Discussion
The 'serpentine' engine is an evolution of the same engine. There's a number of differences, most visible at the front of the engine. Sepentines have a 'polyvee' drivebelt (a wide, flat belt with multiple vee shapes on the back of it). Previous engines have an ordinary vee belt. Both the water pump and oil pump (which are mounted at the front of the engine) are uprated.
One of the biggest differences though is the distributor: true serpentine engines don't have one. TVR actually use a hybrid of the two engines as they retained the distributor.
One of the biggest differences though is the distributor: true serpentine engines don't have one. TVR actually use a hybrid of the two engines as they retained the distributor.
Pink_Floyd said:
Any idea as to why TVR went for the distributor and not stick with presumably an electronic version? I am assuming that a real serpetine engine has electronic timing and distribution.
Range Rover developed the Sagem 'GEMS' ignition system with no distributor. I don't know, but I imagine TVR didn't want the expense of R&D with the same system and retained the distributor and Lucas 14CUX?
zumbruk said:
One of the biggest differences though is the distributor: true serpentine engines don't have one.
The two things are completely unconnected.
For the benefit of all, please explain.
Wooah...hold on a moment.
There are three timing cover/engine varients.
The first is the from the dawn of time until 1993/4ish which has your traditional multiple belt configuration and the oil pump driven off the bottom of the distributor.
From 1994ish to 1996 there is the intermediate engine which has a serpentine front end, with the oil pump co-axial to the crank, and crank driven. This is the basis of the TVR serpentine engine, and while I believe the block have the casting lugs for cross bolting, weren't actually delivered cross bolted. This setup still used a distributor and is found on V8 Landrover's of the era eg the later Series 1 Disco.
The final incarnation of the RV8 in our context is the post 1996 dizzy-less serpentine engine, where the timing case similar to the 1994ish to 1996 case but with no hint of a dizzy, not even a casting blank. These engines were fitted to the RangeRover running a GEMS/Sagem injection system and the Discovery running the Thor/Bosch setup and (I believe) were cross bolted ex-factory. The Thor Bosch system is derived from the Bosch system used by BMW, not surprising given BMW owned Landrover at the time o the Disco II's development.
The GEMS system is effectvely self mapping. Mark Adams reckons that if it cottoned on he'd quickly be out of a job. What it effectively does is chase a target Lambda reading given various set boundaries, this means that if you change your camshaft, and go for a drive, it will remap itself accordingly. The trick fo the tuner is to know where to set the boundaries to best achieve the target lambda reading. I believe some of the aftermaret ECU's are now adopting this approach, clever stuff.
Hope all the above is accurate and helps!!!
Regards
Iain
There are three timing cover/engine varients.
The first is the from the dawn of time until 1993/4ish which has your traditional multiple belt configuration and the oil pump driven off the bottom of the distributor.
From 1994ish to 1996 there is the intermediate engine which has a serpentine front end, with the oil pump co-axial to the crank, and crank driven. This is the basis of the TVR serpentine engine, and while I believe the block have the casting lugs for cross bolting, weren't actually delivered cross bolted. This setup still used a distributor and is found on V8 Landrover's of the era eg the later Series 1 Disco.
The final incarnation of the RV8 in our context is the post 1996 dizzy-less serpentine engine, where the timing case similar to the 1994ish to 1996 case but with no hint of a dizzy, not even a casting blank. These engines were fitted to the RangeRover running a GEMS/Sagem injection system and the Discovery running the Thor/Bosch setup and (I believe) were cross bolted ex-factory. The Thor Bosch system is derived from the Bosch system used by BMW, not surprising given BMW owned Landrover at the time o the Disco II's development.
The GEMS system is effectvely self mapping. Mark Adams reckons that if it cottoned on he'd quickly be out of a job. What it effectively does is chase a target Lambda reading given various set boundaries, this means that if you change your camshaft, and go for a drive, it will remap itself accordingly. The trick fo the tuner is to know where to set the boundaries to best achieve the target lambda reading. I believe some of the aftermaret ECU's are now adopting this approach, clever stuff.
Hope all the above is accurate and helps!!!
Regards
Iain
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