172 Flywheel mods in the 5

I have a 172 flywheel to go in the 5 to accept my 6 paddle helix clutch for future plans ;) as The engine will be out soon to investigate my power dropping off @ 6.5k and to rectify an annoying top end tappetty noise I thought I'd move this forward and get it in there whilst everything is out and apart.

Looking at the 172 wheel, the stud pattern is exactly the same as the 5 but further out from the centre by about .5mm. My engineer has suggested moving the wheel round about 22 degrees and to re-drill the holes at the right distance from the centre inbetween the existing holes. This will put the missing tooth about 115 degrees btdc and I'll have to re-mark the TDC mark on the flywheel to match this.

My main question really is:-

- is 115 degrees too far advanced for my adaptronic unit or will it cope with it?

Any other observations???

BTW - I am aware that the 7 crank end holes are not universal.

Thanks

TNT Andy

You should be able to go into the software and adjust the crank reference number to account for it fella, best thing to is set the engine at tdc, fit the flywheel and working exactly how far the gap is from tdc

Quote:

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Originally Posted by Os8472

You should be able to go into the software and adjust the crank reference number to account for it fella, best thing to is set the engine at tdc, fit the flywheel and working exactly how far the gap is from tdc

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Hi Oli - Yup I know I can adjust it through software - I'm just wondering if it causes problems being that far before TDC. Standard is about 90 degree's and I know that less than 90 can cause issues.

Shouldn't do, I saw an escort RS with an emerald on it, he'd got the trigger wheel 180degrees out, a quick tweak of the ref settings and it ran sweet as.

OK done a bit more - Well Dave has!

First he made an adapter up which is basically a copy of the end of the crank as seen here.

https://www.rtoc.org/files/Miscellane...o/DSCF4006.JPG


et voila

https://www.rtoc.org/files/Miscellane...o/DSCF4005.JPG

That basically gives ham a jig to work to in re-drilling the 172 flywheel

This next picture shows how far out the existing crank and 172 flywheel are out

https://www.rtoc.org/files/Miscellane...o/DSCF4007.JPG

and the next picture shows the new holes lining up well.

https://www.rtoc.org/files/Miscellane...o/DSCF4008.JPG

The missing tooth is now about 120 degrees btdc instead of 90 degrees which can be rectified with the adaptronic and also the TDC marking will have to be altered.

Now I should be able to use the standard 172 pick up on this wheel and remove the trigger wheel from the end of the crank.:)

won't that bigger flywheel hit the GTT engine dowels?

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Originally Posted by Andrew Cooke

won't that bigger flywheel hit the GTT engine dowels?

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i think just the back dowel area needs grining down?

The Flywheel is 2mm bigger in total, that's just 1mm each side - I don't think that will cause any problems, but we'll know for sure next week.
:)

What made you not want to elongate the holes?

Quote:

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Originally Posted by Tony Walker

What made you not want to elongate the holes?

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That was the decision of the engineer - He's always been a bit critical when working on flywheels for some reason. He thought there would be more strength with new holes. But to be honest, this is such a light flywheel, a lot of stresses have been reduced already.

The weight of the flywheel being reduced is negligable compared to the weight of the car the clutch plate applies to it. Just seems like a lot of the material around the centre is gone? I'm sure he has a better idea of it than I do.

Quote:

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Originally Posted by Tony Walker

The weight of the flywheel being reduced is negligable compared to the weight of the car the clutch plate applies to it. Just seems like a lot of the material around the centre is gone? I'm sure he has a better idea of it than I do.

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I hear you Tony, and tbh that hadn't crossed my mind. I'll fill the old holes to be safe. Thanks for the point made.

:agree: