Lola SL142/20 Restoration

[Reto Kuprecht]

Yes, it does sound nice indeed. Perhaps that's due to the double firing order swap we applied on this motor. If it doesn't make more power this way, it sounds great at least

The suspension is pretty much complete now, including the anti-roll bars:



To keep the period looks I combined the vent and springs elements of a modern radiator cap with the top of an old one:



The cooling system though needs further attention. I thought I'll be very clever and tried the waterless cooling system from http://www.evanscooling.com. It's main advantage is (and that might be the only one), that it doesn't boil, it's boiling point is so high. But during the first engine runs I found out about the disadvantages: It's a slippery, very smelly substance, and - of course - does not evaporate. A spill stays there forever. Distributing this on a racetrack would probably not make friends. At this point I am thinking to switch to water...

Coming back to the suspension and springs, I warned you I'll narrate on the calculations I did. Some might skip this part I guess Please let me know, if I made fundamental mistakes here - though I must say that the resultant spring rates worked perfectly and the car settled on the exact ride heights I had planned for.

So what I wanted to know were the spring rates and lengths. To calculate these I needed the following elements:

1. Motion ratio MR
2. Wheel to spring rates Wr and Sr
3. Sprung mass
4. Shock absorber lengths fully extended, at bump and ride height and resulting spring lengths

1. I measured the motion ratios which is how much the wheels move per movement of one unit at the springs. This came out at 1.6 to 1, both in the front and rear.

2. If movement and weight/force are combined, the square of the motion ratio applies. So, 1.6square = 2.56. This means that the spring rates are 2.56 times the wheel rates.

3. We measured sprung mass by putting the car on two scales, in the back and front, wheels and uprights resting on the ground. We measured 212 kg per side in the rear and 112 kg per side in the front.

4. Shock travel from fully extended to ride height was 4cm both rear and front. The resulting (relaxed) spring lenghts were 9in front and 10in rear.

Then I solved the formula "Sr/Wr = MRsquare/1" for Sr:

Sr = Wr x MRsquare x sin a

Whereas:

- Wr is 212 kg / (4cm x 1.6) = 33.13 kg/cm in the rear and
112 kg / (4cm x 1.6) = 17.5 kg/cm in the front.

- MRsquare is 1.6 x 1.6 = 2.56

- sin a corrects for the inclination of the shock absorbers. The rear shocks are inclined about 70°, so sin 70° = 0.94. The front shocks are vertical, so sin 90° = 1.

So, spring rate for the rears is: Sr = 33.13 kg/cm x 2.56 x 0.94 = 80 kg/cm, or 450 lbs/in
and spring rate for the fronts is: Sr = 17.5 kg/cm x 2.56 x 1 = 45 kg/cm, or 250 lbs/in

As mentioned before, these rates resulted in the exact ride heights I wanted - so something must have worked right However, what really put me off was to find out - and this probably shows that I still don't really understand what's going on - that I could get to the same results much more easily by calculating the weight the spring has to support at the respective ride heights and divide by shock travel from extended to ride height:

Rears: 224 kg x 1.6 = 340 kg
340 kg / 4cm = 85 kg/cm, corrected by sin a = 80 kg/cm

Fronts: 112 kg x 1.6 = 180 kg
180 kg / 4cm = 45 kg/cm

Good night

[knotan]

A spill stays there forever. Distributing this on a racetrack would probably not make friends

probobly better to use water , it is enough for most racecars , maybe use waterwetter if ordinary water doesnt do it??

[Reto Kuprecht]

I did already drain the Evans coolant and replace with water. If anybody wants to pick up a couple of gallons of Evans NPG-R give me ring.
As you saw Lola ran the coolant in the chassis tubes. I wanted to keep this feature, but I knew it could be prone to leaking if weldin and brazing is involved. And so it is - coolant is leaking into a frame tube where it shouldn't . It's clear now, I have to run the upper tube separately (as actually required by most sanctioning bodies). Apart from weight considerations, does anything speak against running a flexible (rubber) tube all the way from the engine to the radiator?

[Rhino]

Just saw your Youtube video Reto....I must say there is a little bit of jealousy on my part ,but Bravo!
Be careful with the Evans cooling. Some tracks will ban you if they see it in your cooling tanks

[Reto Kuprecht]

Well, if you are jealous regarding my restoration, I'd be green with envy looking at the fantastic job on your Lola

Thanks for your comment on the Evans. It underlines my decision to switch back to water - among others for the reason you mention.

[knotan]

didnt you test pressurize frame/coolingpipes bofore painting it

[Reto Kuprecht]

Well, yes, we did pressure test the tubes. But apparantly not good enough, or a little crack developed at some later time. Anyway, now we will do an independent tubing arrangement and that problem will be solved too.

I got the body parts back These were done expertly by a specialised shop nearby - Harder Paintworks in Tössriederen, a quaint little village right on the banks of the Rhine river. I did my best to prepare the fiberglass pieces as good as I could. But what I got back from them really blows my mind . Have a look at these first pictures of a test fitting, more will follow:

[Reto Kuprecht]

My little ROLAND STIKA plotter comes in very handy now. With this machine I can create and cut vinyl graphics myself. The basis for the chosen livery are several black and white photos I found, such as these:

Found on the internet - author unknown to me:


With Denny Hulme. Found on the internet, author unknown to me.


Still from a period British Pathe film. I bought the cleared film from them:


The livery as I have recreated it. I also have very nice repro period sponsor decals, such as Autolite, Lucas, Koni, Girling, etc. and I am tempted to put them on the car - just because of the looks. However, in period, there were no such sponsors, so, I should perhaps not do that. I would appreciate inputs from forum members on this topic:

[Chris Fox]

Wow Reto,

What a job it looks perfect.

Will you run the car at Hockenheim?

Can't wait to see it in the flesh.

Have a good Christmas

All the best Chris

[knotan]

have you made the moulding yourself?? is it fiber glass or carbon fibre???

very nice result with painting!!,
i am thinking about doing some carbon fibre parts for my car, but never done any work before and feeling a bit unsure if i can make it...

[Reto Kuprecht]

Hi Chris - thank you for the kudos but, it's not quite done yet. But not that much left to do either, the cooling system for example, and some other minor things. I am planning to take the car to Hockenheim in mid April, it's called "Bosch Hockenheim Historics" now, and I hope should benefit from that new sponsor. A Merry Christmas to you and your family!

Knotan, these fiberglass body pieces come from TWM in the UK, http://www.tw-mouldings.co.uk. They still have the original moulds for Lolas and McLarens, and they have aways been helpful and quick and delivered a good quality. Call the owner Tony for help.
I had original body pieces, but they were old and rotten and therefore I had to have new ones made. So, no, I did not make these myself, but worked on them to make them match with each other and also to create good mounting solutions. Getting these body pieces to stay in the right place on the car took me much longer than I had anticipated

[911hillclimber]

Breath-taking job on the body let alone the whole car.

West Brom is West Bromwich in the Midlands, England, just 5 miles from where I'm typing this waiting for the family to wake for Xmas day!

The body on my Lola T 492 is a TW body as is the seat, all from the original moulds, but also very 'race weight' and start cracking up quickly.

Graham.

[Reto Kuprecht]

Thanks Graham for your comments - and I hope everyone has had a good start into the new year.

Not too much happened during these days - I am still waiting for a set of custom formed silicone hose from the UK and I cannot really continue until I have these.

What came in though is a set of custom made stack filters. Besides the ones I made myself, I thought I'll contact Bill at "BBR Filters". He has started producing stack filters some years ago and has since steadily increased the applications and types of filter solutions. At this point he can also make custom filters for any induction arrangement. My specs were filters covering two carbs at once, a mate black silicone base and brass support mesh. Bill was extremely helpful and delivered exactly what I was looking for. Contact Bill at stackcovers@aol.com.

Top and bottom view. Filtering is achieved by a very fine SS mesh screen which is sandwiched between a coarser mesh. This outer mesh can be ordered in various colours and metal types:


These filters integrate very nicely with the overall scheme of the engine and are perfectly functional:


Bottom view. The silicone base holds and seals against the stacks. I think the way Bill has formed the inside retaining lip, airflow disruption should be minimal:

[Reto Kuprecht]

I have finally received the custom radiator hoses. Obviously this is better than splicing several hose sections together with off-the-shelf pieces - but it was a long wait They are however very nicely done, of modern silicone construction, mimicking the old hoses with fabric outer cover:



The hose routed along the outside now, connecting to a temp sensor piece, and on to the radiator:



With the custom 90deg and 45deg sections, only one connection was necessary, compared to three with standard sections:

[Reto Kuprecht]

The finished installation. I filled it with coolant and next weekend I'll make a test run - and if that's OK I can close up the left side:





For a possible change to old style valve covers I needed to have a look at the current set-up. Here's a look at a pretty rigid valve train - which is certainly NOT period