Bradford CC Lorry (The Tramp)

[Forumadmin]

I would check mixture, if it is not ignition, preferably with a Gunson colour tune or Gas analyser but failing that the colour of the plugs.

[AlanBartlett]

I'll have another look at the timing, pretty happy with all the ignition components, Coil, Points, Rotor arm and condenser are all new. I've recently replaced the coil which cured the intermittent starting issue a while ago. (It was previously running with the long saloons Spare, I remember now why it was the spare one!) Now its on the button. It is just trying to solve this rather hesitant carburettor problem.

[BarryCambs]

I'll be interested to see what you find in the end as this is exactly the same problem I struggled with. It's a right pain trying to find different jets to try and it did occur to me it might be an idea if JCS or someone put together a 'Jet Library' that could be borrowed when people are trying to set things up. I have a few odd ones now so it could be I can help if I have the size you want to try.

I think my carb could have been from a different car as only one of the 5 jets corresponded to the JCC technical notes, which did day the same as the original Zenith spec I managed to find here. http://www.stationary-engine.co.uk/Zeni ... kapps6.htm Unfortunately, it doesn't seem to have any postwar data

[Forumadmin]

I bought a set of drills that I use to test the size of the jets. Note that jets do wear, so often a worn smaller numbered jet might do the job if you cannot obtain new.
Take care of course as the steel drills might upset the brass jet.
viewtopic.php?f=2&t=3337&p=19814&hilit=Jets#p19814

[k. rogers]

Are you sure it's not just running a bit rich, hence, the ok running at speed then getting choked up at idle - what do the plugs look like?

[Forumadmin]

Ken, that was my thought as well. Many causes of rich running, usually the float chamber, but it can be worn jets. Hence my advice to check with gauges (drills). If you have known good jets then all the better. Can also be a bent or distorted or worn idle metering valve screw.

[AlanBartlett]

Now then I think progress has been made. Timing & Mixture

I first rechecked the timing, it was about an 1inch after tdc. Reset that the dizzy back to TDC, ran the engine until warm. Now revving and running the engine, it was then popping back through the carb, struggling to pick up. Removed the plug, black and sooty (Too rich.) Backed off the mixture screw less than a quarter of a turn, ran it again. No popping back, responsive and no sign of lagging or flat spotting. Took it on a short test run, testing out on junctions pulling away and not even a hint of spluttering. Will give it a longer run over the week to see again, but fingers crossed. Though not entirely sure how the timing got to be so retarded, though I think I was fiddling with it at some point over Christmas to bring it down idle to a nice and slow tick over. (As Ken will know how far past the timing was on the Saloon a while back!) If it isn't broken don't fix it! Lesson learned! Again!

[AlanBartlett]

Oil pressure:

What should be the ideal oil pressure gauge reading on a CC? Currently reading around 50 when first starting up and cold on the gauge dropping down to between 40 and 50 when out and the road when warm. Is this too much or just right? Being used to the pre war where it just stays around 30 all day long. I am wondering if this is too high, as after a few longer runs, an oil leak has developed from the oil pump (Again!) So perhaps it could be too high forcing out. Or just gasket failure. Any ideas?

[StevenGray]

Alan
According to the technical info sheets oil pressure should be 35-40 psi under normal conditions, this I would expect to mean the engine upto normal running temperature. The CC that we had in then family used to run at a rock solid 30 psi without any issues.

[AlanBartlett]

Following my recent query post about the high oil pressure, now is a change to low oil pressure.
After a run back from the beach on Monday, a glance at the gauge considerably lower than my usual 50psi, dropping down to about 30 and hovering above 0 at a warm idle. I have tried a second gauge with the same results.
I've drained the oil, checked the oil ways, all the oil is clean, clear and no sign of anything horrible in the filters, with it dropping once warm, it is a worry. It is escaping somewhere. And rather bad timing when hoping to run up to Buxton, but by the sounds of above its not going to end well!
Anything else I can test or check before rolling up my sleeves and turning the air.

Alan

[David Kemp]

Check the oil pressure relief valve, if worn , sticky or grunge has collected it may play up.
Unfortunately I can't recall if it can be checked without pulling the car 1/2 apart.

[Tony Fearn]

Have a look at pages 11 and 12 of the Bradford notes below.
http://jowett.org/jowettnet/dt/tech/jti/brad.pdf
Also if the PRV is similar to the pre-wars, has the plunger spring broken, or as David says is the plunger stuck open with goo/grunge.? (I don't have a drawing of the Bradford PRV.)
Tony.

[Forumadmin]

Or this bulletin. or elsewhere in the Bradford Technical Library.

The link kindly provided by Tony (and others in JowettTalk) may well break soon unless changed as all the stuff in the old jowettnet site on Jowett.org has moved into Jowett Talk. The JCC Service notes referred to are now here.

[k. rogers]

Hi Alan, Sorry this has developed so close to the annual! If the oil is already out the car I would suggest taking the PRV out and giving it a strip down and clean so you can inspect the piston and spring. Can't see it's much else as you have no other symptoms and your engine sounded superb when I heard it!

[AlanBartlett]

The Pressure Relieve Valve is on the drivers side of the block, below the timing chain adjuster. It is a Large Nyloc nut, with a threaded bar and square end and a deep recess in the bar for the spring to locate. I've had this off, to clean out the oil ways, I can't see any obvious wear in the piston. Maybe its where it sits in the block, or perhaps a weak spring. Though that wouldn't explain why it is losing it when warm. With the spark plugs out, to ease the starter, you can see the oil gushing out from oil pressure valve hole, which I believe to be a straight flow directly from the pump.

Looking at the pdf that Tony put up, possibly an air leak on one of the joints of the filter?

Something to have a look at.