Transmission Reinforcement/upgrades?

N

Ninereeds

Low Mileage
Hi Folks,
I'm scheduled to buy a 1981 X1/9 next week and I've seen a lot of threads on potential engine swaps, but nothing about preserving a stock transmission on a more highly tuned engine.

To get into the specifics, the car has the 1500 and a 5 speed. I'm looking to boost the power of the stock motor, since it's in good shape for it's age and it would be a shame to scrap it, and because I like the high-revving sort of characteristic it has (although VTEC is tempting there). Current plan is an E85 conversion and maybe a small supercharger if it doesn't make enough power on corn juice. The issue I'm running into is that people have been telling me that the stock transmission gets very fragile above around 100 HP.

Is there any way to preserve the transmission for boosted power outputs? Or god forbid a drop in replacement that's a bit tougher? Or is this a lost cause?

My best backup plan is to drop a smaller Honda engine in (not K20, that's gotten quite expensive for my taste), but that requires throwing out a lot of decent components, and a good bit of extra work.

Thanks in advance for any advice.
 
Treated properly, not speed shifting, dropping the clutch and so on the transmission can be good for the amount of power you suggest.

One reinforcement which might be of value would be to add the reinforcement Steve Hoelscher has performed and was also done by another member (I will find his thread which shows it) to take the load off the transmission housing.

You might speak with Steve who has been responsible for rebuilding many X transmissions for some better views of how to ensure a healthy transmssion.

The behavior of the driver is the biggest harbinger around the expected life of an X transmission.
 
kmead said:
The behavior of the driver is the biggest harbinger around the expected life of an X transmission.
Click to expand...
Karl is right. What is tough on a transmission would also be racing. If you intend to do some track or slalom, you will have to do some quick shifts and it will be hard on the transmission. But racing is hard on all parts of the car and more maintenance is to be expected.

The 5 speed transmissions are known to have problems mainly with the reverse and bad syncro to third. In the last 40 years, I had many x19 and I had to change a reverse gear once but I learned to live with the bad third syncro (after a while, it's always coming back) by shifting smoothly and/or double clutching (if I remember well, the double clutch worked going up but not down).
 
Thanks for the responses. I have to say this is more encouraging info than I was expecting. I don't expect to take the car racing, but I do still want the extra power to enjoy the small car experience (and to dodge lifted trucks on the highway).

I found the Steve Hoelscher 5 speed 101 guide, which I'm sure will be useful and I've saved for later, but couldn't find the specific thread on the reinforcement job unfortunately, so if you know where to find that I'm all ears.

The car I'm getting only has 37k miles, so I'm hoping the transmission is already in good shape, I'm mostly concerned with how it will hold up at more power. (My hope for tuning is to bring it up to ~125 - 150 hp depending on how it takes E85).

Again, big thanks for the responses. At this point I think I will shoot for maintaining the stock motor + transmission (rather than swapping), but if anyone has any further tips or links for bolstering the 5 speed it would be appreciated.
 
There are/have been members with built 1600/1900 motors still running stock transmissions, so they can hold up if not abused. My 1600 was probably around the 120 or so range, and the trans was OK (130k+ miles) - I had some shifting issues before, that didn't get worse after. The lack of significant low end torque with this motor helps, I'm sure :D
 
ng_randolph said:
I think Karl was talking about this thread by Steve Hoelscher; post #18 in particular,
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Ninereeds said:
Thanks for the responses. I have to say this is more encouraging info than I was expecting. I don't expect to take the car racing, but I do still want the extra power to enjoy the small car experience (and to dodge lifted trucks on the highway).

I found the Steve Hoelscher 5 speed 101 guide, which I'm sure will be useful and I've saved for later, but couldn't find the specific thread on the reinforcement job unfortunately, so if you know where to find that I'm all ears.

The car I'm getting only has 37k miles, so I'm hoping the transmission is already in good shape, I'm mostly concerned with how it will hold up at more power. (My hope for tuning is to bring it up to ~125 - 150 hp depending on how it takes E85).

Again, big thanks for the responses. At this point I think I will shoot for maintaining the stock motor + transmission (rather than swapping), but if anyone has any further tips or links for bolstering the 5 speed it would be appreciated.
Click to expand...

Thank you Bjorn.

Post 18 describes the solution, post 31 shows a way to do it. Link below:

Random Transmission Failures

I have a solid bottom mount and solid dog bone. I like them. No more engine rocking. When I gave gas, the car is moving, no delay no jet lag. But I will be happy to have spinning tires. Maybe I will with my rebuilt engine and DCOE's...:rolleyes:
xwebforums.com
 
Welcome to the 'club' here. I'll be glad to assist if I can.

I have been building these transmissions since I was a starving college student who couldn't afford to pay somebody to fix their busted X1/9 4 speed.

Along the way I have been involved with a broad range of X1/9 racing and performance builds. A healthy transmission would be fine with virtually any normally aspirated SOHC street build. I had a 125 rwhp X1/9 that I beat the living daylights out of for several years. The transmission was fine. In addition to street driving, it was autocrossed and tracked regularly.

When tracking these cars, especially with high output engines. what kills transmissions is inadequate oiling or excessive oil temperatures. A pump and cooler will solve these problems, assuming you are using the correct oil.

Turbo cars are a little different. If you are running a fair amount of boost the resulting torque can actually strip the teeth on 3rd, 4th or 5th. The fix here is to cryo treat the input shaft and 3rd, 4th and 5th driven gears. Cryo treating the diff carrier is also a good idea.

If you're staying NA I wouldn't worry about it. A small supercharger would likely not be a problem as you're not going to boost power substantially.

There are two things that most people don't understand about these transmissions: 1st is age. You said the car has 37K miles on it. That's actually a problem. With 37K miles over 30+ years, the car obviously sat quite a bit. And with only 37K miles I'm willing to bet that the transmission fluid has never been changed. Depending on the periods of storage and where and how it was stored the transmission fluid could be severely contaminated and have caused an excessive amount of wear/damage, even for the remarkably low mileage. There could be rust inside the transmission from condensation. The clutch arm could be rusted and eat its bushing up in short order. There are endless possibilities. Most people will thin that the low mileage will mean the transmission is like new. It might be, but then again, its just as likely not.

The 2nd reason is the transmission does have its flaws. A weak reverse is un-related to the amount of power the car makes but rather the driver's care in using it. Same for 3rd gear. The 3rd gear syncrhonizers are typically the first thing to show wear and a ham fisted driver will hasten the failure. Also, I have seen many X1/9s with complete synchro failure on 1st and/or 2nd gear at less than 30K miles. This due to a manufacturing defect on some gears. I address most of these issues when I build a unit and things like reverse, I can tell you how to prevent failures.

Much of the reason for the belief that the transmission tends to break at over 100 HP isn't due to the transmission not being able to live with the power so much as the power was added to a transmission what wasn't healthy to begin with. So when the power was added, the pre-existing issues became failures.
 
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