XJ40 ( XJ81 ) 1986 - 1994

So why does the XJ's Bonnet hinge at the front? and other engineering wonders.

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Old 04-06-2012, 11:37 PM
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Default So why does the XJ's Bonnet hinge at the front? and other engineering wonders.

I've worked on cars for over 25 years and am always coming across stuff that makes me wonder, "Who really thought ______ was a good idea?"

Since I purchased my XJ, a few things have made me wonder exactly this and I thought I would throw it out and see what sticks. Nothing to heavy here just some light pondering about English engimineering.

The first being the hood/bonnet being hinged at the front. Who really though this was a good idea? I've worked on/for Volvo for 10+ years and they are number one in doing anything and everything for safety and if that was the reason Volvo would have done it and it just seems to make almost everything a PITA. I mean really guys.

The second is the single windshield wiper. Though it works, almost everyone else uses 2 (Certain MB's come to mind) and 2 is usually better than one.

And Third. Why does it seem they designed the HVAC to not blow a large volume of either hot or cold air out of the center vents? Now its possible something is wrong with my car but the owners manual doesn't address this very well but say the car will heat or cool it self "gently".

Discuss.
 
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Old 04-07-2012, 12:50 AM
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Jaguars are full of mysterious features :-).

I think the forward opening hood and single wiper probably have some sort of [hidden] rationale but are novelty items as much as anything else. Personally, I don't object to either.

In fairness many other makes use a forward opening hood so Jaguar isn't alone, at least.

My Ser III had a great HVAC system but both my XJS and X300 are a bit weak in comparison....despite being much newer designs. Oh, they do the job, yeah, but could use more ooomph in extreme temps...esp when heating is called for.

<shrug>

Sorry I don't have sensible answers. I gave up trying to figure these things out ages ago. Jaguars are just a little quirky in certain respects...sorta like people :-)

Doug
 
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Old 04-07-2012, 02:27 AM
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When arguing with the French about the illogicality of their noun gender I asked why a réfrigérateur was masculine.
Because, of course, replied my French friend, if it was feminine it would be a réfrigératrice.
So, I can safely say the bonnet is hinged at the front so that it opens at the back.
 
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Old 04-07-2012, 03:17 AM
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Rolls Royce also used same hood opening same as Jaguar , may be that was a Brtish thingy but I saw an image in Rolls Royce catalog , Silver Spur . It demonstrated how to protect a front windshield in case of accident the way the hood pops up .
Windshield wiper , only 1 but I like the way it sweeps the windshield , bad point there are insufficient speed settings
A/C is not the strongest point of these cars , I find it pretty archaic too
 
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Old 04-07-2012, 08:10 AM
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MMMMM, many stabs in the back of the head from Mk2, S-Type bonnet pins was a damn good idea, NOT. OK, S2 and S3 pins stabbed the head also, but nothing like those early models, that was a "special" experience indeed.

The single wiper just makes perfect sense, you only got ONE thing to go Bugga-Up, instead of 2.

I do agree also on the a/c air flow issue, it was acceptable on the XJ-S, and I also thought that the newer system would deliver more air, just by being "newer". OK, the cars with pollen filters do lack air flow as those filters do restrict the flow somewhat, but X300 has none that I know of??.
 
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Old 04-07-2012, 09:01 AM
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What baffles me about Jaguar isn't quirky design features so much as decades-long problem areas that could, seemingly, be easily corrected.

HVAC, as mentioned, is one issue. Jaguar has upgraded climate control systems several times over the years and *still* we often hear complaints about weak performance....at least as far forward as the X300 cars. I can see no reason that Jaguar climate control systems of the 90s are not as powerful as those seen on USA cars as far back as the 70s.

Next, idle-quality issues, another very common complaint over a wide variety of Jaguar cars. All three of my Jags have suffered various rough idle issues and I am most assuredly not alone. However, I have owned and driven scores of clapped-out "ordinary" cars from the 80s-90s where the engine is absolutley dead-smooth at idle and has been for years without an iota of repair or fussing to make them that way.

Any others? :-)

Actually I hate to bash Jaguar too much. I still love 'em and I give full credit for the many improvements that *have* been made over the years.

Cheers
DD
 
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Old 04-07-2012, 05:46 PM
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Saab hoods hinged at the front.

It's a safety thing. If the hood latch pops, or the hood is not latched to begin with, the hood will not fly up while in motion. And, in the event of a collision, the hood will tend to ride up the slope of the windshield rather than levering back on rear mounted hinges.

These days, there is also a security aspect. It is almost impossible to jimmy the hood open without a great deal of effort since the latches are inaccessible without going through the fender well.

Single wipers also have their place when you need high tension because there is no arm synchronisation to worry about. On a dual wiper system, if the arm synchro fails at the wrong place, both wiper arms can jam resulting in no wiping ability at all ... just as you pull up to the rear of an 18 wheeler throwing up tons of spray.
 

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Old 04-08-2012, 12:23 AM
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I figured the hood was a "British" thing and somewhat assumed the HVAC was just lack of practice since it doesn't get hot there. Volvo was the same way with their A/C, unless you really played with r12 levels and adjusted the valve the a/c was always a bit lackluster but being from the Arctic Circle you had to forgive them, though my 240's a/c worked the heater would cook you out of the car.

Good to know its not just my car with a crappy a/c.

I really do need to get the windows tinted soon. 20% all the way around and I'm tempted to do the windshield as well, its been getting warm already.
 
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