Dave-ger

so, I don't have an RX7, but I do have a 12A from an 83 RX7 with a transmission from an 82 RX7 in my BMW E21 3 series. Anyways, I have a wicked vibration, and I do have a professionally made driveline. I even had to get an adapter made to make it all work with the obscure bmw drive flange at the diff. anyways, I can wiggle my slip yoke, and I think this might be the problem. I don't think it should wiggle nearly as much as it does. I was told there is some kind of bushing or possibly a bearing or something that goes around the slip yoke that is likely shot or possibly about non-existent. Anyways, I want to try to replace this piece, but I'm unsure what it's called, so I don't know what to look for or ask for when trying to find the part, if it even exists. I'd be surprised if this said part didn't exist since the person I discussed this with is a straight shooting certified mechanic.


my oil leak question regards oil blowing out the side of my engine. I think it's coming out from between a housing and the iron that the oil filler is on. there is always and has always been a small puddle that forms on the rotor housing in front of the oil filler equipped iron. the engine is stock to my knowledge, and I have no idea how many miles are on it. the oil metering pump is deleted, I run 2 smoke oil in the gas, I have deleted emissions, and I have mechanical secondaries on the carb as well as a lengthened accelerator pump lever to accommodate.. not that those details effect this much... anyways, I am thinking I should take this as an opportunity to rebuild the engine, so I'm wondering how alarmed I should be about this in the mean time. I haven't found a straight answer on what my oil pressure should read on here, but my VDO gauge that's hooked up to the stock sending unit always says I have about 75 PSI whenever the engine is running. that seems a little high to me, but it is within the range of pressures I've read are okay on here. since that hasn't changed and my oil consumption is very minimal even with a likely rear main seal leak and maybe another one or two, I haven't been too alarmed yet, just figured I'd get a few opinions.

anyways, sorry to make that into a novel, thanks in advance for any info, advice, and/or opinions.

7aull

iTrader: (2)

Hi Dave-
wow, rotary Bimmer...! Thats a twist

This thread deals with the dowel leak you are experiencing:
https://www.rx7club.com/forum/showthread.php?t=969772

Can't comment on oil pressure, sorry.
As to a rebuild, if the leak is your worry this may save you doing it. It did on my '7!

Driveline: I know there is a bushing that I think just pushes into the rear of the tranny and these are cheap, tho never heard of those specifically being a vibration source. Usually out-of-balance drive line or damaged/broken transmission mounts...

Stu Aull
80GS
Alaska

Dave-ger

thanks. here's a pic of the engine bay, it's not as clean now with the leak, lol!


I have a build thread on here in "other rotary" called "rotary bmw" or something like that, but I haven't updated it in a long time.

I've been considering a rebuild for a while now since I have no idea how many miles are on the engine. the leaks seemed like a good excuse to do it. I was considering a street port too, but I haven't yet gotten around to checking how that effects fuel mileage. I don't really want to reduce my fuel mileage at all.

as for that stop leak stuff, i think I might give it a try. I guess the worst case scenario is that it doesn't work or messes something up and I'd have to rebuild the engine anyways. that doesn't sound likely anyways if it's proven to work on these engines.




as for that bushing for the rear of the tranny, I think that is the problem with the amount I can wiggle the driveline. it's worse on deceleration than it is with acceleration too. I had a very unbalanced driveline before this one, and it was different. I think that bushing probably became shot with the old driveline or something. do you know what I would call this part though if I were to order it? I might do some more research and hopefully find out in the meantime.

thanks for the help!

j9fd3s

iTrader: (3)

http://www.mazdatrix.com/getprice.as...m=22-3330-0398

0398-22-333 is the Mazda part number for that bushing. trans needs to come out, and the tail housing needs to come off, which isn't too bad, but it might be a good excuse to pull the engine too.....

t_g_farrell

iTrader: (1)

Make sure that leak isn't just the oilfilter pedastal orings leaking. Pretty common on
older 12As. The 2 orings go flat and fail to hold under pressure under there.

Dave-ger

thank you very much for the help. one of these days soon I'm going to order that tailshaft bushing.

As for the oil leak, it is coming from in front of where said O rings would be, but I appreciate that insight. I might double check anyways just in case.


as for the vibration, I was talking with my friend and PO of my engine and tranny. I guess he very apathetically connected the engine and tranny, and he's almost certain that the clutch wasn't lined up right. I'm thinking this caused the vibration.


notice the past tense? well, It seems the clutch went out. as I downshifted to turn onto a side road on monday night, the clutch pedal that once had a really firm feel felt really loose like my toyota and suzuki clutch pedals. then I noticed that it kind of felt like the clutch wasn't engaging. I pulled over and observed that the clutch system was visually okay as far as the master and slave cylinders. everything was working right... but why was the pedal feel different? anyways, I limped the car home, and noticed that no matter how long after the clutch was engaged, it would still slip above a certain RPM, really badly. I could hardly get it up to 40 MPH. anyways, so I'm like 80% sure that my clutch is done, and while I wasn't looking for it, don't recall my horrid vibration being there on the drive home.


So, could that have been my vibration? I have to pull the trans to replace the tail shaft bushing, so I'll be sure of some things either way.


one more important question: I'm seeing on a site that some clutches and flywheels are for up to an 82 RX7, and some are from 83 to 92. my engine is from an 83, and the transmission is from an 82.... what do I do? should I just get the stuff for an 82? what's the difference? I'm confused.


once again, I really appreciate the advice and info so far, I look forward to more. you guys are the bee's knees!

boyee

iTrader: (3)

quite possibly your clutch assembly was damaged or your flywheel is incorrectly installed or you have mismatching counterweights.

i quickly pulled these links off mazdatrix's website since these came up off the top of my head:
http://mazdatrix.com/faq/Rcounterweights.htm
http://mazdatrix.com/faq/flywheel.htm

hope they give some insight. good luck and lets see some more pics of your bmw!

j9fd3s

iTrader: (3)

Mazda used a 215mm clutch disc from the late 60's up to 1982, in 83 they went to a 225mm disc. the trans input splines are the same, as well as the ring gear, so the trans works with both clutches.

really the ONLY things that changed were the clutch disc, pressure plate and flywheel.

Dave-ger

I don't think it's the counter weight, because I can rev to 8k while not moving and pick up no noticable vibrations, I'm betting it's just the clutch and all that being messed up horribly.


as for the clutch stuff, I probably have an '83 flywheel, so I'd want to get the stuff for an '83, right? I really appreciate that info. I was considering looking into a light weight flywheel or possibly seeing if I could get mine lightened at a machine shop to try and get more ponies on the ground. I'll probalby be investigating that more soon.

Dave-ger

Finally ordered the tailshaft bushing from mazda trix. it was a little cheaper a couple of other places, but I knew mazda trix was legit.

anyways, I've been quite distracted with my truck for the past month, but I think I'll get this car back on the road within the next month. I really appreciate all the help, it's good to know that I need to order a clutch for an 83 (because that's the year of the engine) rather than an 82 (the year of the trans)

Once again, huge thanks to you guys!

Dave-ger

still having some vibration issues. the tail shaft bushing was a huge help. I also discovered that my diff was causing some of the trouble. I tried 3 different diffs in the car, all with varying discomfort, so I had the best one rebuilt by a friend with a great reputation with differentials. The situation has continued to get better, but it's still there. basically, at a higher speed, in neutral, or with the clutch in, there is still a bit of a vibe. Also, if I'm in gear and kind of inbetween coasting and maintaining speed, like staying slightly on the gas on a slight downhill section, there is a vibration just in that spot. probably just above 2000 RPM. all this is only noticeable at like 40 mph or over, and more speed makes it more noticeable. I also noticed that 5th gear seems to be a little worse than 4th. I need to drive the car more to trouble shoot more, but the weather is crappy, and I have no choke (cause chokes make engine bays ugly ) and no HVAC in the car at all (foggy windows and stuff ) so, I haven't been driving it as much as I'd like to.


I have sourced probably one of my problems. I have wheel spacers on the back of the car that were hub centric for a honda, the BMW bore is big, so I ground them out with a die grinder. Now I'm also on scion wheels, and I had to grind down the outside hub centric part for that too. my front spacers are un altered, but they are hella non hub centric. I have 1" of spacer up front, and 2" out back. this is because my BMW probably has the worst hub placement of any car, I can't clear any kind of normal wheel without the spacer up front. So anyways, I might get someone to clean up my rear spacers with a lathe to reduce some of the out of wackness those provide, but until I can afford bawler wheels that will fit right or something, I can deal with a little of that, and I can pick up on it separate of the other vibrations going on with the car.

anyways, more opinions are welcome and appreciated. Thanks for reading my short novel about my car that consumes too much of my time.