Rear Adjustable Lower Links

[My S1]

Some where, some time I downloaded this drawing from the internet.  Maybe this Forum or maybe Lotus Europa Central.  Beautiful drawing and I assume it is perfectly accurate though I don't understand why they are showing two different half shaft lengths...one does not need to modify the half shaft if you crank the camber into zero on an Europa, do you?  Can the zero degrees camber lower link length dimension be trusted?

My question is this;  I would like to be able to crank it into 0.0 degrees of camber and back out to -3 but I want to minimize the lengths of visible threads when all the way out.  Could one of you gents who have adjusted yours in to zero please tell me your final dimension from CL to CL of your joints?  Also,  I have not disassembled mine yet but I do see that they are using 1/2" bolts and assume that there is no fancy machining going on and simply a 1/2" heim joint is required.

[BDA]

My rear suspension is different from the stock so measuring my lower links wouldn't necessarily help you.

If I understand the drawing (and I'm at a disadvantage because I don't have access to the text that goes along with it), the author is adjusting his camber by changing the length of the half shaft. That's a very strange thing to do. Changing the length of the half shaft is a lot more complicated and expensive than changing the length of the lower link.

So you probably want adjustable lower links. You can buy them (I think r.d. has them? Dave Bean?) but they are pretty simple to make. You can buy the threaded ends and rod ends (eg. https://www.ebay.com/itm/236088625436)  have someone cut the ends off your lower links and weld the ends such that the rod ends will allow you to make the link longer and shorter than the original length (a right hand threaded end on one end and a left hand threaded end on the other).  Since the ball in the rod end is narrower than the mount where the lower link attaches to the tranny, you'll need to fill up that area with some spacers. This sounds more complicated than it really is.

This drawing seems to imply that it is building the links from scratch (http://lotus-europa.com/manuals/misc/suspension/Rear%20Link.pdf). He doesn't mention the spacers I mentioned above but does include spacers for the outboard end of the link which is a very good idea. I would use steel for those rather than aluminum. You can also buy misalignment spacers (e.g. https://www.ebay.com/itm/330840156157). They are aluminum but they are thicker than the spacers he suggested. Lastly, the length of the threaded ends can affect the length of the tube you'll use for the link. His end is shorter than the end in the ebay kit mentioned above so the length of the tube might have to be shorter. I do not know if his dimensions are accurate for an S1.

As for having exposed threads, you will want some room for adjustment in both directions. If your link was long enough so that you had more negative camber than you wanted, you wouldn't be able to adjust to the way you want.

[My S1]

Thank you BDA.  Yes, I will build my own.  I have some 1" O.D. 4130 left over from building trailing links and sway bar drop links on my home made car.  I got all of my parts from Chassis Shop https://chassisshop.com/  and highly recommend them.  I just need to know the final CL to CL dimension when the arms are cranked in to zero degrees camber so that I can draw up the arms based on Chassis Shop bits.

[Benjy]

This might be helpful from Serge...

https://www.youtube.com/watch?v=LNIELWMgKJk

[My S1]

Thank you Benjy.  I've seen that video before.  He is using the factory CL to CL then adding a few mm more and a few mm less for adjustments in and out.  I will not go further in than the factory -3 degrees...I'm going out to zero degrees or at the most -1 degree. 

What I'm hoping is that someone can tell me what the MINIMUM distance CL to CL of the joints is when the camber is dialled all the way out to zero degrees and the links are cranked all the way in towards the center of car.

[kapps]

Remember ride height affects this length. As ride height drops, you need shorter lower links.

I can’t directly answer your question because I’ve never set mine to zero camber but I can say that when I made adjustable lower links for my S2 over 15 years ago, I made the end-to-end of the welded tube and end fittings to be 15.75”. Outside of the welded assembly, I left enough room for the jam nuts plus 1/2” of exposed threads on the Aurora helms. The final as-assembled center-to-center length is very close to stock at 19” long.  With 1/2” exposed threads on the helms at both ends, I would easily be able to get to zero camber and there is not excessive thread showing at the stock length.

[jbcollier]

The diagram show both the half-shaft and lower link being modified.  The are both shortened (most likely to allow for wider shoes without requiring flares) but not equally (most likely for the wider shoes to be more effective on the street).

[GavinT]

According to the workshop manual, the effective length of the lower link is 478.029 mm - the actual length, somewhat more, of course. (pic below)

I reckon dive into some trigonometry with your trusty slide rule to discover the length needed to attain 0° camber. I don't see the half shaft length listed in the manual, however.
Cardboard aided design to the rescue?

Rob Siegel did a similar exercise on his TCS as detailed in a Hegerty article (link below).

https://www.hagerty.com/media/opinion/the-hack-mechanic/building-adjustable-links-with-heim-joints/

[My S1]

Thank you gents.  I did a crayon drawing and a paper mock-up and as best as I can deduce, to go from -3 degrees to 0 degrees would require a length reduction of about 3/4".  For you guys with adjustable links, does this sound about right;  1/4" of adjustment results in 1 degree of camber?

[My S1]

apps, 

thank you for those dimensions.  I think I will be fine if I start with the factory dimensions as you did, then give myself 1/2" of adjustability on each heim joint.  I may be overthinking the matter as I don't believe I need more than 3/4" per side to get to 0.0 degrees.

Gavin T,

that video is worth watching.  The high misalignment spacers are an interesting addition (don't know if there are actually needed) but they may increase the overall size of the joints and get closer to the shock mounts.  I do like those rubber grommets.

[BDA]

You will need spacers of the proper size for the inner attachments and you should have something for increased misalignment for the outside attachments but I don't think it is as important because the movement is almost entirely vertical. The ball of the rod end should be tight so it doesn't move. The rest of the rod end is supposed to rotate around it. Not only that but you don't want the rod end to move forward/aft on the mounting bolt.

[314159td]

There is a mistake in the unit conversion on that workshop manual page, don't recall exactly where but check the inch and mm values and you'll find it.

[Bryan Boyle]

You will need spacers of the proper size for the inner attachments and you should have something for increased misalignment for the outside attachments but I don't think it is as important because the movement is almost entirely vertical. The ball of the rod end should be tight so it doesn't move. The rest of the rod end is supposed to rotate around it. Not only that but you don't want the rod end to move forward/aft on the mounting bolt.

Look for 1/2" ID cone spacers to center your heim joint in the tranny mount.  I can send a photo, but here are the ones on my site under 693R photo album...from July 2007:
http://www.lotuseuropa.us/0693r/photos/index.php/2007/07-24-07-Lower_Link_Attach

Apologies for the quality, was the best I could do with a Palm Treo phone at the time. 

[My S1]

Absolutely Bryan.  Those are preferable because they won't increase the outside diameter of the joint and squeeze the shock mount.  Do you recall where you sourced them?  It appears as though they sell multiple lengths or did you cut them down in a lathe?

[kapps]

You will need spacers. If you have access to a lathe, they’ll be easy. You can also get Seals-it washers to help keep dirt out of the helm. You may also want to try to source AN bolts that are sold as a specific grip length so you minimize the amount of threads bearing on the aluminum upright.

Excuse the 15 years of grime…