Lotus 7 Project Arrived

[MV8]

It would be based on the installed axle flange and wheels with the same tolerance as an alignment. Flange runout is typically less than .010". I forget the wheel run out. There is no need to fully weld a brace. 1/2 to one inch stitches every three inches is plenty for a brace. Long beads are more likely to warp. Weld a few, wait a few, wet towels to suck the heat out faster. Alternate between axle ends. Use enough heat for a fairly fast weld instead of a slow weld that has a greater heat affected area.

Edited Sunday at 08:49 PM by MV8

[ianashdown]

2 hours ago, anduril3019 said:

If the goal is zero toe and zero camber, what's a reasonable tolerance?

The Lotus S2 owners manual doesn’t quote any alignment figures for the rear suspension, probably because there is no adjustment.  It’ll be whatever the manufacturing tolerances of the Axle were.

 

I am certain that what the welding is likely to do, induce toe-out, is bad.  Some induced positive camber is not preferable, and I’ve heard of some deliberately inducing a small amount of negative camber.  Probably a trade of performance for potentially shorter life.

 

Ian

[ianashdown]

2 hours ago, MV8 said:

It would be based on the installed axle flange and wheels with the same tolerance as an alignment. Flange runout is typically less than .010". I forget the wheel run out. There is no need to fully weld a brace. 1/2 to one inch stitches every three inches is plenty for a brace. Long beads are more likely to warp. Weld a few, wait a few, wet towels to suck the heat out faster. Alternate between axle ends. Use enough heat for a fairly fast weld instead of a slow weld that has a greater heat affected area.

All good advice, thank you.

 

If I have to do this myself, which is looking increasingly likely, then I will build some kind of fixture.  I hoped to avoid this.

 

I’m going to follow the advice of Chris Beebe and use rectangular tubing rather than the 1/4”, or whatever, steel plate.  Too agricultural for my preference.  So there will be a minimum of welding and therefore less shrinkage.

 

All my fabrication experience has taught me that welds always have shrinkage and it’s better to build compensating for that rather than trying to correct afterwards.  Straightening is doable, stretching not so much!  Shrinkage in this case will induce toe-out what is never good in my experience.  I’ll have to think about how much toe-in to build in to the fixture unless anyone who has done this can relate past experience.

 

All part of the journey!

 

Ian

Edited Sunday at 11:16 PM by ianashdown

[IamScotticus]

I am getting closer to deciding to remove my brace plate.  Not for alignment reasons, and I don't plan on going over 150hp, but for safety. 

My brace plate is a big knife ready to slice into the gas tank if I get squished.

Edited Sunday at 11:59 PM by IamScotticus

[Christopher smith]

6 minutes ago, IamScotticus said:

I am getting closer to deciding to remove my brace plate.  Not for alignment reasons, and I don't plan on going over 150hp, but for safety. 

My brace plate is a big knife ready to slice into the gas tank if I get squished.

That is why I have an ATL fuel cell with internal bladder and foam.

[IamScotticus]

1 minute ago, Christopher smith said:

That is why I have an ATL fuel cell with internal bladder and foam.

That's a good idea.  Which model?

[Christopher smith]

4 minutes ago, IamScotticus said:

That's a good idea.  Which model?

 

4 minutes ago, IamScotticus said:

That's a good idea.  Which model?

 

4 minutes ago, IamScotticus said:

That's a good idea.  Which model?

It is the rectangular 8 gallon ATL sports cell like we always used for SCCA in other cars. But it is too big to fit in usual 7 place so we mounted it above the axle. Higher center of gravity of course. I think the custom ones can go behind axle but they are even more pricey. I was setting up to go D production racing but it took so long I felt too old for serious racing. Almost 80 now.

[ianashdown]

1 hour ago, IamScotticus said:

I am getting closer to deciding to remove my brace plate.  Not for alignment reasons, and I don't plan on going over 150hp, but for safety. 

My brace plate is a big knife ready to slice into the gas tank if I get squished.

You make a very good point on the safety of that style of reinforcement.  I like the tube much better, but then again, safety was never a 7 strong point!

 

I haven’t got to it yet, but I have some thoughts about cutting an access panel in the front of my original tank and fitting a custom made bladder, with foam.  I feel the sloshing of fuel can be felt in a car this light.

 

If there is any interest I’d be happy to see if a group buy could be arranged.  I have a long term contact in the fuel cell business and years of experience designing fuel cells, pickup systems etc.  We could also accommodate an internal collector tank with a high pressure pump for anyone running injection.

 

Ian

Edited yesterday at 01:24 AM by ianashdown

[IamScotticus]

@ianashdown

Sending PM

[SENC]

Here's how mine was done (likely when it lived in Australia), in the event it helps...

 

[ianashdown]

That’s an interesting approach.

 

Thank you,

 

Ian

[pethier]

16 hours ago, SENC said:

Here's how mine was done (likely when it lived in Australia), in the event it helps...

 

I don't think that would clear the fuel tank on my 1979 car.

 

All in all, I'm happy to have the deDion setup on my 1991.