Help - need Miata upright outer tie rod end for 5/8-18 (L/H)

[redbull]

I need some help identifying a "fit" alternative for the Miata upright outer tie rod ends to mate with 5/8" rack (L/H) - I mesureed the standard Miata tie-rod end (taper) and the small size is ~ .53 and the large taper is .59 and searching the MOOG catalogue was... frustrating!

I am looking for an outer tie-rod end that will fit the Miata upright steering control arm (taper as noted above) and have rod thread dimensions of .625-18L (or 5/8"-18 Left Hand ) So far the closest I found was:

Moog-ES379RL - the 5/8-18L/H will work, but ONLY the small taper is listed (.554) - no Larger stud taper listed???
Another possibility is Moog-ES297RL that also fits the 5/8-18 L/H red thread but the taper is WAY big (Small=.666 and large is .750 so I would have to have the upright milled to match this taper... argh!

In searching arround I saw a posting that 240SX outer tie rod ends "may" work, but I was getting frustrated trying to locate the thread rod end details.

Another option is to "make" an adapter for the 12 x 1.25 (righ hand) standard Miata rod end to a 5/8-18 (Left hand) stud so I can use off-the-shelf control arm tubes. (Seems 5/8 left and right hand thread are common in many parts listings)

I appreciate any help you can provide... Thanks in advance!
~John
(Sonoma, CA)

[Miatav8,MstrASE,A&P,F]

The actual Moog Catalog is missing a lot of information.

Sure, you can ream the spindle to fit a different joint, but it makes more sense to use what works with that spindle and rack, then make the adjuster to accept as necessary.


Male threads should be rolled versus cut. Welding should be performed away from the heat treated threads.

The miata adjuster inboard end can be pressed into a tube that is tapped as necessary for the inboard joint. If the tube ID is too great for the adjuster OD to press into, the tube can use a reducer bushing. If the distance between pivots is great enough, the miata adjuster can be used without modification and the reducer bushing tapped to accept it. If the miata adjuster must be shortened, shorten the inboard end then either tap and weld or press and weld, away from the outboard threads. Plug welds will also help.

I wouldn't worry about the toe link until I knew exactly how long the tie link needs to be for the desired toe (typically 1/8" in) to maximize thread engagement. This is after the caster and camber alignment.

[redbull]

Well I am deferring to your wisdom and can share some discoveries.

Yes using the standard OEM Miata taper (that is rather odd like most because of paten reasons) simply is the easiest and least expensive option. So knowing I have to resolve this metric 12 to SAE 5/6 (LH) issue I discovered:

1.) 1961 Ford F350's used 5/8"-18 Left-hand thread stud bolts, and tempered L/H axle nuts! they are 3.25" long with 2" of threads and the oversize stud recess is 1/16th over thread. - This will make s PERFECT 5/8-18 LH (grade bolt to mate with the M12 - 1.25 RH stud that fits the Miata standard outer tie-rod end.

2.) I will still need to make a "coupler" that looks sort of like this: ---[=]---
I will determine the best fit for the larger 5/8 stud, knowing I will have to either drill and tap then weld the void to accommodate the smaller M12 stud. I am going to use thick-walled pipe that I can hammer-in the 5/8 stud, then weld material over the back (flush) and drill and tap to the M12 thread (also tig welded for security). This effectively welds both bolts together (well away from the threads) and bonds them mechanically as well as fused back-to-back. Since other builders will likely need this remedy I will detail the parts and materials needed and finally resolve the way to use off-the-shelf 5/8-18 swedge tubes for adjustable tie rod arms to Miata outer tie rods! Whew, it just takes a lot to say all this!

Parts are ordered and expected to arrive next week in the mean time I will mount the Woodward colaspable Steering to the rack... and I have taps to make mock-up tie rods to get the exact leangth and dile in zerro bump steer and high ackerman.

~ John

The actual Moog Catalog is missing a lot of information.

Sure, you can ream the spindle to fit a different joint, but it makes more sense to use what works with that spindle and rack, then make the adjuster to accept as necessary.


Male threads should be rolled versus cut. Welding should be performed away from the heat treated threads.

The miata adjuster inboard end can be pressed into a tube that is tapped as necessary for the inboard joint. If the tube ID is too great for the adjuster OD to press into, the tube can use a reducer bushing. If the distance between pivots is great enough, the miata adjuster can be used without modification and the reducer bushing tapped to accept it. If the miata adjuster must be shortened, shorten the inboard end then either tap and weld or press and weld, away from the outboard threads. Plug welds will also help.

I wouldn't worry about the toe link until I knew exactly how long the tie link needs to be for the desired toe (typically 1/8" in) to maximize thread engagement. This is after the caster and camber alignment.

[redbull]

The actual Moog Catalog is missing a lot of information.

Sure, you can ream the spindle to fit a different joint, but it makes more sense to use what works with that spindle and rack, then make the adjuster to accept as necessary.


Male threads should be rolled versus cut. Welding should be performed away from the heat treated threads.

The miata adjuster inboard end can be pressed into a tube that is tapped as necessary for the inboard joint. If the tube ID is too great for the adjuster OD to press into, the tube can use a reducer bushing. If the distance between pivots is great enough, the miata adjuster can be used without modification and the reducer bushing tapped to accept it. If the miata adjuster must be shortened, shorten the inboard end then either tap and weld or press and weld, away from the outboard threads. Plug welds will also help.

I wouldn't worry about the toe link until I knew exactly how long the tie link needs to be for the desired toe (typically 1/8" in) to maximize thread engagement. This is after the caster and camber alignment.

------

reply reposted from PM:

Since the only bending load is from joint friction, another option is to use bolts on both ends, butt welded to a 1xxx steel tube with an OD and wall thickness, and length where the tube will bend before the welded area fails, maintaining control continuity after failure; IMHO, a tube .250” larger than the M12 head should be adequate. The welding is critical and should be high quality TIG and a thick bead. The bolts should be longer than necessary with an unthreaded shank. They should be tacked then welded a little at a time with cooling periods and heat sink putty or a wet rag around the threads.

You could use the miata adjuster, press fit and welded to a tube which is butt welded to the wheel stud, but the strength of the weld at the stud is critical.

You can post this in your topic.

[oldejack]

to each there own but i don't personally see a problem with using a taper reamer to "adjust" things so they fit a little better. or easier to find matching parts for that matter. as long as you watch the depth of cut you should be fine. we used a sunnen hone on 1 and 1.5 ton truck front ends(field service trucks) all the time with fantastic results, ie less slop/longer wear periods/less steering wander/etc. the new shops don't have technicians trained to the same level of, umm, in depth schooling that the older guys did it seems so it may be harder to find/ get done but today i'm also feeling a bit olde. maybe its time for me to move to boynton beach?

[Miatav8,MstrASE,A&P,F]

Your right Jack, but the reamer costs around $100 and a link will still be necessary.

[oldejack]

so very true, taper reamers ain't cheap. .. but i can make an offer that may help. sonoma is about an hour maybe 90 minutes from me, if you wish i can ask our machinist for a price on milling the parts to whatever taper desired. i'm not allowed on the machines at the moment since my field of vision is so restricted it's become a safety hazard but it should be inexpensive and means you can pick and choose parts based on fewer variables. pm me here or my yahoo user name is "jackcars". (i worked for years as a repossession agent getting paid to steal cars )

[redbull]

Well I decided to machine the 5/8-19 LH stud so it is M12 x 1.25 RH on one side and 5/8 LH on the other... it's the simplest answer and it will work fine. The trusted machinist will lath off the excess stud and the lath-cut the M12 x 1.25 RH thread and I have all 5 (box) of studs so I will have spares... well at least one since I will be building a second car sometime soon and will need to resolve this problem again!

Cost... well ~ $120-150 that is still cheaper than buying two spherical bearings, a taper reamer, a tapered bolt and still needing to machine the control arm on the upright(s) so simple is better, and cheaper too! Now I can use off-the-shelf tie rod (swedge) tubes and simple tune-buckle adjust toe-in perfectly.

Photos of the finished product will be forth coming and I bet at least a few other builders have run into this problem too! Just add this to the budget if you plan on using a standard racing rack and pinion. The "de-powered" Miata rack is... well, a big compromise on both performance, and due to its length, a conflict in design on a book built space frame Lotus (shorter track) so I feel the Woodward complete solution (albeit expensive) is a ideal improvement to a critical function. Surprise! It cost more and delayed the build almost a month!

[redbull]

My machined tie-rod conversion studs were finished… they came out perfect and finally resolve the pesky Miata M12 x 1.25 RH female to the more standard 5/8”-18 LH steering rack so I can buy and standard SWEDGE tubes and fine-tune toe-in! Very anti climatic, but sometimes simple solutions seem so ho-hum. Later today I will mock-up rod-end tubes so I can put back on the A-arms I plug welded the bungs and the chassis will be rolling, suspended and steering! Ready for engine positioning.

[chetcpo]

That's slick. What did that set you back to have those made. It might be worthwhile to make a few extra and sell em to offset your cost.

[redbull]

That's slick. What did that set you back to have those made. It might be worthwhile to make a few extra and sell em to offset your cost.

Well I did have a box made do I would have extras ... I will add the exact cost but I think my cost all tolled is ~ $35 each (including LH jam nuts) Y just mounted them and linked-up the Woodward complete steering and everything worked exactly as it was suppose to! Toe-in is perfect, and with 1.25 turn I get am extreme angle with cool Ackerman in the inner wheel, positive caster and outside edge camber - PERFECT. Then I checked for bump steer... there was NONE! Less and 1/16" movement from extreme bump and sag! Everything is tight and now I can focus on ENGINE mounting!

Let me know if you need these special M12 to 5/8 LH stud conversion I can arrange to make more if the market needs them and using the OEM tie-rod is a very good thing since I can get Miata replacement parts easily and in a bad accident, the tie-rod ball joint is the failure part. Here are some photos of the finished steering.

[skou]

Nice solution.

searching the MOOG catalogue was... frustrating!

Were you using the online catalog? http://www.moog-suspension-parts.com/Universal_Outer_Tie_Rod_Ends.asp It seemed pretty easy to use, albiet it doesn't have much information.

Following are the closest Moog outer tie rod ends in terms of taper dimensions for anyone still intertested. Nothing with the same taper and an Imperial threaded rod unless you can live with an 8.66" long rod (ES406L).

[nisseven]

If I might add, you would be hard pressed to find a tie rod end with the correct offset and angle to suit the MX5 upright when used in its original configuration, as it should be. As a matter of interest it looks as though you are using the OEM bottom ball joint? Where is the shorter inner bolt that usually goes in from the top?
Bruce

[redbull]

If I might add, you would be hard pressed to find a tie rod end with the correct offset and angle to suit the MX5 upright when used in its original configuration, as it should be. As a matter of interest it looks as though you are using the OEM bottom ball joint? Where is the shorter inner bolt that usually goes in from the top?
Bruce

I mounted this lower ball joint securing bolt from below, and tig welded in a spacer so it is easily removed if needed. One of the many things that are not easily visable but make my project a servicable road car.

[redbull]

I replaced the "black tube" tie-rods with 6160 left/right 5/8" threaded tubing and it is PERFECT!