Pretty sure the 2.2 pushrod transmission has a 3.94 FD.
The shafts are retained in the outer case half by bearings which are pressed in place. The bearings at the outer end handle the axial loads on the shafts from the helix angle of the gear teeth.
The pinion of the ring & pinion is integral on the output shaft. That means you have to remove the output shaft from the transmission in order to swap the FD from one outer case to another. You can't remove just the output shaft, though. The input cluster and output cluster have to come out together.
IOW, swapping cases on the same gear clusters is a whole lot more work than swapping the bellhousings on two different transmissions.
394:1 FDR on the Cavi. My bad. All the more reason to get rid of that!
Now correct me if I'm wrong, but it appears the differential assy mounts into the bell housing. Meaning if you simply swap bell housings, you lose that tall FDR, which is why you bought the Cobalt tranny in the first place! In that video, it appears once the case is split, it's a simple matter of removing the shift forks, then lifting each of the three shaft clusters out. It's the differential that's more involved. And as Will said, the pinion being integral with the output shaft & the output & input clusters work together as a pair. Which means swapping the FDR involves not only swapping the bell housing, the ring gear assy, & output cluster, but the input cluster as well. As long as you're doing that, why not swap the intermediate cluster too? Am I missing something? Maybe I need to watch that video again.
Granted, it is a bit more work. However, none of mounts I've seen for the metric bell housing/Cobalt tranny really appeal to me. The Cavi's rear case, on the other hand, has those feet.
[This message has been edited by Monstertone (edited 04-24-2020).]
Thanks Will. Since I don't have that handy little fixture, I'm thinking remove the back up switch & those two shaft retainers before removing the bell housing. Hopefully, that will allow me to utilize the case for the same function as that fixture, albeit everything will be upside down. Maybe that "kit" is available on loan from Mopar, or some other parts store. Or is that a pipe dream? How has everyone else gotten by sans that kit? Barring the bearings & seals look good enough they won't need replacing, it should not be all that difficult.
I now have both 2000 Cavalier and 2010 Cobalt transaxles on the bench, cap & oil guides removed, the tool kit & assy fixture arriving Monday. At this point, it seems rather than going to all the trouble of swapping all three shafts and the differential (FDR) in each trans, as I had previously planned, simply swapping the bell housings will be the way to go.
After going back & forth between WCF & Thelinsells, I bit the the bullet & ordered WCF mounting brackets. To their credit, the WCF brackets arrived in less than two weeks. They appear to be very well made. However, they only fit the Cavalier transaxle. So much for a simple bell housing swap. Grrrr. I am now faced with a complete swap of all internals, save the bearing races, in both transaxles, or returning the WCF mounts & using someone else's mounts. And the more I think about it, running 10 year old bearings on 20 year old races does not exactly sound like a smart thing to do.
I would prefer to keep the entire Cobalt transaxle, save the bellhousing. True, the metric bellhousing brings with it 20 year old bearing races on the front end. But, that's only 50% rather than 100% of the races. What are my options regarding mounts for a 3800/Cobalier Frankentranny? Can anyone post pics of Roger Thelin, or anyone else's mounts on such an animal?
[This message has been edited by Monstertone (edited 05-06-2020).]
I now have both 2000 Cavalier and 2010 Cobalt transaxles on the bench, cap & oil guides removed, the tool kit & assy fixture arriving Monday. At this point, it seems rather than going to all the trouble of swapping all three shafts and the differential (FDR) in each trans, as I had previously planned, simply swapping the bell housings will be the way to go.
After going back & forth between WCF & Thelinsells, I bit the the bullet & ordered WCF mounting brackets. To their credit, the WCF brackets arrived in less than two weeks. They appear to be very well made. However, they only fit the Cavalier transaxle. So much for a simple bell housing swap. Grrrr. I am now faced with a complete swap of all internals, save the bearing races, in both transaxles, or returning the WCF mounts & using someone else's mounts. And the more I think about it, running 10 year old bearings on 20 year old races does not exactly sound like a smart thing to do.
I would prefer to keep the entire Cobalt transaxle, save the bellhousing. True, the metric bellhousing brings with it 20 year old bearing races on the front end. But, that's only 50% rather than 100% of the races. What are my options regarding mounts for a 3800/Cobalier Frankentranny? Can anyone post pics of Roger Thelin, or anyone else's mounts on such an animal?
Agreed- pictures would be great ! I too am planning this swap and do not want the 3.94 FD of the Cavalier transmission. Thanks to anyone jumping in with photos who is already in the middle of doing this, or has already done it.
I take issue with that video showing thread locker being applied to every single bolt on that transaxle. For instance the speed sensor retaining thingy, the rear cover plate, the drain plug? That is ridiculous. How many broken tools or buggered the heads can be attributed to this nonsense? Certainly those parts not under stress will remain tight, if torqued to spec, as should any part, if properly designed.
It takes heat to break some of these threads loose. A lot of heat!
I take issue with that video showing thread locker being applied to every single bolt on that transaxle. For instance the speed sensor retaining thingy, the rear cover plate, the drain plug? That is ridiculous. How many broken tools or buggered the heads can be attributed to this nonsense? Certainly those parts not under stress will remain tight, if torqued to spec, as should any part, if properly designed.
It takes heat to break some of these threads loose. A lot of heat!
Threadlocker is a belt-and-suspenders approach to reducing the possibility of things going wrong, in the hopes of reducing warranty claims, and as an insurance against possible lawsuits.
Most folks aren't overly concerned with the opinions of Saturday mechanics who may wish to service these things later.
After serious consideration, I followed Will's advice & took the easy way out. That is, swapping bell housings only. After breaking two HF T-50 sockets, (grrr) someone clued me in on MAP gas extreme heat to break loose Locktite red. (Grrr again) Easy when you know how but tough learning experience non the less. Due to the fact they rely on a complete Cavalier case, this rules out WCF mounts. No love lost there. Don't ask how I know. lol But I'm not out of the woods yet. One would like to think a metric bell housing is a metric bell housing. As such at least the mounting points for the tranny would be similar to, if not the same as the M282. But no, the powers that be couldn't have that. What have others done for mounts on a setup such as this? All links, pics, appreciated. Thank you all.
[This message has been edited by Monstertone (edited 07-31-2020).]
As discussed in this thread, Thelin's rear bracket should work. ONE bolt of Thelin's front bracket lines up on the Ecotec case, so you can probably use that bracket as a starting point.
Transaxle is a 2010 Cobalt (ecotec) gears & rear case with a 2002 Cavalier bell housing. Ended up going with Roger Thelin's mounts. Had to drill & tap two holes mentioned earlier, Not difficult at all if you have the proper tools. ie There are cutting taps & dies, & cleanup taps & dies. (HF) The former cuts thru aluminum like butter.
Bolting up the trans to the engine is another story. I'm using a cut down Camaro flywheel from FieroRog & a Ram 54007 9.75 Ø clutch from the Fiero Store. (figured I could use all the surface area I could get) Everything seemed to be going well tightening up the trans to the block, until the last .060 or so. At which point everything binds up & am no longer able to turn the crankshaft, even with a 24" breaker bar! Not seeing any scratch marks inside the bell housing, or on the pressure plate. The disk is facing the right direction. Did I miss something along the way? Do I need a spacer between the engine & trans? Or does the input shaft or fly wheel need to be modified?
Transaxle is a 2010 Cobalt (ecotec) gears & rear case with a 2002 Cavalier bell housing. Ended up going with Roger Thelin's mounts. Had to drill & tap two holes mentioned earlier, Not difficult at all if you have the proper tools. ie There are cutting taps & dies, & cleanup taps & dies. (HF) The former cuts thru aluminum like butter.
Bolting up the trans to the engine is another story. I'm using a cut down Camaro flywheel from FieroRog & a Ram 54007 9.75 Ø clutch from the Fiero Store. (figured I could use all the surface area I could get) Everything seemed to be going well tightening up the trans to the block, until the last .060 or so. At which point everything binds up & am no longer able to turn the crankshaft, even with a 24" breaker bar! Not seeing any scratch marks inside the bell housing, or on the pressure plate. The disk is facing the right direction. Did I miss something along the way? Do I need a spacer between the engine & trans? Or does the input shaft or fly wheel need to be modified?
The F23 bellhousing is tighter in several areas than the Fiero 282 - so many of the custom or upgraded flywheels and clutches for the 282 end up interfere with a portion of the case around the differential. Here is a picture of the issue.
I have no scratches like that. Could be I have not made enough turns to generate them. However, I would think it would not take much to at least make some visible marks in aluminum, once you know where to look. Perhaps I should try it with the standard Fiero clutch first?
Edit: I had neglected to take into consideration the slight difference in distance between the input & output shafts of the M282 vs F23. I don't remember the exact numbers but, the F23 is somewhere in the neighborhood of 6 mm shorter. This would indeed account for the possibility of clearance issues, especially with the clutch I ordered.
[This message has been edited by Monstertone (edited 07-20-2020).]
I keep on reading about this particular interference issue, along with the TOB spacer requirement. I guess I have two questions...
1. Does the face of the Cavalier flywheel sit the same distance from the face of the block (and, by extension, the bellhousing flange) as the Fiero /282 flywheel does from the Fiero or 3800 block? 2. Does anyone build a "maximum effort" Cavalier (yeah, I know, mutually exclusive) clutch, that would support "our" application(s)?
Sorry if this is old ground. I've never seen those asked.
I keep on reading about this particular interference issue, along with the TOB spacer requirement. I guess I have two questions...
1. Does the face of the Cavalier flywheel sit the same distance from the face of the block (and, by extension, the bellhousing flange) as the Fiero /282 flywheel does from the Fiero or 3800 block? 2. Does anyone build a "maximum effort" Cavalier (yeah, I know, mutually exclusive) clutch, that would support "our" application(s)?
Sorry if this is old ground. I've never seen those asked.
Just about all the FWD engines have the crankshaft basically flush with the bellhousing, but there can be 0.030 +/- between different engine families. Part of the problem is the way people reference custom flywheels. They say how thick is, when the true critical dimension is protrusion from the bellhousing for the specific application (because like I said, flush crankshaft flanges can be +/- 0.030" from each other and oftentimes 0.030" is the different between fitting or interfering. Stock Fiero 2.8 has the face of the flywheel 0.830" from the bellhousing face.
The F23 was designed for small, low power motors and came with a less than 9 1/8" (stock Fiero 2.8 size) clutch. If you run the stock F23 application clutch and pressure place, 90% of all the issues with HTOB over extension and interference go away, but I have only seen a few go this path (with success), the rest mix and match parts from the Fiero and other applications and run into fitment issues.
[This message has been edited by fieroguru (edited 07-19-2020).]
Originally posted by fieroguru: ... The F23 was designed for small, low power motors and came with a less than 9 1/8" (stock Fiero 2.8 size) clutch. If you run the stock F23 application clutch and pressure place, 90% of all the issues with HTOB over extension and interference go away, but I have only seen a few go this path (with success), the rest mix and match parts from the Fiero and other applications and run into fitment issues.
Perfect. Thanks for that. I've seen a few clutches listed for the Cavalier, at 9 1/8", and (strangely) some at 8.5". With that said, the Fiero Ram clutch is described as anywhere between 9 3/8" and 9/5/8". (Whatever it is, it seems to hold the torque from my 4.9 just fine.) That kind of gives me some hope that there is something heavy duty, but streetable, available for the Cavalier, that won't require the reinvention of the wheel.
I had to grind down the input shaft for the 3800. Might not have to on the 2.8. I don't know. See my sig.
None of the earlier pics on this thread are visible anymore. Could you be more specific about grinding the input shaft? What diameter, how far back? And exactly how did you do it? Remove the shaft & turn it on a lathe, or what? The scant info I have been able to find is that #1 there is no pilot bushing, #2 the shaft does extend into the crankshaft on some applications, but when it does there is ample clearance so it's not really a pilot. This is NOT a minor operation! If everyone is having to modify the input shaft, how come hardly anyone is talking about it?
[This message has been edited by Monstertone (edited 07-31-2020).]
The Ecotec bellhousing is 3/8" deeper than the "metric" bellhousing. As a result, the Ecotec input shaft is 3/8" longer than the input shaft used with the "metric" bellhousing. When you install the metric bellhousing on the Ecotec XFE transmission, the input shaft then sticks out 3/8" further than the input shaft in the metric transmission.
I think JustinBart just ground down the OD of the interfering snout on the shaft rather than cutting it off completely.
FWIW, the VSS reluctor on a F23 has 29 teeth(at least, the one I took apart does), pulse per mile can then be calculated by multiplying tooth count (29) times revolutions per mile of your tire size, in my case, 780.
780 rev/mile X 29 pulses/rev=22,620 pulses per mile. this should give a decent starting point for speedometer calibration.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
To my knowledge, yes. A company called California Push-n-pull (or something akin to that) makes cables, and the non-stock one needed (right length with the appropriate connectors on it) is in their catalog thanks to the efforts of Emc209i. If you call them up and let them know you need shift cables for an F23 going into a Fiero, they should know what you're talking about. Back when I got mine, I think it was 110 dollars for the two cables.
I recently put an F23 in a POS Grand AM (The Gran Damn) and since install, I had noticed the trans made lots of undesirable noises, and I had a noise that I had thought was coming from the power steering. today, I dumped the ATF out of the trans and refilled it with Synchromesh, to the 2.6 quarts recommended by the TSB, and the trans is now WAY quieter, and the noise I had thought was coming from the power steering, almost completely went away, it wasn't impossible to induce the noise, but it took way more aggressive driving than it did before.
At this point, I recommend filling F23's with Synchromesh and not ATF, that being said, I only have a couple of miles on the car with it, so I have no long term data, and any long term data might not be valid, because the transmission wasn't rebuilt, and could have some preexisting problems, so a failure at this point doesn't mean it's the Synchromesh either.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.
I have some questions; I'm thinking about doing an F23 install in my Fiero, which currently has a Muncie:
1. When building transmission mounts, do I keep the bellhousing position in the same position as stock Fiero? The telescoping range of the axle tripods should work out okay if I do that?
2. Is the fore-aft positioning of the differential similar to stock Fiero? I have a turbo oil drain line which passes a bit close to the RH tripod; I'm wondering if there could be a clearance issue with this transmission swap.
3. My current exhaust crossover pipe would run above the plastic oil fill cap. Can/should this be blocked off somehow, perhaps with a metal plug? Is there an alternate method of filling the case to the correct level with oil if the plastic oil fill cap is not accessible? VSS hole maybe? Another hole?
4. I was thinking of grinding teeth off the VSS reluctor wheel, so I could send a 4000 PPM signal (5 teeth should do it) to the instrument cluster (possibly with tweaks to account for the difference between variable reluctance and sine wave). How is the VSS reluctor wheel attached to the differential carrier? If I don't want to modify the stock reluctor, would it be feasible to make a new one as a laser-cut part?
5. Do the Cavalier and Cobalt transmission cases (the non-bellhousing side) have the same shifter shaft angle / position? The more "horizontally inclined" the shifter shaft is, the more the shift cable will have to come from up high, complicating things. Is one case easier than the other with regards to building a shift linkage?
6. If an HTOB spacer is used, will this not cause bending in the hydraulic lines which are also fixed to the case? How is this dealt with?
Those are some great questions. Most of which I can't answer, but I can try to get a hold of emc209i and ask him if he could provide the answers.
What engine swap did you do?
I would not recommend taking apart the transmission to grind off any teeth. That transmission is REALLY finnicky with coming apart and going together, even with the Kent-Moore toolkit, which has this "template" that holds various parts in the right relationship as you put things together. Not to mention if you start grinding off teeth, the internal balancing would be affected, no matter how small. To fix the VSS, I would suggest getting the Dakota Digital adapter and go with that.
If the crossover is blocking the cap, I would suggest looking into modifying the cross over. I think any other ports to try to fill the transmission would be slow and challenging.
I don't think the spacer will cause any issues with the lines, or I can't imagine how it does? It's only impacting the clutch and PP engagement by "adding" some length to the HTOB 'reach'. There is a method for doing all the measuring for that, definitely something you want to do before you get the spacer. On Mike's initial swap using my old F23, he used the HTOB with the same spacer - no issues. On the next one he installed, which was out of a different year car, something was just different enough that he either didn't need the spacer at all, or he needed a thinner one.
I have some questions; I'm thinking about doing an F23 install in my Fiero, which currently has a Muncie:
1. When building transmission mounts, do I keep the bellhousing position in the same position as stock Fiero? The telescoping range of the axle tripods should work out okay if I do that?
2. Is the fore-aft positioning of the differential similar to stock Fiero? I have a turbo oil drain line which passes a bit close to the RH tripod; I'm wondering if there could be a clearance issue with this transmission swap.
3. My current exhaust crossover pipe would run above the plastic oil fill cap. Can/should this be blocked off somehow, perhaps with a metal plug? Is there an alternate method of filling the case to the correct level with oil if the plastic oil fill cap is not accessible? VSS hole maybe? Another hole?
4. I was thinking of grinding teeth off the VSS reluctor wheel, so I could send a 4000 PPM signal (5 teeth should do it) to the instrument cluster (possibly with tweaks to account for the difference between variable reluctance and sine wave). How is the VSS reluctor wheel attached to the differential carrier? If I don't want to modify the stock reluctor, would it be feasible to make a new one as a laser-cut part?
5. Do the Cavalier and Cobalt transmission cases (the non-bellhousing side) have the same shifter shaft angle / position? The more "horizontally inclined" the shifter shaft is, the more the shift cable will have to come from up high, complicating things. Is one case easier than the other with regards to building a shift linkage?
6. If an HTOB spacer is used, will this not cause bending in the hydraulic lines which are also fixed to the case? How is this dealt with?
1. The F23 seal sits proud of the bellhousing face about 1/4" further than all the other Fiero manuals, so there is something different with the width of offset of the differential, but lots of people keep the bellhousing placement side to side stock. The tripots have over +/- 1/2" (Probably closer to +/- 3/4") available range of motion, so 1/4" should be within the normal operational range. Also, with this being the passenger side with the longer axle, the tripot end will rotate less with suspension travel vs. the drivers side. It is always good to verify, but stock axles and stock bellhousing placement side to side should be fine.
2. No. The axle centerline from the diff to the engine centerline will be closer and lower on the F23 vs. the 4 speed. This picture isn't 100% accurate due to the pic of the F23 being slightly angled and the one I had for the 4 speed was straight on. The red circle is the placement of the axe centerline on the 4spd and it was overlayed onto the F23 using the same rear bellhousing bolt hole reference.
3. No reason you couldn't fill at the VSS. If blocking off, need to verify where the vent is on the transmission. It might be the cap as the F23 doesn't have a visible vent line or vent cap off the shifter base (location of F40 vent).
4. F23 VSS reads the teeth on a reluctor wheel that is pressed onto the rear carrier. It has a 24K pulse/mile, so the majority of the teeth will have to be removed to get to a 4K pulse/mile. )
5.Shift shaft inclination angle is the same across the entire F23 line. If you don't get a shifter modification kit, the shift cable will snake around the engine bay and come in by the strut tower.
6. HYOB spacers come in 2 flavors. 1 is typically installed on the nose of the throwout bearing, extending its length. This one doesn't change the location of the hydraulic fitting. The 2nd style is a spacer behind the body of the HTOB. When this 2nd style is used, the lines pass through the hole about 1/8" more, but isn't normally any issue.
You didn't mention it, but there is a very good chance your current pressure plate could interfere with the differential bearing bosses inside the transmission, so you might want to factor in the cost of a new clutch as well if you go F23.
Those are some great questions. Most of which I can't answer, but I can try to get a hold of emc209i and ask him if he could provide the answers.
What engine swap did you do?
I would not recommend taking apart the transmission to grind off any teeth. That transmission is REALLY finnicky with coming apart and going together, even with the Kent-Moore toolkit, which has this "template" that holds various parts in the right relationship as you put things together. Not to mention if you start grinding off teeth, the internal balancing would be affected, no matter how small. To fix the VSS, I would suggest getting the Dakota Digital adapter and go with that.
If the crossover is blocking the cap, I would suggest looking into modifying the cross over. I think any other ports to try to fill the transmission would be slow and challenging.
I don't think the spacer will cause any issues with the lines, or I can't imagine how it does? It's only impacting the clutch and PP engagement by "adding" some length to the HTOB 'reach'. There is a method for doing all the measuring for that, definitely something you want to do before you get the spacer. On Mike's initial swap using my old F23, he used the HTOB with the same spacer - no issues. On the next one he installed, which was out of a different year car, something was just different enough that he either didn't need the spacer at all, or he needed a thinner one.
I would like to keep the Fiero Muncie Spec 3+ clutch that I already have, since it was a bit pricey and is still good, but if I have to change it, I will.
I think the car was making about 227 whp, so I'm surprised that I broke a Fiero transmission. I didn't baby the car, but I don't think I was abusive either. I was lucky that I broke the 3rd gear near home; I was able to limp home in 2nd. I think that the F23 will be more robust and give me peace of mind, especially when I drive far away from home.
I understand about the trickiness of servicing the F23. I might go for more of a homebrew electronic solution than the Dakota Digital. My friend has a Dakota Digital on his Fiero, and it doesn't seem very reliable. The speedo needle is sometimes twitchy; not smooth.
I think I would like the stock Cavalier ratios for my car, so I don't necessarily need to be swapping parts inside.
Crossover is tricky to modify without changing a bunch of stuff, so maybe I'll just fill the transmission with oil, and then install the crossover pipe. Transmission oil doesn't need to be changed often, so this aspect of the transmission install doesn't have to be perfect.
quote
Originally posted by fieroguru: 1. The F23 seal sits proud of the bellhousing face about 1/4" further than all the other Fiero manuals, so there is something different with the width of offset of the differential, but lots of people keep the bellhousing placement side to side stock. The tripots have over +/- 1/2" (Probably closer to +/- 3/4") available range of motion, so 1/4" should be within the normal operational range. Also, with this being the passenger side with the longer axle, the tripot end will rotate less with suspension travel vs. the drivers side. It is always good to verify, but stock axles and stock bellhousing placement side to side should be fine.
2. No. The axle centerline from the diff to the engine centerline will be closer and lower on the F23 vs. the 4 speed. This picture isn't 100% accurate due to the pic of the F23 being slightly angled and the one I had for the 4 speed was straight on. The red circle is the placement of the axe centerline on the 4spd and it was overlayed onto the F23 using the same rear bellhousing bolt hole reference.
3. No reason you couldn't fill at the VSS. If blocking off, need to verify where the vent is on the transmission. It might be the cap as the F23 doesn't have a visible vent line or vent cap off the shifter base (location of F40 vent).
4. F23 VSS reads the teeth on a reluctor wheel that is pressed onto the rear carrier. It has a 24K pulse/mile, so the majority of the teeth will have to be removed to get to a 4K pulse/mile.
5.Shift shaft inclination angle is the same across the entire F23 line. If you don't get a shifter modification kit, the shift cable will snake around the engine bay and come in by the strut tower.
6. HYOB spacers come in 2 flavors. 1 is typically installed on the nose of the throwout bearing, extending its length. This one doesn't change the location of the hydraulic fitting. The 2nd style is a spacer behind the body of the HTOB. When this 2nd style is used, the lines pass through the hole about 1/8" more, but isn't normally any issue.
You didn't mention it, but there is a very good chance your current pressure plate could interfere with the differential bearing bosses inside the transmission, so you might want to factor in the cost of a new clutch as well if you go F23.
Did you already have that CAD drawing done, or did you just prepare it for me? Thanks either way.
The diif being more forwards is not good for clearance, but lower helps me, so I think it will work with my existing turbo drain.
The F23 fill cap was referred to as the vent in the GM service video that I watched on youtube, so I'll need it, unless I install another vent elsewhere.
Since the shift shaft inclination is the same for both F23s, I guess I don't have much reason to get a Cobalt case. I was thinking of re-clocking the shift lever (by cross-drilling a new roll pin hole in the shifter shaft) so the cables could approach from a more straight-in direction.
Now I understand about the HTOB spacers.
If I can't get my existing pressure plate to fit, then I guess that the solution is to get a clutch for the F23 Cavalier? Is the bellhousing-to-flywheel distance the same between the Fiero V6 and Cavalier 2.2?
Originally posted by pmbrunelle: Did you already have that CAD drawing done, or did you just prepare it for me? Thanks either way.
If I can't get my existing pressure plate to fit, then I guess that the solution is to get a clutch for the F23 Cavalier? Is the bellhousing-to-flywheel distance the same between the Fiero V6 and Cavalier 2.2?
I have use CAD weekly if not daily for close to 30 years, so the drawing took less time than typing all the other responses, but it was the best way to show the issue.
The flywheel depth is very, very close across the entire GM FWD platform, so that isn't what causes the issue with the F23, but a too tall modified flywheel on a 3800 swap will absolutely cause it. Most of the stock clutches for the F23 are slightly smaller diameter than the Fiero 9 1/8". There are some 9 1/8" pressure plates that work, but it is hit and miss these days as the manufactures like to mix and match pressure plates on the same application. I would mock up yours and try it, you might get lucky. If it does interfere, you could explore what is interfering and see if it is something you can clearance away on a lathe.
Was the pressure plate to flywheel interface (number of bolts, thread size, bolt circle diameter, dowel pins if applicable) standardized among FWD GM cars?
In other words, will a Cavalier pressure plate bolt to a Fiero flywheel, or is that likely to require machining?
Was the pressure plate to flywheel interface (number of bolts, thread size, bolt circle diameter, dowel pins if applicable) standardized among FWD GM cars?
In other words, will a Cavalier pressure plate bolt to a Fiero flywheel, or is that likely to require machining?
I believe the 2002 Cavalier bolt spacing and threads are the same as typical fiero. Rock auto lists a 9" pressure plate as well as a 8 1/2" pressure plate, but their flywheels don't specify a specific clutch setup. The flywheels also show an equally spaced 6 bolt pattern at the limits of the 142t flywheel, which is what the fiero has as well.
You can also see that the 8.5" pressure plate has protruding tabs to pick up the pressure plate bolt holes.
Here is the 9" one for reference:
The big thing is to make sure the pressure plate clutch ring is large enough for your clutch.
It might be worth calling spec and asking about the differences between your Spec Stage 3+ and the Cavalier/F23 one:
Originally posted by fieroguru: The flywheels also show an equally spaced 6 bolt pattern at the limits of the 142t flywheel, which is what the fiero has as well.
I checked on Rockauto, and the same flywheel is sold for both 88 2.8 Fiero and 2.2 F23 Cavalier applications.
[This message has been edited by pmbrunelle (edited 09-09-2024).]
It does. Take the total range of motion of the HTOB (say it is 1.5") and you want it setup with 2/3's (or 1") of the available travel to the front for disengagement, and 1/3 (1/2") for it to retract backwards as the clutch disk wears.
Where does the 1/3 - 2/3 rule come from? Is this simply a "rule of thumb" that seems to work?
****************************************
It seems to me that the available disengagement_travel must be slightly greater than the fluid volume pushed by the master cylinder, divided by the surface area of the slave cylinder.
Where does the 1/3 - 2/3 rule come from? Is this simply a "rule of thumb" that seems to work?
****************************************
It seems to me that the available disengagement_travel must be slightly greater than the fluid volume pushed by the master cylinder, divided by the surface area of the slave cylinder.
It follows that: wear_travel = HTOB_total_travel - disengagement_travel
In my understanding, disengagement_travel is a requirement that is independent of HTOB_total_travel, so I do not understand.
You are missing several critical things: 1. Release distance is not consistent from clutch to clutch, pressure plate to pressure plate. 2. Depth of the pressure plate fingers is not consistent from clutch to clutch/pressure plate to pressure plate. 3. Excess range of motion for release will help when there are issues with bleeding or parts wear and hydraulic performance suffers - you don't want to have the bare minimum of release travel. 4. Balancing the packaging of the flywheel, spline engagement on the clutch disks, and pressure plate clearance to the bellhousing will likely be larger drivers of the the precise placement of the HTOB range of motion. But if you over extend it, you will kill it and be pulling it all apart again.
Take these into account over several combinations and you start to see the sweet spot is between 1/4 to 1/3 of the HTOB range of motion for wear, and the rest for clutch release. It will maximize the life of the clutch while allowing proper function across a vast mix of clutch combos.
When I had to make a new flywheel for the twin disc clutch for the LS4/F40 swap, it was a super tight fit with bellhousing clearance, spline engagement, and keeping the HTOB happy, but it all works perfectly.
If you want to detail out your specific clutch and pressure plate finger range of motion:
Install the clutch and pressure plate on the flywheel and measure the height/depth of the pressure plate fingers from the face of the bellhousing flange on the engine.
Remove the pressure plate and clutch, make a shim about 0.90" to cover the fiction surface of the clutch, reinstall the clutch, shim and pressure plate. Measure the pressure plate finger height/depth (it will ne numerically lower) - Consider this the minimum extension needed to release the clutch (many mfg look for about 0.60", but the fingers will flex some as the clutch is released, which is why I recommend using 0.90").
Remove the pressure plate and clutch, measure the thickness of the rivets holding the pad material to the disk. Install just the pressure plate with shims the thickness of the rivets. Measure the pressure plate finger height/depth (this will be a numerically higher number) - this will establish the maximum amount of wear distance needed.
Now you have the key heights/depths of the pressure plate fingers for your specific clutch and pressure plate. You can overlay the HTOB range of motion and see if it can accommodate all 3 without needing a spacer.
Just watch the video starting at 7:55
What have others done for mounts on a setup such as this? All links, pics, appreciated. Thank you all.
