lightened flywheel, is it worth it???
Discussion
Bassfiendnoideawhathp said:
Just in case there was confusion over the question that I was asking - I was meaning how come the 4.0's were supplied by TVR with cast iron drain covers for flywheels whereas the 5.0's had significantly lighter flywheels. Was this just cost cutting on behalf of TVR on the "cooking" 4.0 cars or is there an inherent reason why the 4.0 cars should have a heavier flywheel than the higher capacity versions...
Price 
IMO if cost wasn't an issue on the so called lesser models then why was the 4.0HC modified so crudely for example its just business I guess TVR may of realised they was spending to much money on the motor it would certainly explain some of those early car engine specs i.e Wedge motors being a bit tasty 
Sardonicus said:
Bassfiendnoideawhathp said:
Just in case there was confusion over the question that I was asking - I was meaning how come the 4.0's were supplied by TVR with cast iron drain covers for flywheels whereas the 5.0's had significantly lighter flywheels. Was this just cost cutting on behalf of TVR on the "cooking" 4.0 cars or is there an inherent reason why the 4.0 cars should have a heavier flywheel than the higher capacity versions...
Price IMO if cost wasn't an issue on the so called lesser models then why was the 4.0HC modified so crudely for example its just business I guess TVR may of realised they was spending to much money on the motor it would certainly explain some of those early car engine specs i.e Wedge motors being a bit tasty Just sticking a 435 cam in a standard 4.0 litre and calling it an HC then claiming it made 270hp was a bit of a con really, a cam was never going to give you 30hp more than the standard 240hp figure. Anyway from what I read a standard 4.0 litre made roughly 220hp from new not the 240 TVR claimed, the 4.0HC may have just scraped in at the 240 mark if you were lucky but no way did it ever make the 270 figure TVR claimed it did.
For a 4.0HC to make the 270hp TVR said it did it would need both the 435 can and the type of costly and time consuming cylinder head work given to the mighty 5.0 litre cars, and just to be clear from what I've seen of my 4.0HC TVR did little or nothing to the HC heads.
I'm in no doubt TVR made a bigger margin on the 4.0 litre cars and they sold a lot more of them too, I suspect TVR saw the less profitable 5.0 litre as the flagship model to demonstrate some serious 911 Turbo competing performance numbers to help get people through the showroom doors.
I've driven my mate's 5.0 litre a few times and it's certainly quite a step up from my car, although neither are slow by any stretch and on the road the true difference isn't as much as it feels when I swap from one to the other. The other thing that's clear is to give my 4.0HC a set of decent heads which should get it up to the 280hp mark will cost at least £2,500, so given my TVR is still pretty rapid with 250hp I've chosen to spend the cash on making it as smooth, economical and drivable as possible while sill keeping that decent turn of speed.
That's not to say I haven't been eying up a set of nice CNC heads from ACR
http://www.automotivecomp.com/
I still don't get how simply switching one flywheel for another isn't going to completely bugger up the balancing of the whole rotating assembly..?
Revving quicker means getting into the higher RPM range quicker - meaning that balancing is even more crucial for lightened fly's surely..?
I looked into this as I still really want a lightened fly - got the garage to phone Dom to see what was involved, and word came back that the whole assembly was going to have to be removed and balanced with the associated costs.
Are the 4 & 5 litres balanced using a different method to the 4.6 or something..?
Confused
Dom
Revving quicker means getting into the higher RPM range quicker - meaning that balancing is even more crucial for lightened fly's surely..?
I looked into this as I still really want a lightened fly - got the garage to phone Dom to see what was involved, and word came back that the whole assembly was going to have to be removed and balanced with the associated costs.
Are the 4 & 5 litres balanced using a different method to the 4.6 or something..?
Confused
Dom
Dominic TVRetto said:
I still don't get how simply switching one flywheel for another isn't going to completely bugger up the balancing of the whole rotating assembly..?
Revving quicker means getting into the higher RPM range quicker - meaning that balancing is even more crucial for lightened fly's surely..?
I looked into this as I still really want a lightened fly - got the garage to phone Dom to see what was involved, and word came back that the whole assembly was going to have to be removed and balanced with the associated costs.
Are the 4 & 5 litres balanced using a different method to the 4.6 or something..?
Confused
Dom
No idea mate, all I can tell you is:Revving quicker means getting into the higher RPM range quicker - meaning that balancing is even more crucial for lightened fly's surely..?
I looked into this as I still really want a lightened fly - got the garage to phone Dom to see what was involved, and word came back that the whole assembly was going to have to be removed and balanced with the associated costs.
Are the 4 & 5 litres balanced using a different method to the 4.6 or something..?
Confused
Dom
A: V8 Developments said it would be fine
B: So I fitted one of their machined down flywheels and it was fine
C: I then went to an even lighter all steel one and it was... errrr... FINE!
On each step down in weight the engine became progressively more responsive and generally more willing to rev, I'm now at 18.74 Lbs whicj I feel is right for me and the car remains a total pussycat around town.
At no time have I ever noticed any additional engine vibration, indeed only yesterday I was testing her at 120 leptons yet again.... and I'm pleased to confirm (as always) 'Ol Gasbag' was smooth as a baby's bum
Just do it, you definitely won't regret the change
No - I really want to do it... I already run a 6kg flywheel in my Rover Tomcat Turbo, and love the effect it has on pickup and response.
Really want to change my RV8 one too - but what Dom has said seems to be at odds with whats here (not saying anyone is wrong as different balancing methods could be employed on different engines?), and I don't want to start a course of action until I know it's 100% correct for my engine.
Just trying to get the facts straight re: my engine....
Dom
Really want to change my RV8 one too - but what Dom has said seems to be at odds with whats here (not saying anyone is wrong as different balancing methods could be employed on different engines?), and I don't want to start a course of action until I know it's 100% correct for my engine.
Just trying to get the facts straight re: my engine....
Dom
As I understand it some engines are balanced as an assembly so go together as a balanced set of parts, you cannot 'just' change the flywheel without having the whole assembly rebalanced which means stripping down the engine.
Some rebuilt engines are 'internally' balanced, each individual component is balanced so you can change the flywheel for a new balanced fly without problems.
M V8D engine was internally balanced and Rob has told me I can change the flywheel without issue.
Some rebuilt engines are 'internally' balanced, each individual component is balanced so you can change the flywheel for a new balanced fly without problems.
M V8D engine was internally balanced and Rob has told me I can change the flywheel without issue.
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