Hey guys I need some info
I am in the process of getting parts for a 3.8SC swap with a 5 spd.
I had a Camaro flywheel cut down to .840 ,
now I am having a hard time finding someone who can "balance it to match the 3.8 flex plate"
I have talked to 3 diff machine shops and they keep referring me to another shop saying that they can't do it.
Here are a couple of questions:

Is the Camaro flywheel neutrally balance ?
what is so hard about balancing the flywheel to match a 3.8 flexplate ?

Is a 3/4" length bolt long enough to attach the flywheel to the crank ?
I got some 1" length bolts and they seeam to be too long.

Do any of you know the size of bolt to get to bolt the preasure plate to the flywheel ?

Thanks for your help guys

when I got mine done it took me a few calls to get a machine shop that did it. to answer your questions

- yes the camaro flywheel is neutrally ballanced.
- i'm not sure but the shop that ended up doing it was a well known performance machine shop up here in CT, you might have to find a similar shop.
-dont use any old bolt or you might end up like this guy.... https://www.fiero.nl/forum/Forum2/HTML/094808.html

I will try and find the ARP part number for the bolts I used...

Jrgicehc
Did you take your 3.8 flexplate to the machine toghether with the flywheel ?
Or did you just take the flywheel and told them here I need this balance ?
thanks for the links.

I will be using grade 8 bolt to mount the flywheel per what fieroflyer wrote, but I am still not sure if the length he uses is 3/4 ":
I also need to find out the size of bolt I need to mount the preasure plate to the flywheel.

quote Originally posted by FIEROFLYER: I usually torque to 40 PSI with strong bolts grade 8 or ARP ones if you try and torque to 40 PSI with the ones some manufacturers supply they will break at just over 20 PSI. The clutch assembly bolts get 15 PSI to the fly wheel. Dan

your correct i had to bring the flexplate with the flywheel to the shop. as for the size of the bolt i wish i could help but i just avoided that whole situation and went with the ARP bolts.

/\ /\

Made a bunch of calls for an east coast Fiero owner on the same topic.

Still haven't found anyone who does flywheel balancing or rotational balancing in general. Seems these days all they do is weight balancing! Looks like the new engine iron doesn't require the same amount fo balancing as in the "old" days.

I'll let you know if I find someone.

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Marc in sunny Titusville, FL

• 84 SE son's car, loaded
  
• 85 Coup w/V6 transplant
  
• 85 GT newly on the road
  
• 86 SE/GT "The Chameleon" - big plans!

Hey Marc

I've call 3 different machine shops and every time I explain to them what I am doing they refer me to someone else.
The last guy I talked to is in Tavares Fl, the name of the place is JB Racing, he told me he could do it and suggested that I also take the preasure plate to balance it together with the flywheel, he also asked me to take him the flexplate.
I asked how much to balance it and he said about 150.00, I was a little surprised, that seams like a lot of money just to balance a flywheel.
One of the problems is that the place is about one hour away and they are only open mon-fri.
He also asked me if the eng is externally balance, I told him I did not know.
I'll talk to you on thursday at the club meeting.

You might check West Coast Fiero: http://www.westcoastfiero.c...rsion_flywheels.html

Regards,

David

MountainHiBlue87GT
Thanks for the link, but I need to find a place to balance the Flywheel I already have.

When I did my 3800 swap, on the advice of PBJ, I didn't bother with balancing the flywheel. that was 2006 and it's never been a problem.

Dave

[This message has been edited by Dave E Bouy (edited 03-02-2010).]

quote Originally posted by Dave E Bouy: When I did my 3800 swap, on the advice of PBJ, I didn't bother with balancing the flywheel. that was 2006 and it's never been a problem. Dave

Thanks for the tip but I am trying to do this only once and I really don't want to have take the eng down.

When I first did my swap I did not rebalance the flywheel. I also had a few tell me it wasn't necesary. I always had a strange vibration at certain RPM's that I no longer have since I swapped to the 65E-HD. I think the problem with the balance was the flywheel had balance holes drilled into the outer edge of the friction surface, so when the thickness was turned down those holes became "less deep" changing the original balance job.

If the Camaro 3800-II is internally balanced, then all 3800 Series 2 engines should be internally balanced, stick or auto, FWD or Camaro, blown or not. You could hardly expect otherwise from GM.

Mike
Thanks for posting, that is what I was afraid off and I really want to do the best job possible.

Isolde
From what I found the 3800SC is an externally balance eng.
That is why the flexplate have the big "weights" on them, I also found that some eng ( I am not sure about the 3.8 )
have a Harmonic balancer that has "weights" on them, to help balace the eng.

That is why I decided to have the Flywheel balance to the 3.8 SC Flexplate, instead fo the flexplate that came on the L26 eng.

BTW I am doing a top swap on a 3.8 NA eng.

The L36 (na) bottom end, is more or less neutrally balanced, with a slight offbalance. I would probably run a neutral balance flywheel on a L36.

In my 10 years doing it for a living, I've been lucky that none of the engines I've balanced were 90-degree V6s. I'm very very familiar with balancing V8s, modifying flywheels, and the dampers. But the 3800s just never come into the shops where I've worked, so I know very little about their specifics. I thought I had a good grasp of GM's tendencies, but it's not too much of a stretch for me to believe that maybe the supercharged 3800-IIs are balanced differently than the non-supercharged ( excuse me, dinnercharged :-) ) versions, if the pistons are heavier to cope with the forced induction. This seems reasonable, considering GM's history.

quote Originally posted by darkhorizon: The L36 (na) bottom end, is more or less neutrally balanced, with a slight offbalance. I would probably run a neutral balance flywheel on a L36.

NO 3800 Series 2 or 3 V6 is classified as "neutrally" or "internally balanced".

All versions of the 3800 Series 2 and 3 engines (SC and N/A) are EXTERNALLY balanced engines. Both the harmonic balancers/pulleys and flywheels/flexplates used on these engines have counterweights built into them - which means they are NOT neutrally balanced items. Furthermore, the SC versions of these engines have more external counterbalance (I think it is around 40 grams more) vs. N/A versions; which means not only do the flywheels/flexplates have different amounts of counterweight, but so does the harmonic balancer pulleys.

If you compare the counterweight on a 3800 S2 SC flexplate side-by-side with a counterweight on a 3800 S2 N/A engine, you will notice the counterweight is bigger/heavier on the SC flexplate vs. the N/A flexplate...



If you hang a "neutrally balanced" (something that has no counterbalance whatsoever) flywheel on a 3800 Series 2 or 3 N/A or SC engine, you will end up with a vibration and you will trash the bearings in your engine.

-ryan

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6+ years on this same swap -- NO engine or transmission failures...

Custom GM OBD1 & OBD2 Tuning | Engine Conversions & more | www.gmtuners.com

[This message has been edited by Darth Fiero (edited 03-04-2010).]

ryan. where do i, we, us, get a flywheel balanced?

quote Originally posted by tomsablon: ryan. where do i, we, us, get a flywheel balanced?

My local machine shop will do it for me if I take them the machined down flywheel and a flexplate I want it balance-matched to.

There was a guy on this forum offering his services to do this for mail-order a few years ago. But I don't know if he is doing it any more. His member name was: markviiisvt4

I also think WCF sells a 3800 flywheel already machined down to the proper thickness and balanced...but you will need to get the details from them.

Can you run a machined down flywheel that has not been balanced matched to what the SC engine needs (and just leave the counterbalance stock for an N/A engine)? Sure. But you will undoubtedly notice some vibration during certain RPMs. Is the imbalance enough to cause immediate damage? Probably not, but consider the amount of money you are investing in this swap -- do you really want to skimp here and not have this done which can possibly shorten the life of your engine? Keep in mind gaining access to it later if you decide you want it balanced will be no easy task -- you will need to pull the trans back out to get it off.

quote Originally posted by Darth Fiero: All versions of the 3800 Series 2 and 3 engines (SC and N/A) are EXTERNALLY balanced engines. -ryan

Ryan
Thanks a lot for confirming what I read

Would you please give me your opinion on this:

I am doing a top swap on a L26.....
I was planning on having the flywheel balace to the Flexplate from the SC eng
because I will also be using the SC eng harmonic balacer.
My reasoning is that the harmonic balancers are different and I wanted them to match the "balance from the flywheel to the balancer ".
am I correct to have the flywheel balace to to the SC eng Flexplate ?

Please let me know

quote Originally posted by 85LAMB: Ryan Thanks a lot for confirming what I read Would you please give me your opinion on this: I am doing a top swap on a L26..... I was planning on having the flywheel balace to the Flexplate from the SC eng because I will also be using the SC eng harmonic balacer. My reasoning is that the harmonic balancers are different and I wanted them to match the "balance from the flywheel to the balancer ". am I correct to have the flywheel balace to to the SC eng Flexplate ? Please let me know

Well here's the problem. If you are using the stock L26 (3800 Series 3 n/a) internals, then what you should use for external components are L36 or L26 parts. Using the SC balancer is going to put about 40 grams (if I remember this weight correctly -- it has been a while) too much imbalance on the front of the crank. Adding an additional 40 grams on the back by balancing the flywheel to SC engine specs is going to make the total imbalance WORSE, not better. You would be better off leaving the stock L36 balance on the flywheel if anything. The best thing to do would be to get a balancer with the SC pulley on it that is balanced for an N/A engine, or have an SC balancer balance-matched to an N/A balancer.

i bought a flywheel from wcf (cut down camaro flywheel ) . after looking at some of the info on the forum, to balance/not to balance i called chris at wcf. he said i was good to go .there flywheel was ready install. i guess they have it close? i did take them to a racing engine machine shop the( flexplate and the flywheel) .they wanted me to pull the crank , they wanted to balance the damper ,crankshaft and flywheel together. i wasn't going to do that so i took wcf word for it. ryan what your saying makes sense and that's what scares me. i don't want a problem aaarrhh!!!!!!!!!

quote Originally posted by tomsablon: i bought a flywheel from wcf (cut down camaro flywheel ) . after looking at some of the info on the forum, to balance/not to balance i called chris at wcf. he said i was good to go .there flywheel was ready install. i guess they have it close? i did take them to a racing engine machine shop the( flexplate and the flywheel) .they wanted me to pull the crank , they wanted to balance the damper ,crankshaft and flywheel together. i wasn't going to do that so i took wcf word for it. ryan what your saying makes sense and that's what scares me. i don't want a problem aaarrhh!!!!!!!!!

I have never known WCF to balance there flywheels but can't say 100% that they are not. In the end people have been running unbalanced flywheels for years and years with no issues. So you will be alright either way you run it so I wouldn't worrry to much about it.

Why not just call WCF and ask them....661.822.8111

For sake of arguement, lets say the balance difference between L36 and L67 parts is 40 grams on each end.

The debate: Is 40 grams enough to cause engine damage? I can't answer that outright. It depends on a lot of factors. I can say that something being 40 grams out of balance is probably going to cause a vibration you might notice from the driver's seat (depending on engine RPM) and it will probably wear more on the engine bearings vs. if the component had the correct balance.

If I were building an engine or doing a swap like this, would I feel comfortable sending something out the door that I knew had a 40 gram incorrect balance? The answer is NO.

Now I'm sure there are 100 different opinions on this out there. And I'm sure at some point someone else is probably going to jump in and say 40 grams isn't that much and they would have no problem running that. Just keep in mind this is YOUR car and you are the one that needs to decide whether or not you want to go that extra step and spend that little bit of extra money to make sure something is done right.

Disassembling your engine and taking everything (balancer, crank, rods, pistons, and flywheel) in to a machine shop to have a complete balance done would be the BEST thing to do. The second best thing to do would be to make sure the new flywheel and/or crank balancer you are using matches the counter-balance of the parts that came off your engine -- that way you could at least maintain factory engine balance which would certainly be better than throwing something on there that has 40 grams out from what was on it.

Just consider that most all engine swaps are a large investment. Seems to me it would be a bad choice to skimp on a balance-match job when you've already spent all of this money to do the swap in the first place. But that's just my opinion.

-ryan

quote Originally posted by Dave E Bouy: When I did my 3800 swap, on the advice of PBJ, I didn't bother with balancing the flywheel. that was 2006 and it's never been a problem. Dave

We've done stick swaps the same way and there have also not been any balance problems.
When the 3800 engine was assembled at GM, they didn't bother to take the time to balance each engine individually. Flywheels and flexplates were manufactured to be within a tolerance and they were used accordingly. As long as you don't intend to rev at 10,000 RPM the factory balance spec should work. However, many of the replacement flywheels are imported, being manufactured by the Communist Chinese so anything is possible.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, 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 "

quote Originally posted by Darth Fiero: Disassembling your engine and taking everything (balancer, crank, rods, pistons, and flywheel) in to a machine shop to have a complete balance done would be the BEST thing to do. The second best thing to do would be to make sure the new flywheel and/or crank balancer you are using matches the counter-balance of the parts that came off your engine -- that way you could at least maintain factory engine balance which would certainly be better than throwing something on there that has 40 grams out from what was on it. Just consider that most all engine swaps are a large investment. Seems to me it would be a bad choice to skimp on a balance-match job when you've already spent all of this money to do the swap in the first place. But that's just my opinion. -ryan

Ryan
I found a machine shop that is willing to work with me, he suggested that I balance the whole rotational assembly, I told him I could not do that, so he said that he would be willing to balance the flywheel to the flexplate and is also willing to try to balance the harmonic balancer, but ask me to get more info on how to balance the flywheel:
Do you know how the flywheel is balace to flexplate?
Is it by taking weight off the flywheel to make it the same as flexplate ? ( that doesn't sound right...???)
If you are not sure would you mind providing me with the contact info to the guy who does the balancing for you ?
You could pm the info if you don't want to post it here.
I am really trying to do this right and am hoping that it would last me quite a while.

Thanks a lot for all the info and advice

[This message has been edited by 85LAMB (edited 03-05-2010).]

quote Originally posted by 85LAMB: Ryan I found a machine shop that is willing to work with me, he suggested that I balance the whole rotational assembly, I told him I could not do that, so he said that he would be willing to balance the flywheel to the flexplate and is also willing to try to balance the harmonic balancer, but ask me to get more info on how to balance the flywheel: Do you know how the flywheel is balace to flexplate? Is it by taking weight off the flywheel to make it the same as flexplate ? ( that doesn't sound right...???) If you are not sure would you mind providing me with the contact info to the guy who does the balancing for you ? You could pm the info if you don't want to post it here. I am really trying to do this right and am hoping that it would last me quite a while. Thanks a lot for all the info and advice

First they will need to make sure they've got both your flywheel and flexplate indexed correctly. There should be a master hole on both that is slotted and narrower than the other bolt holes (where it bolts to the crank). If you got an aftermarket flywheel that does not have one of these master alignment bolt holes, you will need to work with your machine shop to determine which one is. All of the bolt holes are unevenly spaced so the flywheel/flexplate can only be put onto the engine one way. If it is off by just one hole, all other holes should not line up to allow you to put bolts in them.

Once they start the balance matching process, what my machine shop usually does is drills the back side of the flywheel to remove weight from it opposite from where the machine says it needs weight added to attain the proper counter-balance. Make sure they drill these holes in the back side and not in the face because if you ever needed to have the flywheel resurfaced, it would decrease the size of the balancing holes that were drilled in the face which could throw it back out of balance.

Ryan
Thank you very much for being so helpful,
I would give you another plus if I could

One thing that the guy from the machine shop said, is that the flywheel will be a lot heavier than the flexplate.
Just to make sure I explain it correctly to the guy.....

Does it matter that the flywheel will be heavier ?
Do you happen to have a picture of the back of a flywheel that has been balanced ?

Again thanks a lot

quote Originally posted by Darth Fiero: First they will need to make sure they've got both your flywheel and flexplate indexed correctly.

Are you saying that they should bolt the flywheel and flexplate together indexed 180* opposite each other and balance the system back to neutral about the axis of rotation?

quote Originally posted by Jefrysuko: Are you saying that they should bolt the flywheel and flexplate together indexed 180* opposite each other and balance the system back to neutral about the axis of rotation?

That's not what I'm saying at all.

The flexplate that came off the engine needs to be mounted to their balancing machine. The typical balancing machine an engine machine shop usually has is set up to spin a crankshaft, not just a flywheel or flexplate. My machine shop has a blank shaft they mount my flexplate and flywheels onto so I don't need to take them the crank out of a 3800. They then need to mark a part of the flexplate so they know how it is oriented when it is bolted on the crank (ie: where the counterweight on this flexplate is located in relation to TDC #1). They have just used the indexing bolt hole on the factory flexplates and flywheels I have taken them in the past. But the problem is I don't know if all aftermarket flywheels will be machined with this indexing hole in the same location or if it is even present at all. So they will need to make sure all of the bolt holes line up between the flywheel and flexplate so they know exactly where the counterweight's center of mass needs to be when it comes to setting up the balance.

Once they have the flexplate mounted up, they should run the machine and it should tell them how much out of balance it is - and note that amount. Then they should install the new flywheel, degree it into the same position as the flexplate was (in relation to where it would be on TDC #1 when mounted on the engine), and run the machine again. Then they should do whatever is needed (drill lightening holes in the correct location) to arrive at the correct amount of counter balance that matches what the flexplate was set up for and in the same location.

They should know what to do and what you are asking. If they're not sure what you're asking, tell them that 3800 n/a engines have a different amount of external balance than 3800 SC engines and you need to have the N/A parts rebalanced to match the same external balance of the SC parts you are bringing them to use as a reference. If they have no idea what you are talking about, either take them your whole engine to have a full engine balance done or find another machine shop.

does the said balancing machine spin, or does it just tell where the weight is off center?

quote Originally posted by Darth Fiero: That's not what I'm saying at all.

Thanks for the clarification

I have been thinking about doing this swap for a daily driver but have been put off by the large volume of bad information so thank you for all the clarification you have provided in this thread.

Ryan

Thanks you very much for the info
I will go and talk to the guy from the machine shop and hopefully he will be able to do it.

quote Originally posted by Genopsyde: does the said balancing machine spin, or does it just tell where the weight is off center?

Spin - and the machines I've seen use an optical sensor to determine the position of the flywheel (or crank) to determine where it is and where weight needs to be added or removed.

I'm glad to see that Darth posted some clarification with pics since my last visit. If you were to bring the flywheel and flexplate to me at any of the shops where I've worked, I would be able to make the flywheel have the same imbalance as the flexplate. It would run you around $50 in summer 2010 U.S. dollars.

quote Originally posted by Isolde: I'm glad to see that Darth posted some clarification with pics since my last visit. If you were to bring the flywheel and flexplate to me at any of the shops where I've worked, I would be able to make the flywheel have the same imbalance as the flexplate. It would run you around $50 in summer 2010 U.S. dollars.

You should open up a mail order business for us 3800sc 5spd swap ppl

Well, I do have an L67 sitting here, ... we'll see.