transmission issue on a oval track rx7.
#1
transmission issue on a oval track rx7.
i apologize is this not the right place to ask this question but i need help. first of all a little story behind. last year a good friend of mine decided last to go circle track racing with a rotary, 1/4 to 1/2 mile local circle track. i just join his team this year to help him with his mechanical stuff. the car is a 83 rx7 with a street ported 13b with a ida 48 carb, 4.77 kia rear end gear weight 1811 pound with driver and 5 gals of gas. anyways engine and suspension wise is perfect but we been having issues with transmissions. we went thru 3 transmission in the past year. kept breaking the tail shaft housing in two. so we sorted that because the engine was still in stock motor and transmission mounts. we put solid ones and got a new drive shaft. now on our last transmission we were having issues with the tail shaft seal coming off and we put silicone, lock tite and still came off and now last night the actual tail shaft bearing came off in the feature. i'm dumb founded. i never experienced or seen something like this. i don't know what can cause it. does anyone experience this problem in the past and how did you got it resolved? i apreciate any help or suggestions please. thanks
eddie
eddie
Last edited by eddierotary; 05-03-15 at 09:07 AM. Reason: grammar fix
#2
Old [Sch|F]ool
Lose the solid transmission mount and fix your U-joint angles. The U-joints must be the same angle relative to the driveshaft, and angles of more than about 3 degrees significantly shorten tailhousing bushing life and U-joint life.
Also, get your driveshaft rebalanced. Is your new driveshaft "NEW" or a used one, or rebuilt with old parts?
Also, get your driveshaft rebalanced. Is your new driveshaft "NEW" or a used one, or rebuilt with old parts?
#4
Old [Sch|F]ool
Tailshaft bushings will die quickly regardless of what you do, so all you can do is make sure its life is easy.
IE - Make sure the U-joint angles are correct when at acceleration ride height, make sure they aren't excessive, make sure your tailhousing has the sheetmetal oil feed channel in place, make sure the trans is kept full-to-overfull (I'll fill it with an extra half quart by putting the left side on stands).
IE - Make sure the U-joint angles are correct when at acceleration ride height, make sure they aren't excessive, make sure your tailhousing has the sheetmetal oil feed channel in place, make sure the trans is kept full-to-overfull (I'll fill it with an extra half quart by putting the left side on stands).
#5
Rotary Freak
Great advice on the overfill remark. I need to do that with mine as well and I then end up with the car spitting oil out the upper breather and filling the car with fumes. I agree that the extra fluid is necessary, so I changed the breather for a fitting and ran the hose up to a catch can bottle. Got rid of the smell and dripping after a race and I have never lost a rear seal or tailshaft bushing.
Eric
Eric
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#9
Full Member
iTrader: (2)
Differential
You guys are scaring me. I've been doing all those things and knock on wood same tranny and rear end. Imagine a bunch of FWD cars and one Rotary spins side ways in the pack shifting near 9-10 grand when you grab 3rd gear, or they hit your rear bumper and you pull away slideways. Not so lucky today Eddie, we threw the belt on lap 1 coming through the field. You left out one thing that might have started the problem before they got the car. Hint: we learned it last night. I told them I have a GT Panhard and Tri Link left. That would help with the pinion angle. The chassis may be doing all kinds of stuff with the watts linkange going roundy round, and its the same repetitive forces every turn going left. That car has definitely taken more hits than mine. Fell off the hauler once at speed on the highway.
Last edited by Oval-RX7; 05-09-15 at 08:46 PM.
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