So, my B2600 tranny came in about 20 minutes ago, and I've got the bellhousing seperated already...but I figured "Hell, why not try to seem helpful...surely someone can use it."...SO HERE WE GO! I'll put the pictures in a quote with the text describing what the picture is of. I apologize for the large pictures, but I want everything in detail, so there's no squinting. That being said, I still apologize, since this is with a 2 megapixel camera phone.
This is showing the difference between the bellhousings, both the bolt patterns as to why we can't really use an RX7's housing, as well as how odd the tilt is between them. On the left is the RX7's original housing...the right is the B2600. The board I have there is there to identify the "bottom" of both bellhousings. Notice both the starter locations, as well as direction of both starters (for you new guys who just stumbled across this place)
This is a closeup of the RX7's housing, incase the last picture didn't show enough.
This is a closeup of the B2600's housing. Notice the tilt difference...again, I tried to keep both pictures geometrically similar so you can get a feel for the tilt.
I couldn't really find a decent angle to show it properly, but in this picture, the B2600's bellhousing is slightly taller (deeper) than the RX7's housing. It's extremely minute, and frankly I think it was because of my driveway. I'll go out later and put them both on a board to take a better shot and make sure I'm not talking out my ass.
In this, both are flipped over, but RX7's is still on the left. Bolt pattern is more readily apparent in this view. And yes, I still tried to keep both housings straight with eachother, so you can get a better view of the tilt with this picture.
Really don't know how this'll help, but for shits and giggles...
Now THIS is helpful. In this picture, it shows the RX7's length from where the bellhousing meets the rest of the transmission. Since both housings are the same relative depth, the next picture will show the difference of shifter position, as well as overall length.
This is the B2600's overall lenth, also from where the bellhousing mates with the rest of the transmission. Notice both the size difference, as well as shifter location difference.
I'll leave them both disassembled for a little bit, incase anyone needs more specific detail about either of the trannies or housings. Probably a day or 2.
Not sure if this posting is really all that helpful, but who knows.
I'm sure this information will be helpful. I noticed that the RX7 bellhousing has 2 extra bolt holes in it to mate with the transmission located at the 12 and 6 positions in the pictures.
I don't advise that you disassemble the transmissions, but if you do, perhaps we can get some idea as to what the gears are like between the two. As well as syncros and such. We do have gear ratios on here somewhere for both trannies don't we?
From experience, I suggest you take a ton of pictures for documentation. Measure anything you can think of and hold on to both units as long as you can. At some point someone will need some specific info and we should be able to assist them if everything is documented.
Do it in a Datsun!
1972 Datsun 510
7-bolt 4G63T, EVO 9 pistons and rods, Garrett GT3076R, "flipped" stock intake, Toyota R154, Z31 R200 w/ CVs
jeffball610 wrote:I'm sure this information will be helpful. I noticed that the RX7 bellhousing has 2 extra bolt holes in it to mate with the transmission located at the 12 and 6 positions in the pictures.
I don't advise that you disassemble the transmissions, but if you do, perhaps we can get some idea as to what the gears are like between the two. As well as syncros and such. We do have gear ratios on here somewhere for both trannies don't we?
From experience, I suggest you take a ton of pictures for documentation. Measure anything you can think of and hold on to both units as long as you can. At some point someone will need some specific info and we should be able to assist them if everything is documented.
The extra 2 bolt holes are mentioned on the RX7 transmission page
Some B2600 bellhousings use ten bolts to the gearbox, others use eight. The bolt pattern is the same though and not having those 2 bolts will make little difference.
Mine just happens to be an 8 bolt B2600, but I'm glad you pointed that out. I was kinda freaking out when I discovered it was 8 bolt instead of 10...had to make sure with Mike that it wouldn't affect anything...thank god it doesn't.
While I may not disassemble the RX7's tranny (there's plenty of documentation on it somewhere, no doubt), the B2600 I'm debating ripping apart. I'm trying to decide if it's worth trying to sell to the RX7 guys after telling them it's actually a B2600 tranny with an RX7 bellhousing, but I don't think they'd appreciate that. If I decide to go through and rip it apart, I'll definitely measure everything and report it all back...too bad I don't have a micrometer measuring tool.
While I'd love to assist someone with an extremely specific question like that, I have to put the transmission back together at some point so I can store it until I get the rest of my parts. That being said though, I'll try to get as much information together as possible before doing so.
So is there anything holding the bellhousing on other than those 10 bolts? I'm having all sorts of trouble tryin' to get it off. Do these transmissions have a circlip holding in the input shaft bearing?
stealthx32 wrote:So is there anything holding the bellhousing on other than those 10 bolts? I'm having all sorts of trouble tryin' to get it off. Do these transmissions have a circlip holding in the input shaft bearing?
As far as I know, it's just the 8-10 max bolts that hold it on.
Have you tried smacking it with a rubber mallet? It's what I did to get it to separate. One quick, firm smack as close to the transmission as possible.
Since no one has interest, I'm going to rip the B2600's tranny apart later today.
stealthx32 wrote:So is there anything holding the bellhousing on other than those 10 bolts? I'm having all sorts of trouble tryin' to get it off. Do these transmissions have a circlip holding in the input shaft bearing?
Just to add a little information to this thread. I bought an FD transmission, and this is the input shaft. It's about 6" long measured from the transmission, or 5 and 7/8's measured from the machined base of the shaft.
There's two options here (if you want to use the B2600 bellhousing). Get another input shaft, or find/manufacture a spacer and use longer bolts.
Here's a plate that's sold in Japan (available from RHDJapan.com for $500 or something) that spaces out the bellhousing for you:
Why do you have to get a spacer plate? There was no mention of DJ running one, and I ran without it and had correct pilot bearing depth. (I would site other examples, but I dont knwo who else was running one.)
I haven't lined it up yet, but it's a pretty large discrepancy. Unless you had the bellhousing spacer, you'd have to have a short pilot bearing and a super thin flywheel, otherwise the clutch disc wouldn't be fully engaging all it's teeth.
Getting the engine bolted in is about 10% of the way there.
The next 80% can go quickly with help and skill.
That last 10% takes about as long as the 90% that came before it.
