Flywheel and Flexplate?

Anonymous · Post by **Anonymous** » Fri Dec 03, 10 3:29 pm

Input Needed

Most of you know I'm fitting a Jag v8 engine in my MK2 cortina.

The Jag Engine was never fitted with a Manual Box?

I can't find a flywheel to match the Jag Flexplate for starter ring gear and flywheel bolt pattern, but I have found a BMW flywheel with the same mounting bolt pattern. SO-

I was thinking of using both?

using the original for starting purposes and the BMW for clutch purposes.

I can't see this as being a problem as long as all balanced and aligned properly but just after some other opinions

Blue · Post by **Blue** » Fri Dec 03, 10 4:15 pm

No, you can't do things like that! Think about it, the weight of the flywheel and clutch supported only by a thin steel plate, the whole lot would vibrate like crazy if the engine was running. The flywheel wouldn't be running true either without a positive location on the crank itself. You really need to know what you are doing to get a conversion like this to work. Is there a manual transmission that will bolt directly to the engine or are you thinking of adapting that as well?

Anonymous · Post by **Anonymous** » Fri Dec 03, 10 4:23 pm

Blue is right and if you fixed a clutch to a flex plate when you depress the clutch it will flex.
Years ago I mated a MGB engine to a VW box (that's another story.)
Took the MGB flywheel and machined of the starter ring and clutch face part of the flywheel, then bored the centre out of a vw flywheel it so it was an interference fit and heated the vw part slipped it on and the job was a good un.

Blue · Post by **Blue** » Fri Dec 03, 10 4:42 pm

Manual transmission conversions are really tricky and not for the feint hearted. At best you will need to have a flywheel made that puts the ring gear where you need it and the clutch in the correct position in the bellhousing for it to work. The input shaft length on the box is critical, it has to the right length to mate with the crank or else you're on a hiding to nothing from the start.

Anonymous · Post by **Anonymous** » Fri Dec 03, 10 5:25 pm

And you might have to bore the crank for the input shaft to engage.
Blue is right done it twice and both times were bstard's

Anonymous · Post by **Anonymous** » Fri Dec 03, 10 9:02 pm

Cheers Fellas.
Was looking at doing it with dowels and bolting through the BMW flywheel through a 5.5mm spacer plate through the flexplate and into the Crank. Would of been Keeping the mating surface diameter of the crank with the spacer for rigidity.

Looks Like I am gonna have to re think this one then. Have been qouted over £500 for a custom basic flywheel so was just trying to cut the cost down

The input shaft and crank are sorted with the b/housing for length and being parrallel to each other.

Anonymous · Post by **Anonymous** » Fri Dec 03, 10 9:49 pm

Sounds like fun fish keep us updated

DaveMadders · Post by **DaveMadders** » Fri Dec 03, 10 11:10 pm

What Jag V8 is it ?? You can get a V8 XJR Manual - I was just looking at one on Ebag this week.

Anonymous · Post by **Anonymous** » Sat Dec 04, 10 7:54 am

Can get the new ones in a manual dave but its out of a first gen XJR only Auto

Anonymous · Post by **Anonymous** » Sun Dec 05, 10 2:31 pm

Hi Sickfish,

Made a few flywheels in my time, just need a chunk of Aircraft Ali and orf you go!
TrevD is your man for this project, if he's too busy I can possibly do it 4 you?
As its alot of work, most folks go 4 a twin plate set-up!
We used to use circuit racer style system, smaller, lighter, readily available etc.

Bacca.

Dave999 · Post by **Dave999** » Mon Dec 06, 10 9:57 am

have a chat with Dermot

http://www.power4peanuts.com/

tell him dave with the aussie hemi sent ya

won't get you a discount...he'll just laugh.......

he knows his jag motors..... builds race v12s 6s etc
road(saloon car) and circle/cinder track racing banger/stock car as well...i.e mainly manual boxes
does engines mainly and race car prep

gets his flywheels and ring gears made by JB racing or just makes em himself depends what you want

everything takes a good while but he knows his jag stuff
will come up with a novel idea i'm sure

otherwise if the cost aint too prohibitive

castlemain rod shop or dellow automotive in Aus will do a kit of parts engine swaps are a national pass time downunder

Dave