Discussion
Hey folks,
As part my soon to start upgrades and refurb, if planned on getting my 450 engine frehened by V8D. I'm fitting GEMS, so need to fit a trigger to the flywheel and modify the for t cover for a GEMS cam, so thought best to go the whole hog and get it all balanced, top hatted and new bearings.
The question is, how much difference do you think there would be if I increased it to one of V8D's 5ltrs??? I know more torque, but there'll be loads of that anyway on the 4.6. Really I suppose it's what difference the forged pistons and rods would make, if any, to the character of the engine?
As part my soon to start upgrades and refurb, if planned on getting my 450 engine frehened by V8D. I'm fitting GEMS, so need to fit a trigger to the flywheel and modify the for t cover for a GEMS cam, so thought best to go the whole hog and get it all balanced, top hatted and new bearings.
The question is, how much difference do you think there would be if I increased it to one of V8D's 5ltrs??? I know more torque, but there'll be loads of that anyway on the 4.6. Really I suppose it's what difference the forged pistons and rods would make, if any, to the character of the engine?
One of RR's posts from about 4 years ago....
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Might help with the decision process
Personally, I'd stick with the original 4.6 (refreshed and with GEMS as you mention) and spend spare dosh on heads/induction/cam (assuming you're going to stay with NA)
Here's mine which Rob rebuilt 5 or 6 years ago, its a V8D 5 litre with a few extra goodies..... my original block went porous so the later cross bolted Coscast block seemed the right way to go at the time...
The turbo brigade will probably be along later for a willy waving fest...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Might help with the decision process
Personally, I'd stick with the original 4.6 (refreshed and with GEMS as you mention) and spend spare dosh on heads/induction/cam (assuming you're going to stay with NA)
Here's mine which Rob rebuilt 5 or 6 years ago, its a V8D 5 litre with a few extra goodies..... my original block went porous so the later cross bolted Coscast block seemed the right way to go at the time...
The turbo brigade will probably be along later for a willy waving fest...
...............as if motul1974 said:
Funny thing is... I'm not chasing horses, I'm more concerned with feel a character more than anything, so just wondered did V8D'S 5ltr bring anything extra to the experience. 
Like your thinking..... character is everything.
Revving the tits off it,,, so uncouth,,,, says the guy with a 125 two stroke go cart lying around,,,
Gems, the right Cam, glorious running conditions.
For all the extra power heads or big cams make its character that we mostly fall for.
My 4.6 engine refresh consisted of standard pistons honed bores, new rings, so nothing much,
Heads had some work but mostly lapping in valves and a skim, block was decked so slightly better comp ratio at the expense of some combustion chamber some cc but nothing major. Crank was re ground and new 885 Kent Cam with vernier timing gear.
Standard induction, no mods. 38mm trumpets as in the 4.0cars so good for torque at lower revs,,,, where I like it.
There is the inherent problem that many of the RV8 powered Tvr suffer from, low Rev shunt.
Mine did it as many others do,, many don’t so let’s keep things in perspective.
As we know caused by various things.
Worsened over time by wear and tare on the drive train.
Mine being a late car and low milage should have been better but it wasn’t.
Made worse by drag racing,,,
great laugh 
12.60 4.6 standard induction,,,, think about it, as most Cerbs can’t beat it! Joke,,,,,,,,,
So from the day I had engine work and the thought of Mbe in the future I asked for a Torque filled engine and I wasn’t bothered about hp.
Getting Mbe has allowed all the goodness to come out.
My car was mapped catted and de Catt I’d add a good 10-15 hp to the figures, similarly with the torque curve but catted it was just shy of 300 Bhp and about 348 torques.....
5.0 territory. Drag racing even showed the difference, I’m fast to 5000 revs then loose out a yard or two at the top end and it’s the same every gear compared to a fast 5.0 car. Yellow ones especially...
It does feel starved of air up there as you’d expect and there’s a feeling there’s loads more power I could get at.
But I live the other 364 days a year at 2400revs where my power is and it’s fab.
1000 revs off roundabouts are my speciality without needing clutch slipping, awesome.
My left leg is returning to its normal size.
Drivability and this feeling of massive power from very low revs coupled with your mapping Gems will give you.... game changer and we use this lots but simply tranforms the car.
Torque had proven to work in my car for what I want from it more than hp ever could.
I was forced to sort a new diff or re build, I chose to buy new ( old stock) all with a grimace on my face but it’s proven to be a great addition to the smoothness stakes. Best thing ever for tightening up the car.
Ecu or no, if the diff has been getting shunt hammered for years it’ll still be slack and very low revs will still be a problem.
I’ve replaced the brakes for something that can handle all this power
It’s very strange driving it thinking of how it was to how it is and mostly how satisfying these implemented changes have slowly come together and created the car my mind imagines it to be.
Its actually exactly that car.
I told my dear son a few days or maybe a year into owning the car as my mind is a Fraxzzked mess these days but I was going to prove a Tvr could be reliable and as good as any other car, little did I know I really meant it as it was a daunting prospect.
After a lot of driving and water under the bridge I can at least say I achieved that aim.
As we all know they are reliable so I’ve done nothing exceptional but just taking it that step forwards has made it a dream machine.
12.60 actually very fast and most 5.0 standard cars won’t beat it,,, unless someone wants to prove otherwise. Drag radials but I did a 12.8 on Rainsports on 19 psi without getting it right! ! !
I have a personal time of 12.4 to beat. Alex fantastic bloke daredevils time has been my goal all along but I bust me diff trying so that’s that.
It’s all just to show how hp isn’t everything rather than some bragging rights and I totally love my 300hp but 350 ft lb torque engines car.
You will have one very fast car whatever you do.
Fantastic and something great to follow on PH so all the luck to you.
Edited by Classic Chim on Thursday 9th November 18:59
Edited by Classic Chim on Thursday 9th November 22:04
It's been a while since I had mine but I realised 2 things when the crank snapped on my 5L:
1. Lots of people who know about this sort of stuff said the RV8 design was really being stretched to it limit with the 5L.
2. i should have spent the ££ on a 4.5, not had the bottom end rebuilt.
However it came from factory as a 5L and that's the way it had to stay!!
1. Lots of people who know about this sort of stuff said the RV8 design was really being stretched to it limit with the 5L.
2. i should have spent the ££ on a 4.5, not had the bottom end rebuilt.
However it came from factory as a 5L and that's the way it had to stay!!
Ive just been through a similar thinking exercise and decided to go with the 4.6 option. I did consider a 5.0 but I wanted to be sure that the money I was spending would leave me with a very strong engine.
I decided to invest my time and money into a rebuilt 4.6 with nice heads, induction and cam etc.
I decided to invest my time and money into a rebuilt 4.6 with nice heads, induction and cam etc.
They reduce friction and make the whole valvetrain more efficient.
You can also adjust each lifter and push rod independently rather than just an average by shimming the rocker posts.
It is a luxury, I agree. It depends on how much you want to throw at it and how long you're going to keep the car.
As a cunning little advertisement states, "every little helps ".
You can also adjust each lifter and push rod independently rather than just an average by shimming the rocker posts.
It is a luxury, I agree. It depends on how much you want to throw at it and how long you're going to keep the car.
As a cunning little advertisement states, "every little helps ".
I'm not 'planning' on ever selling....i said that about my old Range Rover, and that's just gone to fund all this! Lol
I read something from Lloyds in which adding the them had little effective than to increase wear...i don't remember wear on what part, but it just sound a worth while upgrade, but I could be very wrong any it all arse about face!
I read something from Lloyds in which adding the them had little effective than to increase wear...i don't remember wear on what part, but it just sound a worth while upgrade, but I could be very wrong any it all arse about face!
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