First job jobbed - 2 more found !!!

[Alan_M]

Nice write up. I had similar and found just adjusting the one rod for it all working again.
Before adjusting I could only get mine to latch if I held the handle in the open position, pushed the door shut and released then handle.

[MetBlue]

Driving down a side road near home the other night, thinking to myself " These headlights really are poor. I need to upgrade to LED".
Soon after, I pulled up behind a car and thought changed to " These headlights ain't on !!"
Main beam working fine on both flash and switched. Main beam relay removed and checked to be working fine, so power wasn't making that last leap between the relay and the head lamp.
The car should have Dim / Dip but a PO had linked it out - a link I was fully aware of and previously had looked reasonable so I had no reason to investigate. This picture from a year ago when the dash was out ( the Red U wire under the black connector near the lower door hinge bolt):


Checked it out this morning and it had been getting hot. Cut the tape off and found this:


The bullets weren't "in" the connector, just pushed up close and taped in place.
There's a moral here. If you know a PO has been there before you, check it out and ensure it's up to your standards - Especially if it's electrical. This could have been a lot worse !!

Pleased to say all working fine again now - and that red wire is in the bin.

Tony

[Alan_M]

The curse of the PO!!!
At least it wasn’t too hard to sort and in time before anything worse happened.

[MetBlue]

Recently been having problems with drivers door lock. Slam closed - it doesn't latch and just bounces open.

A few weeks of the car letting me think the bouncing door was fixed, and it started doing it again.

I had a feeling that the z plate wasn't pointing at the levers on the outside door handle. Seemed to be pointing more to the outside of the car ( hope that makes sense).
So dismantled again, tweaked the bends in both parts in the latch the Z plate attaches to and put back together. The outside door lock lever went in a lot easier and without feeling it was fighting the Z plate ( applying any twist to it).

Pleased to say door latched first time and better than ever before. Pretty convinced this was the route cause of my problem. The slide in the Z plate needs to be very free to move up and down without any resistance.

Tony

[MetBlue]

I've had issues with the Power steering all the while I've owned the car. Slow speed manoeuvring with engine revs below about 2000, and often there was no assistance.
I found a Saginaw Steering pump on Ebay so fitted and things were no better - Actually worse.
The initial fluid drained out was "blackened".
First lesson learnt was that I should have checked the drained fluid for contamination AND FLUSHED THOROUGHLY before fitting the new pump. After fitting the new pump and still having a problem, I drained the now clean fluid and could immediately see significant contamination ( both ferrous and alloy). I took the pump along with the rack to the company for reconditioning the rack and flow testing of the pump ( Kiley Clinton in B'ham). Their feedback on the pump was that contamination had jammed open the pressure relieve valve. They fitted the pressure relief valve from my old pump and now tell me it working fine.

So, to the rack.
It was impossible to get the high and low pressure pipes out of the rack, due to Alloy to steel corrosion. Rack had to be removed with the pipes still attached, which added an extra challenge.

Not easy to see, but A LOT of the alloy has disintegrated above where the O ring would sit. Re sealing would have been difficult if not impossible. The removed pipes still had a lot of furred Aluminium between the O ring groove and the clamp face.

A week into the refurb, I got a call saying the rack was scrap. On collection today, I understood why.


Anyone whose stripped a rack will know that those 4 perfectly machines shiny rings at the bottom you can see shouldn't be there. It's meant to be a clean parallel piston sleeve. They said they have tried machining out and sleeving in the past, but not an ideal solution. They had a "spare" casing that they used to refit my old rack and piston into, so I now have a freshly refurbished rack to fit and a supposedly tested and good pump.
Looking forward to the fight to get the rack back in
Second lesson : Kiley Clinton told me that the blackened fluid was a tell tail sign Aluminium was being machined away. This was definitely the route cause of my steering problem, but a new pump won't hurt anyway.

Tony

[MetBlue]

Steering now sorted and I have another 12 Months MOT with no advisories
- Every year though I get a comment that "technically" the emissions are a bit high, but the tester is of the belief that the 912 engine performs better a little rich, so why should I argue.
Car has never been great on fuel economy though ( absolute max 25 even on a gentle run) so I decided to take a look at the jetting and with the timely posts last week about carb setting and balancing, a tune up..
Turns out someone's been in there playing - I know which business, the evidence is in the cars history file ( not one of the usual Midlands players)
Incorrect Jets were:
Main Jet 125 - Spec 10 cars should be 135
Main Air corrector jet 170 - should be 150
Idle Jet 62 - should be 55
The rest were to spec.
Mention here to Eurocarb Ltd, who delivered a set of the correct jets less than 24 hours after I placed the order, so yesterday was carb day.

I started by connecting up a set of vacuum gauges to the F ports to see how balanced things seemed (with the incorrect jets). In short, it was pretty close.


Then changed jets over, but struggled to detect any change to engine rev's when adjusting the idle screw. All documentation I have says correct setting is between 3 1/2 and 6 turns open, except for Tim's excellent write up that suggests anything over 3 1/2 is more than should be done by the taper jet. With the #62 Idle jets, screws were around 3 turns out.
I've left them pretty much at this position for now, but I have significant hesitation between around 1800 and 2500 on the pick up.
I also think the plug colour looks a bit weak.
Approx where do others have the idle screw set to?
Should I wind the screw out a bit further or maybe fit the #62 idle jet leaving the main jets as Lotus recommendations.

Tony

[MetBlue]

Below cribbed from a thread titled " Low RPM hesitation" from a few years ago. - Another great post from Tim Engel - Hope he doesn't mind me copying forward. This sort of gold dust can't be posted too often IMHO.

In an older engine, time can take it's toll on every component and make all the above suggestions possible. My first reaction to your description of the symptoms is that it's a fuel mixture problem; but the first step in tuning or re-jetting the carbs is a thorough ignition tune-up (including frayed wires, cracked vacuum hoses, broken thermal vacuum switches, etc). With all the non-carb issues resolved first...

The Dellortos were jetted lean from the Lotus factory. They weren't crippled by emissions tuning like the poor Federal 907 was, but the 912 still had to meet EU standards. As such, the stock jetting was on the lean side to begin with, such that the engine could be weak or hesitant off-idle (Idle Air Corrector), during throttle transitions (Accelerator Pump and Pump Jet), and at the idle transition rpm (Idle Jet).

All of that is compounded by the fact that years of use (or worse, prolonged storage) will result in dirt & deposits building-up inside the carb body and jets. Crud in the jets effectively reduces their size and ability to flow fuel, causing the mixture to go leaner. It could very well be that fixing a lean mixture-related hesitation will only require a thorough cleaning of the carb body and 'all' of the jets. By 'thorough,' I mean take the carbs apart and manually clean everything. A bottle of 'fuel system cleaner' poured into the petrol tank is NOT going to get the job done.

The stock Idle Air Corrector (aka, Idle Jet Holder) for both the DHLA45E (912LC) and 45D (912HC) is the 7850-9... the third leanest. It's no surprise that the off-idle / low-rpm performance is weak, or that there is an off-idle hesitation. If you wish to sneak up on the perfect jetting, then try installing a step or two larger Idle Air Corrector, then test driving, and repeating until the off-idle hesitation just goes away. However, buying jets in sets of four can get expensive, so it's understandable if you wish to take bigger steps or skip right to the final solution. Sorry, carbs don't work that way, so be patient in your tuning.

Start with the Idle Air Correctors (aka, Idle Jet Holders).

Idle Air Corrector Sizes:
7850.5 .. Leaner, going down the list gets richer.
7850.10
7850.9
7850.4
7850.1 .. Normal
7850.3 .. Normal
7850.6 .. 6 & 7 are very similar, almost interchangeable
7850.7 .. The Lotus 9XX likes 7
7850.2
7850.8 .. Richest

1 and 3 are considered 'normal'.

6 and 7 are very close to one another. If you want 7 and can't get it, then a 6 is a close approximation. IMHO, the 9XX engines with 45mm Dellortos (both E & D suffix) like the 7850-7 Idle Air Corrector. It's on the rich side, and probably a little too rich for 'normal' driving and best fuel economy; but the 9XX engine gets up and goes when you ask it to.

For the most part, 5-10-9-4 are too lean to be good for anything other than emissions, and 2-8 are too rich. Don't waste your time with any of them.

The Idle Air Corrector and the Idle Jet are closely related, and changes made to one will affect the other. Make any adjustments to the Idle Air Corrector first... don't jump straight to the Idle Jet like most people do. Once done with the air corrector, you may find that a minor lean stumble at the transition rpm (under, but approaching 3200 rpm) has also gone away. You got lucky. If not, then go a step or two richer on the Idle Jet until the transition stumble (ie, the '3200 two-step') just goes away... no richer. A 58 Idle Jet is the largest a 9XX should ever require. If you need to go larger than that to cure the transition stumble, then something else is wrong. Figure out what it is and fix it before simply throwing a bigger jet at it.

In the two-circuit 45E carbs (912LC), enrichening the Idle Circuit may be all that's required... the stock Main Circuit is typically pretty good as it came from the factory.

In the three-circuit 45D carbs (912HC), the stock Main Circuit may also be a little lean. The whole point of the third circuit was to allow the Main Circuit to be tuned leaner for mid-range emissions and fuel economy, then rely on the new PowerJet circuit to kick-in at full throttle and provide the extra fuel needed for maximum power and pulling to redline. So the stock 'D' main circuit is jetted leaner than the old 'E' main circuit, and may also benefit from a little re-jetting. But one problem at a time... address the Idle Circuit first.

All the above presumes that you did the thorough ignition tune up, including wires, vacuum hoses, etc.

Tim Engel.

The detail on getting a richer Idle by changing the Idle Air Correctors, not the jet very enlightening.
Totally illogical though that the corrector numbering doesn't go up sequentially. I guess there's good reason
If I'm right, I think the Elite from 1974 I have sitting in the garage will have Correctors that are a couple of grades richer than my Spec 10, so as soon as time permits, it's play time.

Tony

[rbgosling]

Hi Tony - I don't know if you've come across Northampton Motorsport. I read an article about them in a Practical Classics several months ago. They took their car along (I forget what it was), then they can put it on the rolling road and they have a full range of all the Dellorto (and other carb) parts that they can swap in and out to get it running sweetly. Even if you don't use them to get it set up, it may be handy to have somewhere nearby who supplies the parts, who knows, if you ask nicely maybe they can supply several different options and you return the ones you don't use?

[AndrewWebber]

Even living in Kent, I use Northampton Motorsport for my Hill Climb and Sprint (2 Weber DCOE) Elan+2 and Turbo V8 (4 Weber IDF) 'Europa/Esprit', I find them very knowledgeable and helpful.

Haven't fiddled myself or let them fiddle with the Elite so no actual experience of them on Dellorto



Andy

[Lotus-e-Clan]

Just playing Devil's Advocate (as usual), but my 89SE is still on stock OE jetting with no hesitation, all engine management gizmos in play, and 75K miles.

I've had it like this for about 25 years with no hesitation. However, when I first bought the car at 32K miles, it ran very badly, and it did not want to rev beyond 6K rpm. I never touched the ignition timing NOR the idle jet screw set positions because they still had their 'anti tamper' covers in place. I changed the plugs and leads, put V-Power in the tank, and it ran well after that. Unfortunately, some years later, a helpful, but ignorant, MOT man ripped off the 'anti-tamper' covers and twiddled the idle set screws because HE thought it was running too lean with less than 1% CO @ IDLE. So the helpful garage man set the idle screws to give 3% CO, ... because 'that's where old cars like this should be' ... IHO ... (well, we all know on here by now that an 89SE is designed to idle at <1% CO!!!)

On the subject of idle jet holders (idle air correction) I have gained some useful practical experience tuning the Clan's DHLA's over the years. I have a good range of fuel jets, emulsion tubes, jet holders, and chokes to play with. I've tried many combos of jets, holders, emulsion tubes and chokes, measured against on-the-road, real world, AFR readings. To clarify a point, and in support of the chaps at Lotus who made the OE jet selection, the lean number 9 air corrector would have been selected for fine-tuning idle CO values at the idle set screw, without (during service) the risk of adding or subtracting too much fuel to the correctly-set progression circuit mixture.

The air correction holder allows fine-tuning (or otherwise) of the mixture range available at the idle set screw, as well as absolutely leaning or enrichening the mixture within the internal progression circuit.
So for the purpose of re-tuning off-idle progression (where the hesitation is noticed in your case), the corrected mixture (for the state of ignition) can be achieved by either fuel jet selection, or indeed holder selection (assuming you keep the OE idle jet). But if you want to precisely home into, and sneak-up to, a target 0.5% CO at idle using the idle set screws, then the OE No9 (lean) holder combined with the OE idle jet, effectively gives you more available turns of the idle set screw as you sneak up to the low idle CO target value of 0.5%. If you set the progression overly rich either by a larger fuel jet or via smaller air corrector holes in the holder (richer holder), then the idle set screw sensitivity is coarsened, making it difficult to dial-in a low CO at idle. And therefore a small turn of the idle screw will add, or subtract, significant fuel to/from the off-idle progression.

That said, if the DHLA's have air leaks at the butterfly spindle (worn), or they've been rebuilt carelessly such that the butterfly plates aren't absolutely concentric to the barrel, or the butterfly plate mechanical synchrony between carbs is off (often overlooked by using ONLY vacuum meters to balance carbs!), or there's an ignition fault, or there's a vacuum leak within the engine management system, or the engine's worn (less vacuum, low cylinder pressures), then making the progression circuit mixture richer may well indeed reduce the off idle hesitation. But it will also make achieving a low CO at idle (without misfire) more difficult to set, and moreover, a small miss-turn of the idle screw, either way, could upset the progression mixture, frustrating the process, and the goal.

Sorry for long post, II can't help it, I have poor social skills ...

[MetBlue]

Called into Northampton Motorsport earlier today.
Patience is the word if I wanted to get it set on their rolling road. They are fully booked until end June.

I've taken the Idle air correctors out of my 907 elite and they are 2 grades richer. But after 35 years just sitting dry, the O ring was square in section and brittle. NMS were good enough to give me 4 new o rings to sort that little issue out.

Played again with balancing using Vacuum Gauges yesterday. I don't think dial gauges are sensitive enough really. Could just detect change in vac, but not easy to see. Finally lead to idle mixture screws now being on average 5 turns out. - still 100% jetting as Lotus spec'd. Seriously thinking about buying the Carbtune manometer from Eurocarb before fitting the slightly richer idle air correctors.

Despite not yet quite being there, cars running better than ever on these jets. Much more low down response and less black soot gathering in the tail pipe. Sure the mpg is already better to. Wondering whether a dose of Redex might be a good idea after 5000 miles of running too rich. Thoughts anyone ?

Tony