Lola SL142/20 Restoration

[Reto Kuprecht]

I am really glad I was able to realize the fuel system as I had planned it. The header tank has been welded and I could finish the plumbing too.

In the foreground is the -12 connection between the tanks, the header tank in the middle with the -6 vent on the top, and the -10 feeder lines going into the header tank. A -10 line connects the header tank to the fuel pump:



The feeder lines are a design compromise. In a perfect world, such lines would be longer and routed in a bend to provide important slack. As much as I was trying to find space for such a routing - I couldn't. Either there was no space, or it was impractical from a fuel delivery standpoint. So I did make the compromise by using short straight lines into the header tank. I used rubber lines instead of steel braided lines which would have zero flexibility in the push/pull direction. Because I had no space either for in-line flapper valves, I thought about a way to move the valves close to or into the header tank. I bought -10 inline one-way valves at Summit, cut them in half, and used the cut tube part as weld bungs to screw in the flapper valve part with the male -10 connector (black part). Worked out perfectly

I have to cut the -12 line a bit shorter. It touches the header tank now and the steel braiding would chafe through the aluminum pretty quickly

[Reto Kuprecht]

Didn't have time to do much lately but I did correct the fuel tank connection, i.e., made it a tad shorter:



Also made a support for the external battery connector with a cable to the starter and a ground cable to the engine:



The holes I cut in this part serve a double purpose - to make it lighter, and also as lead throughs for the crankcase oil evacuation hoses:

[Reto Kuprecht]

These "lead through" holes were a great idea - but obviously they didn't work, as there would have been no way to get the hose ends through the hole So out came the angle grinder and the holes were opened to make enough space. Here you see a test installation of the first hose:



Forcing rubber hose around such tight bends is possible. I did check every possibility, but this was the only way because space under the rear engine cover is very limited:



The trick is to use these flat wound springs which prevent the hose from kinking. I wouldn't do that in a fuel or oil application where flow is important, but for crankcase venting this is fine:



Here's the finished installation. I am glad these were the last hoses to do, there's no space left under the engine cover for anything more

[Rhino]

Looking Good Reto
How is the brazing coming along?

[Reto Kuprecht]

Thanks Reinhold. I saw your brazing and felt so intimidated that I decided to practice another year or two before showing anything . Well, seriously, I have tack welded most of the brackets, gussets, tabs, etc. and will be ready pretty soon to take everything apart and then work on the bare chassis. This will be the time I have to get my act together and do the brazing.

Thanks again too for your comments on painting the frame - very helpful indeed

[Rhino]

My brazing is enough to make an Englishmen's eyes water yet it is strong enough to work.
I guess that is what really counts... no?
Keep practicing Reto......but you will always want better than what you can do. The worst critic is always your self

[Reto Kuprecht]

Next thing I'll do is the magneto. I had one put together by Joe Hunt Magnetos, with a tach drive, degree ring, and a pretty solid base clamp:



I am planning to use this old brown magneto cap I found on ebay. But I don't know wheter the part can take the heat generated by this magneto which has stronger magnets But I HAVE to use this as it says: "Made in Switzerland"

[Reto Kuprecht]

This is the result of last Saturday's work session - which doesn't look like much I have to admit

However, for a beginner with old magneto ignition systems like me, it was quite an achievement to get everything together: Determine the necessary clearance to the oil pump drive and make the correct shim, my father making the hold-down clamp fit the distributor base, trying a magneto position which is good to attach the tach drive cable, making a pointer to the timing degree ring, determine cylinder 1 TDC and adjust the magneto accordingly, including fixed advance (36deg on the crank, 18deg on the magneto degree ring) - and have a coffee brake and eat a sandwich

[Reto Kuprecht]

Thanks a lot Gerald to keep this forum working. While you were fiddling with the forum, I did the same with SL142/20 to be
We continued with the magneto system, my father fabricated great spark plug wire holders to keep things in order. And I was very much relieved to see that the turning direction of the tach cable drive on the magneto matched the chronometric Smiths tach. One headache less



With this done, we had the car in a "raw state", with all parts made, temporarily attached, tack welded and fitted. In the background you can see the shelf space which I had cleaned out and prepared for storing the parts:



It took us three sessions then to take everything apart, including hoisting the engine off the frame. Now I can permanently weld/braze everything and get the frame ready for blasting and painting. At the same time I'll try to finish all other parts which will be nickel plated - smoothing sharp edges, making them lighter etc. Don't know yet what to do with the gear shift linkage which has permanently brass brazed u-joints - can these be plated as a complete unit I have to find out.

[Rhino]

Reto,
I disassembled my "U" joints and kept the internals wile the outer cages were plated in nickel.
If your "u" joints are tight, then you may have to file the mating surfaces. If they were loose, then the plating will be a benefit
Cheers,
Reinhold

[Reto Kuprecht]

Thank you very much, Reinhold, for the expert advice. I thought it's going in this direction but hoped there might be an easier way. Now I see you did go through these steps.

I started with the brazing on the frame. It's going quite well, especially after I found a very good filler rod from Eutectic Castolin which is readly available here. Its called Castolin 146 and is the equivalent of Sifbronze nr. 1. The rod I used before, Castolin 18, flowed too quickly and was more difficult to build up. I will post pictures soon, perhaps no close shots though

[Reto Kuprecht]

As promised I am showing pics of my latest brazing efforts. These are actually the ones which came out quite well, with nice and uniform beads. There are others, which are perfectly strong, but wouldn't win a beauty contest :

Instrument panel posts:


Combined frame gusset/belt attachment:


As if I had nothing more important to work on, I tackled my favourite topic, the carburetor velocity stacks. My stackomania started with the buildup of the McLaren engine. With the engine on the dyno we realized how much influence intake stack length and shape have on torque and power. We achieved the optimum with pretty tall stacks, which were milled from solid stock. To keep the large bits out, I formed metal mesh covers attached to milled aluminum baseplates which mounted flush with the stack tops. I think these plenum style covers are the best as they don't disturb the airflow. Similar to the modern ITG foam filters - but I didn't like the looks of these.



I have also experimented with various styles using individual mesh covers - accepting the disadvantage of disturbed airflow (but looking period):



When I came across new billet stacks made by Geers Engineering and offered at VeeDub Parts (http://www.vwparts.net/CB6377.html) for a really good price, I thought again about the ultimate way to integrate wire mesh covers.

The idea was to mill a very narrow slot into the stack top, into which tea sieve wire mesh cups could elegantly be inserted and attached. My friend Martin though made clear that this was not possible and that we had mill out a portion and make rings which would leave the desired 0.55mm gap open to insert the wire mesh. The following pictures show master machinist Martin cutting the metal on his trusty Schaublin 102. Martin worked for the now defunct Studer Revox company, which was well known for their ultra-precision mechanical pieces in their tape machines:





The end result: The wire mesh cups emerging from the stacks inlet radius without any obstrusive attachment ring or similar :

[Reto Kuprecht]

The crossbeam which I made of rectangular steel tube was too massive and heavy and was a candidate for some swiss cheese action, i.e., I wanted to cut holes out Didn't do this on Martin's milling machine though, but tried it with my home shop tools using hole saws on the drill press and high precision clamping devices :



I had also prepared tubing sections which were matched with the hole saw diameters...


... which I then brazed into the beam. I haven't calculated this of course , but strength should be more than enough, but it'll be - and look - lighter:

[Reto Kuprecht]

Went to pick up our fabricated parts from the plater - and here they are in all nickel-glory:



Looks great, but creates more work, as some reaming and thread chasing will have to be done due to the nickel build-up. But what we are actually working on now is the bottom of the car. Don't want the racetrack to abrade my back side so we are taking this step extremely seriously. Cutting aluminum sheet to size and drilling holes in the right place to attach them beween the frame and bodywork. Not really exciting, this picture, but that's it



The long easter weekend coming up, I wish all forum members happy egg hunting. And if that's not enough, here's a link to some laps at Hockenheim last weekend in the other car - not a Lola though, so sorry

http://www.youtube.com/watch?v=igZS1Zindjg

[Reto Kuprecht]

Work continues on finishing the frame and preparing it for sand blasting and painting. The trick is not to forget important pieces at this point. Also tested the tubes which carry cooling fluid for tightness and will then seal them on the inside to prevent rust. This also is the time for final fitting of the body pieces - so far everything fits well - uff! The nose piece attaches to the chassis on steel locating pins and dzuses hold the piece down on these pins. Works perfectly .

The cooling issue came up again. Because I altered to front section quite much, I think I have to provide for air outlet on the top of the nose piece. I also went through period T142 photos and saw that there were quite a few of these cars whith added air outlets - they must have had a reason to do this...

First I thought I could use louvered aluminum panels - but that's not possible because the piece has compound curvatures, so again, I'll make them myself. Here are photos of a cardboard model visualizing the planned openings and flaps which will be cut and bent from aluminum sheet and epoxied into the openings. The cardboard model is a good template to make these and transfer the openings onto the nose piece on both sides: