Building a cheap daily beater
06-26-07, 09:35 PM
#1
Building a cheap daily beater
So I just graduated and I wanted to finish my S4 T2 but I feel its just going to take to long. Let me also type before I forget that I did A LOT of searching.
I got a 84 GS with over 200k, body is good,interior will be basically gutted, nice light weight 15" 5 spoke rims, it has one blown apex seal but will start up it just wont hold an idle. Beside these problems it needs a driver door handle,pass mirror,and steering box. So far I got $1200 that is mine but my dad is gonna hold it for me. The graduation money im using for the T2 short block rebuild. Im getting a 12a short block with 90k for free, story goes some guy got a rag into it and hasn't ran the engine since. I wanted to get the rotary aviation basic rebuild kit with apex seals for $600, do some porting, intake, and exhaust. Anyone had any nice 12a guides? I know their easyer but I like to know what Im getting into. I also have an S5 T2 block a part and wanted to try and use some other parts....maybe try using theS5 T2 turbo? I don't know how difficult it would be to do. I do know it isn't to hard on the 13b I just don't have enough money for that now. If I cant go turbo for cheap enough its no big deal I will just keep it n/a. Any input on whats best to do with my money would be great. Also can a header ment for a 13b fit onto a 12a engine? I doubt it but just wanted to know. Thanks, Nick
I got a 84 GS with over 200k, body is good,interior will be basically gutted, nice light weight 15" 5 spoke rims, it has one blown apex seal but will start up it just wont hold an idle. Beside these problems it needs a driver door handle,pass mirror,and steering box. So far I got $1200 that is mine but my dad is gonna hold it for me. The graduation money im using for the T2 short block rebuild. Im getting a 12a short block with 90k for free, story goes some guy got a rag into it and hasn't ran the engine since. I wanted to get the rotary aviation basic rebuild kit with apex seals for $600, do some porting, intake, and exhaust. Anyone had any nice 12a guides? I know their easyer but I like to know what Im getting into. I also have an S5 T2 block a part and wanted to try and use some other parts....maybe try using theS5 T2 turbo? I don't know how difficult it would be to do. I do know it isn't to hard on the 13b I just don't have enough money for that now. If I cant go turbo for cheap enough its no big deal I will just keep it n/a. Any input on whats best to do with my money would be great. Also can a header ment for a 13b fit onto a 12a engine? I doubt it but just wanted to know. Thanks, Nick
06-27-07, 09:21 AM
#4
Yeah rotary aviation has a basic kit and they say it is a full kit to put together a 12a short block for $600 shipped. Then I was gonna buy any other gasket or part separate. I do want the car mostly stock just a rebuild,slight porting,intake and exhaust will be good enough for me. I would really like some tips, I know people on here have built a lot of 12a's but I haven't found any good detail. Some input would be great. Also can a 13b header kit on a 12a.
06-27-07, 10:33 AM
#5
No, the rotor housings on the 13b are 10mm wider than the ones on the 12a, which makes your exhaust studs further apart and your exhaust ports wouldn't be centered on the pipes. You could technically bolt it up if you oval'd the holes or drilled new ones in the header flange, but you'd still have the problems with the exhaust ports not lining up properly.
As for rebuilding the 12a... If you tear down both of them and get the proper tools to measure clearance on all the parts, you'll probably have enough parts for one good engine, hopefully.
With the rebuild kit you get what you pay for. I'm not saying RA isn't good quality, I'm saying that I don't see any corner seals, corner seal springs, oil control rings, oil control ring springs, or side seals in that kit. That's almost definitely why it's only $600.
I'd go with a Racing Beat or Atkins Rotary rebuild kit. It'll cost about a grand, but you won't be missing things.
For porting, if you haven't done porting before but you have the tools, buy some templates from somewhere (racingbeat, mazdatrix, pineapple, atkins, wherever), and practice on the worst housings you have, the ones you aren't going to use. Then port your good ones.
If you don't already have porting tools (and a large selection of carbide bits counts for "porting tools") then you'll have to get someone to do that for you. That's gonna cost you some.
If you do an average sized street port (read: not wild Ito-style port), you check your clearances, resurface the irons and use a full rebuild kit, you'll have an engine for a reliable DD FB.
If you skimp on the kit, or don't resurface the irons, or go too crazy on your ports, or don't check your clearances, or ignore things that are out of spec, then you're building an engine that's setup for failure.
Take your time, spend the cash, and do it right. Or don't do it at all. If you aren't going to do it right, you might as well just buy a running junker 12a, ATF it, slap it in and then run it for a short while until it dies. But then most of us would probably smack you for ruining what would be a perfectly good core for an engine that's getting harder to find good cores for.
Jon
As for rebuilding the 12a... If you tear down both of them and get the proper tools to measure clearance on all the parts, you'll probably have enough parts for one good engine, hopefully.
With the rebuild kit you get what you pay for. I'm not saying RA isn't good quality, I'm saying that I don't see any corner seals, corner seal springs, oil control rings, oil control ring springs, or side seals in that kit. That's almost definitely why it's only $600.
I'd go with a Racing Beat or Atkins Rotary rebuild kit. It'll cost about a grand, but you won't be missing things.
For porting, if you haven't done porting before but you have the tools, buy some templates from somewhere (racingbeat, mazdatrix, pineapple, atkins, wherever), and practice on the worst housings you have, the ones you aren't going to use. Then port your good ones.
If you don't already have porting tools (and a large selection of carbide bits counts for "porting tools") then you'll have to get someone to do that for you. That's gonna cost you some.
If you do an average sized street port (read: not wild Ito-style port), you check your clearances, resurface the irons and use a full rebuild kit, you'll have an engine for a reliable DD FB.
If you skimp on the kit, or don't resurface the irons, or go too crazy on your ports, or don't check your clearances, or ignore things that are out of spec, then you're building an engine that's setup for failure.
Take your time, spend the cash, and do it right. Or don't do it at all. If you aren't going to do it right, you might as well just buy a running junker 12a, ATF it, slap it in and then run it for a short while until it dies. But then most of us would probably smack you for ruining what would be a perfectly good core for an engine that's getting harder to find good cores for.
Jon
06-27-07, 01:45 PM
#6
Thanks john finally got some good input here. You have a really good point about the RA kit. I do have the money for a racingbeat kit but I kinda wanted a little extra cash for any other little things I need. But yeah I guess i shall do it rightand by a racing beat kit. (but not relaping the irons if its still fine) One thing i didnt quite get about the racingbeat kit, they have a race kit and regular. The race kit is cheaper but is it better? Anyone who actually knows about this product can they put some input for me? I got all the tools im gonna need basically so that is not a problem. So anyone else have some good advice to making a well worth it 12a DD? - Nick
06-27-07, 01:57 PM
#7
Aah.. yeah their race kit is cheaper but it is *strictly* a track-only kit. It comes with carbon apex seals which are only good if you're constantly running up around the 6k rpm range. They don't seal well at all at low RPM and are made for peri-port race engines pretty much.
If your irons are still in-spec you'll be able to run without lapping them, but check the local shops around. Lapping isn't *that* expensive compared to many other things you do to a car, and it's better to lap them and know they'll be reliable rather than not lapping them and risking having to tear the engine apart again. Every time you tear and engine down you need another "soft seal" kit (all the seals that you can't easily re-use such as the water jacket o-rings) which costs about $300ish and takes time to pull the engine out of the car and reinstall.
It's a personal choice, but if you're lucky and it's a good condition low miles motor, you might be able to get away without lapping the irons.
Go with the regular racing beat kit or the 12a "Overhaul Kit C" from atkins:
http://www.atkinsrotary.com/store/cu...cat=590&page=1
It's slightly cheaper and still a good quality kit.
Jon
If your irons are still in-spec you'll be able to run without lapping them, but check the local shops around. Lapping isn't *that* expensive compared to many other things you do to a car, and it's better to lap them and know they'll be reliable rather than not lapping them and risking having to tear the engine apart again. Every time you tear and engine down you need another "soft seal" kit (all the seals that you can't easily re-use such as the water jacket o-rings) which costs about $300ish and takes time to pull the engine out of the car and reinstall.
It's a personal choice, but if you're lucky and it's a good condition low miles motor, you might be able to get away without lapping the irons.
Go with the regular racing beat kit or the 12a "Overhaul Kit C" from atkins:
http://www.atkinsrotary.com/store/cu...cat=590&page=1
It's slightly cheaper and still a good quality kit.
Jon
Trending Topics
06-27-07, 03:08 PM
#8
Thanks jon thats exactly what I was looking for about the RB race kit. Guess i will be using the atkins kit just because I have used them before and I know there worth it. Got any pointers on what else to replace while the engine is out? I wanted to remove basically all the emissions since i can have it inspected upstate NY, I have a good idea about removing the 13B emissions but not so much for the 12a. Anyone have good links for this? What else can be removed? I want this as light as possible without extensive modification. Also im getting a apexi exhaust for free can I use this as long as I get a header to go with it? I wish some others would chip in with some help since VIPERNICUS is the only one so far. Thanks -Nick
06-27-07, 03:34 PM
#9
Also I forgot to say I want to block off the OMP and get a header. How much is the most any of you guys would pay for a pacesetter header, reason being I know Racing beat will cost most and just gonna settle with a pacesetter to apexi exhaust. -NICK
06-27-07, 03:54 PM
#10
that exhaust will be INSANELY loud and sound like ****. buy a used RB. **** the pacesetter. RB isnt the most expensive.
also, not trying to be a dick. but pretty much ANY question you want to ask can be answered by using the SEARCH button. try it and do a little research.
also, not trying to be a dick. but pretty much ANY question you want to ask can be answered by using the SEARCH button. try it and do a little research.
Last edited by dbragg; 06-27-07 at 04:07 PM.
06-27-07, 04:08 PM
#11
Yeah, exhaust is hard to get right on the FB unless you go Racing Beat. Rotaries are much hotter than piston engines for starters (1800-2000degrees F for rotaries, compared to 1400-1600 degrees F for your average 4-banger) so it'll make short work of anything that's not made of good quality steel and steel wool packing. Fiberglass is out of the question.
Then you add the fact that they're much louder as well. If you haven't heard an open-header rotary, then you've never felt what it feels like to have your ears bleed before you even open your secondaries... If you don't mind loud, tinny, crappy sounding exhaust and just want straight-through flow for the power on as low of a budget as possible, then yeah you can go ahead and put a header and straightpipe it to a muffler. Though I wouldn't recommend it (ask me how I know, lol).
The RB system isn't cheap, and certainly not in the range of "daily driver beater car" budget in my opinion... but it's the best damn exhaust you can get for an FB in terms of balancing sound and performance.
I'd stick with the stock exhaust if you don't want to shell out for RB. But the RB header+presilencer+muffler combo is hard to beat.
Why are you blocking off the OMP? Are you going to run premix? OMPs can easily and cheaply be rebuilt. The kit costs like $20 and it takes all of 30mins to rebuild one, and that includes 20 mins of soaking the OMP in Mineral Spirits to clean it out. I'm keeping mine, and when I go for my performance engine I'm just going to get one of the Rotary Aviation 2-stroke adapter and a resivoir, and then just lock my OMP in "full-on" mode. It removes the guess work from how much 2-stroke you have to add at the gas station, and makes it more convenient. Just fill the resivoir and go.
For anything that's close to stock, keep the OMP, especially if you've got a stock carb with the provisions for it. If you were changing to something like a Weber or Dellorto carb I'd understand why you'd elminate the OMP.
As for stripping the rat's nest and the carb, there are a few good threads on it. Carl wrote a tutorial on how to remove it and ray recently posted pics of his after he followed that tutorial. There is also a nice simple way to use an ACV in place of the purge valve used in Carl's tutorial, and there's a good thread on that somewhere in the archive with pics of my old setup. For stripping the carb itself, I'm in the process of writing a tutorial for that, it'll probably be posted in a few days.
Don't worry about me beating the others to the punch.. I've had a slow day or two at work... Scott (trochoid) usually beats me to most threads nowadays, and we all toss in whatever we've got for info. Most people log on once every day or two, so if they get to a thread and the info's there, they'll read it, smile and move on.
Jon
Edit: don't forget to check ebay and the for sale sections for exhaust stuff. It goes up pretty often since the RB systems usually outlive the cars they're installed on.
Then you add the fact that they're much louder as well. If you haven't heard an open-header rotary, then you've never felt what it feels like to have your ears bleed before you even open your secondaries... If you don't mind loud, tinny, crappy sounding exhaust and just want straight-through flow for the power on as low of a budget as possible, then yeah you can go ahead and put a header and straightpipe it to a muffler. Though I wouldn't recommend it (ask me how I know, lol).
The RB system isn't cheap, and certainly not in the range of "daily driver beater car" budget in my opinion... but it's the best damn exhaust you can get for an FB in terms of balancing sound and performance.
I'd stick with the stock exhaust if you don't want to shell out for RB. But the RB header+presilencer+muffler combo is hard to beat.
Why are you blocking off the OMP? Are you going to run premix? OMPs can easily and cheaply be rebuilt. The kit costs like $20 and it takes all of 30mins to rebuild one, and that includes 20 mins of soaking the OMP in Mineral Spirits to clean it out. I'm keeping mine, and when I go for my performance engine I'm just going to get one of the Rotary Aviation 2-stroke adapter and a resivoir, and then just lock my OMP in "full-on" mode. It removes the guess work from how much 2-stroke you have to add at the gas station, and makes it more convenient. Just fill the resivoir and go.
For anything that's close to stock, keep the OMP, especially if you've got a stock carb with the provisions for it. If you were changing to something like a Weber or Dellorto carb I'd understand why you'd elminate the OMP.
As for stripping the rat's nest and the carb, there are a few good threads on it. Carl wrote a tutorial on how to remove it and ray recently posted pics of his after he followed that tutorial. There is also a nice simple way to use an ACV in place of the purge valve used in Carl's tutorial, and there's a good thread on that somewhere in the archive with pics of my old setup. For stripping the carb itself, I'm in the process of writing a tutorial for that, it'll probably be posted in a few days.
Don't worry about me beating the others to the punch.. I've had a slow day or two at work... Scott (trochoid) usually beats me to most threads nowadays, and we all toss in whatever we've got for info. Most people log on once every day or two, so if they get to a thread and the info's there, they'll read it, smile and move on.
Jon
Edit: don't forget to check ebay and the for sale sections for exhaust stuff. It goes up pretty often since the RB systems usually outlive the cars they're installed on.
06-27-07, 05:27 PM
#12
I was going to get rid of the omp just because I dont want it to fail on me during sometime. Your right though, im going to just get the kit and be done with it. I going to get the pacesetter header since it will be cheap and easy to get. As for the problem with the steering wheel, it goes back and forth like 5 inches before the play stops and it starts to turn the wheel. I forgot what the problem exactly was and my dad remembers but I wanted to know if I can just get rid of the steering box to remove more stuff. - nick
06-28-07, 07:52 AM
#16
OMP Rebuild Kit:
https://www.rx7club.com/showthread.p...we+performance
OMP Overhaul Info:
http://www.mazspeed.com/oilmeteringpump.htm
Steering Box Info:
http://www.mazspeed.com/steeringgear.htm
Rat's Nest Removal Tutorial:
http://maz_tutorials.ten15.net/
Jon
https://www.rx7club.com/showthread.p...we+performance
OMP Overhaul Info:
http://www.mazspeed.com/oilmeteringpump.htm
Steering Box Info:
http://www.mazspeed.com/steeringgear.htm
Rat's Nest Removal Tutorial:
http://maz_tutorials.ten15.net/
Jon
06-29-07, 02:07 PM
#22
It might be just my computer, but I really doubt it. It seems the character set that Bob used when he wrote the steering gear restoration article was not quite right. I went through it and corrected everything as best as I could from the context.
Jon, if you do archive this thread, don't do it before I've had a chance to post the edited steering gear retoration article. I'll post it in its intirety next...
Jon, if you do archive this thread, don't do it before I've had a chance to post the edited steering gear retoration article. I'll post it in its intirety next...
06-29-07, 02:08 PM
#23
Steering Gear Restoration By Bobrx-7
Get Connected to the Ground Again
The following entry is in draft form. All of the procedures have been done at least twice and are believed to be correct. I will be verifying a couple of details in the next week or so (late March). Any changes will be noted in a revised version. Please feel free to e-mail me at; bobrx7@yahoo.com with questions, or to let me know your results.
One of the unfortunate truths about the 1st generation Rx-7 is, that the steering leaves something to be desired. While most import and many small domestic cars of the time were equipped with rack-and-pinion steering systems, Mazda's bean-counters insisted that as many parts from the corporate "parts bin" as possible, be used to get the new model out the door. The steering gear is essentially the same unit used in Mazda B-Series and Ford Courier pickup models of the time. The result, is steering that even when in top working order) is vague and VERY slow. With a ratio of 18.5 to 1 compared to a ratio of 15.8 to 1 for 84-85 power steering cars (compare that to about 15 to 1 for many R&P cars of the time) and the large 15 in. steering wheel used to accommodate small female drivers; "Can you say, "school bus??" A 13.5 inch steering wheel and adapter from Barry Grant (or MOMO if you're rich) will improve this somewhat. Summit Racing can hook you up with the Grant parts for about $60.
Like any mechanical device, the Rx-7 recirculating ball (RB) steering gear is subject to wear. As such, that vague sensation is amplified to a point that becomes downright numb. When I first purchased my `84 GS, I referred to the system as "wonder steering," as in, "I wonder where it's going next." Having had experience with RB units from Ford and GM cars and trucks, I made the usual adjustment to the sector shaft preload, to remove the excess play. This improved feeling lasted about 3 days and then right back to "wonder steering." The reason, as it turns out, is fairly simple. Unfortunately, not as simple to correct.
Tools Needed
To make the needed adjustments, you'll need the following tools. All are easy to come by.
40 mm or 1 9/16 in. socket (a six point socket works better). I bought one at Sears with a ¾ to ½ in. adapter for about $17. The open end of the socket MUST be ground down to completely remove the chamfer in the opening. I'll explain later. This takes about 5 minutes on a bench grinder.
14 mm socket and combination wrench, one or two long extensions and long-handled ratchet
A ½ in breaker bar, one or two long extensions and a length of pipe for a cheater bar.
A ½ in. wide cold chisel and ball peen hammer and a deep socket that fits snugly over the chisel shank will be needed with an extension.
A 0 - 1 inch dial indicator and stand. I bought an excellent dial indicator and magnetic base from J&L Tools for about $35 and it comes in handy for many other things as well.
How it works
There are three individual adjustments on all 81 ½ to 85 models with manual steering. 79-81 ½ models have only two adjustments. I'll cover what you need to know about each as we go. The order in which these adjustments are made is VITAL. Doing it wrong will result in no improvement at all and possibly irreparable damage on the later units. But first, some basics.
The steering wheel and shaft are connected to the worm gear. Think of this as a coarse threaded bolt, held in place by two tapered roller bearings. Mounted on this is the ball nut, which rides on a couple dozen small steel ***** that ride in the threads of the worm gear and ball nut. This is nothing more than a regular nut that has threads cut on both the inside and outside. As the wheel is turned, the ***** are rotated through the threads of the worm and nut and a small tube on the outside of the nut. Thus the term, "recirculating ball." As the worm is turned (no pun intended), the ball nut will move up or down on the worm gear.
The sector shaft is mounted vertically through the housing. The teeth on the sector shaft mesh with the threads on the outside of the ball nut. As the ball nut moves up and down the worm gear, the sector shaft will rotate accordingly. This motion is transferred to the pitman arm and then into the steering linkage. For the steering gear to work as intended, all of these parts must maintain some very precise clearances. When the clearances become excessive, the steering will become vague, with an excessive amount of freeplay in the wheel when centered, AKA "wonder steering".
The Fix(es)
I must stop and point out, that the balance of this article assumes that you have checked and verified that your ball joints, tie rods, idler arm, pitman arm and wheel bearings are all in good condition and properly adjusted. If not, you'll be wasting your time trying to adjust the play out of the steering. Once the items above are all verified, proceed. For those of you with power steering, or using a power gear with no pump, I'll provide a short entry later, since much of this will not apply to you.
Ideally, all of the adjustments that follow should be made with the steering box on the bench. However, being the lazy sort that I am, I found a way to do this in the car. Those of you with AC will thank me many times over, since pulling the steering gear is a pain in the butt on non-AC cars and downright unpleasant on AC cars.
1.
Make sure the steering gear is filled with 75W90 gear lube. With the front end lifted and on stands (please use stands), make sure the column lock is engaged to prevent the steering shaft from turning and disconnect the center link from the pitman arm. You need to do this to get accurate results.
2.
Mount a dial indicator and place the tip on the side of the pitman arm ball socket and set to zero. Gently move the pitman arm and read the indicator. If more than .001 in. play is present, you need to proceed. This is most of the free play you feel in the wheel. Note I said most.
3.
On all 81 ½ to 85 manual gears, there are two separate adjustments on the sector shaft. The large 40 mm nut and adjusting plug, sets the preload on the sector shaft bearing. The 14mm nut and adjusting screw is used to set the sector shaft and ball nut mesh clearance (This is the only sector adjustment on 79 - 81 ½ cars.). The 14 mm nut is covered by a metal cap from the factory. Pop the cap off with a pair of pliers and throw it in the neighbor's front yard. Loosen the 14 mm nut, then snug it in place for now. Loosen the 40 mm nut. This requires that you maintain a very straight alignment on the nut since it's very thin. If you round it off, you're screwed. Thus the need to grind the chamfer out of the socket opening. Remove the nut and turn it upside down. The bottom side has square corners and is easier to grip in the future. Turn the large adjusting plug counter clockwise ½ turn.
4.
Reconnect the center link to the pitman arm temporarily. With the front wheels on the ground, note the large amount of free play in the steering wheel. Note also that there is very little effort needed to turn the wheel, since the preload on the worm shaft bearings is gone from wear and there is some axial play (end play). This is where much of the vague feeling comes from and why simply adjusting the sector shaft doesn't work.
5.
Loosen the worm shaft adjusting plug lock nut (where the column tube meets the gear box), with the hammer and chisel, by tapping counter clockwise, as viewed from the driver seat. This is tough to do since space is limited. I found that inserting the chisel in a socket, taping it in place and using an old extension really helps.
6.
Using a 12 in. crescent wrench, turn the worm shaft adjuster plug clockwise (from driver seat) just a tiny bit and check the steering wheel. Keep going in tiny steps until you begin to feel a slight resistance to turning the wheel. You have now restored preload to the worm bearings, so the worm shaft does not have any axial play. Tighten the lock nut with the hammer and chisel.
7.
Put the front end back up on stands and disconnect the center link again. For 79 - 81 ½ cars, go to step 8. For 81 ½ - 85 cars, tighten the large adjusting plug on the sector shaft, just until it starts to feel snug. Check the turning effort of the wheel. When it starts to feel a little tighter than just after the worm bearing adjustment, stop. Lightly tighten the 40 mm nut for the time being. You have now set sector shaft preload.
8.
Lock the steering column so the steering shaft cannot move. Recheck the free play in the pitman arm with the dial indicator. Turn the small adjusting screw counter clockwise ¼ turn and check free play again. If the free play is less, keep going until there is zero play. If free play is more, turn the adjusting screw ½ turn clockwise and recheck. Keep going until you have zero play. Hold the adjusting screw with a screwdriver and tighten the 14 mm nut lightly with an open end wrench. Rotate the steering wheel 1 full turn each way, re-center the wheel and recheck the pitman arm play. If OK proceed. If not, repeat step 8.
9.
Reconnect the pitman arm and center link, install a new cotter pin and put the front end on the ground. Gently move the steering wheel left and right and watch the left front tire. If you did it as instructed, the tire will move with even the slightest movement of the steering wheel. If so, great, you're done. If not, go back and check your adjustments. I can assure you, if you followed this procedure exactly, you'll be right on the money.
10.
Tighten the 40 mm nut snugly. Don't over do it. Tighten the 14 mm nut to about 20 lb. ft. Test drive and be amazed at how much better your steering feels. You may need to tweak the fine adjusting screw slightly after a few miles and everything takes a set. This you can do by feel.
Power Steering
For those of you with power steering boxes, the sector shaft adjustment works like the 79 - 81 ½ cars. There is a worm shaft preload adjustment, but it requires that the gear be pulled from the car and partially disassembled. I have never done a Mazda power gear, but they work much like the Ford XR-70 unit. If you simply cannot get good steering feel with the sector shaft adjustment, take the gear to a pro and let him do it. I know when I'm over my head and it's worth the money to get it right the first time. A new power gear costs in excess of $1200. Certainly not in my budget.
Happy rotoring.
Bobrx7
Get Connected to the Ground Again
The following entry is in draft form. All of the procedures have been done at least twice and are believed to be correct. I will be verifying a couple of details in the next week or so (late March). Any changes will be noted in a revised version. Please feel free to e-mail me at; bobrx7@yahoo.com with questions, or to let me know your results.
One of the unfortunate truths about the 1st generation Rx-7 is, that the steering leaves something to be desired. While most import and many small domestic cars of the time were equipped with rack-and-pinion steering systems, Mazda's bean-counters insisted that as many parts from the corporate "parts bin" as possible, be used to get the new model out the door. The steering gear is essentially the same unit used in Mazda B-Series and Ford Courier pickup models of the time. The result, is steering that even when in top working order) is vague and VERY slow. With a ratio of 18.5 to 1 compared to a ratio of 15.8 to 1 for 84-85 power steering cars (compare that to about 15 to 1 for many R&P cars of the time) and the large 15 in. steering wheel used to accommodate small female drivers; "Can you say, "school bus??" A 13.5 inch steering wheel and adapter from Barry Grant (or MOMO if you're rich) will improve this somewhat. Summit Racing can hook you up with the Grant parts for about $60.
Like any mechanical device, the Rx-7 recirculating ball (RB) steering gear is subject to wear. As such, that vague sensation is amplified to a point that becomes downright numb. When I first purchased my `84 GS, I referred to the system as "wonder steering," as in, "I wonder where it's going next." Having had experience with RB units from Ford and GM cars and trucks, I made the usual adjustment to the sector shaft preload, to remove the excess play. This improved feeling lasted about 3 days and then right back to "wonder steering." The reason, as it turns out, is fairly simple. Unfortunately, not as simple to correct.
Tools Needed
To make the needed adjustments, you'll need the following tools. All are easy to come by.
40 mm or 1 9/16 in. socket (a six point socket works better). I bought one at Sears with a ¾ to ½ in. adapter for about $17. The open end of the socket MUST be ground down to completely remove the chamfer in the opening. I'll explain later. This takes about 5 minutes on a bench grinder.
14 mm socket and combination wrench, one or two long extensions and long-handled ratchet
A ½ in breaker bar, one or two long extensions and a length of pipe for a cheater bar.
A ½ in. wide cold chisel and ball peen hammer and a deep socket that fits snugly over the chisel shank will be needed with an extension.
A 0 - 1 inch dial indicator and stand. I bought an excellent dial indicator and magnetic base from J&L Tools for about $35 and it comes in handy for many other things as well.
How it works
There are three individual adjustments on all 81 ½ to 85 models with manual steering. 79-81 ½ models have only two adjustments. I'll cover what you need to know about each as we go. The order in which these adjustments are made is VITAL. Doing it wrong will result in no improvement at all and possibly irreparable damage on the later units. But first, some basics.
The steering wheel and shaft are connected to the worm gear. Think of this as a coarse threaded bolt, held in place by two tapered roller bearings. Mounted on this is the ball nut, which rides on a couple dozen small steel ***** that ride in the threads of the worm gear and ball nut. This is nothing more than a regular nut that has threads cut on both the inside and outside. As the wheel is turned, the ***** are rotated through the threads of the worm and nut and a small tube on the outside of the nut. Thus the term, "recirculating ball." As the worm is turned (no pun intended), the ball nut will move up or down on the worm gear.
The sector shaft is mounted vertically through the housing. The teeth on the sector shaft mesh with the threads on the outside of the ball nut. As the ball nut moves up and down the worm gear, the sector shaft will rotate accordingly. This motion is transferred to the pitman arm and then into the steering linkage. For the steering gear to work as intended, all of these parts must maintain some very precise clearances. When the clearances become excessive, the steering will become vague, with an excessive amount of freeplay in the wheel when centered, AKA "wonder steering".
The Fix(es)
I must stop and point out, that the balance of this article assumes that you have checked and verified that your ball joints, tie rods, idler arm, pitman arm and wheel bearings are all in good condition and properly adjusted. If not, you'll be wasting your time trying to adjust the play out of the steering. Once the items above are all verified, proceed. For those of you with power steering, or using a power gear with no pump, I'll provide a short entry later, since much of this will not apply to you.
Ideally, all of the adjustments that follow should be made with the steering box on the bench. However, being the lazy sort that I am, I found a way to do this in the car. Those of you with AC will thank me many times over, since pulling the steering gear is a pain in the butt on non-AC cars and downright unpleasant on AC cars.
1.
Make sure the steering gear is filled with 75W90 gear lube. With the front end lifted and on stands (please use stands), make sure the column lock is engaged to prevent the steering shaft from turning and disconnect the center link from the pitman arm. You need to do this to get accurate results.
2.
Mount a dial indicator and place the tip on the side of the pitman arm ball socket and set to zero. Gently move the pitman arm and read the indicator. If more than .001 in. play is present, you need to proceed. This is most of the free play you feel in the wheel. Note I said most.
3.
On all 81 ½ to 85 manual gears, there are two separate adjustments on the sector shaft. The large 40 mm nut and adjusting plug, sets the preload on the sector shaft bearing. The 14mm nut and adjusting screw is used to set the sector shaft and ball nut mesh clearance (This is the only sector adjustment on 79 - 81 ½ cars.). The 14 mm nut is covered by a metal cap from the factory. Pop the cap off with a pair of pliers and throw it in the neighbor's front yard. Loosen the 14 mm nut, then snug it in place for now. Loosen the 40 mm nut. This requires that you maintain a very straight alignment on the nut since it's very thin. If you round it off, you're screwed. Thus the need to grind the chamfer out of the socket opening. Remove the nut and turn it upside down. The bottom side has square corners and is easier to grip in the future. Turn the large adjusting plug counter clockwise ½ turn.
4.
Reconnect the center link to the pitman arm temporarily. With the front wheels on the ground, note the large amount of free play in the steering wheel. Note also that there is very little effort needed to turn the wheel, since the preload on the worm shaft bearings is gone from wear and there is some axial play (end play). This is where much of the vague feeling comes from and why simply adjusting the sector shaft doesn't work.
5.
Loosen the worm shaft adjusting plug lock nut (where the column tube meets the gear box), with the hammer and chisel, by tapping counter clockwise, as viewed from the driver seat. This is tough to do since space is limited. I found that inserting the chisel in a socket, taping it in place and using an old extension really helps.
6.
Using a 12 in. crescent wrench, turn the worm shaft adjuster plug clockwise (from driver seat) just a tiny bit and check the steering wheel. Keep going in tiny steps until you begin to feel a slight resistance to turning the wheel. You have now restored preload to the worm bearings, so the worm shaft does not have any axial play. Tighten the lock nut with the hammer and chisel.
7.
Put the front end back up on stands and disconnect the center link again. For 79 - 81 ½ cars, go to step 8. For 81 ½ - 85 cars, tighten the large adjusting plug on the sector shaft, just until it starts to feel snug. Check the turning effort of the wheel. When it starts to feel a little tighter than just after the worm bearing adjustment, stop. Lightly tighten the 40 mm nut for the time being. You have now set sector shaft preload.
8.
Lock the steering column so the steering shaft cannot move. Recheck the free play in the pitman arm with the dial indicator. Turn the small adjusting screw counter clockwise ¼ turn and check free play again. If the free play is less, keep going until there is zero play. If free play is more, turn the adjusting screw ½ turn clockwise and recheck. Keep going until you have zero play. Hold the adjusting screw with a screwdriver and tighten the 14 mm nut lightly with an open end wrench. Rotate the steering wheel 1 full turn each way, re-center the wheel and recheck the pitman arm play. If OK proceed. If not, repeat step 8.
9.
Reconnect the pitman arm and center link, install a new cotter pin and put the front end on the ground. Gently move the steering wheel left and right and watch the left front tire. If you did it as instructed, the tire will move with even the slightest movement of the steering wheel. If so, great, you're done. If not, go back and check your adjustments. I can assure you, if you followed this procedure exactly, you'll be right on the money.
10.
Tighten the 40 mm nut snugly. Don't over do it. Tighten the 14 mm nut to about 20 lb. ft. Test drive and be amazed at how much better your steering feels. You may need to tweak the fine adjusting screw slightly after a few miles and everything takes a set. This you can do by feel.
Power Steering
For those of you with power steering boxes, the sector shaft adjustment works like the 79 - 81 ½ cars. There is a worm shaft preload adjustment, but it requires that the gear be pulled from the car and partially disassembled. I have never done a Mazda power gear, but they work much like the Ford XR-70 unit. If you simply cannot get good steering feel with the sector shaft adjustment, take the gear to a pro and let him do it. I know when I'm over my head and it's worth the money to get it right the first time. A new power gear costs in excess of $1200. Certainly not in my budget.
Happy rotoring.
Bobrx7
07-03-07, 08:12 AM
#25
Update, picked up the ragged 12a block. It wouldn't turn over no matter what. I was just hoping for some good parts out of it. I take it all apart and turns out the whole engine block was f-ing mint! The rag was in a million peices but the housings,plates,and rotors were perfect. There was no signs or wear anywhere. So im going to be using this entire short block. Now im hoping someone will come along and give me the specs I need to make sure everything is within spec. Once I know what I will absolutly need them i will be ordering a rebuild kit and porting it. So0o0 anyone who can help and give me the spec on everyting that would be great. - Nick