Lola SL142/20 Restoration

[Reto Kuprecht]

The motor is back in the chassis This procedure went quite well, but did take some squeezing, wiggling and the plastic hammer in some places because of the tight tolerances everywhere. This sure made the day for a friend who helps sometimes. He is a retired aircraft mechanic and he always tells me to build more slack into my constructions and make every hole at least one size bigger I do have a hard time with this, but he's probably right . I just continue with the assembly of the prepared parts and so far no real problems have surfaced:



Now it gets apparent how Lola has wrapped the tube frame around that big motor - it really is a tight fit:

[Reto Kuprecht]

Continuing with the assembly. We forgot about the sequence in some cases and had to start over once or twice I just hope the engine will run and we don't have to take it out again . Ignition hooked up, oil plumbing attached and hopefully tight:



Roll hoop braces attached and locked, fuel system connected and secured, water in and out connected:



Detail of the Accusump blumbing. The valve can be operated via push-pull cable from the cockpit, a -10 hose connects with the main oil circuit:

[CMW]

This really is a great thread, thanks for such a detailed and well documented posting, an inspiration to many of us, I am sure, and such VERY enjoyable reading and viewing. Thank you!! I can almost feel your excitement and enthusiasm, I only wish I could share your talents.

[Reto Kuprecht]

Thank you Chris for your supporting words. And you are correct, I really am quite enthusiastic, perhaps mostly so because this is not my day job, and I actually look forward to spending a few hours in the workshop around a pretty tight agenda. And, talking about talent - I admit this is not the first project I am working on, however, I learn a lot on the way, by asking the real pros, reading, using clever tools, and trying things out. So, sometimes, there's actually much more trying and fiddling behind the nice end-results I am reporting here The acid test of course still lies ahead - that the engine and all systems work well together and the wheels won't fall off at unsuitable moments

[Reto Kuprecht]

The rear end is pretty much finished, except suspension and final drive. My plan is to assemble the car as much as necessary to run the engine - which of course means hooking up the motor with oil, cooling and ignition. I've already put in the gear oil for the LG 500, 2.4 liters of 85W-140 EP Hypoid Oil, and the engine oil will be next. The exhaust still fit too, as you can see I gave it a most elegant satin brushed finish





Here's a detail of the carburetor linkage in its final configuration (for now ). At the beginning I wanted the movement to be progressive, but it was enough of a challenge just to make it work properly, and the "progression" is now just what it is. I also added a stronger pull-back spring for safety and checked for proper travel and end stop. Let's see how this system does in real life. The beauty of this is the symmetrical actuation and that everything is neatly packaged on the manifold. However, smooth functioning relies on an accurately centered pivot point. If that changes, for example due to heat warpage, the thing will bind. I have to keep my eyes open for this



The front end with the suspension, steering links and radiator is together as well. I ran out of time on that last hose clamp though. This will be the next sessions first thing to do - and then we'd actually be ready to add the fluids and try starting the motor

[knotan]

amazing

did these cars even have this finish when they were brand new??

[Reto Kuprecht]

Hi knotan
Well, I think the finish of a new T142 was just as good as this one. Of course some components were not available then, or not thought worth using. Safety dictates certain improvements too. But apart from these, or using replacement parts because originals are not available anymore, there's actually not many parts on this car which are totally un-period or could not have been made the same way in the late sixties.
Regards, Reto

[knotan]

well, i just thoght that they didnt spent so much time and effort in finisch etc on a racecar

keep up the good work

[Reto Kuprecht]

Thanks knotan, and yes, I absolutely agree with that. To build up a racecar during such a long time is about the most uneconomical thing one can do - and there's no way a professional manufacturer would work in such a way But it sure is a fun thing to do for a hobbyist like me. As we all know, this is the kind of thing one does not to meet a time line, or do something in the cheapest possible way, but to do it exactlyl the way one wants it, without any time constraints either. I can assure you that my approach in my real life job is quite a bit more economical

So here's the current situation: I ran the motor which sounds like boring, but it was quite a step for me. Would all the plumbing, ignition, cooling, work properly, not leak, and not give me an instant "wrong-try again" sign? It did - the motor started at the first push of the button and sounded marvelous. When the exhaust fumes in my workshop got too thick I had to stop

With this little test done I continued finishing the rear end with the suspension, uprights and drive shafts. My father installed the brake pads which had to be prepared to slide freely within the aluminum calipers:

[knotan]

first startup of newbuilt cars should always be posted on youtube

[Reto Kuprecht]

I heard you knotan and will record sights and sounds next time

I have reached a point where I have to tackle the suspension - something I have not done before and which I approached with much respect And if anybody discovers fundamental mistakes I am making in the following, please let me know
To choose the correct type and length shocks was a first step, but now it's time to find the right springs to finally put the car on its wheels. Armed with some dry theory I knew the first thing to do was to find out the motion ratios and sprung mass to eventually calculate the spring rates. Here you see my high-tech wheel motion measuring device. This way I could pretty accurately put wheel and shock movement into relation. Surprisingly this motion ratio came out the same in front and the rear at 1.6 - i.e., for each unit the shocks move, the wheels move 1.6 units. This will be important for all following calculations:



Then we put the wheels on the car and set it down on two scales - placed between the wheels in the front and rear - so that the wheels touched the ground. This way, we would only measure the sprung mass, without the weight of the wheels, uprights, brakes and parts of the suspension. We would measure this with myself in the seat, half-full tanks, and added the weight of the body parts which are now in the paint shop. This came out at 424 kg in the rear and 224 in the front.

I had also noted extended and compressed lenghts of the shocks, and most importantly, length at assumed ride height. With that I set about some calculations based on the simple formula of: Wheel Rate = Spring Rate / Motion Ratio ^2, and: Spring Rate = Wheel Rate x Motion Ratio ^2. These calculations resulted in certain spring rates and sizes I need and I have put in an order for these springs. An apology here - I will only provide detailed information on how I did the calculations if they really work out as I had planned. Because, otherwise, I know I made mistakes and don't want anybody to repeat these and hold it against me And, as quick and dirty as this sounds, with my limited knowledge of this, it took me hours boiling over the various sources I have on suspension theory (among them the Caroll Smith books) to understand what's going on and what I should do



Here's a back view with the big wheels and the chassis at ride height. The wheels I am using here are "replica" three piece wheels from Fox Racing Developments. But I would still be interested in a set of good one-piece magnesium wheels, all 15" diameter and 4.5" backspacing, the fronts 9" wide, the rears around 14" wide.

[Reto Kuprecht]

We had prepared attachment points for "string-bars" fore and aft at an early stage - and now they come in very handy. On the photo you can see the front bar and the barely visible string, dark coloured fishing line for accurate measurements. I knew we would sure walk into the strings working around the car and hung paper strips on them to make them more visible. We still walked into them and tore them down more than once

So we did castor and camber and that went pretty straight forward. I used a 50$ digital level with magnets which can be stuck nicely to the brake rotors to do these measurements - half a degree negative camber, 5 deg castor. And we had a first shot at toe with the help of the aforementioned strings:



Next came the dreaded bump steer. I really hoped it wouldn't be off too much because the only corrections I could make would be moving the steering rack up or down. And as I did not have an original rack but had one made, I wasn't sure whether I got the position right Therefore the first check with the "Longacre Bump Steer Gauge" was kind of a revelation (showing toe-in of about 1/5 of an inch on 1" of bump). That was at least in the right direction, but much too much toe change Took me a while then figuring what to do, and then started lowering the rack. And it got better indeed "Lowering the rack" of course means unbolting the rack supports in an impossible location, elongating bolt holes, putting everything back together - checking bump steer again - and all that at least three times. Took us a whole day



The springs are here too. I will not go into detail what I had ordered, but will install them first and see how they work. At least in static mode. I have to start with something now, based on the calculations I had made. But I am quite sure that when I check them on the car - and of course on the track - I will have to reconsider lengths and rates:

[Reto Kuprecht]

Springs installed on all corners and the car settled down to the ride height I had planned for. So my calculations did work out fine I'll come back to this later. We could have gone on indefinitely adjusting camber and caster, but we left things at a certain point and will check again after first runs:



Statically, this all looks great, dynamically, i.e., on the track, under braking and in the corners, I don't know yet. But I stood on the car in the front and back, putting my weight on it, and I think the springs are strong enough:



Now came the moment to fill the hydraulic system The clutch went very well, no problems at all. The brakes were more difficult. Took a while to get the air out of the lines. And, everything was tight, except the connecting lines on the calipers, another thing to check

[Reto Kuprecht]

Knotan, you said you wanted a video of the running engine Here it is:

http://www.youtube.com/watch?v=NyoJ33k2M54

[knotan]

it sound very nice
i can really understand how satisfying the feeling must be hearing it after so much work spent.
it is s really lovley car and restoration

also i felt the need to post youtube on my car with new exhausts .