Problem encountered when removing choke assembly

[zak_62]

Hi~
I am in the progress of cleaning up my carb. I was trying to start from the choke assembly. However, after I removed the choke spring and lever, I ran into a plug with a groove and an axle protruding from the center. How do I remove this plug? Is this a screw in or a plug in? Would I need any special tool?
Thanks.

[lotusguy]

zak_62 said:

Hi~ I am in the progress of cleaning up my carb. I was trying to start from the choke assembly. However, after I removed the choke spring and lever, I ran into a plug with a groove and an axle protruding from the center. How do I remove this plug? Is this a screw in or a plug in? Would I need any special tool? Thanks.

Zak,

The 'plug' you refer to is actually the choke. The groove and axel are what allow it to move up/down (open/closed).

From memory, it is secured under a brass hex cap. But, there's little reason to remove it, just shoot a little carb cleaner into it and then blow it dry.

So far as your floats are concerned, they are set by holding them perpendicular to the ground with their actuator arm just contacting the needle valve. In this position, and allowing for the thickness of the carb top gasket, you want a gap between the float and the carb top of 14-14.5mm. This is best measured by setting a vernier caliper at 14.5mm and locking it. Then slide it along the carb top while watching the float for any movement. When properly set, you should get the very slightest of movement of the float as the caliper passes beneath it.

If off, slightly bend each float arm until the proper gap is achieved. Remember, there are two floats/carb and each must be set to a gap of 14-14.5mm. Happy Motoring! ...Jim'85TE

[zak_62]

Thanks Jim!
Also, the oil pressure gauge pipe is sheared at the union. The previous owner replace the take-off on the engine block with a solid bolt to block off the oil. I want to fix the pressure gauge, could you tell me how is the oil pressure pipe routed to the back of the dash? What do I need to remove to re-place the oil pressure pipe? Would you recommend an electrical pressure gauge over the mechanical gauge?
Thanks.

[lotusguy]

zak_62 said:

Thanks Jim! Also, the oil pressure gauge pipe is sheared at the union. The previous owner replace the take-off on the engine block with a solid bolt to block off the oil. I want to fix the pressure gauge, could you tell me how is the oil pressure pipe routed to the back of the dash? What do I need to remove to re-place the oil pressure pipe? Would you recommend an electrical pressure gauge over the mechanical gauge? Thanks.

Zak,

The electrical gauge offers the advantage of not having to route an oil pipe through the cockpit to the dash, but you will need to route a power supply to the sender. Also, matching the gauge face will be difficult.

If sticking with the mechanical gauge, it uses a single nylon tube which routes through the firewall, under the armrest and through the center console to the dash. It may be difficult to find a single long piece of tubing (maybe 16'-17'), but you do not want a joint in it because joints can leak and that could be disastrous. Happy Motoring! ...Jim'85TE

[DrieStone]

lotusguy said:

If sticking with the mechanical gauge, it uses a single nylon tube which routes through the firewall, under the armrest and through the center console to the dash.

That's what that is! I saw it recently and wondered why there was oil in one of my vacuum lines.

[zak_62]

What's the face diameter for our oil gauge? 46mm?
Routing a power supply to the sender shouldn't be too difficult as we have a lot of room to work on at the back. But matching a good looking gauge is very difficult as most of the modern name brand gauges are too flashy for me~

[lotusguy]

DrieStone said:

That's what that is! I saw it recently and wondered why there was oil in one of my vacuum lines.

Hi,

Yep... it's the supply line to the oil pressure gauge. Take great care when working around it because you do not want it to crack, split or otherwise leak.

I have a friend w/ an '83 who's line came loose at the gauge. He noticed it instantly as the hot oil shot right on his leg.

Another friend bought a '78 S2 that had a minor engine fire in it's past life. He hasn't truly sorted the car yet and was noticing an oil spot every time he parked it. At first, we thought it might be an A/C leak as the A/C was inoperative when he bought the car, but as the oil continued, we started to suspect the oil pressure line. On deeper investigation, we found it was indeed the oil line which had been spliced (due to the fire most likely) using a brass compression fitting (great for pipe, lousy for plastic tubing). Anyway, it had been leaking for possibly years, slow, steady. By the time it became visible, it had thoroughly saturated the insulation and carpeting. He and Calvin spent an entire day ripping the carpet out and wet-vacing the interior (I was there, but fortunately was working on another's Jensen Healey at the time), a real mess and I doubt he'll ever get the oil smell out of the car. Moral of the story - Don't ever put a joint in the oil pressure line. Happy Motoring! ...Jim'85TE

[Esprit2]

zak_62 said:

Also, the oil pressure gauge pipe is sheared at the union. The previous owner replace the take-off on the engine block with a solid bolt to block off the oil. I want to fix the pressure gauge, could you tell me how is the oil pressure pipe routed to the back of the dash? What do I need to remove to re-place the oil pressure pipe? Would you recommend an electrical pressure gauge over the mechanical gauge? Thanks.

Zak,

The pipe is Nylon tubing and is commonly used for oil pressure gauges, replacing the brass capillary tube that was common in vintage applications. The Nylon tube is totally up to the task of oil pressure gauge feed line, as long as it's routed in a way that doesn't bend it sharply/ kink it or subjected to outside forces that would tend to pull it sideways at the compression fittings.

In the US, the Nylon tube is used as some sort of sensing line for the controls in residential water heaters, so it's sold by the foot off bulk reels at hardware stores along with the appropriate brass fittings. Better auto parts stores that sell gauges and installation supplies will also have it in stock... usually smaller cut-lengths in a polybag. Your favorite Lotus parts supplier can provide you with a new piece of Nylon Tubing to replace yours.

Petroleum products will attack most plastics over time, Nylon included. But, Nylon is pretty resistant and will last many years before it's significantly embrittled. However, as long as you have to deal with this problem any way, and the tubing is so cheap, it would be wise to simply install a virgin pipe.

The Nylon tubing does work with compression fittings just fine, and their use is not a flawed method. If the tubing is otherwise sound and was damaged by some outside influence, then a splice is normal practice. Or, in your case where the tube broke right at the engine's oil gallery cover, just replace the union, cut the end of the tube clean and square, and re-install it.

Brass compression fittings are available in a wide variety of shapes including double-ended splices and straight unions like the one Lotus used to attach the tube to the engine's oil gallery cover. When I replaced mine, I used a 90 degree elbow union rotated to direct the pipe forward right off the engine. That eliminates the need for the pipe to come off the engine laterally and then make the bend forward toward the firewall.

The typical failure mode (especially in the Esprit)is at the transition line between the rigid brass fitting and the Nylon tube. A side load in a long, continuous run will just cause a gentle bend... no problem. But a side load right at the junction with a rigid fitting will invariably cause a kink, followed shortly by a break.

In the Esprit, the tube needs to go forward to the gauge. But Lotus used a straight union at the engine that points the tube to the right side of the engine bay. So the tube does a looping turn toward the firewall and cabin. That routes it where it's in the way of most access to engine components under the intake... oil filter, distributor, vacuum lines & solenoid valves, etc. Somewhere along the way, someone usually finds the tube blocking access and moves it out of the way. Unfortunately, the tube doesn't move very far before it kinks at the brass union. Once it's kinked, a fracture isn't far behind.

Replacing the straight union with a 90 degree elbow, and pointing the bent leg forward, allows the tube to be routed where it will be in the way less. It also points it in a direction in which the most common tugs will put it in tension rather than bending at the union.

If a splice is installed in the middle of a long run, care must be exercised to ensure it's either in a place where the tube is not likely to get bent sharply (not usually likely, since it has already broken there you're fixing it) or where it can be supported by attaching it to a frame tube or similar structure.

Put a splice in a congested place like the rat's nest inside the instrument binnacle and the tube is likely to get bent enough to kink at the fitting. Or if the fitting is located at a rigid spot like the passage through the firewall where the fitting can't move freely, then any side-pull on the tubing will result in a kink and fracture.

Compression fittings are normal hardware for Nylon tubing. Just be thoughtful about installation. You can do better than Lotus did with the straight union at the engine's oil gallery cover.


Mechanical gauges are simple, reliable and accurate. Their common problem area is plumbing leaks. But with a little care, the plumbing can be routed and strain-relieved in such a way as to eliminate those issues.

Electric gauges, their senders, non-linear response, voltage stabilizers, system supply voltage variations... all bring more potential problems to the table. Electric gauges are used for convenience (easier to run wires) or where integration into a "system" is desired. But where simple reliability is required, mechanical gauges are normally the solution to electrical gremlins, not the other way around.

Just my humble opinion, but I would caution against converting to an electric oil pressure gauge. You have one broken pipe that broke where it's common for them to break on an Esprit. Fix it, use a 90 degree elbow, and route the tube to keep it out of the way. If you completely replace the tube, then consider installing a 45 or 90 degree elbow in the back of the gauge as well. That will minimize the last tight bend going into the gauge.

Regards,
Tim Engel
Lotus Owners Oftha North
Minnesota, USA

[f1karting]

I personally dont like the idea of using any nylon line that delivers oil (or fuel as it is on some english cars!!) The nylon pipe in the Esprit is well buried, difficult to review and assess, fairly easy to damage, and therefore is at risk of failure. The mess and inconvenience that a broken oil line could cause, not to mention the POOR fire resistance it carries, is just not worth it.

I have opted for steel brake pipe, using double flared ends, with oil, pressure, and fire-rated 1/8 ID rubber hose and suitable fittings.

I run/mount the pipe along the chassis or bulkheads. At flex points I install rubber hose connection pieces over the double flares on the pipe and secure the hose using Oetiker ear clamps.

Brake piping is easy to bend, route and mount, and terminal end fittings/ unions are easy to adapt.

The steel piping and rated hose has a much higher fire resistance rating, which we all care about, and as a bonus, the pipe can be polished/ plated or whatever you like. You no longer have to tread lightly around your oil guage lines.

A slight downside is the "start-up" response time of the guage because the interior volume is a bit larger than the nylon pipe.

Jan 83ET


>> Edited by f1karting on Wednesday 4th August 02:35

[lotusguy]

Esprit2 said:

Zak, ... Regards, Tim Engel Lotus Owners Oftha North Minnesota, USA