1985 rx7 gears grinding
 

hello everyone I'm new to the rx7 I bought it off a friend who could no longer work on it in his old age it drives fine for the most doesn't seem to have much power to it but the problem i'm noticing most of all is the gears grind in 1st 2nd and 3rd but 4th and 5th seem fine also reverse is fine no grinding I was wondering what I should do about this or if there is a way to fix it myself without taking it to a shop cause this car is now my baby and I want to do everything myself if needed but I was just wondering what is causing the gears to grind and what is needed to fix it it's a 1985 rx7 (sorry dont know anything else past that) if you could help I would appreciate it very much thank you ^_^

First thing to do is change out the tranny fluid. Try Redline, many have had good results with it, or an old racers concoction, 1/2 manual tranny fluid and 1/2 ATF.

Since you're new, welcome to the forum. Below is a copy of my sig line. Download and read the FSMs, carb manual and other rotary related reading. Start your rotary education early and enjoy.
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Download YOUR copy of the FSM Then read it.

http://www.wankel.net/~krwright/cars/rx7/manuals.html

I won't tell you again.

Attention: newbies. READ THE FAQs, OR

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My toy. https://www.rx7club.com/build-threads-293/unvieling-12a-bp-widebody-462184/

thanks for the quick reply I'll try that in the morning and hope it works it has 140k miles on it and needs a tune up very badly -_- but thanks and hope it works

I'm stuck with a problem now I was wondering if I could put a 84 transmission into a 85 cause apparently I've been told that the tranmission is going out and that in a shop it would be 1200-1800 but i dont want to pay that much rather change it myself if possable or rebuild it I dont know anything about transmissions so if anyone has any ideas your help would be very nice ty

When do you hear the grinding? I have a 2nd gear Synchro that is a little testy and occasionally grinds when downshifting.

As for the Tranny, you should be able to swap it easily, Only two flavors of Manuals in the first gens. SA and FB as far as I know.

it grinds as soon as it's in first gear also in 2nd and 3rd while the car is driving but 4th and 5th gear doesn't grind neither does reverse and I found a 84 rx7 for 300 that doesn't run and could use the transmission if it would be easy to just do a straight swap but i dun wanna pay 1200-1800 for a rebuild when I can just buy another rx7 and swap (I refuse to pay the over priced transmission shop a dime cause they say it's easy for them to do it basicly calling me an idiot) -_-

As far as I know there's no reason you can't swap an '84 tranny into the '85. Mazda pretty much stuck with the same housing for their rear-wheel cars for a long time, with just minor changes in bolt pattern. If you're getting a used tranny, dump the $150-$250 for a rebuild kit and a new clutch, throwout, etc... at the same time.

Prior to doing that though, when you swapped out the fluid as Trochoid suggested, where there piles of metal shavings on the magnetic drain plug or just a few slivers?

1200-1800 for a rebuild is just plain nuts, especially when the parts may not even run 300. If the fluid change doesn't make much difference, you can swap in any 81-85 RX7 tranny. A decent used one shouldn't run more than $250.

Yeah, used trannies are cheap and rarely go bad. I've got a couple spares in my garage that I've been keeping around "just in case". Haven't had to use one yet...

if you can get bearings and synchros, and all the other little parts (seals, springs) for under $300 i'm buying from you!

Have you checked your clutch hydraulics? After 140k, and if the car wasn't driven much, it could be bad hydraulics not disengaging your clutch enough. Before you go though all of the hassle of swapping trannys (not too hard, but why work harder than you have to), check out your hydraulic system.

Very good point Whitey. If the hydraulics are weak, then you might not be fully disengaging the clutch when shifting. :)

I haven't done the pricing. Hope I didn't speak too soon on parts pricing.

ive been rebuiding these for a while, and theres just a lot of stuff worn out, and most of it you cant (or dont want!) aftermarket.

just to give an example, when we were doing the race car, 3rd gear syncrhro, hub sleeve, fork, 2 nuts, snaprings, and seals was $250.

http://www.drivetrain.com/mazdaendload4_5sp.html

If I'm building my BOM out correctly, parts for a total overhaul, from bearings to seals to synchros run about $325 from these guys plus S&H. It looks like a T2 tranny will run a bit more.

Here's a question, (not looking to hijack, but curious anyhow), can you convert a standard tranny into a T2 tranny by just rebuilding it with T2 parts or is there something integral to the construction?

t2 is a totally different design. case is different, gears are bigger etc etc

Aye just stick with doing the swap with the 84 with some fresh redline and a clutch kit.

hmmmm I'll check the hydrolics in the morning I guess have to figure out how to do that now lol but in either case I just bought two more rx7's a 86 all it needs is the engine put back together and should run fine and a 84 rx7 the only problem with the 84 is someone jacked the deck out of it and ripped out some wiring or messed up the wiring in the car somehow when the deck was stolen both cars cost me 1150 total so I have some extra parts left over and maybe an extra car now not sure what to do with them all yet lmao but I can get parts for rx7's cheap if anyone is interisted let me know ^_^ and ty for all the advice I'm looking into everything so far you've suggested but it's late so I'll have to get back to working on it in the morning (dont want the neighbors calling the cops on me again for loud noises even tho you can hear them partying two blocks away....)

Man, sounds like you're starting your own car lot! :)

haha not trying to but if thats the only way to get this car into perfect condition then yea sure why not ^_^

got the grinding noise to stop now that I've swaped trannys and did the clutch and redline but kinda wondering if I can put my 86 tranny and engine in my 85 for more power or just so I have a second gen engine and transmission hmm or would that be worth it? also thx for the help for getting the grinding to go away everyone your input was helpful ^_^

The 86 will go into the 1st gen body easily. The electronics are a pain. You will need a front cover and oil pan from a gsl-se, but those are pretty easy to come by around here. you'd probably be better off to go with a racing beat carb setup just for the simplicity, and a racing beat exhaust system (at least the header), again, fairly easy to come by on the forum.
I was happy with the power from my 12a, and swore I'd never change to a 13b.....and then I did the swap, and immediately wondered why I didn't do it years ago.
Oh yeah, the 2nd gen transmission would be WAY more work than it's worth. Your 1st gen tranny will bolt up just fine.
I'lltry to get a chance to post some pics of the 86 motor in my 83 body later today.

The 2nd gen N/a transmission just requires the tailshaft housing to be swapped over from the FB transmission then install.

The only advantage is if you want a taller 5th gear.




[quote=bstrange99;846997
Oh yeah, the 2nd gen transmission would be WAY more work than it's worth. Your 1st gen tranny will bolt up just fine.
I'lltry to get a chance to post some pics of the 86 motor in my 83 body later today.[/quote]

I stand corrected. Thanks Doc.

it works great now ^_^ took me and my friend all day long but we did it and the car is coming along nicely engine and tranny swap was well worth it been driving it like it's stolen for the past 3hours it's great lmao hmm wonder what other preformance mods I can do to it now with the 13b in it...any good suggestions maybe turbo?