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heim joints on wcm ultralite /xr7 and other 7s


RGTorque

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Hello all,

This post is geared mostly to the ultralite members here and as far as I know all cars built by Brian use chromoly heim joints. I’m not sure what other 7 type’s use these heim joints but if they do this is an opportunity for them as well.

Chromoly joints have been known to wear, creek, squeak over time, and can make the car feel a little loose when driven on the street. to fix this issue i contacted Gary at fastener specialties and he set me up with fk heim joints with t2 teflon inserts. These joints have an estimated lifespan THREE TIMES THAT OF REGULAR CHROMOLY.

Here are the part numbers for the joints that fit my ultralite, they would be the same for most of the ultralites. The prices below are what I paid for mine last year. if we get a few people ordering we can knock the price down a bit (25-35 cents per joint less then my past order).

CMXL10-8T ----- 1/2 by 1/2 w/ 5/8 shank (18 on the car) $14 each

CMX10T ----- 5/8 by 1/2 w/ 5/8 shank (4 on the car) $14 each

CMX10-8T ----- 1/2 by 1/2 w/ 5/8 shank (8 on the car) $14 each

CMXL8T ----- 1/2 by 1/2 w/ 1/2 shank (2 on the car) $12 each

The shop I bought from is called fastener specialties and their number is (717) 249 1757. you can ask for Gary and tell him you want the same kit as Roman (me) or just give him the product numbers listed above.

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I replaced the heim joints in the rear of my Ultralite. I did not feel any bad handling effects but there were a few "clanks" on the bumps. I guess you should expect that on a car with no rubber bushings in the suspension, but it was winter, and I needed to do SOMETHING to the car to feel like I was working on a Seven.The road dirt can cause some wear of the joints, but I could not really feel the wear. I did not replace any front end links.

 

I am not disputing EvilRomeO's selection, and I hope that he gets good life, and reports back to same to us, but I was scared off the teflon lined joints by the tech guy at QA1.

 

QA1 recommends their XM rod ends, with the kevlar reinforced teflon races for longest life, and recommends against plain teflon rod ends because they "pound out" in rough use applications. However, as Brian has noted on the Ultralite forum, the XM rod ends do not have enough angular misalingment travel to be used on an Ultralite. I had noted this when examining the QA1 catalog, the misalignment is about half the ability of a plain rod end. Also, the moly rod ends that Brian uses have a very high load rating.

 

So, my selection was to use the QA1 PCM series moly rod ends, and to add Heim Seals on each side of each of them. This to hold in some grease, and to keep out the road dirt.

I got these seals from Speedway Motors pn 910-01504 and 910-01503. $84

 

The rod ends I got from QA1, (10) PCML8-10 ($89), (6) PCMR8-10 $53, and (4) PCMR10 $36.

 

Note that the original rod ends from Brian are wider than the rod ends from QA1, and there is NO room to put seals on the original rod ends, you need a narrower rod end to allow room for the seals.

 

In the install process, I removed the vertical bolt for the forward lower traverse rod link, and mounted the link to the upper frame mounting point. This had been reported to reduce bump steer.

 

In order to duplicate the length of the links, I used a large caliper from Cummings (Harbor Freight Tools has them at about $20). I jammed it into the old link, locked it in place, removed the old rod ends, then installed the new ones (with anti-seize), and adjusted them to the same length as the caliper, so as not to mess up the aligment(much). I realigned, and was all set to go.

DSC_6363_Small.JPG

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some good info here. ive been running the teflon inserts for almost a year now and they show no sign of being pounded out or getting loose. this time includes multiple autox days and countless miles of street driving.

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Also relevant to this topic, a while back IIRC Loren mentioned the value of fitting Shoulder or Stripper Bolts in place of the socket head cap screws that come with the kit/car. These are hardened and high tensile bolts which have a precision ground center section between the head and thread. Since the ground section fits very closely within the bore of the rod end, it keeps the rod end from beating itself to death prematurely by rattling around on its pivot. If you look at the socket head cap screws used to serve as the pivot for the rod ends, you'll see that there is no small amount of slop when you put a rod end on it - for any ordinary bolt, diameter at the thread is less than the diameter at the shoulder, and even the shoulder diameter isn't normally presicison. Rattle, rattle, rattle . . . and you've got your 'rod end death'.

 

Also, there are two designs of rod ends: two piece and three piece. The three piece are very strong, expensive and called "high quality", but they have relatively limited misalignment capacity (range of motion at right angles to the pivot). The two piece, when installed with suitable spacers allow a large range of motion. These are naturally weaker than the three piece, but some mfgs like FK and Aurora have started supplying them with chrome molly housings, and these are strong enough. Also, there's a rod end pattern called "high misalignment" which saves you the bother of putting spacers on either end of the rod end in order to get full motion. These are very strong, but a bit costly. They're particularly useful at the Steering Arm - Tie rod joint.

Happy engineering.

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some good info here. ive been running the teflon inserts for almost a year now and they show no sign of being pounded out or getting loose. this time includes multiple autox days and countless miles of street driving.

 

That is good news. I have suspected that with the light weight of an ultralite, the teflon lined rod ends would hold up OK, but I just wasn't sure. Your good experience with them is reassuring, and the seal route I took was a bit of a pain, because I had to find rod ends that were thinner to make room for the seals.

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  • 3 years later...
I replaced the heim joints in the rear of my Ultralite. I did not feel any bad handling effects but there were a few "clanks" on the bumps. I guess you should expect that on a car with no rubber bushings in the suspension, but it was winter, and I needed to do SOMETHING to the car to feel like I was working on a Seven.The road dirt can cause some wear of the joints, but I could not really feel the wear. I did not replace any front end links.

 

I am not disputing EvilRomeO's selection, and I hope that he gets good life, and reports back to same to us, but I was scared off the teflon lined joints by the tech guy at QA1.

 

QA1 recommends their XM rod ends, with the kevlar reinforced teflon races for longest life, and recommends against plain teflon rod ends because they "pound out" in rough use applications. However, as Brian has noted on the Ultralite forum, the XM rod ends do not have enough angular misalingment travel to be used on an Ultralite. I had noted this when examining the QA1 catalog, the misalignment is about half the ability of a plain rod end. Also, the moly rod ends that Brian uses have a very high load rating.

 

So, my selection was to use the QA1 PCM series moly rod ends, and to add Heim Seals on each side of each of them. This to hold in some grease, and to keep out the road dirt.

I got these seals from Speedway Motors pn 910-01504 and 910-01503. $84

 

The rod ends I got from QA1, (10) PCML8-10 ($89), (6) PCMR8-10 $53, and (4) PCMR10 $36.

 

Note that the original rod ends from Brian are wider than the rod ends from QA1, and there is NO room to put seals on the original rod ends, you need a narrower rod end to allow room for the seals.

 

In the install process, I removed the vertical bolt for the forward lower traverse rod link, and mounted the link to the upper frame mounting point. This had been reported to reduce bump steer.

 

In order to duplicate the length of the links, I used a large caliper from Cummings (Harbor Freight Tools has them at about $20). I jammed it into the old link, locked it in place, removed the old rod ends, then installed the new ones (with anti-seize), and adjusted them to the same length as the caliper, so as not to mess up the aligment(much). I realigned, and was all set to go.

 

Just wondering - how did your heim joint selection work out? And was that price following the joint size for EACH or for all of the required joints in that size? If each - holy cow! Thanks!

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Just wondering - how did your heim joint selection work out? And was that price following the joint size for EACH or for all of the required joints in that size? If each - holy cow! Thanks!

 

That was the price ( in 2008) for the total number of joints listed. The PCML8-10 were $8.90 each, for example. They have worked out just fine for me.

 

 

The rod ends I got from QA1, (10) PCML8-10 ($89), (6) PCMR8-10 $53, and (4) PCMR10 $36.

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An aquaintance involved in F1 claimed that F1 cars receive an entire fresh set of rose joints for EACH race.

Unlikely that price /quality of components is the factor in this.

Leading to the observation: unless in F1 why suffer the aggro of rose joints ?

Clearly Daft for street uses other than Boulevard cruising :-)

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An aquaintance involved in F1 claimed that F1 cars receive an entire fresh set of rose joints for EACH race.

 

Heard much the same from a high-end alignment shop here with years of racing experience. Ampep was the brand he had worked with (http://www.skf.com/portal/skf_gb/home/aboutskf?contentId=244062).

He changed them, I suspect, because that's what someone higher up in the technical staff decreed, but I wouldn't put past him having acquired his own usage-based experience in the matter.

 

I doubt that my pitiful little attempt at a contemporary race car is going to put anywhere near the stress on it's probably way over-sized rod ends that an F1 car would on its, and those rod ends are spec'd by the engineers to fit their usage exactly (those guys DO tend to focus a lot of effort on things like lightness) and, weighing the pluses and minuses, the units they run may be intended as single-race fittings.

 

When I changed all of mine from the poor-quality units I got with my "kit" to FK teflon-lined two-piece units, beyond the wonderful transformation that came from the car all of a sudden no longer sounding like a bucket of bolts, there was a pronounced increase in road feel - much greater sense of having your hands right on the asphalt. Road cars have compliance built into their suspension and steering links for driver comfort and quiet - at the cost of feedback and suspension control.

 

Unless I find that I have to spend another $550 and the few days work every year, I judge the change well worth the cost and effort.

Edited by JohnK
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  • 5 months later...
some good info here. ive been running the teflon inserts for almost a year now and they show no sign of being pounded out or getting loose. this time includes multiple autox days and countless miles of street driving.

 

 

Hi, Evilromeo (and anyone else with experience in upgrading S2K rear heims). Got a question regarding the teflon heim joint upgrade to the rear suspension of the S2K. I attached jpegs of the suspension mounts, and I hope they display properly, but the description should suffice. If not, I can email pix to you:

 

We are installing new teflon-lined heim joints in the rear suspension of an Ultralite S2K. The heim mounts are U-brackets, with the bottom of the "U" welded to frame members. There are holes in each of the upright arms of the "U", through which the heims are fitted. Note the photo of the top of one of the heim mounts. On the top of the mount, the provided hole is larger than on the bottom.

 

The head of the bolt slips thru the top bracket mount with the heim joint removed. It is a clearance fit on one end.

 

My mechanic believes that, on the clearance fit end, we should insert a spacer and cover it with a large washer. He feels this would allow the bolt to exert more pressure on the heim joints.

 

Is there a reason for the current configuration, with one end a slack fit? If we install a spacer, covered by a large washer, and create tight fits on both ends, would that improve location of the rear axle and improve handling?

 

Thanks!

 

car.jpg

car1.jpg

car2.jpg

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Bruce I sent you a response on the PM the other day. Maybe you didn't get it. I like to use these bolts (http://www.fastenal.com/web/products/details/26352?searchMode=productSearch&rfqXref=&rfqKeyword=&rfqId=&rfqLineId= on the joints. The original bolts have a slight bit of movement because the threaded section of the bolt is slightly smaller than 1/2 and this will allow some wiggle in the joints. These bolts have a machined 1/2 shoulder and makes the joints tight. You will need to use a flat washer with a nylock nut to tighten the joint down. I do not recommend using any type of fastner that will sandwich the bracket to pinch the joint. This can cause some binding and adds no strength to the connection. The brackets are made to have the head thru the bolt as originally done. If you just add the teflon rod ends with the the shoulder bolt it makes a very tight suspension pick up.

 

Be sure to check each bracket some of the brackets have a welded in spacer which can vary in thickness depending on the brand. So when you get the shoulder bolt the length can vary 1/4 inch between bracket brands.

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also, since ive been asked again. they joints i installed 4 years ago are still perfect. they do not creek, squeak, or rattle. they have also not pounded out.

 

i know what my next project's gonna be...

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  • 1 month later...
Bruce I sent you a response on the PM the other day. Maybe you didn't get it. I like to use these bolts (http://www.fastenal.com/web/products/details/26352?searchMode=productSearch&rfqXref=&rfqKeyword=&rfqId=&rfqLineId= on the joints. The original bolts have a slight bit of movement because the threaded section of the bolt is slightly smaller than 1/2 and this will allow some wiggle in the joints. These bolts have a machined 1/2 shoulder and makes the joints tight. You will need to use a flat washer with a nylock nut to tighten the joint down. I do not recommend using any type of fastner that will sandwich the bracket to pinch the joint. This can cause some binding and adds no strength to the connection. The brackets are made to have the head thru the bolt as originally done. If you just add the teflon rod ends with the the shoulder bolt it makes a very tight suspension pick up.

 

Be sure to check each bracket some of the brackets have a welded in spacer which can vary in thickness depending on the brand. So when you get the shoulder bolt the length can vary 1/4 inch between bracket brands.

 

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?

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