I have noticed on Archie and others websites that for a V8 swap there are 2 different flywheels you can get. One for 86 and newer, and one for 85 and older. I was wondering what the differences between the two were. (specs on # of teeth, outside ring diameter, etc.) Thanks for the help.
Yes he's right Pre 86 sbc cranks had a flange that ran outside of the rear of the block that was bigger than the bearing making a 2 pc seal necessary. These cranks were internally balanced and thus used neutral balance flywheels. In 86 they changed to a one pc real seal and the crank now had no strange shaped counter weight on it as the seal had to slip over this end of the crank. I have a picture from a chevy power book of this-I'll see if my digital cam will pick it up.... Having problems with that at the moment so I'll try later. Other than these 2 issues there is also 2 different sizes. One is 12.75" in dia and has 153 teeth and 3.58" bolt circle, the other is 14" in dia. and has 168 teeth with a 3" bolt circle. It's worth noting that the 3" bolt circle flywheels having a counterweight can only be bolted on one way since at least one of the bolt holes is "off pattern" by several degree's to act as a "key". There are 6 part #'s listed in my book, 2 each for both sizes and seal types and one each of the smaller flywheel in a lightweight nodular iron. Hope this helps, ask away if u need more specifics........
Answering question below while posting the pic: Nope both flywheel sizes and are made both pre 86 internal balance and post 85 external balance. That explains 4 of the part numbers, the other 2 are 153 tooth lightweight flywheels, one for each seal design.
[This message has been edited by 85GToronto (edited 03-08-2002).]
This is the 2 crank snouts. Not the best pics but you can see the difference anyway. The late model one pc rear seal crank is on the left, supposedly you can covert an early block to this style of seal but then you need to corresponding crank and need to address the balancing accordingly......
[This message has been edited by 85GToronto (edited 03-09-2002).]
[This message has been edited by 85GToronto (edited 03-09-2002).]
The 153 and the 168 tooth flywheels were made for both pre '86 and '86-up. You can get a one piece rear main 153 tooth flywheel from an 86 305 Camaro.
------------------ Timothy E. Smith 1986 SE V6 BACK ON THE ROAD AGAIN!!!! 1984 Coupe 1996 Ford Probe GT 1999 Chevrolet Silverado Z71 1975 Chevrolet ElCamino SS
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07:38 AM
tstroud Member
Posts: 527 From: Chariton, Iowa Registered: Feb 2002
Originally posted by tstroud: But niether one of these flywheels will fit inside of a fiero transmission. Archies flywheels are custom billet steel SFI rated pieces.
I know for a fact the 153 tooth flywheel WILL fit in the bellhousing of a Fiero transaxle. I also know the 4.3 liter flywheel and the small block 153 tooth flywheel are one in the same (To justify this claim I must state that I have a 4.3, a couple 350s and several flywheels and clutches in my possesion, so I have first-hand knowledge of this). I have a non-Archie kit (a crappy copy- let's not go there) with a 153 tooth Camaro flywheel that was bolted to an Isuzu 5 speed with an S-10 clutch installed in my 86 SE, but never finished the project. I still have the parts, and I will put them in another car. Trust me, it WILL work.
FWIW, I think the Duke flywheel will bolt to the pre-'86 SBC crank. I have to investigate. I know for a fact the RWD Duke flywheel will bolt up. I did that when I put a SBC in a Chevy Monza years ago. I used the Duke flywheel and a V8 Monza clutch. NO mods required.
------------------ "Its a Fiero thing... Heck, even I don't understand!"
Timothy E. Smith 1986 SE V6 BACK ON THE ROAD AGAIN!!!! 1984 Coupe 1996 Ford Probe GT 1999 Chevrolet Silverado Z71 1975 Chevrolet ElCamino SS
[This message has been edited by tesmith66 (edited 03-09-2002).]
[This message has been edited by tesmith66 (edited 03-09-2002).]
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09:13 AM
PFF
System Bot
85GToronto Member
Posts: 927 From: Red Deer, Alberta, Canada Registered: Dec 2001
Hey Vortec, was I sitting across from you at the last GTA club meeting??? hehe I was telling someone about your fw for sale last week but I don't recall who it was. I talk to alot of people about them. It will come to me and mow I have a meber name to pass on! I'll see if I saved the PM. I'm surprised to hear that the 153 tooth fits into the Fiero transaxle because the closest measurment I can get of of my spare Muncie 11 7/8" inside dia. Clearly that means it won't fit. What transaxles are you dealing with Tesmith?
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09:51 AM
tesmith66 Member
Posts: 7355 From: Jerseyville, IL Registered: Sep 2001
I've had it in the Muncie 4 speed and the Isuzu 5 speed. The ring gear just sits inside the flange. I'll have to get another tranny, bolt it up and take some pics for ya. The 5 speed I was using is in the car behind a fresh 2.8. I'll have to measure it and post the dims. I'll also look for a part number and post that. I do know that Chevy only had 2 SBC flywheel sizes- 153 and 168 tooth. I don't know what the diameters were.
------------------ "Its a Fiero thing... Heck, even I don't understand!"
Timothy E. Smith 1986 SE V6 BACK ON THE ROAD AGAIN!!!! 1984 Coupe 1996 Ford Probe GT 1999 Chevrolet Silverado Z71 1975 Chevrolet ElCamino SS
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10:02 AM
85GToronto Member
Posts: 927 From: Red Deer, Alberta, Canada Registered: Dec 2001
OK, now I'm beginning to think I've lost my marbles. Iknow for a fact I have a flywheel from a 1986 Camaro. It is a 153 tooth affair. I also know I have it bolted to a 1988 350 block with a 1" thick adapter plate installed. I also knoe for a fact that I bolted a 1985 Isuzu 5 speed (from a 4 cyl Fiero) to it and only had to put a 1/4x45 degree chamfer on the flywheel and clean up the tranny casting a bit with an angle grinder to get it to fit and spin freely (with clutch installed). I do not recall if the ring gear fit completely inside the bellhousing or stopped short of it, but I do know it fit. I also have a 153 tooth Camaro flywheel from a 1984 car. The two flywheels are identical in every way except for the crankshaft interface and the balancing. Are the flywheel diameters measured at the face, or across the ring gear?
------------------ "Its a Fiero thing... Heck, even I don't understand!"
Timothy E. Smith 1986 SE V6 BACK ON THE ROAD AGAIN!!!! 1984 Coupe 1996 Ford Probe GT 1999 Chevrolet Silverado Z71 1975 Chevrolet ElCamino SS
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10:58 AM
LS1swap Member
Posts: 1181 From: McHenry,IL.USA Registered: Jan 2001
They are right about the 153 tooth flywheel not quite fitting. I came to this conclusion my LS1 project. The solution I came up with was to buy an aluminum flywheel (mine was from fadanza) and have an aluminum insert samwiched between the removable friction surface and the flywheel itself. Here is a pic of mine. The main thing to remember is that you have to keep the same clutch geometry no matter what. The friction surface of the flywheel needs to be 7/8" recessed into the trans. The thickness of this insert will depend on the thickness of the adapter plate being used. You will also have to have this assembly balanced after you are done. For a 350 it may actually be cheaper to buy a kit like archies unless you plan on doing allot of work and research yourself. A 350 will be different for you will not need to clear the ring gear with the adapter plate like I did, but the principle is the same.
tesmith66, your not loosing it... I also used an 153 tooth flywheel on my 84 4 speed. The teeth just stops short of the lip of the trans. which means it does not go inside the trans. Thats using a 1" plate....
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12:18 PM
85GToronto Member
Posts: 927 From: Red Deer, Alberta, Canada Registered: Dec 2001
You're on the right track or rather line of thinking Tesmith. The ring gear runs inside the adapterplate on your setup. and yes a small bevel on the front edge is all that is needed to clear the bellhousing. The dia's I gave are to the outside of the ring gear. The only way to avoid that kind of interferance is to make/modify a Fiero size flywheel with a smallblock bolt pattern. THEN the limiting factor on the system become the clearance issue with the snout of the crank and the center of the clutch disc as we've been discussing. I swear I am almost ready to put a SBF in the thing and avoid all this hassle. Its crank snout is flush with the block like the 2.8. (I could put a HUGE "POWERED BY FORD" decal on it and piss off BOTH camps-lol) Its worth noting that when thinking about this part of the swap you CAN gain 1/2" of width in the engine bay by using a 1/2" adapter vs a 1" adapter. Some people would say its not worth the hassle of engineering this but its 1/2" more room in the bay for pulleys or 1/2" less material you have to modify on a framerail. Something I think is worthwhile. How do you plan to drive the other accesories LS1?? Its hard to tell from the pic but it looks to me like the crank pulley sticks out miles! lol This becomes the NEXT big issue with V8 swaps, forget about the waterpump, how are you gonna drive the OTHER accesories! hehe
This is all getting more and more interesting and informative, I likey...
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12:26 PM
LS1swap Member
Posts: 1181 From: McHenry,IL.USA Registered: Jan 2001
Most of the picture you are seeing of the crank pulley are old. If you look close there isn't even a bolt in the pulley it is just put on by hand. Even after it was tightened up it still sticks into the frame rail. So I added a pulley to the back of it to drive the alt. And A/C. I did use a ASP under drive pulley to minimize the cutting. I have also added support not originally there. The thing to remember when modifying the frame is to add more strength back than you remove. Here are some pics. The one pic shows the steel Gusset I will have welded in place to tie the frame and strut tower together. This should make things more clear.
If I am correct Archie uses the 153 tooth 12.75" flywheel. So specifically looking at Archie's flywheels how would I know if its the pre 86 or the 86 and newer.
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01:45 PM
85GToronto Member
Posts: 927 From: Red Deer, Alberta, Canada Registered: Dec 2001
Yes he does, as most do, use the 12.75" Basically:
Once pc rear seals are the newer 350's (86 and up) and need a counter weighted flywheel. This is pretty easily seen on the backside facing the motor.
The older 2 pc rear seal cranks (pre 86)are internally balanced and the crank looks basically symmetrical front and rear. The counter weight COULD be machined off of a post 86 crank to make it neutral balance but you will still have the different bolt circle to deal with as I mentioned above.
Measure the bolt circle, thats the easiest way to tell. Or if its counterweighted its late model, 86/up
If its been used before and had a circular "outline around where you can see it was bolted to the crank its late model. If it has a strange shape where it was bolted to the crank its an early one-the shape is like in the right pic i scanned above.
I am assuming that to measure the bolt pattern you measure from the middle of the bolt hole to the middle of the bolt hole, so my flywheel measures 3.58, so this would be the old style flywheel, correct?
