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 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.
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, 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...
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 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.
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.
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.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
For what it's worth, I watched a ton of YouTube videos, and found several websites that showed before and after dyno curves, and there seems to be a 1.5-2% increase in horsepower across the entire RPM range with a lighter flywheel (some were lighter comparatively than others). They all seemed to say the same thing though, not to expect a better quarter mile "drag time" with a lighter flywheel, but that the flywheel helps on road courses (as you guys said).
Regardless, I'm not building the car to drag race, but to enjoy the car through upshifts and downshifts.
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.
I'm sure whatever washers you are using have sharp edges removed, and were carefully inspected, but ARP's instructions explicitly state to NOT use any kind of washer under the bolt heads.
quote
Originally posted by La fiera: 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.
This is a documented material property, in engineering terms, it's referred to as "creep" it can occur with or without cyclic load changes.
------------------ "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.
I don’t see why a suitable washer couldn’t be used beneath an ARP bolt.
Probably some folks used soft washers beneath a highly-tightened ARP bolt, and then when the washers creeped, customers blamed ARP for bad bolts that loosen.
Their instructions most likely originate from problem customers in the past.
I don’t see why a suitable washer couldn’t be used beneath an ARP bolt.
Probably some folks used soft washers beneath a highly-tightened ARP bolt, and then when the washers creeped, customers blamed ARP for bad bolts that loosen.
Their instructions most likely originate from problem customers in the past.
I agree, I didn't inquire as to why my Coyote bolts have heads that are as big as the washers I was going to use, so I omitted them.
------------------ "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.
I'm sure whatever washers you are using have sharp edges removed, and were carefully inspected, but ARP's instructions explicitly state to NOT use any kind of washer under the bolt heads.
Yes its very obvious! That's because the Coyote engine doesn't have an aluminum flywheel.
