Discussion
Yes...
Depends on which manufacturer made and supplied it and when. Each one of the 100 odd 390 enegines was close to a custom build and the specs do vary dramatically.
Steve
www.tvrbooks.co.uk
Depends on which manufacturer made and supplied it and when. Each one of the 100 odd 390 enegines was close to a custom build and the specs do vary dramatically.
Steve
www.tvrbooks.co.uk
By a bizarre coincidence I've been researching something similar today, in an attempt to resolve my pistons problem!
In the early 390s, NCK used a 93.5mm bore, with forged pistons (allegedly from Cosworth). The same bore was used with a long-stroke crank to create the 4.2 of the SEAC etc.
When Rover started production of their own 3.9L, they used a 94mm bore; this has become the standard across the Landie/ Rangey range, bad English I know...;-)
When the V8S came along, the engine was practically a bog-standard Rover unit, including the 9.35:1 c.r. pistons, although a lot of published figures claimed it was 10.5:1...!
Hence the apparent (slight) power advantage the smaller 3905cc engine had over the 3948cc of the V8S. Or so I'm told; before you jump on me, I'm just repeating things here..
What I haven't managed to ascertain is whether the liners used by NCK are the same outside diameter as those subsequently used by Rover.
I've managed to find some forged 94mm pistons with the requisite flat top and valve pockets; a snip at GBP350+ VAT for 8....
W.
In the early 390s, NCK used a 93.5mm bore, with forged pistons (allegedly from Cosworth). The same bore was used with a long-stroke crank to create the 4.2 of the SEAC etc.
When Rover started production of their own 3.9L, they used a 94mm bore; this has become the standard across the Landie/ Rangey range, bad English I know...;-)
When the V8S came along, the engine was practically a bog-standard Rover unit, including the 9.35:1 c.r. pistons, although a lot of published figures claimed it was 10.5:1...!
Hence the apparent (slight) power advantage the smaller 3905cc engine had over the 3948cc of the V8S. Or so I'm told; before you jump on me, I'm just repeating things here..
What I haven't managed to ascertain is whether the liners used by NCK are the same outside diameter as those subsequently used by Rover.
I've managed to find some forged 94mm pistons with the requisite flat top and valve pockets; a snip at GBP350+ VAT for 8....
W.
So why are you asking?
Steve
A Range Rover specialist very near me says he has some experience of TVRs and would be confident about servicing the 390 I am likely to buy shortly.
But then he told me they were based on a standard 3.9 Rover block. I had read that they were based on a 3.5, so I wanted to find out how much he actually knew.
He also says that wedges are generally more reliable than Griffiths / Chimeras - which I find a little surprising, the relibility indicator I'd have gone with for any of them is "luck of the draw", from what I can gather.
I'd expected the answer would be one or the other for something as fundamental as that - hence my surprise - guess I should have learned by now ...
John.
wernt all the landrover 3.9's serpentine...
im not sure about what they put in the range rover but i know the discovery had 3.5 pre serp then 3.9 serp on the change over...
also interestingly my 4ltr chim says 3952 on the reg docs and the wifes 3.9 disco 3947 on the reg docs..
mind you i've heard of 4.5 cerbies with 4.2 on the reg docs.
wedge more reliable than a chim/griff yeah right... early griff/late wedge maybe but not as a rule i'd have thought
which l/r specialist ( mail off list if you dont want to name on here) as i know most of them
G
im not sure about what they put in the range rover but i know the discovery had 3.5 pre serp then 3.9 serp on the change over...
also interestingly my 4ltr chim says 3952 on the reg docs and the wifes 3.9 disco 3947 on the reg docs..
mind you i've heard of 4.5 cerbies with 4.2 on the reg docs.
wedge more reliable than a chim/griff yeah right... early griff/late wedge maybe but not as a rule i'd have thought
which l/r specialist ( mail off list if you dont want to name on here) as i know most of them
G
My 3.9 V8S isn't Serpentine, it's '91 vintage.
From
www.rpiv8.com/engine-6d.htm
"The later, V8 engines from Rover (1993. on) used a different front timing cover and the oil pump is "direct drive" from the Crank. This later engine is generally described as the Serpentine type, Basically this means the front end pulleys, are not driven by the std V-belt type. (fan belt) but a flat 2cm wide grooved belt."
In terms of Wedge reliability, I had a 350i for four years (60,000 - 90,000 miles) - never let me down once.
Steve
From
www.rpiv8.com/engine-6d.htm
"The later, V8 engines from Rover (1993. on) used a different front timing cover and the oil pump is "direct drive" from the Crank. This later engine is generally described as the Serpentine type, Basically this means the front end pulleys, are not driven by the std V-belt type. (fan belt) but a flat 2cm wide grooved belt."
In terms of Wedge reliability, I had a 350i for four years (60,000 - 90,000 miles) - never let me down once.
Steve
Happy to name them, I like them. Seton Engineering, Longniddry, East Lothian.
I'd be surprised if you've heard of them, they're quite small. But they've done good work on my Nissan, and their head guy is friendly and helpful, and doesn't act like he thinks I'm thick, unlike many places.
I'm inclined to give him a try - I'm pretty sure he'd be amenable to discussing exactly what to do before actually doing it.
John.
I'd be surprised if you've heard of them, they're quite small. But they've done good work on my Nissan, and their head guy is friendly and helpful, and doesn't act like he thinks I'm thick, unlike many places.
I'm inclined to give him a try - I'm pretty sure he'd be amenable to discussing exactly what to do before actually doing it.
John.
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