Attempt a rebuild? (long)

[Speed Raycer]

At Gateway this past weekend, we lost the junkyard tranny in our RX. We had just changed over to Valvoline synthetics before the race and I had been having the occasional problem doing the 4-3 shift. I had modified my "attack" on the track to include a 3-2 downshift on one particular turn (running 3.90 rear gear). All of this resulted in pulling off my fastest lap time there and running in front of several SMs and battling for 2nd and 3rd in ITA.

After about 10 laps in the thick of the race, I went to downshift into 3rd coming into turn 2 (basically out of the straightaway) and it wouldn't go up into third... tried 4th.. nothing... by this time I had slowed enough to try 2nd... it finally engaged and I went one more lap. In the next lap, the 3-4 upshift resulted in the motor reving to 7K then dropping back down to around 4500 and pulling from there. At about this time, smoke filled the car (smelled like clutch). By the time I got into the pits, reverse was barely there... 1st would pull slightly until trying to get on the trailer and then it would just feel like a broken u-joint at 60 mph.

We looked at the clutch and it is dry (thought a rear seal on the motor or front seal on the tranny might have let loose because of the smoke in the cab). Any thoughts on what happened and what we can expect?

Also, is it worth trying to rebuild the tranny or should we just throw another JY special in it and hope for the best. I was surprised at the number of other RX guys at the race that said to do the later.

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Scott
It's not what you build...
it's how you build it
Izzy's Custom Cages (http://www.izzyscustomcages.com)
http://www.angelfire.com/mo3/rudder_racing/images/RX7_Pictures/SRsRX/SRsRX7.jpg

[This message has been edited by Speed Raycer (edited January 05, 2004).]

[lateapex911]

Sorry to hear of your diffuculties...sure sounds like my clutch problems ..

I, too just put another JY tranny in the car when the syncros start to get too slow. It's so much faster than rebuilding. Of course, a new clutch, throw out and pilot bearing are the way to go while it's out.

I always say to myself what a great winter project a rebuild would be, but to be honest, at this point I'd have to live on the North Pole to get all the "winter projects" done!

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Jake Gulick
ITA 57 RX-7
Northeast Region
[email protected]

[Allen Brown]

Clutch....Mine did the same two years back. Occasional tough shift to get into 2/3 during our two hour mini-enduros on Sat. Sunday during qualifying....BOOM!!!....Then there was nothing but clutch smoke. There was one piece of clutch facing left about the size of a quarter.

[C. Ludwig]

A bad pilot bearing could lead to clunking shifting. But that doesn't explain all the smoke. Drain the fluid from the tranny and see what comes out with it. Replace the clutch and all the associated pieces and see what happens.

RX7 trannys are a pain in general IMO. A friend of mine is into 1st gens and he can do a tranny install by himself without a tranny jack. He just does them that often and he's pretty big to boot. If I gotta do another one my car is going up for sale. http://Forums.ImprovedTouring.com/it/smile.gif

Chris

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Chris Ludwig
08 ITS RX7 CenDiv

[bcarter]

I just threw a scrap tranny into my RX-7. Had shifting problems from second to third a lot. Last race it got stupid, and I was losing a lot of time stirring soup looking for any gear. Got back to the pits, and it wouldn't stay in reverse.I just hope the new one is better, it feels OK.

These tranny's are not meant for high rev shifting, and we just wear them out. It is REALLY easy to swap them, and they are cheap.

[Silkworm]

Crud, I bought a rebuilt tranny, and already getting grinding going 2->3 at 8K

PaulC

[p99ro]

Gee I 2 had tranny troubles replaced 3rd syncro every thing was fine until NHIS,Grind 4th then second, Just opened up the darn thing and found the syncro in 2 pieces, I am gong to replace syncro`s we also had replaced
bearings my macanik said to check the eng bearing to see if there is to much play.
I can`t wait till I put it back again fun f#$%^%ing Fun,
Scott 99 Rx7 NER

[Speed Raycer]

Well, I was told that the starter was pulled to look up into the bellhousing, and what appeared to be clutch parts came rolling out.

SO.... what clutch do you guys recomend?

[Silkworm]

So far, stock Mazda (very cheap) has worked fine for me. We'll see after 4-5 standing starts though http://Forums.ImprovedTouring.com/it/smile.gif

PaulC

[bcarter]

I'm using a Racing Beat clutch, and it's great, but no standing starts.

As a update on my junker tranny swap, well, it lasted the race weekend, lots and lots of racing including practice, qualifying, three 15 min. races, a one hour race, and a two hour Enduro. Guess what...same problem going from second to third. I think it's me, because at high revs, you have to get the shift exactly right for the synco to keep up. Anyway, I'm not putting another one in til this one grenades.

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G. Brooke Carter
# 10 Challenge Car
Calgary, Alberta

[Allen Brown]

I've used and have a Street/Strip clutch in my RX7. It's starting to get a little spongy, and it's 2 years old. But I do show up for the odd Solo 2 event when time is available.

This winter I'm going to Mazda Comp for a 4 or 6 puck and upgrade the pressure plate. I will then be ON or OFF...

[rlekun]

Racing Beat just went to 4-puck racing clutch which I would prefer not to use. I just put one in since I didn't feel like weighing my clutch options before the next race.

I used to just swap trannies as well. I didn't even spend time diagnosing them. The problem with JY trannies is they're starting to be hard to find with less than 150K miles. And there is nothing that will pi$$ you off faster than to put a JY unit in only to have it fail the first weekend (been there, done that). We're all going to be looking at this issue in the future. Does Mazda offer a factory rebuilt unit?

[Allen Brown]

Rlekun. Are you saying you wish you hadn't went with the 4 puck? Did you upgrade the pressure plate as well to a Racing variety?

I'm looking for something that will last longer the semi-street versions I have been using.

[Allen Brown]

I've spent the money on getting my tranny rebuilt (gsl-se), and after not getting a good rpm match on two or three downshifts from 3 to 2. The synos were cooked (cracked). I didn't think they were that bad of shifts....except one. But, the tranny at that point was almost impossible to get from 3 to 2 in any reasonable time.

As I have found out (personally and second hand info), the synos are just plain weak. And can not take an overly rushed upshift (continuously) or even a handfull of slightly bungled downshifts.

If you are quite consistant, get the tranny rebuilt. If you occasionly, slightly miss-match the rpm on your downshifts like I did a couple years back, save the money, go for the used tranny.

[rlekun]

Allen,

I've always used the RB race pressure plate and disk. I just haven't heard rave reviews from the 4 puck disk...I don't see the advantage of fewer contact points.

Larry

[C. Ludwig]

I believe the benefit of the puck clutched is in the material and not the actual contact area. The material is usually a bronze(?) metallic makeup. They hookup great but can be hard on pressure plates and flywheels. Think Mazdatrix's website says something about them outliving flywheels. I've got a solid hub 4-puck in my ITS car and have had no problems. I seem to be a sympathetic driver though. I've owned a couple cars that a notorious for trans troubles and I have had none to date (knocking on wood). http://Forums.ImprovedTouring.com/it/smile.gif

Chris

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Chris Ludwig
08 ITS RX7 CenDiv

[rgrunenw]

I have never had a 1st gen trans that really shifted well on the 2 - 3 upshift. You just can't seem to rush it like you can the 3 - 4, so just take a little extra time. On clutches, I just put in the Racing Beat 4 puck race clutch and race pressure plate; so far so good with four weekends on it and a couple of solo II's.

Rich
ITA #31 Cendiv

[balz]

GUYS...I have a BIGGER QUESTION>>>>>

Is no one on here a member of Mazda Competition? You get parts at manufactures cost. www.mazdamotorsports.com...you (http://www.mazdamotorsports.com...you) will need to register in their race program to receive the benefits, but its a must.

As for the clutch..IMHO...

The best bet, for the money, is the 4 puck clutch from Mazda Competition. You will need the pressure plate assembly that gives you the clamping pressure required for the copper ceramic 4 puck disk. I believe the manufacture is Tilton. I have had one for the last two years. NOT ONLY is it much bettr for a race application because of the clamping force, but its a LOT lighter in the unsprung weight category, lightening your rotating mass and adding Tq.



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Balz
#67 IT-7
www.balz.myip.org
"I live my life one Apex (seal) at a time"

[Speed Raycer]

I just became a member of Mazdacomp... it's really easy now and you can do it completely online. I tried when we were building the car last year and never received any communication from them, even when I tried to call them!

[Silkworm]

Of course I'm a member of Mazda Comp.

But I still don't see the need for anything more than a stock clutch unless you're doing standing starts.

PaulC

[bcarter]

Back to JY tranny's. I thought the one I put in was OK, but while under the car tonite, I see that I have tranny oil all over the place. Not sure if it came from loose bolts on housing, or if it came from the joint where the drive shaft connects into the tranny. There is some sort of seal there, I guess, is this the "pilot bearing" everyone is talking about in the other thread?

Anyway, any thoughts????

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G. Brooke Carter
# 10 Challenge Car
Calgary, Alberta

[ddewhurst]

Posted by bcarter

*There is some sort of seal there, I guess, is this the "pilot bearing" everyone is talking about in the other thread?*

The pilot needle bearing of the other thread is at the Eccentric shaft end of the transmission. From memory http://Forums.ImprovedTouring.com/it/confused.gif it's about 1/2 inch inside diameter x 1 inch long. After the bearing is installed there is a lip seal that is installed to keep the grease (hand packed in neeedle bearing before installed)in.

If you have a Mazda Comp catalog (or their webb site ?)look at the motor parts & this pilot bearing & seal are item numbers 33 & 34.

Have Fun

David

[Rex B]

If you dropped the driveshaft already, fluid will leak out of the back of the transmission.

As for synchro problems, if you aren't using Redline MTL in your transmission, you should be. It's the only lube specifically formulated with the friction that synchros require to work correctly. It will often "heal" grinding synchros and prolong the life of good ones.

Clutch: I use a 4-puck under a stock (Borg Warner)pressure plate. It does hook up harder and sends a shock down your driveline, but so far it has not been a problem. I also have one in my street Jetta.
The only pressure plate upgrade I'd consider is a Centerforce.


Rex Burkheimer
SRX7 #39 SOWDIV

[Speed Raycer]

Just an update...

The friction material on the flywheel side of the clutch was G O N E ... down to the rivets, although the rivets were still there. There wasn't even evidence that it even existed, it was so clean. The pressure plate side was fine.

Any clues as to what could have caused that? We've got a couple of theories that maybe I zinged it once on a downshift, but I don't recall doing it.

------------------
Scott
It's not what you build...
it's how you build it
Izzy's Custom Cages (http://www.izzyscustomcages.com)
http://www.angelfire.com/mo3/rudder_racing/images/RX7_Pictures/SRsRX/SRsRX7.jpg

[This message has been edited by Speed Raycer (edited January 05, 2004).]