chromoly flywheel
chromoly flywheel
(OP)
I'm designing a chromoly flywheel and I was going to have a shrink fit for the ring gear. The diametral interference fit is .013." I've run the numbers and this fit is acceptable, actually it leaves half the original fit at max speed which is 8000rpm. I've never seen steel flywheels with welded or bolt retained flywheels. Those with whom I've consulted indicate that I don't need anything other than the shrink fit.
Ideas
Ideas





RE: chromoly flywheel
I have seen shrink fit and spot welds.
I have seen cast iron, aluminium and steel flywheels. I have never been aware of any need for special high strength steel.
Regards
Pat
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RE: chromoly flywheel
ISZ
RE: chromoly flywheel
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers for professional engineers
RE: chromoly flywheel
I use an Al flywheel with a steel insert on the Lotus. Ring gear is shrink fit and drilled/tapped...the bolts that fit the clutch cover/pressure plate also hold the ring gear in place. I have had ring gears move on Al flywheels without such effort to secure them. I have seen gears knocked off by the starter drive on iron wheels. For a street car, OEM type, I see no need for any other method than shrink fit. For racing, it makes sense to go that extra mile.
I have, in the past, used Al flywheels with a 'sprayed on' surface. While that makes for a cheap, light weight unit, life expectancy is limited.
If you are curious about what I use as a steel insert, on one of my sprayed on units I "saved" it by installing an insert made from a Skill saw blade!
Rod
RE: chromoly flywheel
evelrod, care to expound on the sprayed on units?
RE: chromoly flywheel
RE: chromoly flywheel
Ancient history... We were not close friends, but I liked Lee. He could be an arrogant a-hole sometimes, but I liked him anyway. He was at Ceders-Sinai getting a heart transplant the same week as Carrol Shelby. Where Shelby is alive and doing well, Lee died shortly afterward.
Rod
RE: chromoly flywheel
RE: chromoly flywheel
"It could be a carbide coating of some type, that's what we used on our aluminum brake rotors for FSAE and it worked well for the application"
Interesting. How was the coating applied? We do HVOF at our facility.
RE: chromoly flywheel
RE: chromoly flywheel
Back in the 60's we used both Schiefer clutch/flywheel assemblies that were aluminum with copper/iron spray applied surfaces and Weber aluminum flywheels that had a steel friction insert. This was for our drag strip only stuff and everyday driver street rods.
Keep in mind that some of us were driving (barely) street legal race cars to our day jobs. Stock clutches did not last and cast iron flywheels and pressure plates were just waiting to come apart, especially with small block Chevies turning over 7000 RPM. We ran the aluminum stuff for safety if nothing else.
Relatively short life was expected on the race cars and they didn't last all that long on the street either. Without the weight of an iron clutch/flywheel, on the street our high end tuned, big cam and over-carbureted, motors would bog as soon as you started to engage the clutch. But, slipping the clutch was not much of an option.
The Schiefer surfaces did not like the slippage needed to get a '56 or '57 Chevy moving on the street and would progressively gall or smear. This made the clutch grab, making you get in and out of the clutch to get underway.
Weber flywheels, their pressure plates were steel, had their own problems because of the splippage as the inserts would warp, reducing clutch adjustment to where you might not be able to fully disengage the clutch.
We all got real good at changing a clutch and flywheel in less than 30 minutes after dinner so we could drive to work the next day. Needless to say, our parts supplier loved us.
First post so must apologize for not figuring out how to provide a link to Paul Schiefer on the SEMA (Specialty Equipment Market Association) web site.
RE: chromoly flywheel
Rod
RE: chromoly flywheel
The ability to disintegrate cast iron was one reason that small block Chevy guys ran them. Nothing else would turn that many revs and live. By the time I got into street rods and drag racing around '61 scattershields were required.
There was another problem with frangible cast iron bellhousings that sometimes were where the rear motor mounts attached. A flywheel would come apart, taking the bellhousing with it, the back of the motor would drop, the trans would do a nose dive and, with luck, the scattershield would catch it by the input shaft.
By the way, as you knew Lee Mueller, do you remember Kas Kastner, who was fielding cars in the same SCCA classes in the '60's and '70's with Don Devendorf driving?
Yosh
RE: chromoly flywheel
Rod
RE: chromoly flywheel
Dave Kent, who later did Toyota and Mazda racing, was doing the metal and paint for Kas. Dave had a shop in ES where Penske would park his CanAm Porsches when in town. They would have two stalls tarped over so no one could see what was going on or get a look at the (Mark Donohue's term) "unobtanium" pieces.
RE: chromoly flywheel
To the point: Jerry Barker and I run in the same VARA class, me in my Mini Cooper and Jerry in a beautifully restored Herald...I'll see him at the Moss Motors British Extravaganza at BRP in May...I'll try to remember and ask about Kastner...If I can remember!!! If your in the area, that first weekend in May is well worth the trip up to Buttonwillow, especially for fans of British cars.
Rod
RE: chromoly flywheel
Losing the electrics on a Lotus sounds like the prince of darkness struck again.
I might be out of town around that time but it sounds like it would be fun. Will try to make it if I can.
Yosh