Best flywheel for a 3.4 V6/60 with a 5-Speed Getrag? (Page 1/2)
82-T/A [At Work] OCT 08, 04:26 PM
Hey guys, I'm starting to acquire parts for my 3.4 build... and I'm curious whether or not I should go with a stock 88 neutrally balanced cast steel flywheel, or if I should go with the Fidanza lightweight flywheel... or if there's an even better option?

Here's what I'll have (at the end of the day)

3.4 V6/60 F-body motor
.020 overbore DOHC pistons (9.7:1 compression)
H272 Crane Cam w/ roller rockers
WCF Stainless shorty headers and 2.5" stainless exhaust all the way back
17# injectors
(probably) EZ EFI 2.0 Controller w/ MSD 6EFI Ignition
SI Stainless Valves with Ported cyl heads
Port matched intake pieces, w/ bored throttle body and (eventually DAWG mod)

I'm shooting for 200 reliable HP.

It's going to have a 5-Speed Getrag that will (if I can get it to work), the internals for the Oldsmobile SCX gearing (3.94:1 final drive).


With all of that said... do I want a stamped steel flywheel, or do I go with the lightweight one? How is one better than the other?

I know it needs to be neutrally balanced...


Thanks!
lou_dias OCT 08, 05:11 PM
I use the Fidanza flywheel. It's aluminum with the replaceable contact area. Some people say you have to use washers on the bolts but I haven't had any problems with them backing out of the crank.

Driving-wise, it's easier to stall the car shifting into 1st but it nets you more power the faster you spin it.
Patrick OCT 08, 06:05 PM

Todd, you need to re-read your thread from five years ago. Flywheel and 5-Speed Getrag Questions


quote
Originally posted by lou_dias:

Some people say you have to use washers on the bolts but I haven't had any problems with them backing out of the crank.



Lou, I wonder if you've not had any trouble simply because your drivetrains are probably not being used for tens of thousands of miles (before being pulled).
lou_dias OCT 08, 08:10 PM

quote
Originally posted by Patrick:


Todd, you need to re-read your thread from five years ago. Flywheel and 5-Speed Getrag Questions

Lou, I wonder if you've not had any trouble simply because your drivetrains are probably not being used for tens of thousands of miles (before being pulled).



A fair point... But when they are used, they take a lot of abuse...
82-T/A [At Work] OCT 08, 08:25 PM
Sounds like a plan. That old thread I posted was a lot of fun Patrick (hahahah)...

Thank Lou, I'll order one tonight.

I'm concerned about the larger bolt holes... I wonder if it's a different part number, or if there was something weird there?

I'll get new bolts for this too... we re-used the bolts (with thread-locker) for my daughter's flywheel, but that was an Iron Duke.
Raydar OCT 08, 10:02 PM
My 3.4 DOHC is getting a stock V6 flywheel.
BillS OCT 09, 12:41 PM
I just machined the stock 3.4 flywheel to lighten it before balancing the engine.
ericjon262 OCT 10, 07:38 PM
I'm using the Fidanza as well, I used Ford Coyote ARP flywheel bolts, they have really big heads and distribute the clamp force over a larger area, I haven't had problems with them backing out, but the car also doesn't have a ton of miles on it. The bolts need to be shortened about .030 IIRC, or they bottom out before clamping. measure yours and be sure.

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

La fiera OCT 10, 09:53 PM

quote
Originally posted by ericjon262:

I'm using the Fidanza as well, I used Ford Coyote ARP flywheel bolts, they have really big heads and distribute the clamp force over a larger area, I haven't had problems with them backing out, but the car also doesn't have a ton of miles on it. The bolts need to be shortened about .030 IIRC, or they bottom out before clamping. measure yours and be sure.




I have the same set up as well with wider hardened steel washers in between the bolts and the aluminum flywheel to give it more area of clamping force but I use blue Loctite on the threads. Reason being because I do lots of transient on/off the throttle and the on full power is longer and more repetitive than average. The washer acts as a buffer between the bolt and flywheel spreading the force over an much ample surface. The problem with aluminum flywheels is that if you don't take into account the aluminum expansion rate depending on how fast you heat it up, the gap between the flywheel and the bolt shrinks which is great but it starts to gouge or eat the aluminum over time if you don't use a washer and a gap gets created and that is when the flywheel gets loose even though the bolts are in the same place they were torqued.
Dennis LaGrua OCT 11, 03:36 AM

quote
Originally posted by Raydar:

My 3.4 DOHC is getting a stock V6 flywheel.



IIRC the 3.4 DOHC engine uses a neutrally balanced flywheel for an internally balanced engine. I believe that Ed Parks may have also used them on his 3.4L P/R engine swaps.They were slightly heavier than the stock 88 Fiero flywheels but apparently they worked for that application.

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