73 replies to this topic

[Tamworthbay]

I know there are a few threads about this on here but a lot seem a bit vague or the spec is different to what I am building so here goes,

Spec:
Piper 270
Flowed and ported large valve head,
Maniflow system
Block will be standard 1275, not over bored at all (too mean to buy new pistons )
3.44-1 FD on ATB diff
Blueprinted

Choices of flywheel are:

http://www.minispare...px|Back to shop

Or:

http://www.minispare...px|Back to shop

It is for a road going car so that would suggest the 420, anyone with experience of the lighter 620 or similar on the road? Any other suggestions?

[brum,brum,mike]

has to be the 620... the only one in stock ;)

[Tamworthbay]

has to be the 620... the only one in stock ;)

noticed that, but in no rush so happy to wait for the right one if needs be.

[Tamworthbay]

No one used either of these?

[racingbob]

used them on race engines but wouldnt put one on your spec

your spec the same as my engine in my car

kept mine standard but balanced, did try a ultralite on this engine

but lost torque so took it off. if i was revving it hard with high cam - yes

if you must put one on go for something not to light, like yours lightened

torque very important for lower revving cars, rarely rev mine over 5000

[A-Cell]

Put the standard one back on. Be much better to drive. You will appreciate the bottom end torque in traffic!

[racingbob]

Put the standard one back on. Be much better to drive. You will appreciate the bottom end torque in traffic!

agreed !!!!

[Tamworthbay]

Put the standard one back on. Be much better to drive. You will appreciate the bottom end torque in traffic!

It's a weekend toy so the most traffic it sees is the queue to Bingley! It will be used mostly on A roads. I know from another thread that Bob wasn't impressed with his, others seemed to disagree before, but no-one has come up with anything definate as yet. Original isn't an option as doesn't exist, leaning towards the 420 unless anyone comes along with positive info on 620.

[racingbob]

in that case put on road lightened flywheel

not a realy light one, say about 20% or so

the torque from say 2000 revs to 4000 very important

in a road car with our cams we have in

thers no way i would ever put in a ultra lite flywheel ass.

unless 6000 to 8000 revs 286 cam plus

[A-Cell]

Racing bob is quite right. I stil think Spec you are proposing would be nicer to drive with a standard weight flywheel even for a 'weekend toy'. Source a second hand one.

[JVA10L]

I think the 620 will be too light for your intended use, especially if you use a lightened pressure plate. The weight of the 420 is not given but is intended for road use so is probably a bit heavier. If you use a standard pressure plate with the 420 you will have a good compromise for road use.

[jaydee]

The 421 is 11 lbs and so it should be the 420, but looking at the description the 420 its just an OEM flywheel..

[racingbob]

as i have said in the past

i fitted one to my current engine

it came OFF the next day

[racingbob]

did on mine

lost that lovley low down torque, couldnt believe the difference was horrible

more suitable for high reving engines

it was an ultra lite assembly off a race engine obviously to lite

it did seem to rev free -er tho but no torque and its torque you need

[A-Cell]

I still agree with Racing Bob. Why don't you ring Piper and seek their opinion.