Esprit Turbo project car - part3 - the further continuation

[910Esprit]

Hi Fabian - In addition to compression, an HC uses larger inlet tracts, different inlet manifold and increased boost.   Additionally, you cannot directly compare DHLA40's to the HC's DHLA45's - as the 45's are a different design with an additional 'Powerjet' circuit and actually runs a smaller choke size than the LC models!  (my guess is they only went to a 45 body to take advantage of the power jet) - To avoid running lean at high speed.

When I was setting mine up, which does run an HC head, elevated compression and increased boost, I experimented with larger idle jet holders in DHLA40's and found them unsatisfactory as they immediately 'kicked' too rich as soon as the throttle was touched from idle, before transition occured.

I get pretty good transition & power off a 43 idle jet with standard holders.  I also run larger main jets and pump jet calibration based on an HC, which has a slightly elevated volume.

NB - What do your plugs look like, now you have a some miles on the engine?

  

 

 

 

 

 

 

 

 

 

[Lotusfab]

Thanks Steve, really interesting, because  of the number of variables maybe a rolling road is really the way ahead. Not sure whether I will even bother with the new jets and holders, now I know what you have already discovered. I knew the carbs were a different model, but didn’t know about an extra circuit. I also believe the HC has vacuum advance. The engine runs great beyond 3000 rpm, so I was thinking the mainjet, emulsion and air correctors didn’t need adjustment? Can you remember what sizes you used? 

[drdoom]

Fabian, please don't presume that the feel of the engine adequately sums up whether it's correctly tuned. With forced aspiration engines it is quite imperative that lean settings are avoided under boost, as is excess spark advance. Don't lean on it much before the pro's have sorted it out. Afterwards you may fiddle with driveability concerns once the base fuel and spark settings are sound. Cracked pistons and/or blown head gaskets are no fun. 

[Lotusfab]

Yep, I need to get it on a rolling road ASAP. I have an expert taking a look at  it next week. Hopefully he can steer me in the right direction. 

[Andyww]

9 hours ago, Lotusfab said:

 I also believe the HC has vacuum advance. 

I believe the vac advance on the HC is not used when the engine is warm, its cut in/out by a temperature controlled valve.

[drdoom]

10 hours ago, Lotusfab said:

Yep, I need to get it on a rolling road ASAP. I have an expert taking a look at  it next week. Hopefully he can steer me in the right direction. 

He will if he's at all worth doing business with. 😑

[Lotusfab]

13 hours ago, Andyww said:

I believe the vac advance on the HC is not used when the engine is warm, its cut in/out by a temperature controlled valve.

Thats interesting. I haven't heard of a vacuum advance being inhibited by temperature before. 

[910Esprit]

Looking at section EMC in the book, I think there is more to it than that.   The vacuum unit is double acting, with one side permanently connected to plenum pressure and the otherside diverted to a different source depending on temperature. 

Below 60 degrees it applies max vacuum/max advance by connecting the the vacuum unit directly to the vacuum pump line.  Above 60 degrees it uses a thermal valve to divert the vaccum unit to a 'throttle edge drilling' which presumably must give a differential between the opposing plenum pressure connection.   So I assume its doing something akin to traditional vacuum advance above 60 degrees.

 

 

 

 

 

 

 

 

[Andyww]

In section TDB though it states the vacuum capsule gives 28 deg advance. If that were added onto the static plus weights, that gives 49 degrees which seems a lot.

[drdoom]

Once again, a reminder of how confounding is Lotus' terminology on ignition timing ?  😬

[Lotusfab]

The solution to tuning these car is probably to fit a Lambda sensor in the exhaust and a gauge.

[Barrykearley]

Then connect that to a fuel injection system 🤔

[Andyww]

36 minutes ago, Lotusfab said:

The solution to tuning these car is probably to fit a Lambda sensor in the exhaust and a gauge.

When I owned my Excel I fitted fuel injection to it and also fitted a mixture gauge to the dash, replacing the voltmeter. The gauge turned out to be quite useless for tuning because the mixture on a properly tuned car varies hugely, its never at the optimum, nor supposed to be, for best performance without engine damage.

What I should have done is had it tuned on a rolling road but at that time I had very little money and what I had I spent all on the EFI 😞 It was a project I should never have started at that time.

Rolling road is the way to go but can be a very long and expensive process and do people still have stocks of different Dellorto jets?

[910Esprit]

43 minutes ago, Andyww said:

do people still have stocks of different Dellorto jets?

And the knowledge of how all the various jets, jet holders, emulsion tubes, diaphraghms, spring weights etc all interact with each other? 

[Lotusfab]

Well I have retarded the ignition timing very slightly to allow for the extra compression. This seems to have improved the acceleration smoothness through 2000 rpm. I removed the 43 idle jets some time back when I thought it might be causing excess fuel. I now believe the excessive fuel was due to the pump jet adjustment. They both were not calibrated. You may remember I then calibrated them using Daves test tube set up. So I have now switched back to the 43s. I have to say its now driving the best it has ever. It seems to be smooth all the way through the rev range. I still plan to put it on a rolling road for the definitive set up.

I was dismayed to find one of my new rear Vredstein tyres got a puncture due to a pothole. Unfortunately it was too close to the sidewall to repair. I could not get another Vredstein, as they don’t seem to be making the size anymore. So after some research I bought a Falken. The next issue was I had to replace the Goodyear decal. I have to say I have become expert at doing this, it only took about 45 mins to take off the existing tyre writing and replace with the decal. The decal came from tyrewallstickers. I am please with the Falken which is 225/60/R15, the same size as the Vredstein. Its a good alternative if you can’t think of what to use. Reasonable quality and price with a good speed rating. Here it is with the decal. I have been out driving in the wet and dirt so need to do a lot of cleaning. The whole point is to enjoy and drive these cars and thats what I will do until it someone else's turn! 

[jonwat]

2 hours ago, Lotusfab said:

I was dismayed to find one of my new rear Vredstein tyres got a puncture due to a pothole. Unfortunately it was too close to the sidewall to repair.

Take pictures & send them to the council demanding compensation for your loss. 

[Lotusfab]

Suspension

finally got around to measuring the suspension using the F1 method. I used four axel stands and two 18 mm dowels about 2.2 m long. I marked each end  so I had four equally spaced marks and used fishing line with a bob weight at one end and the other tied. I then made a rectangle around the car and centred it at mid wheel height. I spaced it equally around all four wheels. I was very easy to get accurate measurements. The result was interesting. The front wheels are 1.5 mm toe in each side.  The rear left is 6 mm toe in and the right 1 mm toe in. The rear camber is already adjusted. The front castor angle needs to be measured again and the toe re checked after any castor adjustment. The castor is adjusted by washers behind the anti roll bar bolts. I have to install shims on the rear left trailing arm mount. Trouble is the heat shielding around the mount has to be removed to access the bolts! I’ll start with a 6 mm spacer.
I rebuilt the drivers door and ended up drilling the rivets out of the door seal and repositioning it in order to shim the frame and stop a water leak. Its now working perfectly, but it was a lot of work. Lubricating the four wheel plate with lithium spray grease really helped the operation. I also shimmed the guide rail using a single washer. Its the best operation of the door mechanism I have experienced so far. They must have released cars from the factory with dodgy window operation judging by the man hours needed to perfect the operation. I ended up using a micrometer to measure and record the shim thickness on the frame. I then made all adjustments to these figures. The are a lot of adjustments possible on the door which is why it is so tricky to perfect. Only persistence and practice helps with setting them up. I must have spent months messing around with the electric windows on both of my cars. So making progress with rolling road to come.

[Lotusfab]

Ok rear nearly done! It took one 6 mm shim plate on the rear left to reduce the toe in to 1 mm. 
The rear left camber needs to be checked again now the shim plate is installed.

The front caster I measured as 1 degree and 45 minutes. So will install a 1.5 mm shim behind the anti roll bar and measure again, it needs to be 3 degrees. This is time consuming, but pretty easy. Should have it sorted in the next few days. I have been working on a Landrover Discovery in between. The fuel burning heater was smoking. I think I have fixed it and my webasto diagnostic software shows no faults. So no more distractions!

[Lotusfab]

Finally the suspension is shimmed!😄😄😄😄😄 The castor took 4.5 mm of shim washers (early type) to increase caster from 1 degree 45 secs to 3 degrees  and 15 sec. I measured the caster using a laser spirit level, trigonometry and a Gunson Camber/caster gauge. There are lots of videos on youtube how to do this. The fishing line and bob weight method to form a rectangle and measure toe is really easy to set up and accurate. The whole suspension is now as good as it can be. I am just waiting for a break in the weather to do some tests.

I found a slight oil leak. It was a very easy fix. One of the brass cam tower plugs needed tightening. These are a very common source of leaks and sometimes not easy to detect especially when its a plug on the lower exhaust side cam tower.
I have noticed my heater has stopped working. I believe the problem is a vacuum line has come off so the flap isn’t moving. This time I am going to superglue the vaccum leads in place. When the heater is fixed thats it apart from building miles and a visit to a rolling road. Once I have proved the reliability its off to Cortina. Oh, I realised I havn’t lubricated the Trunnions since I built it. They used EP90 oil. I have bleed nipples fitted, so have to buy a second grease gun and fill it will EP90. Pretty important to keep these well lubricated. Maintenance is very imported on these cars if you want them to be reliable.

[LOTUSMAN33]

Good stuff Fabian, it’s this attention to detail which sets apart a good car from an excellent one on the road. 👍🏻
Dave  

[Chillidoggy]

Why didn't you just put your car on one of the Hunter laser-alignment machines at KwikFit and have it checked? Last time I had mine done it was about £50. In fact, it would be worth checking it now so you can see how accurate you were with your calculations.

[jonwat]

5 hours ago, Lotusfab said:

I realised I havn’t lubricated the Trunnions since I built it. They used EP90 oil. I have bleed nipples fitted, so have to buy a second grease gun and fill it will EP90. Pretty important to keep these well lubricated. Maintenance is very imported on these cars if you want them to be reliable.

It should have bolts fitted not nipples, you can remove them & then push an oil can spout against the hole then pump away until fresh, clean oil comes from under the seal. Wouldn't have mentioned replacing the nipples except I know what a stickler your for details. 😃

[Andyww]

13 minutes ago, jonwat said:

It should have bolts fitted not nipples, you can remove them & then push an oil can spout against the hole then pump away until fresh, clean oil comes from under the seal. Wouldn't have mentioned replacing the nipples except I know what a stickler your for details. 😃

Book method here but if an oil can will do it that sounds fine.:
 

[jonwat]

22 minutes ago, Andyww said:

Book method here but if an oil can will do it that sounds fine.:
 

Using an oil filled grease gun can get very messy & I though I'd save him the expense of buying one 😀

[Lotusfab]

59 minutes ago, Chillidoggy said:

Why didn't you just put your car on one of the Hunter laser-alignment machines at KwikFit and have it checked? Last time I had mine done it was about £50. In fact, it would be worth checking it now so you can see how accurate you were with your calculations.

I did that with the S1. The main stream companies know nothing about aligning an Esprit chassis. I got them to measure it and then took it away and shimmed it myself and brought it back for a final check.

I had an align check done on this, but the same problem they haven't got a clue what they are doing. I trust my own readings more than theirs. Plus I don’t damage the wheels buy strapping on laser targets. 
In fact Kwik fit damaged my Land rover chassis and told me it had to be scrapped! I told them I have just rebuilt the entire front end and  they have damaged it by not loosening the chassis bolts prior adjustment- I heard the guy swear as he flattened off the chassis lug with a breaker bar and then he disappeared! I suggested they read the Landrover alignment guide and their alignment screen before they attempt to adjust the alignment on something they don’t understand. In the end I told them to get it off the ramp and never went there again.  I bought and ID tool interface and got a company to adjust it under my supervision, after I had put into tight tolerance mode and calibrated the steering angle. 
I am no longer convinced electronic alignment is any better than the old fashioned ways. Lotus aligned it using parallel bars in the factory. Track cars and F1 still use the old methods. Its a personal choice, but I think because I can spend unlimited time on it in the end my result will be just as good or better.