Esprit Turbo project car - part3 - the further continuation

[Lotusfab]

More ride height evidence!

[Fridge]

If you want to replicate the Bond Turbo then that's OK, but don't forget movie cars are props. Nothing more. Those used in car chases and the like are these days different cars, and set up accordingly.

You've already noticed that the still frame of the shot where the front of the car is in the bottom of the frame is a lot higher than in real life which sort of proves my point. Though grip probably just used a brick (the film industry is very practical!). In the same way actors stand on apple boxes regularly to achieve the right framing.

I still maintain that if you had your car weighed at a profession outfit it would look different. Though I note that many Turbo Esprits look very different from their correctly set-up S1 counterparts. Perhaps as a result of tyre choice or whatever.

You didn't answer my question whether you'd fitted aftermarket shock absorbers, such as the Pro-techs on the S1. I tried setting mine to match the cup position of the original Lotus ones, and they were wildly wrong. Even asking others how many threads their cars had showing. I did it by eye, and measurement of the underside before getting it done on a rig, and it did require further adjustment.

Just sayin' Fab. It's your car.

Edited January 21, 2021 by Fridge

[Matt-watts]

I haven't read this blog (as i'm not really into turbos) but knowing you and having seen how well you did on your S1 Esprit  and the pictures of this finished car it looks a really lovely job, I think we both strive for some kind of perfection and its lovely to see how so very very close you have got to perfection. My hat is off to you buddy, well done.

Matt

[Lotusfab]

1 hour ago, Fridge said:

If you want to replicate the Bond Turbo then that's OK, but don't forget movie cars are props. Nothing more. Those used in car chases and the like are these days different cars, and set up accordingly.

You've already noticed that the still frame of the shot where the front of the car is in the bottom of the frame is a lot higher than in real life which sort of proves my point. Though grip probably just used a brick (the film industry is very practical!). In the same way actors stand on apple boxes regularly to achieve the right framing.

I still maintain that if you had your car weighed at a profession outfit it would look different. Though I note that many Turbo Esprits look very different from their correctly set-up S1 counterparts. Perhaps as a result of tyre choice or whatever.

You didn't answer my question whether you'd fitted aftermarket shock absorbers, such as the Pro-techs on the S1. I tried setting mine to match the cup position of the original Lotus ones, and they were wildly wrong. Even asking others how many threads their cars had showing. I did it by eye, and measurement of the underside before getting it done on a rig, and it did require further adjustment.

Just sayin' Fab. It's your car.

The S1 sits a lot lower than the turbo at the rear. On the Turbo I was meticulous. The entire suspension is dry sump. The springs and shocks are new and factory correct. For those that don’t know the dry sump trailing arms, upper lower links and hubs are different to the wet sump. I have seen many cars that appear to sit lower, but the movie pictures all appear to be about the same height as mine and the cars were new when the film was made. I know for a fact in some pictures the car has been weighted down. All I can conclude is some other cars are sitting lower than they were when they left the factory because they have been intentionally lowered, have different shocks or the springs have weakened over the last 40 years. The S1 sits far lower for sure.

[v8vantage]

6 hours ago, Lotusfab said:

Love this picture Fab, you car looks absolutely perfect. Shame someone keeps flogging the dead horse about ride heights! Maybe having 1 pair of skis fitted has altered the weighting somehwat.

[Lotusfab]

Split rim wheels

I have taken these apart and reassembled them more times than I care to count due to a split in a tyre, changing tyres and changing lips. I have learned a lot and now have a rebuild system that doesn’t leak! I had a vibration at 55 mph through the steering wheel and despite having my wheels balanced it was still there! I decided to get to the bottom of it and took the front wheels to Voodoo motorsport. I would highly recommend them if you don’t wish to get involved with rebuilding the wheels. They found a very slight bend in the lip 1.5 mm. Thats not much on a split rim. They also found out the balance was off by 5 grams. They rebalanced the wheels I brought them home and tried it out, perfect! I learned from this, some garages can’t balance wheels! 
I decided to rebuild the wheel again, as I like things to be spot on. This time I removed the front brake calliper, took the tyre off and spun the wheel centre up on my front hub with a dial gauge to check trueness. I found the barrel was very slightly bent as well! I didn’t think to check this when I made the wheels, as I had no spare parts. Luckily I have now got some spares. Voodoo can straighten bends with some limits, but as I have spares I decided to switch them out.
After testing new barrels and lips I have found a pair that are spot on. I need to get the lip polished and then reassemble. I found a company that can anodise, which was the original finish. I may anodise all of them in the future.
I have done some research and found out Hunter make a balancing machine they call elite Road Force. It balances the wheel under load with a roller that creates a 1200 lb force. Trouble is hardly anyone has them. I found a place in Chingford London and Twickenham. The Twickenham garage wants £270 for four wheels. I am going to get them balanced using this machine as the Esprit is very sensitive to wheel balance. It should be ultra smooth after this is done.

Be very careful with bolt torques when you assemble these wheels. You have to use 6 mm bolts that have the correct tensile strength. 8.8 grade is useless. You need 12 grade ideally. Then nyloc nuts only come in 10 grade. Then you need to look up torque tables for the tensile strength and bolt diameter. Be very careful not to overtighten as this could result in wheel failure. 
I use a 4 mm rubber cord cut and superglued at the end to make the seal. New seal for every rebuild. I use Sikaflex 221 to seal them. Very very slight bead on the very edge outside of the rubber on the centre bit. When they are bolted up I smear a band of sealant about 1 1/4 inch wide around the centre overlapping the joins, edges kept sharp with masking tape and pulled off immediately after sealant is applied. This band must overlap the joins and the inside, where the sealant is applied, must be spotlessly cleaned and grease free-I use brake cleaner. Then leave them for 24 hrs before replacing the tyre and inflating. No more than 40 psi to seat the tyre with lots of sugar soap. Ideally less than 30 psi. 
Dynamic balance once the tyre is on.

It has taken me quite a while to learn how to assemble these wheels. I don’t get leaks. When the centre band is on the air pressure forces the sealant into the joints, so it cant leak. Unless of course you haven’t cleaned the inside properly. In this case the band detaches and the air will get behind it and exit through the bolt holes around the bolts.

 

The BBS wheels are far superior engineering wise, but I think most will agree the compomotives are stunning and worth the hassle!

[910Esprit]

If it were me, i'd have correctly anodised Compomotives for car shows and have a set of BBS for everyday road use.    

I know its not the mainstrean view, but I prefer the integrity, simplicity and symmetry of a painted BBS over a polished Compomotive!    

 

[Andyww]

1 hour ago, 910Esprit said:

If it were me, i'd have correctly anodised Compomotives for car shows and have a set of BBS for everyday road use.    

I know its not the mainstrean view, but I prefer the integrity, simplicity and symmetry of a painted BBS over a polished Compomotive!    

 

Swapping between 4-stud comps and 5-stud BBS is a lot of work though!

I am hugely biased of course  but I like my BBS with satin black inlay then full-face machined the best. They are still looking the same as when I had them done a few years ago despite the machined face being bare alloy. They shimmer with a rainbow effect in the light because of the invisible concentric marks.

I really dont like the original grey BBS, they spoil the cars and were a step backwards from the Comps. I dont know why more people havent done what I did, apart from Car SOS Tim Shaw who seems to have done it to his. Although many people have had the rims of the BBS diamond-cut which is a good halfway step.

 

[910Esprit]

4 hours ago, Andyww said:

were a step backwards from the Comps

Maybe in 'bling' terms, but not by any other measure. 

[Lotusfab]

The more bling the better!

[Lotusfab]

Well one wheel lip is away for anodising. Its an experiment to see what sort of finish you will get. Because the lips are over 40 years old there are a lot of imperfections. Each of these may show up, we will see. I will post some pictures when it comes back. When I get the wheel back together thats it. Just tuning to get done.

[v8vantage]

Fab in the quest for a perfectly smooth ride there is one thing you overlooked. Tire roundness, unfortunately there is always some variation due to manufacturing. I had my tire guy shave mine the least amount to get a perfectly round tire, made a huge difference in reducing the vibration. Along with your tire balancing it may help.

[Lotusfab]

Hi Roo, thanks yes your right. I think the tyres are off round as well. I have discovered the cx500 casting is very poor. Close inspection on a lathe revealed the centre has been machined off centre by 0.1 mm. I measured the run out on several lips. It varied between 0.3 and 0.8 mm. I suspect this is the same on all split rim wheels. When I reassemble the wheel I intend to assemble it and loosely bolt it up, put it on the hub and adjust the lip position to achieve the best possible placement. There is a little movement in the lip position before the bolts are tightened. Because the mass of the wheel is very low I suspect the tyre effect maybe significant. My engineering friend does wheel repairs all the time he said he has seen far greater run out that run fine after balancing. The Lotus steering seems very sensitive to imbalance. 
There is a lot to assembling these wheels beyond bolting them up and getting a seal, as I have found out through experience. 
It will be very interesting to see how well the Anodising works. If its sucessful I may take all the wheels apart and rebuild them again. This time using a dial gauge and finally a road force balance. They probably have these machines all over the USA. I can only find two within 60 miles of my house. Maybe a business opportunity for someone?  
How did he shave the tyre, I might have to try that as well?

 

 

 

 

[Andyww]

That all makes sense, the very large scrub radius of the Esprit suspension geometry would tend to amplify any imbalance fed through the steering.

The CX500 casting is indeed poor quality. I spent hours examining and measuring the one I borrowed to do a CAD model from and its not even rotationally symmetrical, the "webs" vary in width all round. 

[v8vantage]

10 hours ago, Lotusfab said:

Hi Roo, thanks yes your right. I think the tyres are off round as well. I have discovered the cx500 casting is very poor. Close inspection on a lathe revealed the centre has been machined off centre by 0.1 mm. I measured the run out on several lips. It varied between 0.3 and 0.8 mm. I suspect this is the same on all split rim wheels. When I reassemble the wheel I intend to assemble it and loosely bolt it up, put it on the hub and adjust the lip position to achieve the best possible placement. There is a little movement in the lip position before the bolts are tightened. Because the mass of the wheel is very low I suspect the tyre effect maybe significant. My engineering friend does wheel repairs all the time he said he has seen far greater run out that run fine after balancing. The Lotus steering seems very sensitive to imbalance. 
There is a lot to assembling these wheels beyond bolting them up and getting a seal, as I have found out through experience. 
It will be very interesting to see how well the Anodising works. If its sucessful I may take all the wheels apart and rebuild them again. This time using a dial gauge and finally a road force balance. They probably have these machines all over the USA. I can only find two within 60 miles of my house. Maybe a business opportunity for someone?  
How did he shave the tyre, I might have to try that as well?

 

 

 

 

A good race tyre shop will have the machine to shave tyres. Essentially it's a lathe that uses a tool to shave off small amounts of rubber evenly around the circumference.

[Lotusfab]

Thanks, didn’t know that.

[Lotusfab]

Road Force wheel balance £24 per tyre including vat.

https://www.thetyreshop.com

not bad if you live near there, in Twickenham they want ££67.50 per tyre!

 

[Lotusfab]

Wheel is finally back together. It just needs a balance. The Anodising came out quite well on my spare lip, although it doesn’t cover any flaws, being forty years old there are bound to be some. For authenticity I may have all the wheels done. Once the wheel is back on I need a road force balance and then its a rolling road tune up. 
I wouldn’t recommend split rims for anything, but looks and pottering around. The later BBS wheels are far superior, although split rims are used for racing! 😬😬I think I know two much about how they are constructed- 20 bolts isn’t many! Just like the millions of rivets, bolts and components in an aircraft it doesn’t do well to think too much about how its constructed before you fly! 😀😀😀😀

[Fridge]

I think about that all the time Fabian, especially in engines. As you say, best leave those thoughts behind, and hope the engineers have worked out the maths.

I think racing split rims may be made to far higher tolerances, certainly these days. Machining and design has moved on massively in 40+ years. As can be witnessed by oil leak free engines etc.

I'm sure you've noticed how poor the plastics are on the Esprits. It just goes to show how polymer science, or whatever it is called, has moved on since the 1970s. It seems the Esprit was made close to the beginning of their wider automotive use. My 1960's car has interior trim in bakelite! Though some high quality (aero grade) vinyls also.

Found this aspect very interesting during my own S1 restoration. Perhaps having a Dad who worked at ICI on these relatively new synthetic materials throughout the 1960s and into the late 1980s.

[Andyww]

Lotus bought their own vacuum forming machine which they seemed to be quite proud of and would show off on factory visits.

Thats why all of the crappy ABS parts exist on the Esprits.

[910Esprit]

I wonder if those 3 piece wheels would have originally been trued up as a matched set after final assembly as the chance of getting 3 large pieces to run true would be pretty tricky.     

 

 

[Lotusfab]

I doubt it judging by the quality. The centre casting is very very poor, they don’t bear up to scrutiny. The lips all have variances. I have assembled a wheel that is as good as these can be, given all the limitations. It will be interesting to see how well it runs. It looks pretty! 
heres the Anodised wheel lip, not bad really.

 

[LOTUSMAN33]

When I spoke to the Compomotive director on the phone doing my dry sump he said the reason they moved to the external fitting centre like you see on many dry sump CX’s is to increase strength/rigidity and to stop deflation issues on the steering wheels. Shortly after they moved to CX501’s with the 30 hole pattern.

The early wheels do look far better though but as Fabian says you pay the price with quality.

I like the anodised outer, when I enquired I was struggling to find someone to undertake on old aluminium. I would have done mine for sure.

My set after I refurbed them, you can see the later type fronts.

Dave  

[Lotusfab]

4 minutes ago, LOTUSMAN33 said:

When I spoke to the Compomotive director on the phone doing my dry sump he said the reason they moved to the external fitting centre like you see on many dry sump CX’s is to increase strength/rigidity and to stop deflation issues on the steering wheels. Shortly after they moved to CX501’s with the 30 hole pattern.

The early wheels do look far better though but as Fabian says you pay the price with quality.

I like the anodised outer, when I enquired I was struggling to find someone to undertake on old aluminium. I would have done mine for sure.

My set after I refurbed them, you can see the later type fronts.

Dave  

They look great Dave. Is your red car restored now? 
on another note have you ever come across a measuring kit made by Dellorto to calibrate pump jets?

I found an old school polisher who did the lip.  He says he can do all the others for me. Maybe a winter job, I want to do some miles this year.

[LOTUSMAN33]

This was the last photo he sent me when he put the wheels back on I gave him later, I will have to email to see if he got the respray done.

No I’ve not seen a pump jet calibration kit, I would be interested though as about to set up my new carbs accelerator pumps on my rig before starting the JPS for the first time. I have a rebuilt set ready to go on the S1 but will hold off putting fuel through these for the time.

Dave