Anybody ever handle an XJS-12 HE before? - Page 3 - PeachParts Mercedes-Benz Forum

Dee8go · #31 12-27-2011, 12:34 PM

Powerpig has one of those. He also has a Rolls and a Ferrari . . . Why anyone would want all of that to keep running is beyond me. I think his XJS is even the same color as the one in your pictures.

Solid Snake · #32 12-27-2011, 02:30 PM

Quote:

Originally Posted by alabbasi

And here he is , late as usual

I'm not sure how I stumbled across this but if you're considering one of this (sometime in the future I guess), here's my 2 cents.

The Jaguar V12 is probably the most reliable V12 ever and definitely the most common. If you've never driven one, then expect to be impressed, the engine is silky smooth. I'm not sure what the US spec H.E models were like but the European models made about 300hp, had a 12.5:1 compression ratio and would rev past 6000 RPM.

These cars were very fast in their day but these days, well your average mid size gets about 300hp so while they are still very fast, they're not as impressive on paper when compared to what you can get from a mid size with a v6. But neither is a 560SEL or a 6.9 for that matter.

People who own them love them, but I've heard the term mistress used quite often buy people that own them. You can't neglect them and expect for them to give you worry free motoring as they have some design "features" that will bite you if you're not careful.

The two most important being.

1) You can't let this car overheat. Even if it gets a fraction over normal, you need to be very concerned as they are alloy engines with pressed in valve seats. Overheating could cause them to drop and ruin an engine.

2) Unlike a V8, the fuel injectors are on the same side as the spark plugs (directly above them on the inside of the V). If you neglect to replace your injector hoses, a leak will pour gas inside the V and cause the engine to catch fire.

3) Another common fire hazard is that caused by the Italian distributor, it could fail on one cylinder which is almost undetectable which could cause raw fuel to get dumped into the catalytic converter and also result in a fire.

Aside from this, the rest of the car is pretty straight forward with the exception of the rear brakes which are inboard up until 1993-1994. Pads can be done quite easily but if the calipers need doing, you should expect to have to drop the rear end.

Transmission is a TH400. A common conversion is a GM700R4 which adds a 4th gear and there is a manual 6 speed conversion available which is said to turn this car it a beast.

The car you looked at seemed to have had all the right things done to it in order for it to be a reliable car. I hope you got a test drive

The car has been moved to storage, but it's still for sale; if they're worth the test drive I may go do it

My main thing is whether or not it's DIY friendly. The M117 may be intimidating to look at, and everything isn't easily accessible

but it is a joy to work on because of how well designed things are. I've basically got my engine down pat; I'm saving the motor mounts for this February when I have to take the engine out for my euro manifolds, and then that's it; just preventative now, thank goodness.

I hear obviously that Jags aren't the most dependable drivers, and while my 560 costs a lot parts wise, they last and don't cause issues past that point. The Jaguar intimidated me in that sense, even though the svelte body was very attractive (like a hot woman who had mental issues

).

The 6 speed sounds ridiculous. I kinda want it even more now...

Power wise, while not exorbitant like it once was, not really an issue. Just like you said, the 560 and the likes are at about what a good midrange car affords you nowadays, at least until I defederalize

Gas economy also like you said isn't that big a deal, my 560 actually isn't that bad. 18 mixed seems pretty good from what I read.

Definitely calling him to set up a test drive now if it's something I should experience.

alabbasi · #33 12-27-2011, 06:56 PM

Once you get past how cramped the engine bay is, the car is DIY friendly. As a matter of fact, a buddy of mine and I just replaced the drive shaft center support on my 77 XJ12C (basically the same setup).

The transmission is a TH400 so anyone can rebuild it for about $600 including R&R. Like I said, the tricky part is the rear brake caliper which if ever needing changing, drop the rear end and replace everything all at once while you have down. Then you won't have to worry about anything for some time.

The other big jag problem is electrics. Electrical connections can corrode, removing them and cleaning with contact cleaner usually sorts these problems out.

A/C compressor is basic GM-A6 and parts are actually quite affordable.

This one looks like it's been well maintained so it's well worth checking out.

Fulcrum525 · #34 12-27-2011, 07:55 PM

Quote:

Originally Posted by alabbasi

The other big jag problem is electrics. Electrical connections can corrode, removing them and cleaning with contact cleaner usually sorts these problems out.

I can assure you that this is definitely one area where Solid Snake has a good amount of experience

alabbasi · #35 12-27-2011, 07:56 PM

Quote:

Originally Posted by Fulcrum525

I can assure you that this is definitely one area where Solid Snake has a good amount of experience

Well it should be right up his street

chasinthesun · #36 12-28-2011, 11:31 AM

The jaguar team ran these in can -am races back in the day, you just had to push the peddle down on the straights .In high school I took a ride in one ,that was real horsepower under the bonnet ,the felling of 120mph was smooth and could have reached more with little effort.It wasnt fun after his dad found the car out of the garage ,I skated out of their pretty quick.

alabbasi · #37 12-28-2011, 11:48 AM

Check this out: Bathurst 1985 TWR Jaguar XJ-S V12 in-car racecam lap - YouTube

elchivito · #38 12-28-2011, 12:55 PM

How many bales of hay could I get in to one of those?

spdrun · #39 12-28-2011, 12:58 PM

Does HE stand for "high explosive?" i.e. "engine WILL blow up"

alabbasi · #40 12-29-2011, 01:12 AM

Quote:

Originally Posted by spdrun

Does HE stand for "high explosive?" i.e. "engine WILL blow up"

No

cmac2012 · #41 12-29-2011, 06:08 AM

Quote:

Originally Posted by alabbasi

Yep, it's an effort to do the calipers, but the setup has been around since the E-type and when you think about how advanced it is when compared to the swing axles that MB used at the time, it is quite impressive.

I have to do the real calipers on my 75 XJ12C. I'm not looking forward to it.

FYI, there are LOTS of MB owners that also own Jaguars. For some reason they seem to be more active , or at least open about it on the Jaguar forums.

Yikes, that is scary looking. What, you have to deal with that so you can have a little less unsprung weight? No wait, more unsprung weight. Or something like that.

cmac2012 · #42 12-29-2011, 01:26 PM

I'll tell you a wild story regarding that ^ ^ axle. A friend of my father's put one in the rear of a '56 Ford pickup (!?) as he was so impressed with the idea of not having the brakes as part of the sprung weight. He was a good ol' boy but must have had a bit too much time on his hands.

I couldn't tell you how it turned out, unfortunately.