Flywheel and Clutch questions

mattpatt · #1 (**permalink**) 10-17-2010, 08:50 PM

I've taken the plunge and, thanks to a number of member here, I am installing the engine myself. The engine is a Keith Craft SBF 427 pulling 550 hp on the dyno (probably 450 installed?). It's carbureted and should idle ~700 - 800 RPM (air gap manifold, hydraulic roller lifers). The car will have the standard 3.45 rear. The tranny will be a T56 Magnum with 2.66 first. I expect about 50 mph in first at max RPM of 6200 with the tire I'm lookig at. This car will be driven on the street only and only in "nice" weather (California). My questions for you guys are:

1) Flywheel weight. Seems that aluminum (~16 pounds) would be fine since the car is so light. But what about engine vibration at idle? How about clutch life?

2) Clutch recommendation? I thought the Mcleod RST twin would give lots of life but I understand they grab very agressively - too much for the street.

3) rECOMMENDATIONS ON A SLAVE SETTUP - i DON'T WANT A HYDRAULIC BEARING (HAVE PLENTY OF ROOM FOR AN EXTERNAL SETTUP

THX

mATT

bobcowan · #2 (**permalink**) 10-17-2010, 09:44 PM

For your application, alum or steel flywheel will feel about the same. In racing, the light weight whel will rev up quicker, and drop down quicker, and that can be a benifit. They drive about the same.

I use a Centeforce Dual Friction 10.5" clutch and pressure plate. Very smooth off and on. No chatter. easy to modulate. moderate pedal effort with a cable. Durable, too. I can get about 3-4 seasons out a clutch.

xlr8or · #3 (**permalink**) 10-17-2010, 10:16 PM

For question #3 talk to Mike Forte one of the sponsors here. He has a great external slave setup and can hook you up with a clutch package as well.

www.fortesparts.com

PANAVIA · #4 (**permalink**) 10-17-2010, 10:55 PM

External slave is non issue, Alum flywheel should not increase engine vibration by an overt amount.

What chassis number are you getting - do you have >?

There is a new Diff that is from ZF, not like the old DANA diff.

Steve

blykins · #5 (**permalink**) 10-18-2010, 02:50 AM

Feel free to give me a call. 502.759.1431 I can answer any and all questions that you have.

A lightweight flywheel is not necessary, but some prefer it. I like the heavier flywheels on cars with higher rearend ratios, bigger cams, and engines with power higher up in the rpm range. Certainly neither one will cause any vibration issues. If you do a lot of stop and go driving, I'd opt for the heavier flywheel. You tend to slip the clutch a little more with really light flywheels.

The RST is a very nice clutch, but is very overkill for your application. The thing with a twin disc is that they provide tons of clamping force for higher horsepower applications, but pedal effort is like the pedal effort in a new production car -- hardly noticeable. You will spend almost $750 for an RST clutch...again, unnecessary for this kind of application.

There are plenty of single disc clutch applications that will handle the amount of horsepower you're making and still have excellent street manners. They won't break the bank either. RAM and McLeod both make excellent choices for this scenario. If given the choice, I would stay away from manufacturers like Zoom, Spec, and Centerforce.

A typical slave cylinder/clutch fork setup will work perfectly fine for you and will be very cost effective. Make sure you talk to me or someone else that's qualified to work with the Magnum transmissions as sometimes they require a little modification to match up easily in certain applications.

This is a very easy combination to supply parts for....I do it on a regular basis.

vector1 · #6 (**permalink**) 10-18-2010, 07:30 AM

kc ought to have a pretty good selection and ideas on the flywheel/clutch setup.

mattpatt · #7 (**permalink**) 10-18-2010, 08:15 AM

Quote:

Originally Posted by PANAVIA

External slave is non issue, Alum flywheel should not increase engine vibration by an overt amount.

What chassis number are you getting - do you have >?

There is a new Diff that is from ZF, not like the old DANA diff.

Steve

The chassis number is 3033 so it will have the new diff. For the T56 Magnum I'll have to remove the welded frame member with the tranny mount and relocate it back a few inches.

mpanten · #8 (**permalink**) 10-18-2010, 08:52 AM

The Mcloed twin disc is perfrect for the street. I love it. I switched from a lightweight aluminum to a steel flywheel. Didnt notice a ton of difference. Personal opinion is spend the money on the twin disc, as brett said it is like driving a new car as far as clutch pedal feel, and go with the steel flywheel if you want to save the money.