mickeyw Posted February 5, 2015 Share Posted February 5, 2015 Last weekend I cleaned up a V8 flywheel I intend to use with an impending engine upgrade. Having gone over it with a wire cup wheel attached to the angle grinder I discovered the friction face is pretty corroded. I would hazard a guess that some of the pitting must be a good 0.5mm deep, maybe more. So this leads to my wanting to know how much I can skim off the face without causing a problem. I am not looking to lighten the flywheel, the engine is going in my 110 after all; but just to restore a decent surface. I feel sure it wouldn't be a problem to remove 1mm, but I'd be interested to hear a few other opinions. It seems that turning flywheels is not the preferred way of skimming, but to grind it to a smooth factory spec surface. Looking on t'internet I have seen this done a few different ways. Side grinding on a cylindrical grinder is one, surface grinding on a rotary table is another. I also saw a cup grinding wheel used in a turret, with the flywheel again on a rotary table. With my toolmaking past, I can't think of a reason why any of these grinding methods wouldn't be suitable. In fact I have used the second myself many years ago, but sadly I don't have access to such plant these days. Quote Link to comment Share on other sites More sharing options...
Hybrid_From_Hell Posted February 5, 2015 Share Posted February 5, 2015 Er....not that much !!! Old Sodbury is prob your friend !@ Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted February 5, 2015 Share Posted February 5, 2015 I wouldnt worry too much,years ago when I used to accept pretty much any workshop work I replaced plenty of tractor clutches.They work hard,esp on loader tractors,often the farmers were too tight to have flywheels skimmed.(Or in too much of a hurry to get it back together) I was told to put it back together... They got away with it too. Glad I dont do ag work anymore. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted February 5, 2015 Share Posted February 5, 2015 you'd probably get a good enough surface finish with a decent wiper insert and enough surface speed if you could nail down to a lathe, or better a vertical borer. You will probably upset its balance in the process however. 1 Quote Link to comment Share on other sites More sharing options...
Boydie Posted February 6, 2015 Share Posted February 6, 2015 I guess it all comes down to cost, a new OE flywheel or it can be fitted with an insert. To do this the face is skimmed (0.010") and then turned down/ bored out just over the diameter of the clutch plate - say to about 12" diameter and to a depth of about 1/4", (0.25") an insert is then machined to be pressed in (12.001") and secured with about eight equally spaced countersunk socket head Unbrako screws tapped into the flywheel. This insert should be about 0.258" thick. The assembly should then be skimmed back to the face of the original flywheel and rebalanced. This procedure was quite commonplace on large truck engines that had double clutches, racing cars (eg. my old Daihatsu rally Car) that have alloy flywheels and is only to be entrusted to a qualified machine shop. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted February 10, 2015 Author Share Posted February 10, 2015 Well it seems there is an official answer to my question. Quote Link to comment Share on other sites More sharing options...
CwazyWabbit Posted February 10, 2015 Share Posted February 10, 2015 Does that mean yours is going to live once more or will you be after another? Quote Link to comment Share on other sites More sharing options...
mickeyw Posted February 12, 2015 Author Share Posted February 12, 2015 Will have to get the measuring tools out Barry, then we'll see. The book doesn't mention the original thickness, so until I know where I am starting from, I don't know how much I can remove. Quote Link to comment Share on other sites More sharing options...
HoggyN Posted February 13, 2015 Share Posted February 13, 2015 If I remember correctly, I had nearly 2 mm taken off an SD1 flywheel without any problems. It was used in a fully balanced, high reving engine. The guy doing it had to go deeper than he originally thought to get under some nasty hard patches on the flywheel face. I didn't know about the minimum thickness. Out of interest, I might measure it if I get time. Quote Link to comment Share on other sites More sharing options...
need4speed Posted February 13, 2015 Share Posted February 13, 2015 I agree with Nige. Just get a cheapo replacement. Also, if you lighten them too much the engine can lose a fair bit of torque. A light flywheel will rev up quicker but the trade off is loss of torque. Dont mess with it. Get hold of another Quote Link to comment Share on other sites More sharing options...
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