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Author Topic:   flywheel and clutch?
Racer98
Member
posted March 01, 2003 09:19 AM
Hello, Im racing a manaul in my imca hobby stock, flywheel rule is 16 lb min. and single disc clutch. Is there any stock parts that are better than others? Or what other poeple run, please help


iowa_dirt_track_girl
Member
posted March 01, 2003 03:27 PM
The only advice i can give you is you can run a vega clutch 9 1/2 inchs it will give you less rotating clutch weight but still keep you on the bare minimun for weight on the flywheel


racinfool
Member
posted March 04, 2003 10:14 PM
Where I run people tell me a stock corvette clutch, 9.4" diameter, is the way to go. That's for a 69-79 10 spline - 350 GM at about $130.00+/- for the kit (clutch, pressure plate, through-out bearing, etc.) This is for a new one (not rebuilt) at your local autoparts store (NAPA, etc.). Of course going to an aftermarket racing clutch setup would be better (heavier pressure plate, etc.) but for about $300.00-$400.00+. Depends on your pocket-book. Also, always turn your flywheel, especially the lighter-weight ones..they have a tendency to 'bow' even when they look OK.


dode
Member
posted March 05, 2003 08:56 AM
I think you mean 10.4" diameter don't you?

John

tilley88
Member
posted March 05, 2003 09:16 AM
Speedway sells a 16 lb. flywheel for $149 new. Go to your local parts house and get a clutch, pressure plate, and throw-out bearing for a '75 Vette (about $150). Total weight will be roughly 35 lbs. Much lighter than stock passenger car or truck stuff. If you can find a Vega flywheel, $125 will get your clutch, pressure plate, and throw-out bearing. Total weight on this set-up is a paltry 27 lbs. I personally would'nt run the Vega set-up on a hi-horse application or a heavy car, tho. Hope this helps! Good luck.


iowa_dirt_track_girl
Member
posted March 05, 2003 10:07 AM
The vega setup is perfect for imca hobby stock your rarley over 300 horspower
The corvette flywheel is illegal for imca hobby but the vega is not just makesure that you get a heavy duty clutch and dont slip it you you need a vega flywheel i have on all redone and ready to go minus clutch


c21
Member
posted March 05, 2003 11:04 AM
c21, what clutch setup are you refering to from a jeep? also how bout the vega? what are the specific apllications for these? what mods if any are necessary? very interested. thanks


racer17j
Member
posted March 05, 2003 10:23 PM
if anybody is looking for a heavier 153 tooth to turn down i just put one on ebay tonite


c21
Member
posted March 06, 2003 11:23 AM
At our track we can run steel or aluminum flywheels but the clutch must be 10" minimum which means 10.4" (or 10 1/2?) for Chevy. When our stock clutch flew apart a couple years back (chunk broke off pressure plate causing big time engine imbalance) we wanted to try the lightweight Ram setup but we didn't have $450 to invest. We got a zoom clutch from advance that was really light compared to what we had. Its lasted two seasons so far.

Those who want to experiment may want to check out the Lou Fegers site. There is an aluminum pressure plate with 9 & 10 1/2" clutch patterns drilled. Also there is a 9" clutch which I assume is the Vega clutch although the disk is solid hub which doesn't sound stock to me. I've seen a similar flywheel on the Afco site. Anyone know anything about this 6lb aluminum flywheel?


Racer98
Member
posted March 06, 2003 04:19 PM
anyone else ever use the Vega, If so what do you think about it?


iowa_dirt_track_girl
Member
posted March 06, 2003 10:21 PM
Ok heres my opinion on the whole 9 1/2 10 1/2 inch clutch
Lets say you go to jr motorsports and buy there 16 lbs fly wheel and light weight clutch setup total weight of the two 26 lbs now the total weight of a vega clutch is 27 lbs 18 lbs of that is fly wheel BUT you have less rotating circumfrance not weight but circumfrance only down fall is you dont have the hold with the 9 1/2 inch clutch that you would with a 10 1/2 inch clutch so i run a heavy duty 9 1/2 inch clutch the biggest advange i have seen with this is it slows down faster in the corner and acceleration is quicker just dont slip the clutch it burns easy.
Any questions on this you can e-mail me at
Bachs_racing_engines@yahoo.com


Slam_Shifter
Member
posted March 06, 2003 10:45 PM
I know a bunch about the Jeep (AMC) clutch as I have ran it before. Also the Vega clutch.

I'll post it here later tonight.

Good luck,
Superdave

------------------
Superdave
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superdave
Member
posted March 07, 2003 10:12 PM
Concerning IMCA hobby stock, the new rule says minimum 16 pounds but that's not permission to lighten the flywheel to 16 pounds. The first rule in the little yellow book talks about using OEM parts. If you machine them or redrill the bolt patterns or lighten them they are not OEM anymore. Simple and cheap. You can resurface the face of the flywheel flat but beware that the springs in the disc will hit the flywheel bolts if you take too much off. You have to use a sprung hub, non-mettalic disc just like OEM. I called and asked specific questions and got answers. I recommend you do the same and/or communicate with your track officials before you do anything to your car.

The Jeep pressure plate is really the AMC Gremlin 6 cylinder pressure plate. It's a little 3 fingered thing with three small springs and a very lightweight pressure ring. I still have one and a picture of it should be attached to this post if it works. It used a 9 1/8" disc. The problem with this pressure plate is the bolt circle is different than any other so redrilling the fluwheel is a must. To get it right you need to have a machinest do it so it's centered perfectly. A little off center at 6000 RPM means serious damage. The springs can be replaced with similar sized valve springs springs with more pressure or you can use a disc with material that has a better grip. This pressure plate won't pass IMCA Hobby rules because you have to modify the flywheel to make it fit. The style is a dead giveaway.

The vega flywheel is a direct bolt on to a Chevy v8. It's 22 pounds. It has a recessed center which takes a unique pressure plate which I couldn't find at the parts store anymore. If you resurface the face flat you can use a pressure plate from an S10 pickup and other cars with a 121 or 151 4 cylinder. This pressure plate weighs 8 pounds. This setup should pass IMCA rules.

The disc I used with either pressure plate was from a 72 Chevy 6 cylinder. It's 9 1/8" with 1 1/8" by 10 spline like most Chevys. 2 pounds.

It's been a while since I ran this setup but the last time was on a Sportsman car with a good engine and good racing tires but the holes on the Gremlin pressure plate kept tearing out after 2 nights. The stock disc was working OK but the plate was really getting twisted. Both setups should last behind a 2 barrel engine.

Most of this is no secret really and if doubtful use the Vega flywheel and pressure plate with the disc above. A couple things to look out for are if the disc splines are all the way onto the input shaft. Don't use the Chevy 6 cylinder pressure plate as it's huge. Also look out for the sprung hub hitting the flywheel bolts. Use thinner MR Gasket flywheel bolts if it looks wrong. You're on your own for a throwout bearing. I can't remember.

Check this web site to search for salvage parts. www.car-parts.com
It's a salvage yard locator. I got a Vega flywheel for $30 and $10 shipping. Pressure plate and disc from Oriellys were $39 and $14.

------------------
Superdave
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[This message has been edited by superdave (edited March 07, 2003).]

tilley88
Member
posted March 08, 2003 12:26 AM
OK, here's my 2 cents. I don't know squat about the Jeep set-up(sounds complicated). I have run both Vette and Vega set-ups. Vega weighs 27 lbs. total, Vette 34-35. If you can find a Vega flywheel, have it turned, if nothing but to clean it up. It won't last as long as the Vette set-up, but it is cheaper. The Vette set-up has better grip, believe me. Dollar per dollar, the Vette set-up is better. Get the 16 lb. Ram flywheel from Speedway, a Vette clutch and Pressure plate from the 'Zone(same as Camaro/Firebird), and let the rpm's fly!


superdave
Member
posted March 08, 2003 12:37 PM
The vette flywheel nor the Speedway fywheel is legal in IMCA. Good units yes but the first poster asked about IMCA Hobby Stock.

Good luck,

------------------
Superdave
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tilley88
Member
posted March 09, 2003 01:05 AM
Ah, rules!


c21
Member
posted March 10, 2003 10:55 AM
The Vega flywheel is 153 tooth.

I'm guessing that 16 pounds was to keep everyone from going out and buying a flywheel to stay competitive. The nodular flywheel for later model (3" bolt circle) crankshafts is listed as "aproximately 16 pounds". I haven't weighed one either. It's a gamble and if surfaced what will it weigh? Expensive at $250. Not as cheap as the old one. Plus you need a later model engine?

If I saw a nodular flywheel on a car I would have them take it off and weigh it. You can't see the bolt pattern while it's on the car to tell which it is. Digital bathroom scale should work well enough. They are easy to spot as are the billet types. Personally I just borrowed one of our racers Vega flywheels and measured it after machining to get an idea of how thick it should be. I have the other various flywheels and clutch combos that I know about so I am familiar with those. If it looks too light to me, the racer will have to take it off and we'll weigh it at the track. Seems harsh maybe but it's fair.

The MOI of any of these is debateable but from a driveability and reliability standpoint the larger clutch and flywheel would be a better choice. Then again the others have proven reliable also with a low horsepower motor like IMCA Hobby Stock. It's such a game of inches anymore. The place to spend if you have to is a better quality disc that has higher grip but is still has an organic lining.

If you want to avoid taking your flywheel off at the track then get your tech familiar with what's being used. If you're legal and know what isn't then help him now so he knows what to look for.

Good luck,

------------------
Superdave
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neil rucker
Member
posted March 15, 2003 08:49 PM
SUPERDAVE, thanks for the info on AMC clutch. what year model GREMLIN and what engine size? i have decided to go this route if ican find out this info. thanks. neil


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