Moskvich 427
Ed finds a stupidly simple solution to a long-running issue
Irebuilt the Moskvich’s brakes from stem to stern last year. This was unexpectedly frustrating, as the old pipe flares were very reluctant to seal against the new wheel cylinders. I dealt with it, but braking was a heartin-mouth experience for almost 500 miles until the NOS shoes bedded in. The whole, protracted episode was not my idea of a nice hobby. Why all the self-flagellation, when I could just buy a nice, new Kia with a seven-year warranty?
With the car finally stopping satisfactorily, I decided it was about time it went satisfactorily, too. Early Seventies road tests complained about carburation flat spots and endemic pinking. I could tick both those boxes and add running-on to the list as well. All had persisted through 20 years’ and 45,000 miles’ worth of on/off investigations.
I’ve always reckoned it should be possible to make most cars function perfectly… if only you can get to the bottom of what’s ailing them. But I’d run out of ideas a long time ago. So I made a fresh start with an open mind...
After a bit of fieldtesting I concluded the carburettor and distributor were absolutely perfect and should be excluded from my enquiries. I did amass some further clues, though. First, altering the ignition timing made no difference to the general malaise. Second, the car ran better with the float level 3-4mm higher than specified. Third, with the choke held firmly shut and the throttles wide open (to simulate full-load running) the float level in the carburettor’s sight glass would drop to half its proper height. This tied in, I thought, with a lethargy that crept in halfway up steep-ish hills and pointed to the fuel supply system.
I removed the fuel pump (already graced with a new diaphragm) and replaced its valves.
The originals were hard Textolite discs. I changed them for moulded ones with a rubber seal. I set the delivery pressure to 0.36 Bar – the maximum prescribed by the manual – by adjusting the gasket thickness between pump and cylinder head.
Thanks to the new valves, and to a lovely, rubber-tipped carburettor float valve picked up in an amazing 364-day, 24-hour car parts shop
in Moscow, the test gauge showed it now maintained fuel pressure indefinitely with the engine stopped. A fairly useless attribute, but pretty impressive, nonetheless. I also examined the tank, the tank pick-up and the vented fuel cap (all good). The rubber hoses were fine.
What else was left to condemn, but the fuel feed pipe which runs under the car? I’d blown it out before – and it had never actually blocked. But it was a rather miserly 6mm outsidediameter, thick-wall copper pipe. An eight-foot length must present a considerable resistance to fluid flow, even before 50 years’ worth of silt build-up is considered. For £7 I bought five metres of 5mm inside-diameter, clear plastic fuel tubing from an ebay listing. This, I reckoned, would fit tightly over the 6mm tank pick-up outlet.
It arrived in record time and I immediately cable-tied it alongside the old pipe, temporarily. It went snugly on the tank pick-up and in the engine bay I fitted it to the 6mm end of a multisize fuel filter. I used this as an adaptor since the (repurposed Lada) fuel pump takes 8mm fuel hose. I used the sawn-off end of an old filter as an adaptor for the 8mm pump outlet, where more new pipe fed the 6mm carburettor stub.
Spring finish
And the result? Miraculous. It no longer requires ‘technique’ to make smooth progress, and doesn’t pink or run on. It’s much faster, sprints up hills and now whirrs enthusiastically up to 30mph in first gear. I’d spent 20 years scratching my head over this. As a result, I’d become fairly expert on the microscopic details of carburation and ignition advance. Indeed, I’d landed a longrunning engagement with this magazine on the back of careful study of such technical minutiae. And the root of the problem in the end was just a simple length of copper pipe.
I’m not sure what the moral of this story is. I suppose it’s that life with a new Kia would be much simpler… yet also a lot less interesting.
‘The fuel pipe under the car was the one thing left to condemn’