Chevy flywheel weight

kiwicar · Post by **kiwicar** » Sat Dec 29, 2007 12:26 pm

Hi all
as the heading says this is a question about chevy flywheel weight. I have a flywheel for an externally ballanced chevy, it came as part of the kit to fit the Chevy to the audi gearbox I have.
Owing to a change of plan I need an internally ballanced flywheel (can't fit in catalitic converters so I have built the engine around a 74 block rather than the '98 block I started with) so I either need to re ballance the flywheel (ie drill 12 holes to 1/2 inch deep opposite the ones already in the flywheel) or get a new flywheel made.
The existing flywheel is 28lbs and is 10.75 inches in diamiter and is to take a 4.2 litre A8 clutch making a set up of about 35 lbs ie heavy!
The engine is intended to rev to about 7800 so the thoughts are that this is probably not ideal.
The alternative therefor is to get one made up in ally with a tilton multiplate clutch and a steel clutch face and use the custom ring gear off the flywheel off the kit.
I would welcome thoughts and comments as I don't really want to fork out for a custom clutch if I can use the one I've got (with modification).
The set up will be used with a 6.25 inch fluid damper (space at the front of the engine is limited.
Best regards
Mike

Eliot · Post by **Eliot** » Sat Dec 29, 2007 5:04 pm

Could you not plug the existing holes, which would at least make it easier to rebalance?

kiwicar · Post by **kiwicar** » Sat Dec 29, 2007 5:31 pm

Hi Eliot
I've thought about that, I would still need to do quite a bit of work to do that, the machining of the holes is far from nice, so would need tidying up
and securing the plugs would be tricky though not out of the question. Below are some photos, it's a chunky piece of engineering

http://farm3.static.flickr.com/2398/214 ... 7f.jpg?v=0

http://farm3.static.flickr.com/2236/214 ... dd.jpg?v=0

http://farm3.static.flickr.com/2168/214 ... e7.jpg?v=0

Best regards
Mike

Eliot · Post by **Eliot** » Sun Dec 30, 2007 8:43 am

Cant see how deep the holes are.
Bit of bar turned just slightly oversize and pressed into each hole? - and a dash of tig to be sure.

kiwicar · Post by **kiwicar** » Sun Dec 30, 2007 2:14 pm

Hi Eliot
holes are just under 1/2 inch deep, I would have to make up a D bit drill out of silver steel to square up the bottom of the holes to get the cut off bar to seat right down and yes mr tig would hold them in (though for mortels like me Mr Mig will have to do). There is also an issue of no access to lathe

.
It will still have the issue of it being heavy, 28lbs plus cover and plate does seem very heavy especially with the hefty ring around the outside, though I don't know how heavy a standard flywheel is. It looks more like somthing from a edwardian stationary engine to me

Best regards
Mike

dave350v8 · Post by **dave350v8** » Sun Dec 30, 2007 11:52 pm

Hi mate,go to hotrodder.com they know everything about chevy v8s,I have had so much info from them,dave

canzus · Post by **canzus** » Mon Dec 31, 2007 12:29 am

The only externally balanced SB Chev is the 400.
We are talking about a 400 crank aren't we??

By the way, I'm a Ford engine guy, but know a little
about the "Scrubs"...

kiwicar · Post by **kiwicar** » Mon Dec 31, 2007 10:43 am

Hi canzus
its a 3.75" crank in a 350 '74 block (350 mains not 400), the original plan was to use a post '86 (single piece oil seal) block that also takes an externally ballanced crank.
Best regards
Mike

Mark · Post by **Mark** » Tue Jan 01, 2008 10:06 pm

Easiest option would be to stamp the '74 numbers on the '98 block

Flywheel does sound heavy though, I've made one for my 302 Ford engine and it weighs in at just under 24 lbs without ring gear (it is a lot smaller on diameter than the 302 version which would give less flywheel effect for the same weight)

Can't you just drill holes all the way around lightening the flywheel and giving neutral balance ?

Mark