I'm taking a V6 3.8 liter motor out of a 2001 Pontiac Grand Prix GTP and putting it into my Abnormal 944. The motor has a flex plate from being in the GTP with automatic transmission. The T5 manual transmission is from a 98ish Camaro. I have the flywheel (and the rest of the motor from the Camaro). Every time I read about adapting the flywheel over to replace the flexplate I get conflicting information about whether it needs to be balanced or similar. Who's done this successfully and what can you teach me? Thank you oh great and powerful hive!
If it's from a 2001 Grand Prix, it's a 3800, not a 3.8. Those are two different engines, welcome to GM 
That also means it's the same engine as from the Camaro, assuming '98ish means it had the 3800, so you just use it. (They should both be Series II) Assuming here that you are using the naturally aspirated version NOT the supercharged version.
I see what you mean, though. A lot of people claim the Camaro was internally balanced, and then claim that you have to machine the balance pad down when using on some configurations, which is contradictory!
I want the supercharger on the GTP. The Camaro motor is already in the 944. Now I'm upgrading.
In reply to Sparkydog :
Ah, then, if you're using the supercharged engine's bottom end, the imbalance is a little different.
In reply to Pete. (l33t FS) :
Legit question... since the 231 buick v6 (usually longitudinal), evolved (very little change) into the GM 3.8 v6, and (IIRC) evolved into the 3800 fwd (later referred to as series I) and then to the 3800 series II, does it still displace (approx) 3.8 L? I know that there were a TON ov changes by then, but isn't it still same family?
Holden's got other rwd 3800 II's , but I think f body's after 96 ish are only US?
In reply to 03Panther :
They all have the same bore and stroke, but the deck height changed significantly with the Series 2, and at some point the valve order changed as well. They're... weird. IIRC the head gasket pattern stayed the same, as did the oil pan pattern, and you can put a gerotor-pump timing cover on a 3.8 to eliminate the rather crappy external pump... but so much other stuff changed over the years. And I won't even get into the differences between an even fire and odd fire 231, because I think I have seen only one oddfire and I was six. (my Mom had a '77 Century. Even then that might have been even fire)
I've seen the odd fires in old Jeep's. But it was still a 231, 3.8 liter, 3800 cc V6
In reply to 03Panther :
Ayep. But "3800" was a proper noun name given to it, to differentiate it from the older engines.
Sort of like Ford 5.0 vs. 302. Two different engines, although one is derived from the other, displacement is the same, etc.
Not sure about GM, but Ford used to do this for engines being built at the same time. The 390 was a car engine, the 391 was the truck engine, for the main example I can think of. Same displacement, same engine family, but different enough to change the name.
pirate
HalfDork
5/4/21 11:55 a.m.
The bell housing for a T5 manual that fits on the 3.8 V6 is P/N: 12555802. This is a GM OEM Bell Housing for 3.8 (231 CID) V6, 96-02 Camaro & Firebird. This bell housing has an angled bolt pattern which tilts the T5 transmission toward the driver. I currently have one for sale on eBay.
The earlier S10 pickups from around 85 to 93 had a bell housing that mounted the T5 straight up and down and fit the 2.8, 3.1 and 3.4 60 degree V6's. I have seen 3.8 V6 mounted to these bell housings. Those P/Ns were 15679712 & 1406064 All these bell housings used hydraulic slave clutches you would have to do some research to find out what would work for you. I believe all 60 degree V6 engines produced after 1988 were internally balanced and prior to that used a weighted flexplate/flywheel.
I think I may have misread your post. I thought you were looking to convert engine to T5 not just looking for a Flywheel. Disregard if nothing applies.
In reply to Pete. (l33t FS) :
I'm just trying to find out if I need to rebalance the flywheel from the L36 when I bolt it onto the crankshaft of the L67.
In reply to Sparkydog :
The 3.8 in the Camaro IS a 3800 no matter how you look at it. It even has "3800 Series II" cast into the intake. Every single part on that engine is the same as the NA Grand Prix engine except for the intakes, throttles, oil pan/pick-up, and accessories. The RPO codes are the same, and the long blocks are interchangeable.
Now between the L36/L26 (NA) and L67/L32 (SC) the rotating assemblies and therefore external balances are a tad different. Whether you HAVE to rebalance the flywheel is dependent on how picky you want to be. In theory, if you just mirror balance the flywheel with the flex plate you would remedy the imbalance, but I learned that West Coast Fieros doesn't even bother rebalancing the flywheels for their L67 swaps. The reality is that nobody has noticed any issues with with interchanging these parts after 50k+ swap miles and if you truly wanted the balance to be correct, you would need to disassemble the entire short block and rebalance the rotating assembly with balancer and flywheel as a set.
I'm pretty picky with stuff like that, but it's not worth the money or hassle in my opinion. I would just throw the Camaro flywheel on the GTP engine and call it a day.
In reply to V6Buicks :
Thats just a cover; although it may also be in the intake somewhere, I never cared enough to look.
But 231 cu in = 3.8Liters = 3800. The rest is just naming preference by GM. Now the L67, and those designations, they tell the correct story! 
Chevy tried to confuse the issue in the carb'd days by having two diferent 3.8 V6's, the buick derived one, and a short lived chevy 3.8. Either could be bought in a chevy!
Another point of confusion came from pre 95 F bodys having a chevy V6 (60 deg) and later F bodies having the 3800 90 deg. engine. So if a F body guy just refers to his V6 being different than a FWD V6, he may, or may not, be right...
Glad someone was finally able to answer the OP's actual question. I thought that was the answer, but not sure enough to say it. Thanks
In reply to 03Panther :
but I'm talking about the F-body 3800. The F-body has the designation cast into the factory intake, and the intake is the only real difference between a FWD and RWD 3800.
You would be right about the early 4th-gens having the oddball engine, but that isn't even a 3.8. It's a 3.4 which is not the same as the 3400. I think that's where all of the confusion lies.
FWIW I posted the same question (albeit better worded) on the grandprixforums.com. This site doesn't get as many eyeballs as it once did - so thus far this is the only useful response:
"i spent 200$ to check 8 flexplates and 2 meziere rebalanced
early SII L67's could be either 21 or 22 ozin. fwd/rwd na is 20, meziere is 20, later L67/l32 is 21.
lookup a Balancestar location near you or find a local machine shop.
if your not beating the hell outta it and keeping it under 6krpm...youd probably be ok as is.......but if your factory tollerances are closer to 22oz inch (remember these engines are getting tollerance stacking during assembly and can be anywherre on the tollerance bellcurve."
Here's an action shot of my L36/F-body/3.8/3800/1st motor going into the 944 back in June of 2018.
And here's the recently harvested L67/W-body/3.8/3800/2nd motor awaiting it's next life with a flywheel instead of a flex plate.
In reply to V6Buicks :
Good picture. At a glance I had assumed that was a cover as well. It actually looks pretty good cast in like that.
Yep, the 60 deg V6 being in some 4th gens, and the 90 deg also, does cause some confusion for some f body guys. But it was around late 70's chebby had a 3.8 V6, that was different than the buick 231 derived 3.8V6. I've never seen one in the wild, they didn't have it long, it apparently was not well liked, and I know absolutely nothing about them (other than its not based on a buick 231!)
All of this is just for info... not really pertinent to the OP's question! I just like little details.
