Hi All.

The 907 doesn't run quite as smooth as I'd like so as the 45's haven't run in anger for several years (read decades)
I wondered if they might benefit from a strip down. I have ordered a gasket/seal kit (£49) and the plan is once
reassembled to put the car on a rolling road, which is just down the road from me.

This will also be an opportunity to fit points and set up the distributor, timing, etc, as you wouldn't believe where it sits.



What do you think? Money well spent, or money down the drain?


I did pop the plugs for a peek at the colour and they didn't look too bad. (see pic)


Cheers
Paul G


Description


Edit to add:-

I'll be happy to recommend if he does a good job.



[Edited on 24/5/15 by 907]

Carbs can always run out of balance so money well spent I'd say, I had to tune time at least once year,especially after some hard driving,

Who do you use for the rolling road then?

Thanks
Sean

investing in new seals is , imo, wasted money.

i´m driving cars, fitted with double weber/ dellorto / solex, since around 25 years.

i have never needed any gaskets, nor new float needle valves.

the most important thing with those carbs is : owning two of those




and regulary use them

also worn points or weak igntion leads, dizzy cap&rotor may cause the problem.

you should be able to change this dizzy from points to a electronic device from accuspark, ignitor or hotspark.

we are talking about a 907 lotus twincam engine (jensen healey, lotus eclat7elite)?

the carbs fitted are the original ones and still correctly and equaly jetted?

have you checked valve clerances already?

[Edited on 25/5/15 by alfas]

Hi Alfas.

Firstly the history of the engine.

The engine is a Type 907, July '76 taken from an Eclat.
Mid 90's it was taken from the original Lotus and fitted to a hot hatch type track/race car by a group of three blokes.
They drew straws on it's first race day and the winner took the car out on track (Snetterton) for a warm up lap and rolled it.
The wreck was trailered home, useful parts removed and the shell scrapped. Engine wrapped in an oily blanket and left in
the corner of the workshop for ten years. Jets in the carbs may or may not have been changed.

I came along to do some work for one of the three, and happened to mention I was going to scratch build a car.
He said he would love to see his engine running again and sold it to me. This was ten years ago.


I removed the head to free off an exhaust valve. New gasket. Did the valve clearances.
New dizzy cap, points, condenser, rotor arm (not rev limit type), leads & plugs.
Re-fitted Dellorto's without stripping & cleaning.
I assume that after all this time there is solidified sludge inside ???
Set plugs to 25, points to 15, (as a starting point) set timing to setting in the (Lotus) workshop manual I have, but this is a
setting for 4 star fuel I assume.

I have been told that the O rings inside the carbs deteriorate, harden, crack in time, and will need replacing.
( I have already ordered and payed for the refurb kits. )


Don't know what your photo is of, but I assume it is a type of vacuum gauge balance device.
Have you a link or name that I can Google please ?


Thanks for your reply.
Paul G

Hi Paul

I have one of these gauges if you want to borrow it you are more than welcome,

Sean

Or if you want to splash out a few quid a Morgan Carbtune. Sort of quad manometer, so you can see the pull from each carb all at the same time.
I bought one when I had dellortos, made balancing really quick and very accurate. The single ones work, but when you adjust one choke it also has an effect on the others.
Just used mine on my jenveys, again, really easy to use.

Would also add get a few cans of carb cleaner, there are plenty of very small drillings that can cause issues if blocked. Avoid acid cleaners. If you can access an ultrasonic tank, that would be handy, loosen up crud and stuff.

[Edited on 26/5/15 by cliftyhanger]

...now we have more info:

ok...if the carbs have sit such a long time there would be a lot of cristaline deposit from the fuel, which should effect the function.
i would open them and clean the chambers, remove the jets and blow the holes with compressed air.

brake cleaner cans are cheaper and will do the job too.

also a weak point on dellortos is the acceleration-pump. after storage the passages / holes are often blocked.

you should be able to remove the pump-covers and membranes on the bottom of the carb without damaging them, give them a clean and refit them.

if done the cleaning job carefully you should not need any parts...anyway: as you already ordered a gasket set, use it.


o-rings? hmmm dont know any important ones on those carbs....the older ones had some fitted unerneath the mixture screws...but as i remember not on those carbs.

the picture shows a carb balancing tool.

you should have at least two of them..one for the front carb, one for the rear.. quick and easy job for balancing...if such carbs are out of balance idling will never be smooth.

http://www.ebay.co.uk/itm/Dellorto-Weber-synchrometer-carb-balancer-tool-made-in-Germany-not-China-/290682796527?pt=LH_DefaultDomain_3&hash=item43 ae0b79ef

or search for carb balancer or synchrometer

[Edited on 26/5/15 by alfas]

Before going further, a pic of what I ordered. (arrives tomorrow/day after)

Are those the pump covers you mention? (The bits in middle of pic)

Cheers
Paul G


Carb refurb

[Edited on 26/5/15 by 907]

the pumps are the red ones with the metal centre...they are in the same time gasket as well as pump-membrane

I've been puzzling.


Alfas, you recommend a flow meter ( ? ) that measures air speed ( ? ) going into the carb, before the throttle butterfly.


Cliftyhanger, you recommend a quad vacuum gauge that measures vacuum after the throttle butterfly.



As a numpty can I ask yourselves, or indeed anyone, if there's a difference between the two methods?

The reason for asking is that I have a set of gauges that were left in my garage years ago, and when I asked him several
months later he said "Keep them. I don't have a bike anymore."

Cheers,
Paul G



Description

Those should be fine.
I really think they are more accurate and far easier to use once all plugged in. Somewhere (mind is fading as I get older) there should be a blank plug on each throttle, and a mig tip can be screwed in. I think 6mm, but might be 5? Anyway, connect up and it measures the vacuum so easily and without disturbing the airflow. Sticking the individual gauge in each opening must affect the airflow?

So yes, I would be using the ones you have! May be worth checking the calibration. Just swap the connections around once you have balanced the carbs and make sure they still read them balanced.

quote:

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Originally posted by cliftyhanger
Those should be fine.
I really think they are more accurate and far easier to use once all plugged in. Somewhere (mind is fading as I get older) there should be a blank plug on each throttle, and a mig tip can be screwed in. I think 6mm, but might be 5? Anyway, connect up and it measures the vacuum so easily and without disturbing the airflow. Sticking the individual gauge in each opening must affect the airflow?

So yes, I would be using the ones you have! May be worth checking the calibration. Just swap the connections around once you have balanced the carbs and make sure they still read them balanced.

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Ah, you need the hobby mig sized tips then!

quote:

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Originally posted by cliftyhanger
Ah, you need the hobby mig sized tips then!

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quote:

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Originally posted by INDY BIRD
Hi Paul

I have one of these gauges if you want to borrow it you are more than welcome,

Sean

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Thanks for the offers, but I think that balancing is my secondary task.

A clean and blow through the various jets & petrol/air ways is the first job, then new diagrams & seals.

The kit arrived today.



The engine seems to run rough, maybe on three cylinders, but if I blip the throttle repeatedly it picks up and runs
smooth for a few moments.
I assume this is the extra fuel squirted in by the accelerator pumps richening the mixture so I deduce that one or more
jets are blocked or partially blocked.


Half a dozen m5 mig tips will only cost a couple of quid so I'll order some anyway.

Thanks everyone for the advice. It's been a big help.


Cheers
Paul G

If you want to borrow the special gauge thingy for checking the accelerator pump I have one (somewhere).....

I used spray carb cleaner on my old Weber down-draught carb - evil stuff, not to be used in an enclosed space!

Unless you want to talk to the nice little flying pink elephants, that is...

quote:

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Originally posted by cliftyhanger
If you want to borrow the special gauge thingy for checking the accelerator pump I have one (somewhere).....

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quote:

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Originally posted by David Jenkins
I used spray carb cleaner on my old Weber down-draught carb - evil stuff, not to be used in an enclosed space!

Unless you want to talk to the nice little flying pink elephants, that is...

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quote:

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Originally posted by 907

quote:

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Originally posted by cliftyhanger
If you want to borrow the special gauge thingy for checking the accelerator pump I have one (somewhere).....

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You have lost me on that one mate.
What does it check? I've not come across one before.

Paul G

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Hesitation before planting your right foot is nothing to do with the carbs.




It's called getting older……

Or as I prefer to think of it, more experienced.

Paul G

I hope I am growing old disgracefully

quote:

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Originally posted by 907

quote:

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Originally posted by David Jenkins
I used spray carb cleaner on my old Weber down-draught carb - evil stuff, not to be used in an enclosed space!

Unless you want to talk to the nice little flying pink elephants, that is...

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Did the pink elephants clean the inside or the outside of the carbs?
Mine are only 45mm. That's more like pink mouse size.

Paul G

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I will start a new thread.


Is Vaseline soluable in unleaded ?

quote:

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Originally posted by 907
I will start a new thread.


Is Vaseline soluable in unleaded ?

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in the past i used (for years) the pictured 4pcs vacuum gauges...and i thought...there is nothing better on the market.
each time i balanced the carbs i had to unscrew the blankings from the carb for connecting the gauges....some of the blanking screws fell down the enginebay...some got lost...followed by some swearwords....

than i saw a mate of mine dong the same job with the 2 carb balancers which you only need to hold onto the carb body. (due to having a conic rubber they often hold themselves)


much easier, much quicker, much cheaper

both methods are more or less "measuring" the vacuum created by the carbs.

important is getting both carbs balanced to each other...the rest (fiddling around with the mixtrue screws ) is done "by ear" and expirience.

I'm a bit unsure of myself here, but would I be right in thinking that to set all the four chokes to the same vacuum setting
is done by adjusting the butterfly linkages between the chokes so that at tick over they give the same reading, and therefore
are each open the same amount, be it only a tiny amount?


Would I also be right in thinking that at wide throttle openings imbalance of the linkages is of less importance ?


Is it at these wide throttle openings that the important equalities are that the jet sizes are the same, and the mixture screws
are set the same ?


Sorry if I haven't written that very well. Each time when I read it back to myself I seem to understand it less.
It's at times like this I wish I'd paid more attention to the english teacher at school, but there again we didn't have a
welding teacher and I seem to get by with that.


Cheers
Paul G

You mean you went to school? Technique sounds about right although it might be worth getting the emissions checked afterwards

quote:

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Originally posted by rusty nuts
You mean you went to school? Technique sounds about right although it might be worth getting the emissions checked afterwards

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