Dundonian JPS

[innesw]

Update - sorry it has been a while, currently trying to find a job for next year after I graduate in June.

Exhaust saga now over , sent the manifold back to TTR they welded the missing weld, sent it back to me very quickly. I fitted it the other day, now I have a fully sealed lovely sounding and functional exhaust.

Spent the weekend restoring my 5 speed gear shift. Here are the photo's of my work.
I used "plasti-kote enamel" chrome spray paint for the chrome in the end, very happy with it and would say it looks better than in the photo's. (Photo number 2 is a brush on chrome paint = RUBBISH). Did the black infill with some smooth Hammerite and a sewing needle.

Just needs a couple more coats of Clear varnish.

To do list -

- Head lamp pods do not rise and lower fully, I have put new springs in and each time they are operated they require the touch of a finger to aid them to move fully, grease pivot bolts?

- Need to adjust fast idle (engine builders said idle would be fast after it was set-up on the brake) but I am nervous about adjusting the carbs, current idle is 1700 rpm with idle screw backed out fully (the only adjustment I am confident to change, blue arrow) Help?!

That will keep me busy for the moment.

Innes

[innesw]

Once I have the engine warmed up and running smoothly should I be adjusting the idle mixture screws for each cylinder?

Innes

[lotusfan]

Innes

I presume that your engine builder set the slow running mixture screws and balanced the airflows when they ran the engine?

The screw that you indicate is indeed the slow running speed screw and turning anti clockwise should slow the engine down. Does the throttle lever follow the screw or when the screw is fully back can you lift the throttle lever and slow the engine down?

I am wondering if your return spring is not applying enough pressure, I can see that it is there but the bracket off the back of the aircleaners is not the usual one and may be positioned in slightly the wrong location.

There does not appear to be a throttle cable connected in your picture but presumably you have temporarily removed it.

[types26/36]

I think you will probably have to balance the air flow through the carbs so they are both ?sucking? the same, it is done by adjusting the screw I have marked while listening to the suction through a pipe or using a balancing meter.
When the carbs were set up I presume they would have been on another engine so would have been correct for that engine but when the carbs are removed and fitted to a different engine it is unlikely they will be in the same position (relative to each other) as they are flexible mounted.
This will effect the air flow through each carb and I think they will need to be re-balanced, only when they are balanced to each other can you now set the idle speed by the idle screw which controls both carbs.
(This is assuming the carbs were removed and installed after the engine build)

[Robbie693]

You can also balance the front and rear carbs by pulling the plug leads - 1&2 then 3&4 obviously - and listening for a difference in idle between the two. As Brian says, if they are unbalanced this will affect the idle speed

Robbie

[innesw]

Thanks for the replies so far.

Carbs were set up on my engine on a brake (aka dyno) and only removed when body was fitted to the chassis then added back on to the motor.

I made the new throttle cable/spring bracket to the same dimensions as the original back plate (couldn't bear cut up the original) spring is pushing the throttle lever fully home, I can't "lift" the throttle any further to reduce the RPMs.

Adjusted the RED screw as mentioned by Type26/36 using robbies spark plug method and this balancing made the engine run smoother and reduced the revs down to 1500 but still high.

Just used a feeler gauge to check if there is a gap between the fully backed off idle speed screw and the throttle lever and there is a gap. Having a look at the throttle lever I noticed a little clyinder at the lever pivot it contacting the carb body (see picture) stopping the lever travelling any further, is this normal?

Looking at the overhead carb picture I see there is a identical little cylinder on the other carb lever opposite, are these just stops to prevent the throttle levers moving in the other direction?

(might just go talk with the engine builders which are 200m away).

Innes

[innesw]

Sorry I have been very quiet the last couple of weeks, I have just finished my university finals!

Today I was doing some testing of the car on the very quiet side street I live on and all was going so well until...
(It's a rather entertaining story, quite how much I'm going to divulge on the internet I haven't decided yet, just not quite the same as a chat down the pub)

I am fine and the Lotus is completely unharmed in any form.
I now know the brakes work very well, in fact I think I have them working perfectly!
I now know the electric facet fuel pump a friend gave me dosen't work.... (any more at least).

4 hrs later the car is back in the garage, although I might not make it to the MOT tomorrow as planned unfortunately.
Phoned up the MOT garage, they are very relaxed and say they can take the car when ever I am ready...

What was it they say about Lotus' again... ?

p.s. previous carburettor idle issue is now fixed, wasn't rotating freely back to idle.

Innes

[innesw]

Now on the road finally!

Passed it's MOT on Monday and I have since done about 100 miles so far, very exciting for me as before this I had never driven a Lotus let alone a +2 on the road. (still have about 200-300 "running-in" miles to do).

The drive up to the MOT station in Dundee was rather nervous after a previous breakdown due my electric fuel pump failing.

Popped by Agra yesterday and Ian who does most of the twincam engines gave mine a wee tune to get it running perfectly after a set of new 'plugs (as the 1st set were a bit coaked up after I had the engine idling to set up the exhaust and check for leaks(. It was initally set-up on the dyno with just trumpets on the carbs and now as air filtres so it was running a little rich.

Took it for a long run today and it's running great!

Already have a list as long as my arm of adjustments and tweaks I want to make.

Here's some pictures before it rained...

Innes

[Bombay Racing Green]

Well done Innes! Looks like a great job. I'll hopefully have mine on the road soon. Just need to bleed the brakes.

Good luck for the future,

Pete

[ken ob]

Well done. The car looks great.

Ken

[jono]

Fantastic job, well done - wish I hadn't sold my JPS now

...your car will be perfect, ...just as soon as you paint the flanges black on the bottom of the sills

Jon

[Pete Shepherd]

Well done Innes, I'm sure it will be worth all the hard work.

Pete

[innesw]

Well the front page is a bit of a shock! (makes me a bit embarrassed about the some of the stupid question I have written but oh well!)
I now have 300+ and growing miles on the clock.

Returned safely from a 220 mile trip up to Aberdeen and back for the Lotus day at Grampian transport museum with both Club Lotus NE Scotland and LEGS (Lotus Enthusiast Group Scotland).

A fun weekend, photo's to follow... Possibly a video too.

Innes

[billwill]

I think you will probably have to balance the air flow through the carbs so they are both ?sucking? the same, it is done by adjusting the screw I have marked while listening to the suction through a pipe or using a balancing meter.
When the carbs were set up I presume they would have been on another engine so would have been correct for that engine but when the carbs are removed and fitted to a different engine it is unlikely they will be in the same position (relative to each other) as they are flexible mounted.
This will effect the air flow through each carb and I think they will need to be re-balanced, only when they are balanced to each other can you now set the idle speed by the idle screw which controls both carbs.
(This is assuming the carbs were removed and installed after the engine build)

For years I tried setting the balance between the two carbs by various ad-hoc methods such as listening to the suction noise via an air tube and by pulling plug leads, but a month or so ago I bought the proper measuring tool and setting the balance correctly is now a mere 15 minute job.



See this link for how I did it.

lotus-elan-f19/getting-ogu-roadworthy-again-t26101-105.html#p191111


If the idle speed screw (the one you indicated) does not go slow enough, First check the return spring as mentioned above and check that your throttle cable is 'just' slack and not holding the throttle slightly open. Check that the 'choke' (cold start mechanism) is fully closed.

If those don't fix it there is something wrong; the lever that the idle screw bears onto is the wrong one or your throttle discs are not closing completely in the throat.



If they are Dellortos, someone may have opened the idle bypass screws, incorrectly. I believe that in each carb one should be fully closed and the other my be open a tiny bit to balan the suction of the two throats. The meter shown above is ideal for adjusting them.


<later>
Ah having read the rest of the topic, I see that you fixed that problem and all is working well. Pretty much in the same state as me, I've done about 290 miles running in now and am doing short bursts to 70+ Mph

[innesw]

No worries Bill thanks for the info.

Here's a photo from the weekend, think it shows I definitely need to fit some sill trims, the nose moustache trim and paint the sill bolts black!

Photo credit - Gordon Masson courtesy of LEGS (Lotus Enthusiasts Group Scotland).

Innes