Volumex troubles

[Skufy]

My volumex engine troubles are starting to test my patience.

The details, low miles volumex engine (40k)which has never run right since I've had it. Has been left for several months resting in a replica chassis and is now difficult to start, misses on idle, misses on accelerating and will often fire back thru carb/valve, less so when choke flaps are closed. Plugs black and sootey.

Fuel supplied by a facet electric pump via a filter king pressure regulater. New head gasket, no visable signs of damage to old gasket. Ignition module checked out ok and Dizy cap and leads swapped from a working vx engine although when removing no.4 plug lead engine runs much better until lead completly off when it returns to it's sad old self. All other leads when removed cause engine to really miss fire and a drop in revs.

What can it be?

What carb is normally fitted to this engine and is there something similar on another engine?

By the end of the week if there is no improvement I will be looking for a complete and running twin cam engine, anyone have one? I will also have a volumex engine and box for sale, can be heard running...........

Thanks for any help,

Desperate skufy

[chrisc]

From the factory the volumex cars were fitted with weber 36 dca carbs.

Doesnt sound too bad whatever it is, have you checked the plug leads are in the correct order?

[rossocorsa]

sounds to me like idle jets bloked on dca if that is what is fitted typical vx problem

[rossocorsa]

you could fit a 40dcnf or a 45 dcoe both are improvements on the original carb have you posted your query on guy crofts forum good place for tc answers

[Andrew S]

You mustn't give up on this! The VX engine is a fine motor and your problems don't sound like the end of the world; you just need to be methodical about it. Guy Croft's site is excellent for help and advice; be warned however your post should be precise and concise! Your sooty plugs would be where I would start- from your symptoms the fuelling set up may be incorrect; your ignition timing is almost certainly out and your leads possibly suspect. Personally, I would leave it alone if it runs well enough to get you to a rolling road once your project is mobile. Then tell them all the problems, grab a coffee and let them sort it! If you want to do it yourself now- start with dismantling the carb and cleaning/rebuilding with a GENUINE Weber overhaul kit. Then get new plugs (double check they're the correct ones), new leads, etc etc. Set your ignition timing very carefully. Gradually work through it all methodically and you will get there! All these service items are not really expensive and will probably cure any problem. Good luck!

Andrew.

[Will]

The #4 plug issue sounds like it might be a cracked insulator- spark arcs along surface of crack until you get enough distance between the contact in the spark plug boot and the spark plug insulator, at which point it follows the electrode, until you completely remove boot, at which point it is no longer firing.


The sooty plugs could be, as the other guys mentioned, ignition timing, overenrichment, or poor atomization of fuel (IMO most likely) due to a cruddy carb/old fuel. The problem is that if you have poor atomization of fuel on a volumex, you are in trouble because the VX rotors compound the situation as they now centrifuge out liquid fuel to the blower case.

The first order of business would be a jet cleaning. I happen to have two excellent spare volumex carbs that could be swapped in, and you are free to borrow one but it would require a very hefty deposit and your shipping cost both ways. The former because the last time I sent a carb to the UK in good faith I got no acknowledgement of it ever getting received, not a dime for it, and the fellow I shipped it to (Steve Lyons) on this forum has not been on since just before I shipped the carb. Do try cleaning the carb first, it's likely the orifices are sludged up, particularly if sitting in a car with unstabilized fuel in it.

Good luck- have fingers crossed for you.
-Will

[chrisc]

I also have a spare VX carb which got replaced with an overhauled one as part of my HPE VX restoration. If you want to try a different carb let me know and ill see if we can get it sent out to you. Carb was only swapped out as I had a freshly overhauled one, the car was running just fine with it.

[Skufy]

Thanks for all the ideas. Chris, where are you in the country and if not too far from Gloucestershire I could call in at the week end?

Had a fiddle this afternoon, suspect carb is iffy, timimg is approx but the key is still no 4 and taking plug lead off slowly. Compression is like all other cylinders(140), valve clearances are ok at 30 and 45(from memory) swapped plug, closed gap slightly, swore.

I'm off to have a little bite to eat then will try the engine in the dark, will the sparks fly in a dark garage?.................................

[Skufy]

It was the rotor arm, looks can be decieving. bpr7 plugs have less fouling than the bpr6's that were in there.

[Pope1]

Glad you got it sorted and can now move on to the next phase. By the way, is 140 good, bad, or average for a compression test result on a VX?

[chrisc]

Well them being all close is the main thing :)

From memory I think my old VX was 155 except for cylinder #4 which was 140, picked up if you put a drop of oil in the cylinder before the test so I guess bad piston rings on that cylinder. That was a ~80k mile car which had definately been opened before sometime in its life although i cant remember why.

[Pope1]

Thanks Chris. I saw about 160 on all four last time I checked and a drop of oil in each cylinder didn't make any difference. I was pleased that they were the same but wasn't sure how good a reading that was.