Aluminum or cast iron flywheel

CarMichael Angelo · Apr 21, 2013

So I get the trans outta the car today (heavy sonofabitch). 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?

GroverDill · Apr 21, 2013

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

CarMichael Angelo · Apr 21, 2013

GroverDill said:
I got a new surface for my aluminum for 79 bucks.

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

90lxcoupe · Apr 22, 2013

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.

Gearbanger 101 · Apr 22, 2013

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.

85_SS_302_Coupe · Apr 22, 2013

madmike1157 said:
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?

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.

Gearbanger 101 · Apr 22, 2013

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

RangerJoe · Apr 22, 2013

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

CarMichael Angelo · Apr 22, 2013

90lxcoupe said:
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.

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.

Gearbanger 101 said:
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.

Only Billet steel (259.00) or aluminum (389.00) offered for an 8 bolt crank.

85_SS_302_Coupe said:
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.

Meh,..street car, always will be as long as I own it.....I prefer the street manners.

Gearbanger 101 said:
Aluminum flywheels don't generate the inertia that the steel ones do. They may rev quicker, but they also need to be revved higher.

I agree.

RangerJoe said:
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

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.

srtthis · Apr 22, 2013

RangerJoe said:
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

i dont remember them being aluminum...

RangerJoe · Apr 22, 2013

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

Gearbanger 101 · Apr 22, 2013

Interesting.

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

84Ttop · Apr 23, 2013

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

Gearbanger 101 · Apr 23, 2013

madmike1157 said:
Only Billet steel (259.00) or aluminum (389.00) offered for an 8 bolt crank.

Nah, you can get them in Nodular Iron as well.

http://www.mustangpowerparts.com/fora99flnoir.html

CarMichael Angelo · Apr 23, 2013

Gearbanger 101 said:
Nah, you can get them in Nodular Iron as well.

http://www.mustangpowerparts.com/fora99flnoir.html

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?

clement · Apr 23, 2013

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.

Gearbanger 101 · Apr 23, 2013

madmike1157 said:
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?

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

reldla1996 · Apr 23, 2013

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....

Gearbanger 101 · Apr 23, 2013

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.

CarMichael Angelo · Apr 24, 2013

Gearbanger 101 said:
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

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.

Aluminum or cast iron flywheel

CarMichael Angelo

my rearend will smell so minty fresh,

GroverDill

GoldMember

CarMichael Angelo

my rearend will smell so minty fresh,

90lxcoupe

Gearbanger 101

Straight Outta Locash

85_SS_302_Coupe

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

Gearbanger 101

Straight Outta Locash

RangerJoe

I leave the horn on while driving

CarMichael Angelo

my rearend will smell so minty fresh,

srtthis

the guy doing it does every local racers rear end

RangerJoe

I leave the horn on while driving

Gearbanger 101

Straight Outta Locash

84Ttop

They make new pistons every day, so why worry?

Gearbanger 101

Straight Outta Locash

CarMichael Angelo

my rearend will smell so minty fresh,

clement

Gearbanger 101

Straight Outta Locash

reldla1996

Member

Gearbanger 101

Straight Outta Locash

CarMichael Angelo

my rearend will smell so minty fresh,

Similar threads

Aluminum or cast iron flywheel

my rearend will smell so minty fresh,

GoldMember

my rearend will smell so minty fresh,

Straight Outta Locash

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

Straight Outta Locash

I leave the horn on while driving

my rearend will smell so minty fresh,

the guy doing it does every local racers rear end

I leave the horn on while driving

Straight Outta Locash

They make new pistons every day, so why worry?

Straight Outta Locash

my rearend will smell so minty fresh,

Straight Outta Locash

Member

Straight Outta Locash

my rearend will smell so minty fresh,

Similar threads

Privacy & Transparency

Privacy & Transparency