Hey guys, I picked up a V12 out of an 85 XJS TO help mock up some modifications. In buying an engine stand i found the engine weight didn't pop up readily with a search so i thought I'd post it. I weighed my truck at a weigh station before and after I unloaded the engine to see how much the engine weighed.
The weight was 640 lbs as pictured below with no belt driven components, distributer, fuel rail, oil, filter, or coolant.


Just listing a data point.

 

I would have guessed 650, so pretty close!

 

I found it called out somewhere, that it was said to be 700 lbs. I don't remember what accessories if any that included. So a real world weight of 640 sounds spot on. Good to know.

JTS

 

If and when you mount this engine to a stand of you choice, Please use a 2 by 4 to bolster the front of the engine to the front of the engine stand. The stand is only as good as it's welder. A friend of mine is footless because of a broken engine stand.

Thank you.

Larry Louton

 

For those of us outside the United States, that translates to 290 kg. Fairly chunky.
This might help put it in context: Weight of Car Engines

 

I appappreci the tip. This crossed my mind since it is such a long heavy engine.

 

appappreci is Italian for "appreciate"

 

close to a BBC 454, but Chevy has almost double the power!
for sure double the torque!

 

No. The late 7.4 fuel injected engine was 230hp. The 5.3 V12 in USA market emission trim is 262hp ( 299 in Europe). That's 50 hp/L, or 56 hp/L in Europe and the Chev is 31 hp/L. Not even a close contest. If you said the Jag was almost doubt the power you'd be getting closer. And if you referring to the 6.0 version of the V12 , it does have double the power per litre compared to the Chevy.

 

A BBC would make a great transplant into an XJS. The Last BBC was rated at 290 HP and tipped the scales at 650Lbs fully dressed with alu heads. The last BBC's were roller block'd and a simple cam swap will net 400HP even with the Peanut port heads. Swap to oval port heads and 500HP is the starting point. At 100 Lbs less than the V12 a BBC would still provide a big improvement in driving dynamics becasue the weight would be lower and further back in the car.

BBC came in many forms from low HP to extreme race configurations. BBC's ruled the Nascar curcuit in the 70's with speeds in and around 200 MPH for hours on end in car that had the aerodynamics of a brick.

Many low HP BBC's found their way into GM trucks that were in for severe duty service. For Example the BBC Chevy suburban 2500 had solid Axles front and rear are legends. Many are still used for snow removal duty today. GM never had much luck with diesels back then so the GM faithful that needed an HD rig would often spec the unstressed BBC which also came with the worlds most durable transmission the TH400 or 4L80e.

At the other extreme, the worlds fastest Piston Powered vehicle is powered buy a BBC. 3100HP / 450+ MPH.

 

sorry jagboy, my Camaro dynod 525hp at the wheels , fast as hell!

 

how much did the engine cost?

Strange that you're bragging ~500 hp from a 454 now that we are actively discussing that a V12 can get that at the flywheel.

and this thread is just documenting weight of the V12 for future reference and shouldn't be cluttered up with the ever debatable dead horse of V12 vs V8.

 

OK if you say so!