wrenches needed) you'll be in absolute awe of it.. massive forged hardened crankshaft. Connecting rods are pretty well state of the art and good for 8000 RPM and 500+ horsepower.. The cylinders have replaceable sleeves so just press out the old sleeves and replace them with new ones or push them out and chuck them into a lathe or vertical mill to bore them out.. Actually I can't recall an engine with any wear on the bore.

It has a bad reputation because few people bother to read the owners manual.. (too many were owned by poseurs) change the oil regularly, replace the antifreeze with fresh anti freeze every 2 years (it's all aluminum) and follow the owners manual.. For example at every oil change you remove the distributor cap, lift the rotor and put a drop or two of oil inside. 95% of the distributors I work on are frozen stuck because that wasn't followed..

Do those simple things and 300,000 miles is possible.. then you can rebuild it in your garage without sending the block out to be bored..

Jaguar built the V12 from 1971 through 1996 (well actually they stopped making the motors in 1994 but had enough stored up to last through 1996) The first ones from 1971 to 1980 are the best ones to modify to go racing..
From 1971-1975 they were carburated with some really great carbs. (that are sadly misunderstood but really simple to work on) from 1975 to end of production they built fuel injection using the same basic manifold that flows 1200 CFM (on only a little 326 or 366 cubic inch engine)

Here's the good news, the earliest V12 had 9.0-1 compression ratio but that was dropped late in 1972 down to 7.8 -1 compression.
The early ones were all choked down to meet emission laws made less than 250 Horsepower but more torque than a 454 Chevy did at that time..

There is at least 50 extra horsepower in the stock manifold if you simply eliminate the dog leg (ask how) Fuel injected ones made about 300 horsepower and still an awesome amount of torque..

From 1981 on the compression went up to 11.5-1 but the heads wern't as good.. horsepower stayed right around the same until about 1992 when Jaguar brought out the 6.0 litre instead of the 5.3 then the added stroke (same bore) made another 25 horsepower.

So what works and what isn't worth the money.. Headers are a waste of money.. they don't really add power to a V12 unless they are custom designed specifically for a given camshaft.

Cams! The stock cams will rev up to 7850 RPM without the valves floating. aftermarket camshafts don't add any real power.. all they do is take power from lower RPM and add it up above 5000 rpm.. Isky sells reground cams for the V12 and a common set of cams cost 9 horsepower at lower RPM but add 16 horsepower above 5500 rpm.. Piper sells new billet camshafts but plan on reving +8000 rpm to use them to gain power..

Pistons.. That's where there is some real horsepower to be gained.. stock is probably 7.8-1 compression increase it to 10.0 or higher compression and there is some real power to be gained.. (but you'll need good high octane gas)
For racing purposes the heads can be worked on fairly easily and not cost a great deal to make some extra horsepower.. 500+ horsepower is available normally aspirated and will cost you less than building that much power from a small Block Chevrolet.. (Plus the V12 will simply out torque the small block..

Fuel Injection! the early fuel injection had the biggest injectors, later ones got smaller and smaller injectors.. The stock computer isn't easy to modify.. Many will buy a Megasquirt computer (start about $400.00) in order to have ease of adjustment.. It doesn't make any additional power by itself but it makes modified engines easy to adjust..

You can take a stone stock early fuel injected ones. Put two turbo's from used Saabs/Volvo's with the intercoolers and make 500 horsepower for about $300 in parts over the cost of the engine.


Transmission.. from 1971 through1974 some were built with a 4 speed manual gearbox.. the rest had, I'm sorry..... A cast Iron Borg Warner, Yep the old Studebaker tranny.. They stuck with that miserable piece until 177 when they switched over to the GM turbo Hydro 400 But not just any one.. the real heavy duty one used in ambulances and tow trucks.. (with a case designed for the Jag).. So a shift kit will work just fine!! Later (about 1992) they switched to the GM 4 speed overdrive.

A common update is to put a T5 manual gearbox (or the T56) but that starts getting expensive if all you want to do is write a check.. I've adapted my own manual gearboxes and it's not all that hard to do..

 

That's wrong!
first they don't have lifters, pushrods, or rocker arms. Just a camshaft operating the valves.. (SOHC)

Second all you have to do is take your shoes and sox off and V8 guys can count all the way to 12!!!!!!!

 

He'd better have some really small Holley's or Edelbroks.. The engine is only 326 cubic inches.

Yes the Factory runs 800 CFM carbuartors but that's because the factory uses Stromberg carbs.. Stromberg (and SU carbs) are what is known as variable venturi carbs.. They get bigger as needed and smaller when not needed..


A pair of Holley's would be what 600CFM? or maybe you'll buy the really spendy 450CFM ones.. so you're trying to get a little 326 cubic inch engine to run on 900-1200 CFM ? Good luck!!!

 

Too bad you didn't find someone to help you.. It's a Borg Warner not a Ford.
Second because the Jaguar uses shims you seldom (if ever) need to adjust them.. GM bought this basic system when they bought the Jaguar engine and put it in the Chev Trail Blazer, GMC Envoy and Buick,,..... whatever I forget what Buick named their version.

I have that engine in my Envoy with 140,000 miles and nary a tic from it..
Now if you overheated the engine because you used water instead of anti freeze or otherwise neglected the poor thing yes you could have overheating problems.. That will cause the valves to go out of adjustment but instead of adjusting the valves you needed to install new valve seats..
Once someone shows you how simple valve adjustment is all your frustration would go away..

Yes the first time I did it on my own it took me a long time to do right then I read the manual and the next time was a whole lot easier..

 

Amen!!!

I buy used Junkyard parts for most things.. Most of these cars were owned by poseurs who neglected the maintenance they were then sold to someone at a cheap price but needing work.. I can't tell you how many horror stories I hear because people are afraid of spending too much money fixing these.. They're sold a valve job when the only real problem is no-one oiled the distributor and it has no advance. Or the car won't run after hitting a pot hole.. (there is a little white button under the dash that automatically resets the impact sensor that shuts off the fuel injection in the event of a crash)..

All sorts of those "problems" occur because the owners manual is unread..

I have a 1975 Jaguar XJ-S that's a really nice car.. real low miles on it.. owned by the head of the Jaguar club's local chapter.. 30 years ago it went to a garage to be fixed.. They couldn't get running right.. eventually they went out of business and the landlord seized the car for back payment.. He tried to fix it him self and gave up. It eventually wound up in a junkyard where it sat for over 15 years with a part here and there taken from it but still a really good rust free car..

It took me three hours to get it running perfectly.. just a loose wire, some rotted vacuum hoses, and seized distributor..
Knowledge is power..

 

Oh, how wrong it is to be ignorant.. Last E types were made in 1975.
$60,000?? wow someone saw him coming..

By the way the rear end in a Jaguar is the same rear end used in 427 Cobra's (both real and kit cars) easily will handle 600 HP.
They are really simple basic motors once you take your shoes and sox off to count to 12
There are complete kits available to bolt a 5 or 6 speed into Jaguars. With new transmission they sell for about $5500

Expensive? I never pay very much for complete running ones even less for non-runners..

Others here have told you they can get them for $200 to as little as $50.. usually with transmissions..
Over heating? Nah! It happens for the following reasons starting with most common..

Low or out of antifreeze.. OK the British don't know how to make anything out of rubber that lasts.. so how hard is it to fit American hoses in? (Not very) I've gone to silicone hoses because I only like to do it once..

Not properly filled in the first place.. Yep. it gets air pockets in it.

Trash or leaves etc. between the radiator and the A/C unit

Old anti freeze, it's aluminum change it every other year!!

Distributor frozen up because the two drops of oil you're supposed to put in the distributor with every oil change wasn't done.. (remove distributor cap lift off rotor loosen screw underneath and put two drops of oil in) but it's too late now. You'll need to pull the distributor and take it apart polish the shaft that's supposed to get oil and put them all back together.. don't forget to oil it though..

Once in a blue moon the thermostat might seize up although it is possible to install a thermostat that looks right and will cause plenty of overheating issues..
It sounds to me like the owner spent way too much money because the mechanic was either dishonest or didn't know what he was doing.. At $60,000 I'd assume the former..

 

You're absolutely correct! the British never did figure out how to make rubber parts..

However leaking fuel on the early fuel injected cars was very common and not just with Jaguars.. They are so common in California they are called a Car-b-Que. I had a S10 Blazer that blazed. Melted the aluminum rims and nearly everything else.. only thing left was badly warped sheet metal

 

Ok I am interested - I have a 1989 XJS V12 with Marelli ignition. It is currently being rebuilt starting with the suspension and rust removal.

Will get to the engine and power department next.

 

When they are bad they are very bad...but when they are good, they are amazing...when setup and maintained by someone who knows what they are doing. Set up right, the smoothest power I've seen.

This is not a power plant for most DIYers. If you are going to use it, find a Jag V12 maestro

 

OK don't rebuild the engine!! not unless it's either been badly overheated or has over 200,000 miles..
You're wasting your money! If it's been sitting for a while get it started and running replace all the rubber hoses, then do a basic tune up. (Don't forget to oil the distributor) Now drive it a bit, a couple of tanks of fuel at least.. in each nearly full tank dump a gallon of denatured alcohol. Then do a leak down.. If they don't have a leak down gauge don't let them touch the motor.. if no cylinder leaks above 10% don't do a rebuild..
If some do leak more than 10% ask them what's leaking..
A leak down test tells you that.. If the rings are leaking you'll hear air escaping from the oil filler.. if the intake valves are leaking you'll hear it in the air cleaner (Most common, caused by too slow of driving at too conservative a pace, do an Italian tune up and then retest{an Italian tune up is to rev the engine up to redline under load a few times}) That's where the denatured alcohol comes in.. What's happened is too much slow driving has caused fuel to build up on the intake valve stem, denatured alcohol will help clean those valve stems.
If you hear air coming out the tailpipe you know an exhaust valve has an issue.
It's possible to have all three or two of the three or only one.. but extremely rare..

 

OK I know more than most mechanics about the V12 Jaguar but I'm darn sure not a Maestro. In fact the engine is really simple once you get over your fear of it and start thinking the basics..
As far as a Hot Rod engine?

I honestly can't imagine anything finer.. Stick that torquey V12 in a light hotrod devoid of all the nonsense the poseurs seek. Polish the auminum up until you go blind just looking at it and for a few hundred dollars you can have what would otherwise cost you tens of thousands..

You'll be welcome at Jaguar events, hot rod event, car shows and darn near anyplace where you'd go..


OK Webers are really cool looking but they don't make the most horsepower. Plus they need someone who speaks Weber and knows how to select the right chokes, air correction jets, etc.etc. etc. I had more than $1000 at wholesale prices in my carb box and could only adjust for some conditions.. I know racers with $5000 worth of chokes, jets, etc.. in their box.. By the way when the Italians say chokes they are taking about venturi sizes.. which is changeable on Webers and you don't need to take them apart to replace.. In fact that's the really cool thing about Webers. You can change so many things on a Weber and never take them off the manifold or use up a gasket..

You can make just as much power with the fuel injection or if you'd like the early side draft carbs..

 

Veering way off O/T: Actually not so - the genuine factory Mk III Cobra IRS uses upper A arms, sliding half shafts with U joints and outboard disc brakes. This is nothing like the Jag IRS. The Pantera borrowed heavily from the original Klaus Arntz designed rear suspension....

 

There is at least 50 extra horsepower in the stock manifold if you simply eliminate the dog leg (ask how) Fuel injected ones made about 300 horsepower and still an awesome amount of torque..

I am interested in where you can get 50hp from the manifold?