pros and cons of a lightened flywheel

[leebo]

hey, was considerin this for my 1.2 to go along with my ported and polished head, twin 40s, 270 cam and 4 branchand was wonderin if it would be a good buy as its second hand outa a nova rally car. and whats the rough money i should be spendin cheers lee

[Stuart]

if anyone says it gives you more power gets a slap lol

it will allow the engine to spin up faster, but it will also lose speed faster as it wont ahve so much mass to keep the inertia up with.

i think you cac get them machined for ?60 so i wouldnt pay more than that TBH.

incidently what power/torque is your 1.2 curently putting out, and what is its exact spec?

[NovaloadedAgain]

& also if you live in an area with lots of hills etc its not the best thing to do. I had a lightened flywheel & was a bugger up hills! Lol.

[leebo]

thats sorta what i thought but just not totaly sure if i want it. i sappose if i dont like it i can change it back. is it a hard job to change it or many tools needed? have a garage full of bits and pices but have no clue as to whats involved?

i dont have a proper spec as its all parts in my room waitin on the rite nova to come along to spend money on. as regards waht im lookin to get outa it at the end up im hopin for about 30hp+ gane well it would be nice. still to pic the rest of the exhaust system but im thinkin a single bore either side of the car would be different (different for where i live anyway)

[Nick]

yep as novaloadedagain said, you'l find it sacrifices your power up hills.. as theres less of a mass for the hill to stop spinning, thus the resistance will give a greater effect

[Philsutton]

it also depends how much you take off, plus its not going to do much on nova when going up hills.

[Nick]

it will if you lighten it alot..

[Philsutton]

will do if you grind it down to 1kg

[Nick]

as you said tho it's not going to be a massive loss....

take CP's 1.4 SR 16v for example, he's not had his flywheel lightenened e.t.c i think he said it's only on ARP bolts.

and it's putting out pretty big power really.

[leebo]

i do live in an area with a few hills but im not worryed about losin power on them as i have no intensions to use it on hilly roads, its soley for the flat, i got alot of stick in my last diesal nova when all the r plate lads were comin out in the there corsas and i was struggilin to say the least on a wee straight streach as she was a bit nakkered along with alot of the novas about here so iv decided to build a petrol one that will (to put it lightly) shit all over them lol so for short runs or bursts of speed with a good take of and acceleration in low gears it would be good but not when hills and a bita weight are involved

[Nick]

as phil said it's not going to make a massive difference on hills..

it will aid acceleration slightly (less rotational mass) so it may be worth doing.


but you could spend the money on something more worthwhile...

p.s why are you building a 1.2 if you want to "shit on them" ?

[Stuart]

indeed

i mean i think my build will only just be faster than a std 1.6 gte/gsi lol and i belive its not far off the limit of a 1200 engine without a turbo or nos (or bkiekspec)

id have built a 1.4 to spank the corsas etc, or even just drop a 20 xe in

[leebo]

unlucky history means that i just cant afford a bigger engine to insure with work done to it pluse i dont make alot so i cant afford to pay to much for insurance either. but i dont mind playin with a 1.2 for a few years till i have a bit more money about me then i will look into moddin a bigger engine

[NovaloadedAgain]

Drop a 1400 in to start with rather then modifying the 1.2. Although, stick the 1.2 head on a 1.4 & get a nice 32/34 weber & youll have about 85+ bhp I should imagine. That wouldnt cost a great deal.

[leebo]

in a year or 2 i intend to start on a 1.4 but thats a gp5 and if i get my hands on a good sr sure thats me lookin at a gp7 if im rite. wouldnt be able to affored that as im just startin afresh

[Aragorn]

1200 carb block and pistons with 1200i crank and rods

bingo - 1403cc and everything says 1200 on it ;)

failing that get some 1400 pistons and rods from scrappy and bore 1200i block out to take them

both ways will give u 1400cc and will look like a 1200 to anyone that looks

plus how can u insure twincarbs and cam etc if u cant insure a 1.4?

[leebo]

thats a good question man but im hopin the lower insurance group will be on my side. been told that the adrian flux insurance is a good place to go for modified car insurance.

im like the idea of what you were sain about the 1.2i stuff. so i just take my 1.2 engine and replace the crank and rods with that outa a 1.2i is the rods shorter or how dose it work?

[Aragorn]

1.2i has the same crank and rods as a 1400 (obviously so vauxhall can save money) and just has a very small bore to bring the capacity down (about 5mm smaller iirc)

and a 1.2 carb has a very short stroke but a large bore (0.2mm larger than the 1400)

so fitting a 1.2i crank and rods to the 1200 block will give u same stroke as a 1.4 and larger bore than a normal 1400 which gives 1403cc instead of 1389 or whatever it is normally

similarly taking a complete 1.2i block and overboring it by 5mm and fitting the 1400 pistons would also work

if your having insurance trouble i'd think it would be better to do that and keep the engine looking completely standard from the outside and just insure it as a standard 1200 until u get some ncb

insurance on a modified 1200 WILL be much much higher than a stadnard 1400 (or a standard 1200 ;) )

ie a 1200 with twin40s and cam etc will not really be much faster than a "1200" with 1403cc with standard spi throttle body or carburettor with the same cam etc

and if it looks like a standard engine with the original black fryingpan airfilter etc and u do crash it no-ones gonna bat an eye lid at it

[leebo]

cheers man, that sounds like a plan to do to the engine. I wanted to put t40s in to be different but if the insurance is to high i will loose them and put a 32/34 on or something. i take it the haynes manual tells ya how to do all the work with th crank and rods? is ther any special tools required?

so if i was to change cc to the 1403 and have all the mods that i have said on the car what would be your quess on the final bhp?

[NovaloadedAgain]

I should think you'll be looking at around 80-90bhp, Sounds like a plan mate 8)

[leebo]

good stuff i will report back to ya the full bhp in about a years time when i get it together lol
cheers all lee

[leebo]

are all the flywheels the same in petrol novas?

[Snowface]

nope.

[leebo]

i was told that the flywheel for the small block engies are the same 1.2 1.3 1.4 1.6 is that rite?

[Nick]

i think you'l find that twin carbs will make your insurance jump up a couple of groups.

i.e your group 3 nova (or whatever is it) would end up being something like group 5.

[leebo]

lovely lol a well if its to hight i can just take her off nothing else for it i suppose. Well i have no real clue what to expect price wize but when i go on the road i will be 21 with no points and no no-clames but a careless drivin offence :( but as long as my car into the shape i want it i will be happy

[Aragorn]

the 1400sri (late models) and 1600 have a larger flywheel and require the use of an F13 box

[krobinson]

Back to the lightened flywheel.

My flywheel has been lightened and balanced, the car rev's very quickly. So it worthwhile having done. I'd heard about it not being as good on hills, but it makes no differenct whatso ever going up a hill and using your power!

Come to a hill, and plant it, and it will pull up the hill just as fast as a car with an unlightened fly. Lift off the power and the car with the lightened fly will slow quicker.

Keith

[Aragorn]

but similarly even without a hill the lightened car will slow down faster

[leebo]

well im just gettin the man to tell me what it came outa so i will know soon enough but i think from all the chat that its worth gettin cacuse i want what can outa 1st and 2nd

[Clutch]

I have done that too now i?m waiting to try the car :twisted:

The original weight has 7440Kg now have 6020Kg.

I hope feel a lot diference because it was very expensive.

Here is the pic of my Flywhell lightenend and balanced.

http://img165.echo.cx/img165/5317/imagem6597bp.th.jpg (http://img165.echo.cx/my.php?image=imagem6597bp.jpg)

[Snowface]

a 6-tonne flywheel! that is light.

[Nick]

lol at 6 tonnes !

Clutch, i think you mean 700-600kg !

[Clutch]

Sorry mates original weight of my flywhell was 7,440Kg now after lightened have 6,020Kg.

Sorry my mistake :oops:

[Stuart]

for the less educated among us the , in europe is the same as a decimal point here

so its 7.44 Kg to 6.02Kg

[Gunzi]

Cost me ?30 to have mine lightened (I was in the middle of an engine rebuild at the time so had it out), but I can't now remember how much weight was taken off!