Jensen Interceptor Diesel

[roscobbc]

Diesels whilst undeniably efficient in terms of mpg and performance have such a totally 'flat' torque curve and are sooooooooooooooooo boring to drive compared with a petrol V8 which like all petrol engines (and especially two valve per cylinder petrol engines) have lovelly peaky torque curves which make driving so much more fun! My own daily driver 1 series diesel auto had 8 speeds - and really needs 7 of them with the typically short rev range of most diesels.

[jaisharma]

Why go diesel. Surely a 2cv twin would fit and would give the same performance when parked?
There will be a slight loss in performance when driving, granted but I'm sure the improved economy will compensate.
Joking apart, it is the worst idea I have heard this week

[Yertis]

SV8Predator said:

You've obviously never driven an Interceptor, have you?

Thus you plainly don't understand the appeal.

Yet you seem to think that your opinion is valid?

Of course I think my opinion is valid, otherwise I wouldn't have posted it. I drive a big-ish V8 about 20,000 miles a year, though not in an Interceptor, so I think I'm reasonably well qualified to understand the appeal.

As it happens, I personally wouldn't advocate putting a diesel in an Interceptor, but that's not to say the idea (not mine by the way) has no merit, and is not worth exploring.

[XJ Flyer]

roscobbc said:

Diesels whilst undeniably efficient in terms of mpg and performance have such a totally 'flat' torque curve and are sooooooooooooooooo boring to drive compared with a petrol V8 which like all petrol engines (and especially two valve per cylinder petrol engines) have lovelly peaky torque curves which make driving so much more fun! My own daily driver 1 series diesel auto had 8 speeds - and really needs 7 of them with the typically short rev range of most diesels.

In the case of a proper well specced large capacity petrol V8 it's actually the 'combination' of a flat diesel like torque curve in addition to being able to sustain more torque higher up the engine speed range which makes the big petrol engine more fun.Some figures to prove the point.

www.youtube.com/watch?v=0zkOjsxJk1A

2.07

Edited by XJ Flyer on Wednesday 23 April 02:01

[roscobbc]

XJ Flyer said:

In the case of a proper well specced large capacity petrol V8 it's actually the 'combination' of a flat diesel like torque curve in addition to being able to sustain it much higher up the engine speed range which makes the big petrol engine more fun.Some figures to prove the point.

www.youtube.com/watch?v=0zkOjsxJk1A

2.07

Agreed - my 489 BBC engine develops 528 bhp @ 5800 rpm. Real story though is torque of 565 ft/lbs @ 3800 rpm. Even @ 2500 rpm (lowest rpm dyno can be calibrated from) it develops 460 ft/lbs. Will still comfortably rev way past 6000 rpm if needed - something a diesel will never be capable of. The difference will always be petrol engines with total usable rev bands of, say 4 to 5 thousand rpm. Diesels with rev band of 3 to 4 thousand rpm at best (say, Honda diesel), in some cases much less.

[XJ Flyer]

roscobbc said:

XJ Flyer said:

In the case of a proper well specced large capacity petrol V8 it's actually the 'combination' of a flat diesel like torque curve in addition to being able to sustain it much higher up the engine speed range which makes the big petrol engine more fun.Some figures to prove the point.

www.youtube.com/watch?v=0zkOjsxJk1A

2.07

Agreed - my 489 BBC engine develops 528 bhp @ 5800 rpm. Real story though is torque of 565 ft/lbs @ 3800 rpm. Even @ 2500 rpm (lowest rpm dyno can be calibrated from) it develops 460 ft/lbs. Will still comfortably rev way past 6000 rpm if needed - something a diesel will never be capable of. The difference will always be petrol engines with total usable rev bands of, say 4 to 5 thousand rpm. Diesels with rev band of 3 to 4 thousand rpm at best (say, Honda diesel), in some cases much less.

The big torque/power large capacity naturally aspirated petrol idea will increasingly become a dying breed over time which is why it's so important to try to convince people not to butcher the surviving classics built to that formula by putting diesels in them.As opposed to adding to the advantage of that big petrol engine formula with capacity increases and/or some tuning mods.

[NomduJour]

More gears is the answer - big V8s have enough torque to pull a high overdriven top gear.

[roscobbc]

NomduJour said:

More gears is the answer - big V8s have enough torque to pull a high overdriven top gear.

O/D ratios work well in late model cars with slippery bodies - early cars with aerodynamics of house bricks o/d can only be so effective in terms of fuel economy. Best use a conservative o/d ratio and accept cruising will be at a lower speed. There will be someone on here I'm sure will come up with a facts and figures as to why a higher revving engine within the cars ideal torque band may not actually be any less economical than same engine with o/d ratio operating below ideal torque band.

[mph]

roscobbc said:

O/D ratios work well in late model cars with slippery bodies - early cars with aerodynamics of house bricks o/d can only be so effective in terms of fuel economy. Best use a conservative o/d ratio and accept cruising will be at a lower speed. There will be someone on here I'm sure will come up with a facts and figures as to why a higher revving engine within the cars ideal torque band may not actually be any less economical than same engine with o/d ratio operating below ideal torque band.

The three speed autobox is a major compromise for many classic cars. Of course additional gears and/or a lock-up type auto box will improve mpg and give more relaxed cruising.

As for your nod towards high-revving petrol engines I always though the attraction of a large capacity American lump was that it had loads of torque and didn't need to be revved. Bit like a diesel in fact.

I've never driven an Interceptor but I did own a CV8 and I don't recall it as being particularly rev happy through it's three speed torque converter.

Not that I'm in favour of a diesel engine swap but I can see this type of car being used less and less due entirely to the fuel costs, which is a shame.

I've just been reading a period road test, they averaged 11mpg !

[NomduJour]

A four-speed (or overdrive) supposedly makes a fair differrence, in hindsight I should have forked out for one instead of replacing a 727. Will make for a more relaxed car on the motorway too.

[Ubendum]

This is a perfect Jensen engine...(referring to the Mopar 440 dynosheet on side 6)

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

By the way, its normally apsirated, and no giggle gas (before anyone suggests anything else). Just a plain ol' 440 running on unleaded..

Edited by Ubendum on Friday 25th April 13:20

[quiraing]

rollerderby said:

I'm thinking about buying a Jensen Interceptor and talking to guy today who mentioned a mate with a Interceptor. He said he uses it a lot and has a diesel nailed into it. There seems a couple of posts with people saying the same.

Are there people who have done this and enjoying loads of reliable good fuel consumption miles out there?


Not one for the purists but a practical Jensen?

A diesel Jensen Interceptor??!!! Hmmm, a very depressing thought. May as well make it front wheel drive at the same time. Loads of diesel cars and vans in scrapyards.

[Russwhitehouse]

I would rather eat my own flesh than even see, let alone drive an Interceptor with a Diesel engine. What a hideous idea. If the benefits of a diesel are of any importance to you, then an Interceptor is not the car for you.

[Yertis]

I fully appreciate all the invective being heaped upon those who suggest putting diesel into an Interceptor. Horrible idea.

But the Interceptor is a lovely looking thing. What would you zealots say about taking a big-ish four-wheel drive diesel, an A7 3.0Tdi quattro for example, which is a good but mundane looking car, and rebodying it with the shell of an Interceptor?

[Russwhitehouse]

Please see above.

[SV8Predator]

Yertis said:

What would you zealots say about taking a big-ish four-wheel drive diesel, an A7 3.0Tdi quattro for example, which is a good but mundane looking car, and rebodying it with the shell of an Interceptor?

A man of your obvious taste will like this beauty then:



http://www.ebay.co.uk/itm/1970-JENSEN-INTERCEPTOR-...

There you go Yertis old chap, a lovely classic car for you!

[Eagerbeaver]

It is a monster and looks not so good but I like the idea in principle.

How can that legally be registered as an Interceptor. It's a cut and shut. Literally.

[roscobbc]

mph said:

As for your nod towards high-revving petrol engines I always though the attraction of a large capacity American lump was that it had loads of torque and didn't need to be revved. Bit like a diesel in fact.

Yes agreed but you can "have your cake" and "eat it" too. Just because the engine is large capacity with a relatively low rpm torque peak doesn't mean the engine won't rev if you want it to. Two choices - sail along on peak torque - or - have some fun with some cog swapping and let the engine rev. Nothing more exhilarating than a V8 at 6 or 7000 rpm.

[Yertis]

SV8Predator said:

A man of your obvious taste will like this beauty then:



http://www.ebay.co.uk/itm/1970-JENSEN-INTERCEPTOR-...

There you go Yertis old chap, a lovely classic car for you!

LOL.

You seem a bit sensitive about Jensens...

[aeropilot]

Yertis said:

What would you zealots say about taking a big-ish four-wheel drive diesel, an A7 3.0Tdi quattro for example, which is a good but mundane looking car, and rebodying it with the shell of an Interceptor?

The engineering challenge alone to attempt such a task would be immense.......trying to modify all that modern running gear to be able to graft all that into an Interceptor shell that has a different wheelbase, and track etc.....

Other than the challenge to someones' electrical and mechanical skills.......you'd still have to ask......why would you bother.

I can just about understand the logic/motice for putting in a LS lump and matching 700R4........especially as it's very difficult to fit a more modern overdrive autobox onto the back of a RB.

But tractor engines and any other bdisation is beyond my understanding.