Dished Flywheel

General Chat About Drivetrain & Transmission.

Moderator: phpBB2 - Administrators

Post Reply
DEVONMAN
Top Dog
Top Dog
Posts: 1440
Joined: Sat Dec 13, 2008 2:46 pm
Location: Croydon UK

Dished Flywheel

Post by DEVONMAN »

I recently removed a Mcleod Steel flywheel from an RV8 and found it to be dished concave showing 15 thou high at the perimeter compared to the centre. This is irrespective of the wear zone.

A second flywheel I have is exactly the same.

Anyone got any ideas as to the cause.

I've had it skimmed and hope it won't happen again.


1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


Image

User avatar
Darkspeed
Guru
Guru
Posts: 913
Joined: Sun Sep 02, 2007 4:43 pm
Location: Shropshire
Contact:

Post by Darkspeed »

Overheating would be a likely cause - heat one side of a steel plate and leave the other side cool and it will pull in the dircetion of the heat.
4.5L V8 Ginetta G27

DEVONMAN
Top Dog
Top Dog
Posts: 1440
Joined: Sat Dec 13, 2008 2:46 pm
Location: Croydon UK

Post by DEVONMAN »

I tend to agree that heat is the likely cause. I was hoping that someone would suggest that the original billet was not heat treated properly before it was machined into a flywheel disc. Anyone know what the heat treatment process is for such items as a steel flywheel.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


Image

stevieturbo
Forum Contributor
Forum Contributor
Posts: 3979
Joined: Sat Nov 18, 2006 6:22 pm
Location: Northern Ireland

Post by stevieturbo »

I didnt think they were treated at all ?

A friend had a flywheel made a couple of years ago, and certainly it shown no signs of any heat treating etc and I've owned billet pieces before and again no indication of any heating prior to use.

What sort of friction disc was used ? Was the unit slipped a lot ? How many miles ?

They'll never stay flat their entire life, especially if a lot of heat is out into them
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

DEVONMAN
Top Dog
Top Dog
Posts: 1440
Joined: Sat Dec 13, 2008 2:46 pm
Location: Croydon UK

Post by DEVONMAN »

The Clutch is a Mcleod 10.5" (2750lb) and was in the car for about 5000 miles.
It did do a couple of runs up the Pod.

We pulled it out when it started to slip and discovered the dish in the flywheel and as a result the friction plate looked like it had been making contact only for about 3/4" at the perimeter.

A little disappointed having spent £300 on a steel flywheel.

The same clutch in a similar car with a different flywheel has done 10k miles and had no problems --- so far.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


Image

stevieturbo
Forum Contributor
Forum Contributor
Posts: 3979
Joined: Sat Nov 18, 2006 6:22 pm
Location: Northern Ireland

Post by stevieturbo »

That does seem rather low miles for a problem.

Was it an organic or other disc ?

What sort of rating does the clutch have, compared to what you're making ? Have you spoken to McLeod about it ? Certainly on US forums they seem to be very good about problems.
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

DEVONMAN
Top Dog
Top Dog
Posts: 1440
Joined: Sat Dec 13, 2008 2:46 pm
Location: Croydon UK

Post by DEVONMAN »

The plate is organic.

The info out there for the McLeod clutches is very inconsistent.
The 2400 lb version of this clutch is rated at 350 bhp and my clutch (part no 360700) is a 2750 lb version so slightly more clamping force. However some sites show this as 2900 lb. ???

By the way, the plate is not showing any signs of stress or damage. Centre springs still firm in place.

I will do some more asking on line. Thanks for your input.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


Image

stevieturbo
Forum Contributor
Forum Contributor
Posts: 3979
Joined: Sat Nov 18, 2006 6:22 pm
Location: Northern Ireland

Post by stevieturbo »

Maybe the same part changed over the years, hence different rating now vs before ?

15 thou isnt huge...but of course it should be flat. Although the friction disc would soon wear into that shape. Almost surprising it hadnt done so already.

But surely there are signs of lots of heat into the clutch if it has become out of true like that ? Heat is really the only thing that will cause it ?

Either way, definitely call McLeod and/or whoever it was bought from.
9.85 @ 144.75mph
202mph standing mile
http://www.youtube.com/watch?v=XgWRCDtiTQ0

DEVONMAN
Top Dog
Top Dog
Posts: 1440
Joined: Sat Dec 13, 2008 2:46 pm
Location: Croydon UK

Post by DEVONMAN »

The car is rarely used in traffic so plate ware is minimal and same thickness throughout.

Real Steel supplied the steel flywheel (some time ago) but I expect them to say it was overheated.

From what I've read, the cooling method used after the raw billet is manufactured is important to relieve any locked in stresses which, if present, I assume would be released when reheated.
1950 A40 Devon Hotrod with 5.0 twin turbo RV8.
EDIS8 wasted spark, Holley Injection.
Been as far as the Moon and back in 57 years of driving. Same Car, 5 engine upgrades !!!


Image

Post Reply

Return to “Drivetrain & Transmission Area”