Sorry if im beating this to death but... I did a 3800 swap and have serious vibration when reving the motor. At idle its not too bad. When I rev it it has a strong vibration. Im thinking it has to be the flywheel. The flywheel was machined but not balanced. Some say they dont need to be balanced. Also Im curious if I should have considered the counter weight (if it has one) and installed it a certain way. I just lined up the holes and bolted it down.
I would love to avoid dropping the cradle and taking it back apart but I dont know what else could cause that type of vibration. It sounds like its running smooth and idles nice. Just vibrates very hard when reved. I went up to 1500 + RPM's and it just got faster.
If you are doing a 3800 Series 2 or 3 supercharged swap with a manual transmission...
The 3800 Camaro flywheel you ordered has a different amount of external counterweight than the 3800 SC engines require. (I think the difference is about 40 grams or something like that.)
Furthermore, many of the aftermarket 3800 Camaro flywheels I have seen have balancing holes drilled into the face of the flywheel. Which means when they machine it down to work in a Fiero swap, you effectively remove these balancing holes - likely making the imbalance problem worse.
To add to the problems, I have seen a lot of new aftermarket 3800 Camaro flywheels that have serious casting voids (a defect that forms under the surface of a casting when it is made) that further contributes to the balance problem (but can also impact durability of the flywheel itself).
BOTTOM LINE - after the machining work is done to the flywheel, you MUST get it rebalanced to match the same amount of external counter-weight amount the stock 3800 SC flexplate has. Otherwise you will have vibration problems. And such problems could cause premature bearing failure within the engine.
A good machine shop should be able to balance match your flywheel if you also give them the 3800 SC flexplate. Some shops may refuse to do this service unless you give them the entire engine so they can do an entire engine balance job.
-ryan
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The balancing shop I worked with had no idea on how to balance flywheel to match the flexplate until I told them to bolt the two together 180 degrees out of phase and then balance the flywheel for neutral. (you don't want them adjusting the balance of the flexplate to match the flywheel)
btw, it wasn't my idea, I had just read it from the forum.
With my 87 GT 3800 swap, I had an aluminum flywheel that gave me serious vibration. I had it bolted up 180 degrees out. There were no markings on the flywheel to determine the proper mounting position. You might check if yours if its bolted up in the correct position.
I would have it balanced to the flexplate regardless.
Im lost. I dont understand what balancing the flywheel to the flexplate means. I mounted the clutch to the flywheel and installed it. Isnt a flexplate for an auto trans with a torque converter?
Im lost. I dont understand what balancing the flywheel to the flexplate means. I mounted the clutch to the flywheel and installed it. Isnt a flexplate for an auto trans with a torque converter?
The 3800SC is externally balanced. You need to have the flywheel balanced the same as the flex plate... One way of doing this is bolting the two together, with one turned 180 degrees and balancing it to neutral by modifying the flywheel, thereby creating the same balance bias on the flywheel that existed on the orginal flex plate. Nobody said anything about using a flex plate with a clutch.
[This message has been edited by carbon (edited 01-25-2014).]
You need to get the flywheel balanced. It has to match the balance on the flex plate. Yes, the flex plate is for an automatic. You have to get the flywheel balance to match the flex plate balance. As was said earlier, take them both to a machine shop to get it done. Also said earlier, the easiest way it to bolt the two together 180 degrees out and then balance the flywheel to neutral.
EDIT: Deleted erroneous info.
[This message has been edited by n7vrz (edited 01-25-2014).]
You do not need to take the engine in if you don't have the flexplate. The flexplates are replaceable and are not balanced to individual engines. As long as you get a supercharged engines flexplate, it will be correct for a supercharged engine. Get a flexplate from a wrecker or someone on the forums, and have the flywheel match balanced to the flexplate.
Just pulled the motor back out. Gonna split them tomorrow and see what I got. I do ave the flexplate from the original motor as it was manual. Ill call a machine shop or 2 and see if they know what Im talking about. Tanks all!!
While I appreciate people sending customers my way (already had some PM's from this thread), I do not sell anything pertaining to the 3800 engine swap and that includes their balanced flywheels.
Call your local specialty clutch disc maker. Every major city probably has one. The clutch shop may have balancing capability. If they don't, they will know a machine shop that does it.
If you can not find one, I have a shop here in Portland that does them and you can ship your stuff to them. They can be expensive but they do a perfect job. They did tungsten weights on my aluminum flywheel when they balanced it with the 3800 flexplate.
Just spoke with a guy at West Coast Fieros (didnt get his name) really nice guy. He said the flywheel shouldnt need to be balanced unless theres something really wrong with it. Im going to mount the flexplate and run the motor to see if it still has the vibration...
having work in a shop with balancing equipment..... our setup was only designed to balance a crankshaft/flywheel assembly together. they would weigh the rods and bolt weights to the crank and spin the hell out of it. i don't know of other styles of balancing equipment, but that one type we had needed a crank.
if you wanted to get really picky you could bolt the pressure plate to the flywheel (indexed of course) and then balance it all.
[This message has been edited by conan469 (edited 01-27-2014).]
