Aluminum or cast iron flywheel

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by madmike1157, Apr 22, 2013.


  1. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    So I get the trans outta the car today (heavy sonofa****). The clutch pedal was insane for a street driver, and it engaged way too high,..evidence that it was in need of replacing.

    I get it out and find a Mccleod pressure plate bolted to an FMS aluminum flywheel. Both are toast.
    Spec told me that they could rebuild the aluminum flywheel w/ a new insert, but I don't know how much yet.
    I know that the purpose of an aluminum flywheel is to rev more quickly, and that it won't lose as much RPM between gear changes,...I also know that it sacrifices low end off the line dig.

    The question is this: I expect the rebuild to cost as much as a new cast iron replacement. Given the fact that I could care less about the "benefits" of the aluminum flywheel for a 99% street driven car, am I stupid for considering replacing it w/ a cast piece?
     
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  2. GroverDill

    GroverDill GoldMember

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    I got a new surface for my aluminum for 79 bucks.
     
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  3. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    well,..if it is that cheap,...I'll stay w/ what I got.
     
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  4. 90lxcoupe

    90lxcoupe Mustang Master

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    Take it to a local machine shop with a blanchard grinder and see how much to put a new surface on it. I cant imagine they would charge more than 50 bucks.
     
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  5. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    See what a billet steel one will run ya. They're tough and not that much more expensive than iron. I think I paid an addition $75 over the cost of an stocker when I bought the one for my 331.
     
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  6. 85_SS_302_Coupe

    85_SS_302_Coupe it sucks (I know) to be on the receiving end

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    You have that mostly right, except the part about losing RPM between gear changes. The aluminum ones lose RPM much faster than iron or steel, because they have less mass which means less weight to keep them moving. Or in other words, once an iron or steel wheel is spinning, it stays spinning longer than the lighter aluminum version. The aluminum ones can also be tricky off the line and are easier to stall, but I prefer the quicker revs and less rotating mass myself.
     
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  7. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    Aluminum flywheels don't generate the inertia that the steel ones do. They may rev quicker, but they also need to be revved higher.
     
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  8. RangerJoe

    RangerJoe Advanced Member

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    My brother-n-law has an 03 cobra. He claims that they came from the factory with an aluminum flywheel. I don't know if this is true, as he is my only source in this. May just want to double check and see if that is whats supposed to be in there.

    Joe
     
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  9. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    It's pretty well burned, w/ some heat cracking and pretty deep scoring. I don't think that there is .060 before the rivet head will be exposed, even if there is the possibility to resurface it.
    Only Billet steel (259.00) or aluminum (389.00) offered for an 8 bolt crank.
    Meh,..street car, always will be as long as I own it.....I prefer the street manners.
    I agree.
    Whether or not it came that way, this one is hurt. Quite frankly I expected it to be Steel or Nodular iron, and fully expected to be able to resurface the thing. There is a place downtown that rebuilds clutches/flywheels/pressure plates. I plan on taking it down there tommorrow.
     
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  10. srtthis

    srtthis the guy doing it does every local racers rear end

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    i dont remember them being aluminum...
     
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  11. RangerJoe

    RangerJoe Advanced Member

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    Did quick google search. According to svtperformance, mcleod manufactures stock flywheel, aluminum, and must go back to them for resurface. Again, this is based on one strin of post off another sight, so take it for what it is worth.

    Joe
     
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  12. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    Interesting.

    That being said, just imagine how much snottier down low these cars would be with the heavier iron flywheel in place.
     
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  13. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    We swapped in a billet steel flywheel in my brother in laws when we upgraded the trans to 26 spline. I know he liked the steel one much better than the aluminum
     
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  14. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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  15. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    I did a similar search based on your link. He's the only guy in North America w/one.
    Have you ever bought from this guy?
     
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  16. clement

    clement Founding Member

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    ive never tested an aluminum flywheel vs. a steel one. however, I have freshened an engine and went from steel rods to aluminum rods saving almost 400g per hole between the lighter pistons, lighter rods and some very light wrist pins. then the weight savings from pulling mass out of the crank to get it all to balance. the car picked up .3 and 1.5 mph in the 1/8 mile over the heavier reciprocating assembly. went from running 6.30s and 6.40s to 6.0s and 6.teens naturally aspirated.
     
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  17. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    Can't say that I have. I don't think Ford even makes them anymore, but he may still have them in stock. They must not have been a popular item....but I'd say if they're good enough to have in 6-bolt form, they should be just as good in 8-bolt. It think they were standard on the old Windsor's, but probably didn't sell many, as only the trucks (many of which were not manuals) and '99-'00 Mustang were Windsor's.

    In any case, it's worth a shot to save yourself $100
     
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  18. reldla1996

    reldla1996 Member

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    When my 89 had a 306 with roughly 300 rwhp, I switched it to an aluminum flywheel, and loved the way it rev'ed, but it definitely stalled a lot easier. Now that the 89 has a 369, there are no negatives to the aluminum flywheel, in my opinion, less weight (rotating weight), quicker rev'ing, and no issues with stalling. On the 04 Cobra, I've not noticed any issues with the aluminum flywheel, and less weight is a plus with that car....
     
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  19. Gearbanger 101

    Gearbanger 101 Straight Outta Locash Super Mod

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    The point of the aluminum flywheel isn't so much to promote quicker revving per say (although that is a benefit), but more to provide less rotational mass and transfer of engine harmonics in high horsepower, high RPM situations. An aluminum flywheel is less likely to vibrate, or fly apart than an iron one when pushed hard.

    Same principal as an aluminum driveshaft.
     
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  20. madmike1157

    madmike1157 the humor is still lost on me SN Certified Technician

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    here is his reply to my inquiry:

    Was available the site is not updated that's why it's still up
    JOHNNY'S MOTORSPORTS
    Parts - Service - Dyno tuning
    Text: 514 690 2441

    It looks like aluminum comes stock w/ a Cobra. Mine has a factory (non-Motorsport) part number on back. Took it and had it faced,...had to cut it so much the steel friction surface is now only .125 thick. The whole freakin flywheel looks more like a flexplate now than a manual flywheel. I'll not be running that piece.
     
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