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Triple HD8s on Mark 2

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Triple HD8s on Mark 2 #1
Whitworth Ranch Mark H. California, South, USA 1958 Ford Thames Estate Van 1958 MG Magnette ZB Varitone 1964 Jaguar E-Type 1966 Jaguar Mark 2	Posted: November 20, 2010 08:10PM Registered: 5 years ago Posts: 45

Has anyone here put a set of E-type triple SUs on a Mark 2? Appears that a sheetmetal modification at the front is necessary. Would there be a benefit to going to the straight-port head?

My intake setup is all stock and very sweet running, but whenever I drive my E-type, I think the power would be great fun in a Mark 2.

Mark

Edited 1 time(s). Last edit at 11/20/2010 08:10PM by Whitworth Ranch.

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Re: Triple HD8s on Mark 2 #2
Knud Madsen FÃ¥revejle, Denmark	Posted: March 01, 2011 07:53AM Registered: 2 years ago Posts: 5

You need a straight port top. The pattern of inlet holes is much different. The right top would be such as E-type, 340, 420, MK X 4.2.
You can use a top from a XJ, but be avare of the 2 waterholes in back end of the XJ cyl.head. They must be blocked.
If you can get one from a XJ6 series 3, many of them have bigger inlet valves.
rgds
Knud

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Re: Triple HD8s on Mark 2 #3
Curmudgeon Dave C somewhere, USA 1950 Ford Custom 1950 Ford F-1 "The Ugly Truckling" 1964 Jaguar Mark 2 "Elizabeth"	Posted: October 11, 2011 09:16PM Registered: 1 year ago Posts: 27

I've looked at that on my MK2 and the granddad's Mk1.....I don't know how in the world the back carb would clear the battery. On mine, it's also the brake and clutch masters, and the reservoir about where #1 air cleaner would fit.

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Re: Triple HD8s on Mark 2 #4
Robin Phipson Natal, South Africa 1964 Jaguar Mark 2 "THE OLD GIRL"	Posted: December 09, 2011 02:16AM Registered: 1 year ago Posts: 43

I DO NOT THINK THIS MOD IS WORTH ALL THE TROUBLE. A LHD car is easier to do as there is no clutch master cylinder to get in the way. Even so, the engine bay becomes terribly crowded and things like the distributor become almost impossible to get at. Air filtration is also a major problem and the skinny things people fit reduce the power more than the gain of the 3 carbs. Remember the E had long ram tubes going into the carbs which hugely boosted bottom end torque. The wiper motor, brake fluid bottle and fuel filter will have to be moved to different locations and it is worthwhile putting the battery in the boot.
The E got its performance from a lighter all up weight, lower drag, free flow exhaust, straight port head, electric cooling fan(s) and the air filtration system already mentioned. (And of course the triple inlet manifold and carbs!)
To stay sane the best set up if you want to modify a Mk2 is a Series 3 XJ head and cams, series 1 XJ inlet manifold, free flow 45mm exhausts with standard exhaust manifolds and a pair of SU HIF7 carbs from a late S2 XJ 4.2. These carbs are much more compact than HD8s and flow just about the same amount of air. Being shorter in length allows high flow K+Ns to be fitted without cutting the inner fender. I do not recommend porting the head or inlet manifold, but just smooth out any roughness, put a proper 3 angle cut on the seats and a 2 angle cut on the valves. The seats must not be pocketed!

Comparitive air flows:

HD6: 181 CFM at 1.5" Hg

HIF7: 233

HD8: 269

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Re: Triple HD8s on Mark 2 #5
GT6Steve Steve Smith North Las Vegas, USA 1969 Jaguar E-Type 2+2 1970 Triumph GT6+ (MkII) "##$%%@&*"	Posted: December 27, 2011 03:55PM Registered: 2 years ago Posts: 20

Heresy follows, start going LaLaLa right now if easily offended.

Years ago an Aussie came to the Jag forums. He was extremely knowledgable and extremely opinionated. I often thought he was right.

One of his most provocative claims was that the three SU's were pure marketing and were simply too much carburetor for the E's. He backed his argument up with calcs but was lambasted as a heretic. I still have a lot of his posts on an old hard drive. That said, is there a need for three HD8's on your car??

Steve

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Re: Triple HD8s on Mark 2 #6
Whitworth Ranch Mark H. California, South, USA 1958 Ford Thames Estate Van 1958 MG Magnette ZB Varitone 1964 Jaguar E-Type 1966 Jaguar Mark 2	Posted: March 20, 2012 10:26AM Registered: 5 years ago Posts: 45

I thought it would be cool to have three. There certainly are large implications and the points about E-types needing that intake length are quite true. It would for sure run better than the twin HD6s on there now. But I do have a twin HD8 setup that would be relatively easy to install. Also, a friend of mine has done a of performance building and tuning at his shop--land speed Astons and Jags, racing engines--and he said he got something beyond 300 horsepower on a dyno using twin HD8s.

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Re: Triple HD8s on Mark 2 #7
Curmudgeon Dave C somewhere, USA 1950 Ford Custom 1950 Ford F-1 "The Ugly Truckling" 1964 Jaguar Mark 2 "Elizabeth"	Posted: April 03, 2012 11:16PM Registered: 1 year ago Posts: 27

You ought to try getting power out of a MK2 with twin downdraught Solexes.

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Re: Triple HD8s on Mark 2 #8
Whitworth Ranch Mark H. California, South, USA 1958 Ford Thames Estate Van 1958 MG Magnette ZB Varitone 1964 Jaguar E-Type 1966 Jaguar Mark 2	Posted: April 18, 2012 10:08AM Registered: 5 years ago Posts: 45

Things of beauty, they are...

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Re: Triple HD8s on Mark 2 #9
Curmudgeon Dave C somewhere, USA 1950 Ford Custom 1950 Ford F-1 "The Ugly Truckling" 1964 Jaguar Mark 2 "Elizabeth"	Posted: April 18, 2012 02:42PM Registered: 1 year ago Posts: 27

You mean Solexes?

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