I did decide just to go with the stock dual mass flywheel and G6 clutch. Clutch was $187 delivered, Flywheel was $387, both are here. The cost is not that different from a custom clutch and Camaro flywheel, it is all brand new, and a replacement clutch is not that expensive. Flywheel weight is not THAT bad, about 24 lbs. Bolt pattern and pilot diameter are identical to the 2.8/3.4 flywheels. Flywheel "looks" to be neutral balance, I will check it to be sure.
Not finding the flywheel bolts that readily. They would be 10mm 1.0, same as the 2.8/3.4, looks like 25mm would be about right. Local GM dealer just shrugged, online parts store skip right over the bolts. The bolts apparently have a plastic sleeve around the OD to center them in the oversized flywheel bolt holes - I can make these if I need to. I have our local bolt supplier looking for them (Tacoma Screw), but wondered if anyone else has seen a source for the bolts.
Thanks to everyone who posted, I will post on the MU9 when it is running.
McMaster.com has some M10 x 1.0 - 25mm class 8.8 bolts (part # 91180A553) box of 25 for $7.15. The 8.8 class is a little weak for pressure plate bolts.
If the thread pitch is 1.25, then there is a socket head class 12.9 M10 x 1.25 - 25mm (part # 96144A256) box of 25 for 8.60
Are you sure they are M10? Are they the same as the Iron Duke? ARP lists the Iron Duke bolts as 7/16-20 (which they have as a kit for the flywheel). They also sell individual bolts in different sizes, if there isn't a specific kit (don't see any 60 deg V6 bolt kits).
These are the flywheel bolts, so I would tend toward 12.9. The dual mass flywheel has oversized holes, I saw a thread on the G6 forum where someone had mentioned that they had a little plastic sleeve around them, to take up the slack. Also needs a fairly bid head, but the overlying "other half" of the dual mass flywheel has pretty small holes to access the bolts through, so will need to be 12 point or Torx heads.
I did find another dealer who listed them, bought them from him, they should be here in a couple of days. I am concerned, however, they were only $1.78 each - I have afeeling they will be wrong, just because it sounds too cheap.
The OE bolts are Allen head bolts and were so hard to find I had to have the salvager I purchased the flywheel from go back and look for the originals he took out as the passages for the bolts were not big enough for a reasonable size socket to fit through and install a conventional type bolt of my liking.
The rattle varies with every different clutch and engine combo so it's inherit of the transmission, for some it's worse and others little to unnoticealble. My first F40 was quiet with the dualmass, and noisy but manageable without it by raising idle rpm a little.
[This message has been edited by Joseph Upson (edited 08-08-2013).]
Interesting thread. I will soon have an F40 on a LZG engine. Bolts were a bit tough to find for the flywheel. ARP sells a set that works for the Mustang, however you'll need to turn down (grind) down a socket's OD to get them into the holes in the flywheel.
I'd really like to understand the noise issues better. Is the noise present with the OEM flywheel or only non dual mass flywheels?
As for harmonics the 3.4 TDC harmonic signature should be very similar to the 3.9L. The 3.9L crank is almost identical to the 3.4 crank in any spec that effects harmonics (same stroke being the key one). The 3.9 Crank does have larger journals and may be a bit heavier than the 3.4 which can shift the vibration profiles slightly... but I think the dual mass flywheel will be fine with a 3.4 TDC. Actually I'm quite interested to hear the results on this one though I'm guessing you're not the first to use this combo. I would however love to hear a comparison between the 2006 and 2007 trans.
Originally posted by FieroNate: The 3.9L crank is almost identical to the 3.4 crank in any spec that effects harmonics (same stroke being the key one). The 3.9 Crank does have larger journals and may be a bit heavier than the 3.4 which can shift the vibration profiles slightly...
The larger journals overlap more, which increases crank stiffness significantly.
I realize this is an older thread but I'm curious as to any further research into the F40 rattle issues, if there is now another flywheel available, or even if any of you might have a stock G6 3.9 flywheel collecting dust that you would part with. I have an MU9 F40 that I want to use with a 3.9 and need a flywheel!
There is a G6 Flywheel in the first pic, I suppose I don't need it any more. It comes with a clutch and pressure plate but they are used, and not much life left in them. No bolts. PM me and we'll see about it going your direction.
Oh, and by the way, mine rattles too. Not terribly bad, but it definitely does. When I first started the engine it was the worst, but after driving for a while, it calmed down a bit. The symptoms were exactly as described above.
But, In looking at the original G6 clutch, its torsional dampening springs are only rated at just a few lbs. So it takes only a little bit of force to collapse them entirely. It appears that they did this to absorb inertial differences between the clutch disk and the transmissions internals. Theoretically it would help the synchros and dog collars find their homes during shifts by not having to line up the two "heavy" weights exactly, instead compressing the clutch springs slightly. These may have had the effect of eliminating the rattle in the transmission too inadvertantly.
My ClutchNet disc's springs are probably good closer to 50-100 ft-lbs to compress, so they are for engine torque loading solely.
[This message has been edited by Fierobsessed (edited 06-07-2015).]
Fierobsessed, not sure if the PM actually went anywhere, but I'm interested, so please PM me back!!! Dobey, thanks, but I think you're correct - it is G6 GTP specific
[This message has been edited by alpine67 (edited 06-08-2015).]
This is acctually in a 89 Buick Reatta but still applies.
The F40 bolted to the 3800 transmission is extremely noisy, an issue that seems common to using the 3800 with the F40. The only answer I had found was turn up the idle. As for me a 1200 rpm idle is not something I was will to live with. After researching for quite some time, I came to realize that the noise was most likely due to the transmission normally being used with a dual mass flywheel. Well good luck finding something that was never produced. Spec clutch (who produces the clutch for this swap) was no help. After even more research I found that GM, AKA Holden, actually produced a DMF (dual mass flywheel) for the 3800, and amazingly one of the applications had the same tooth count as the current flywheel and spline count as the F40.
So after doing Uncle Sam's bidding in Guam for a year I got back to repairing the car. I never was able to get all the measurements for the Holden clutch/DMF. Really sucked because the cheapest clutch and shipping was $1200. Seeing that the engine had to come out I decided to pull the trigger and ordered the clutch, this was a huge gamble as it is for a RWD car. Thank fully the clutch was a perfect match with the Spec measurements. So I reused the Spec slave and throw out bearing (actually a SAAB part). I have not put many miles on the new clutch, due to the car not being registered yet, but all indications are that it is the perfect solution for anyone that has done or wants to do this swap. Also the clutch will handle, at least stock power from the series 2 SC engine, as it is used in a SC car for at least two model years. Also my next build will be a Fiero.
