heim joints on wcm ultralite /xr7 and other 7s

[rss]

cool. thanks guys.

[rss]

i wonder how much the rattling would be subdued by simply swapping out the standard bolts for shoulder bolts, and retaining the chromoly heims. maybe that would cure the rattling and leave only the squeeking?

[JohnK]

i am ordering parts for this upgrade, and see that the full nylon insert lock nuts offered by fastenal can be had in grades 2, 5, and 8. i'm not sure which i should order, or if it matters that much. i would just match the grade of the shoulder bolt http://www.fastenal.com/web/products/details/26352?searchMode=productSearch&rfqXref=&rfqKeyword=&rfqId=&rfqLineId=

but i'm not sure what the grade of this bolt is.

can anyone help me out?

also, can anyone tell me what grades A, F, G, or 2H refer to in a lock nut?

 

Fastenal has somewhere obvious on its website the best set of pages on fastener strength and classification I've seen (have it hanging on a pegboard in my garage). Grainger also, if I remember correctly, has a good equivalency chart for the numeric and alphabetical designations embedded in its catalog in the fastener section

Re noise, IMHO anything that can move under load will create noticeable / annoying noise. Shoulder/stripper bolts make a huge improvement that can be predicted by comparing the looseness of the fully-threaded allen-type screws that are originally supplied. But if the rod ends rattle, they'll make pretty much the same noise. As a confirmation here, I climbed all over my car searching for the source of a clunk and found it was a barely detectable movement between my front roll bar and the nylon bushing it rides in.

But the bottom line for me is that, when all the slop is gotten rid of in the suspension, you can feel the difference, as well as appreciate the quiet.

[Bruce K]

i wonder how much the rattling would be subdued by simply swapping out the standard bolts for shoulder bolts, and retaining the chromoly heims. maybe that would cure the rattling and leave only the squeeking?

 

thanks to loren and everyone else who contributed info on this thread. the forum does not send me emails, so i was not aware of your PM, loren. RSS, you could be correct that you will tighten the suspension and spend less time/money by swapping in shoulder bolts. however, if you have put lots of miles on your car, and/or a few hundred track miles, you may want to dig into the rear suspension a little deeper, as there could be other problems (read on).

 

i will supply a cautionary tale regarding the teflon-lined heim upgrade. we disassembled the rear suspension, only to discover that the differential brace (which shrouds the driveshaft) had been torn as in other cars. we followed loren and rahal's recommendations, and metal-formed a brace to the tail of tunnel, and then seam-welded it (make sure you also reinforce the welds on the tail bolt, top and bottom).

 

we then followed loren's advice and swapped in a lim-slip 4:111 for the current 3:545 (torque thrills coming - yeah!). finally, we tackled the heim swap. however, the interface between the steel heim studs and the hex aluminum suspension arm threads had fused with corrosion. we could not extract any of the heims without ruining the suspension tubes. either anti-sieze / anti-corrosion grease was never applied to these threads, or it had expired. however, the solution was not overly expensive, costing under $200 for all new hex aluminum threaded tubes for front and rear suspension and all required left / right jam nuts (in-stock and delivered within five days). since prices for these parts are all over the map, i've provided a link for the very reasonable supplier i used:

 

[/url]http://www.portcityracing.com/

 

we also installed shoulder bolts, grade eight. i'm inclined to believe, along with roman and others, that shoulder bolts will provide longer service life, because there is a multiple of contact or patch area on each bolt to distribute rubbing stresses. i would also reason that shear strength is increased, because metal threads are not cut into the shoulders of these bolts. all required grade eight shoulder bolts, washers and crush nuts were obtained for less than $50 locally - a bit less than fastenal pricing. with only a small premium in price for shoulder bolts, i wouldn't recommend using fully-threaded machine bolts.

 

now, shoulder bolts have different standard dimensions than fully-threaded machine bolts. the stud is smaller and shorter. we found that, in order to fit a washer and still have 100% of the nut thread contacting stud surface, "crush" nuts were required. instead of nylon locking surface, these nuts are squeezed slightly out-of-round, and lock in place. they are shorter than nyloks because the nylon locking "hat" is absent. that means they are sized better for the shorter shoulder bolt studs. i would recommend crush nuts when ordering your hardware.

 

our final suspension work involves constructing and installing the crosswise rear differential locating brace recommended by loren and others. we are concluding that work at this time.

 

we also chose to salvage the original aluminum fuel tank. the original tank has anti-surge baffling and carries a full 15 gallons, which is useful for touring. plus, the tank compartment is oddly-sized: wide left-to-right, but short top-to-bottom and narrow front-to-back. this limit standard fuelcell selections to just a couple 8 gallon units (you don't want to know the price of custom units!). problems with the original tanks included top leaks, because the thin top metal deformed around the original filler cap, and the cap lacked adequate clamping force. the original tanks were also secured only with straps (as opposed to brackets and bolts), and thus moved around a bit and suffered chafing. i rewelded all the seams and fittings on the tank and reinforced it on all chafed surfaces. we then installed 4 mounting brackets and two alignment tabs. the tank is bolted and strapped into place, and should not move again. we then cut blocks of fuel cell foam (summit racing) and installed these through the fuel fill hole. i also welded a second plate of aluminum onto the top surface. i then purchased a new fuel cell filler cap assembly (summit racing), with robust metal clamping rings top and bottom. we sealed the top and bottom gaskets with fuel-safe black caulk and tightened the filler cap - end of leaks! for all of these improvements, we paid less than the price of a standard eight-gallon fuel cell. i agree that a new cell with a full bladder would be safer - i'm sure it would leak out slower if punctured. however, many new fuel cells are configured with foam and no bladder, just like mine, my tank is bigger and provides substantial additional range. plus, a bladder tank is kaput in 8 to 10 years (the bladders perforate or crack). i can change the foam in my tank for less than $80 and be good as new. food for thought if you share these problems.

 

i am logging the entire rebuild with pix and notes, and will make the journal available upon conclusion. may help others who want to undertake these upgrades.

 

take care!

[RGTorque]

hey guys, if anyone is going to get a set of new hardware for the rear (shoulder bolts, etc) i would toss in some $ to purchase a set rather than trust my local fastenal, which has failed me numerous times.

[rss]

very helpful posts everyone -- thanks very much.

i just started to place my order with fastener specialties and was asked whether i wanted an F1 or F2 fit. i wasn't even aware there was a choice. F1 evidently is very tight, so that the ball is quite difficult to move within the race by hand. with F2 fit the ball is still snug but can be easily rotated by hand.

i'm thinking F1 is probably the way to go, except that it will make assembly more difficult.

roman, john, bruce -- did you specify F1 or F2?

[Bruce K]

very helpful posts everyone -- thanks very much.

i just started to place my order with fastener specialties and was asked whether i wanted an F1 or F2 fit. i wasn't even aware there was a choice. F1 evidently is very tight, so that the ball is quite difficult to move within the race by hand. with F2 fit the ball is still snug but can be easily rotated by hand.

i'm thinking F1 is probably the way to go, except that it will make assembly more difficult.

roman, john, bruce -- did you specify F1 or F2?

most of the racing heims i have purchased can be rotated by hand. this includes heims for goody's mini-nascar, d sports racer, panoz gts and the s2k. you should ask gary some add'l questions like: will f1 heims heat up when driven hard? are they more or less durable? are they more or less likely to break? i would like to hear what you found out. gary told me that he shipped me mid-grade / racing grade heims. he said that 3 grades of precision are available, with the highest grade used in medical / aeronautical, etc. he did not mention f1 or f2 fit, but maybe that was because i told him to sell me what he sold to roman. anyway, let us know what you find.

[xcarguy]

A good source for heim joints:

 

http://www.qa1.net/

 

A good source for mounting hardware:

 

http://www.aircraftspruce.com/

 

The -AN hardware form Aircraft Spruce can be converted to SAE (ex. -8AN is same as 1/2" SAE). Aircraft hardware can be ordered in pretty much any specific grip length desired (non-threaded area on bolt shaft).

Edited June 24, 2013 by xcarguy

[rss]

xcarguy,

thanks for the links.

 

bruce,

i spoke to someone in engineering at fk and he recommended F2 for our application, so that's what i ordered. i believe you and roman have the F2 fit. he recommended F1 for off-road racing. gary also mentioned that F2 fit is typically specified for sprint cars.

[JohnK]

FWIW - Considering the cost and time and in conversations with the area FK distributor, I always specify the tightest (F1) fit for any rod ends I use. The set up can be a pain, especially if you're using trammel points (look for earlier posts on this by me, or maybe rss wants to post a PM I sent him on this) but, the ends will loosen up under use, and I have never seen any problem with the ends being too tight - i.e. stiction caused problems. I'm figuring that the lifespan of the ends will be longer the tighter they start out. I've heard from a reliable source that F1 teams replace the ends after each race, and I'm certain don't run teflon ends, but that's more than a little beyond my level of sport.

 

P.S. On suspension links: I always use an anti-seize on any fasteners I put together, especially and religiously on things that screw into aluminum. The last setup of the car I did, which involved developing a new steering system, I began using links from Woodward Precision Power Steering - these are light, strong and really lovely. They're made from thin wall 6061 T6 (or is it 6T? anyway, it's heat treated to give the highest hardness) with the ends swedged to form the threads with a special hammering machine that reduces the diameter of the link as the end is created around a threaded mandrel, the process thickening the wall of the end it as it does so, so they're both light and strong. And, of course, as I'm in the middle of redesigning the rear suspension geometry, I'm tossing several of these in the process - helps the economy, right? : - ) I should maybe frame a collection of them and hang it in my den.

Edited June 25, 2013 by JohnK

[rss]

john,

i didn't get your PM but i did just look back to your original post re: trammel points. had i seen it earlier i would have saved myself a little trouble and gotten some trammels, but i didn't know term and probably ended up reinventing the wheel. i ordered some aluminum extrusion and a lockable sleeve bearing that slides on it and will attach shoulder bolts to it so that i will have an adjustable jig to duplicate the length of each rod.

 

re: F1 vs F2, it sounds like there's not a single correct answer. the F1's may last longer, but the F2's will certainly be easier to install. the FK engineer told me that the F2 fit was still very tight and would exclude dust.

 

i'm looking forward to the tightened up suspension and to getting rid of those annoying rattles and squeaks!

 

cheers

[Bruce K]

Grade 8 for sure.

loren - the original rubber differential bushings in my car are worn. additionally, several forums cite the original sloppy oem bushings as a source of klunking, diff twisting and more. we are considering upgrading to urethane. are the original bushings post-2002 stock subaru impreza? they look close without taking measurements. here's a link to an established supplier of handling upgrades including these bushings:

 

http://turninconcepts.com/product_info.php?cPath=1_9_11_260_264_1195&products_id=17

 

let me know if this page identifies the correct replacements. thanks!

[JohnK]

Scott,

The PM I was referring to was the one about trammel points. Sounds like you've got all your ducks in a row (and that's what forums are for!). Best of luck that the work goes smoothly and look fwd to hearing of how you enjoy the change.

[rss]

Scott,

The PM I was referring to was the one about trammel points. Sounds like you've got all your ducks in a row (and that's what forums are for!). Best of luck that the work goes smoothly and look fwd to hearing of how you enjoy the change.

 

john,

thanks very much! i'll be sure to post here when i get the project done, though at the rate i go on these things that could be a few months from now!

[rss]

so i've gotten most of the rear rod ends changed out. one thing i found on disassembly was that the there was a stack of 9 washers between the rod end and bottom shock mount rather than a rod end spacer. before i buy the shoulder screws and spacers to complete this mount, i thought i'd ask about the optimum spacing. right now there's 1" spacer between the upright and rod end and 1/2" between the rod end and shock. i can see that 1/2" is required between rod end and shock to prevent binding, but does the rod end need to be 1" out from the upright? also, the hole in the cast piecefor the bolt is slightly larger than 1/2" diameter, and there's a little slop there that i'd like to get rid of. how do you guys address that?

 

also, what can be done to make the fit tighter for the rod end mounted on the 5/8" threaded shafts (there are 4 of them).

[WestTexasS2K]

Yes John the stock Subi bushing will work. I made some out of Delron that worked pretty well but the Poly Units should be good too.

[rss]

also, do you guys have any specific recommendations for rod end spacers? there are quite a few of them out there. are the ones from JEGS okay? do you recommend aluminum or steel?

[powderbrake]

so i've gotten most of the rear rod ends changed out. one thing i found on disassembly was that the there was a stack of 9 washers between the rod end and bottom shock mount rather than a rod end spacer. before i buy the shoulder screws and spacers to complete this mount, i thought i'd ask about the optimum spacing. right now there's 1" spacer between the upright and rod end and 1/2" between the rod end and shock. i can see that 1/2" is required between rod end and shock to prevent binding, but does the rod end need to be 1" out from the upright?

 

Here's what I did to mount my shock. I found one bolt bent due to the offset load, so I fabricated a sturdier mounting system.

 

I machined a spacer that fit into the large hole in the Subaru upright, then cut off the ultralite supplied spacer so the tension of the bolt would draw the two items together on the upright while providing a solid, slop free mount for the shock bolt. I have included a pic of the drawing of the spacer if anyone wants to make themselves a set.

[rss]

hey that's very slick, jerry!

you have your own lathe? that must be handy.

i see you've mounted the control arm inboard of the shock, which seems the more intuitive way of putting the components together, yet all of the ultralites i've seen (including mine) have the control arm between the shock and upright. i'm sure there's a reason for it but it's not obvious to me.

[Mondo]

Awesome!

 

 

 

.

Edited July 16, 2013 by Mondo