Discussion
Hi,
On my continual research I'm looking at the stats for the 390SE vs the 350i and the 390 has about 80hp more from only 400 extra cc's.
Was that TVR just telling fibs about the 390 power or is it a much more stressed engine and therefore less reliable?
I haven't seen any 390’s advertised so am assuming they are much rarer than the 350’s
Thanks
On my continual research I'm looking at the stats for the 390SE vs the 350i and the 390 has about 80hp more from only 400 extra cc's.
Was that TVR just telling fibs about the 390 power or is it a much more stressed engine and therefore less reliable?
I haven't seen any 390’s advertised so am assuming they are much rarer than the 350’s
Thanks
Nearly 1000 350i's but only 103 390SE's.
Some had very modified engines, some didn't. By now some might have changed too. As an example, 6 original customers ordered the SEAC 4.2 litre engine so the factory produced 6 420SE's based on the 390!! The one I had went back to the factory to have the 450SE 'upgrade' in 89, (BV heads, 73mm plenum etc). Then subsequently had another 'upgrade & rebuild by J.E. Engineering in 92ish with a wild cam, bronze valve guides, roller rockers etc. Produced 293bhp @ 6500rpm on J.E's dyno!!!
Basically, there are some crackers out there & there are some that are just 'special'.
Grab one while they are still affordable.
http://www.youtube.com/watch?v=VDaHlJyBBZU
Some had very modified engines, some didn't. By now some might have changed too. As an example, 6 original customers ordered the SEAC 4.2 litre engine so the factory produced 6 420SE's based on the 390!! The one I had went back to the factory to have the 450SE 'upgrade' in 89, (BV heads, 73mm plenum etc). Then subsequently had another 'upgrade & rebuild by J.E. Engineering in 92ish with a wild cam, bronze valve guides, roller rockers etc. Produced 293bhp @ 6500rpm on J.E's dyno!!!
Basically, there are some crackers out there & there are some that are just 'special'.
Grab one while they are still affordable.
http://www.youtube.com/watch?v=VDaHlJyBBZU
A900ss said:
Hi,
On my continual research I'm looking at the stats for the 390SE vs the 350i and the 390 has about 80hp more from only 400 extra cc's.
Was that TVR just telling fibs about the 390 power or is it a much more stressed engine and therefore less reliable?
I haven't seen any 390’s advertised so am assuming they are much rarer than the 350’s
Thanks
<Rubs hands>On my continual research I'm looking at the stats for the 390SE vs the 350i and the 390 has about 80hp more from only 400 extra cc's.
Was that TVR just telling fibs about the 390 power or is it a much more stressed engine and therefore less reliable?
I haven't seen any 390’s advertised so am assuming they are much rarer than the 350’s
Thanks
Depends on who you talk to. TVR approached Andy Rouse, who had had success campaigning a Rover SD1 in saloon car racing. He'd developed (or had help developing) the 3.5L into a 3.9L and whilst Peter Wheeler was known to favour straight 6's, the Wedge engine bay didn't lend itself to a long-block motor, especially not a tall one. So whilst they'd tried turbo-charging the V6, it was regarded as a fragile and expensive conversion.
The story has it that Rouse built TVR a 3.9 in race trim, that supposedly made 275BHP... but drank as much oil as it did petrol and was nigh-on undriveable on the road. Allegedly TVR never paid the bill, but that's by the by.
Various engine tuners were then drafted in to help with the project (JE Developments et al) who set about 'productionising' the Rouse motor. Needless to say in civilising it for the road they also softened the beast, though that didn't stop TVR claiming the same power output for the revised engine. You can actually read the cynicism of some reporters in the motoring press articles of the day who weren't convinced that it was significantly more grunty than the 3.5L.
I've had my 390SE since 2000 and have read of very few people taking their 3.9 to bits but the few reports that have surfaced suggest that the 390SE engine is a varied beast depending on where in production it occurred and who built a particular unit.
The early engines certainly seem to have the most aggressive modifications and, probably, power output. Later units were built by North Coventry Kawasaki (NCK) which was subsequently acquired by TVR and later became TVR Power. The NCK production run extended into the early 400SE, of which more later.
Typical NCK modifications are:
3.5 block (pre cross-bolted casting) bored out to 93.5mm giving 3905cc total capacity.
Flat-topped forged pistons (some say Cosworth, mine were Omega) with valve pockets machined in; this raised the compression ratio to 10.5:1.
Extensive porting work to the cylinder heads and inlet manifold, though standard diameter and length trumpets (ram stacks, bellmouths, whatever) were retained.
Valve guides shortened, standard-diameter valves retained but with dual springs.
Standard rocker gear retained.
Higher-lift camshaft (precise spec. unknown and some will certainly have been replaced by now, mine has) fitted though standard hydraulic lifters retained.
Adjustable (though not rising-rate) fuel pressure regulator fitted.
ECU and airflow meter retuned.
Some sources claim the flywheel was lightened, some claim the exhaust was a larger diameter though the fabricated manifolds remained the same.
Rear suspension design changed to the supposedly-superior A-frame design.
Differential changed to limited-slip 'PowrLok' design with options of different ratios.
Some claim the springs and dampers were 'uprated' but no specific data has been published that I've ever seen and nobody has done any comparisons of components removed from different models. Certainly Armstrong and Koni only ever listed one type number for their dampers used on all Wedges.
Front brakes changed to Ford Granada vented discs with standard calipers widened.
Some later cars had Princess 4-piston calipers fitted.
Larger wheels and wider tyres (than the 350i) fitted; later cars got the split-rim OZ design.
Everything else was cosmetic - bonnet, front air dam, sills, rear under-wing, badging. As with the 280 and 350, there were Series 1 and 2 versions; I claim there was a Series 1.5 because as production went on, the wheelarch flares got more pronounced (from the prototype that had none really apart from two extra bits moulded to the front skirt); my car has the arches of a S2 but the sills and airdam of a S1
So yes; there certainly was some hype, though the 3.9 does make a fair bit more power than the 3.5. Landrover themselves switched to making a 3.9 for the RangeRover, this was actually 3948cc and 9.35:1 rather than the 3905/ 10.5:1 of the TVR version. The LR introduction worked out quite well for TVR as they were able to source ready-made 3948s to drop into the new 400SE; NCK did some top-end work again but time tells us that 400SE engines tend to be a bit softer in their delivery, if more tractable due to the later injection system which also has more scope for 'remapping' than the earlier system used on the 390SE. In theory a 390SE with a mapped injection/ignition system could be a monster but I have yet to see anyone (at least on PH) do it.
My engine was suffering from broken rings when I bought it so it was rebored to 3948 and lower-compression pistons fitted; it has been dyno'd at 256 bhp/ 280lb.ft. (running Tesco 95 RON UL) which is a bit shy of TVR's marketing claims. What might have been gained by running 100-octane 5-star petrol as would have been available when the car was new is a matter for conjecture
Although the engine now has the same capacity as a 400SE motor, it is rare that a 400SE is quoted on here as having more power, which suggests that NCK must have been doing something right
Only 103 390SEs are known to have been built but just to confuse the figures, some of those cars had more engine work taking them out to 4.2L, producing the 420SE which is identical in appearance apart from badging. If you think the 390SE is rare, try and find one of the probably-less-than-ten 420SEs...
From a price list that Mike Bressington found some years ago, my car would have been about a fiver shy of £23,000 new. Someone pointed out that a family man could have bought a Sierra Cosworth for rather less... but really, which would you rather have now?
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