On Bentley tuning, Sizaire axles and Lambda Head Gaskets

Posted on 22/05/2016 by Mark

First up Des has just added 1.9 litres to his 3 Litre Bentley all done very nicely by Up the Creek Workshop the car is now quite a weapon, however it was running a bit rich. Most of us would at this point start randomly stuffing around with different needles for the SUs, this is where Des’s engineering background makes this a bit more like science.

If you look at Des’s photo on the left you will see the laptop is connected to a camera looking into the inlet of the SU, to the right the 10.3 is my air/fuel gauge temporally lashed to the dash and the gauge above the red lamp is the tacho. The readings in the pic were just in neutral however the next day it was repeated on a long hill, so with some measured guestimation new needles were ordered and it’s now running around 13:1 throughout the rev range, so all those gadgets have at last come in useful.

The Sizaire Naudin has now been off the road for 18 months waiting for a new front axle to be cast after the old one was found to be cracked. Alas after receiving the new one (and a spare luckily) it was found to have a warped spring pedestal so back it goes, hopefully the spare can be used as I don’t fancy waiting another 18 months.

The Lambda has been up to UTCW for some fettling before its holiday to Europe, as with so many jobs the list started small with reset the rear springs, check the brakes and the front wheel bearings. The springs were reset but the rear hubs were shot as were the rear wheel bearings and seals but the brakes and the front wheel bearings were fine so sort of equalled out. But there was a niggling problem of running hot at speed and this would need the head removed. Now any Lambda owner will tell you if you do not have a blown head gasket leave it alone, removing the head usually exposes the sorry state of an aluminium block in its final stages of decay but I just had to know.

The picture on left shows my rather unique block which is not too bad for a Lambda although a bit of a shock was the size of the bores as they have been sleeved down to make good some previously dodgy machining making my car the smallest capacity Lambda in existence. On the bright side it shouldn’t break a crank as overstressed it isn’t.

Lastly, I’ve stymied some oil leaks on le Bébé but I am struggling with my bargain Zenith carburettor that has the engine idling at slightly less than flat out, the throttle butterfly is a bit of a square peg in a round hole so that may be the problem. Once the Lambda is on the boat I’ll get back to this one.

I wonder what normal people do with their spare time?

One track mind

Posted on 25/02/2016 by Mark

I have never been good at doing more than one thing at a time and this last month has shown that to be the case. First off the Bebe has been making an engine speed clattering sound, so my rather fertile imagination had constructed all sorts of theories based on no facts at all. As the sound seemed to be coming from the RHS of the engine I figured it could be a loose cam lobe (these are keyed onto the shaft) however after mucking about with dial gauges and checking cam timing this looked unlikely. The RHS of the Bebe engine also happens to have the magneto and as this one is a later addition and an impulse type the most likely culprit is the impulse mechanism…and it was. Unfortunately, due to an ill-founded belief in my ability to repair the impulse mechanism, I broke a small die cast gear during dis-assembly. Luckily these Fairbanks Morse maggies are well provided for by the stationary engine/ tractor fraternity so a list of new parts including a new impulse spring and replacement gear was ordered. The parts arrived …the gear was wrong, several emails to the supplier and silence, to cut a long story short I have now found a NOS gear on Ebay and even though I have other jobs on the Bebe pending, nothing is going to happen until that gear arrives.
Meanwhile the Lambda is having the same treatment, it’s stuck with its camshaft away being reground. However I did get something done. Before sending the cam away to Clive I was trying do the cam timing and having a hell of a time working out when the cams rockers were “rocking” ( a point half way between the exhaust valve closing and inlet opening) at this point the crank should be at TDC and using the verneer adjustment on the cam gear, all should be good in the world. The problem is that the “rocking point” needs a feel for the mechanical that did not make it to my side of the gene pool.

Here is where I found yet another use for the “Bevel Box” electronic level, using a couple of rare earth magnets and a lump of steel I attached the level to the top of the two rockers in question. I then turned the cam so both rockers were on the heel of the cam, zeroed the level then turned the cam back until it registered level again and that is the rocking point …who needs feel.

So although like the Bebe there are many other jobs to do on the Lambda before the Tasmania Rally in mid March, my right handed, left brained self is stuck in serial mode.
They do say that multitasking is just a way of efficiently producing low grade work. This may not be entirely accurate but it does bring me much comfort.

Bug Bollocks

Posted on 15/12/2015 by Mark

I’m currently waiting for Australia Post again, this time to deliver some glass tubing to replace the broken drippers on the Bebe so in the mean time I am having another crack at the Bug’s low speed chug. In the tradition of fixing one thing and breaking another, this has only been evident since the new diff was installed as I’m now cruising at lower revs.

Up until now I had mistakenly believed the following from the publication “Grand Prix Technicalities” put out by the Bugatti Owners Club UK:

That does seem logical until you think about the alternative firing order of 1,3,4,2, so if Carb A was connected to cylinders 1 & 2 and Carb B was connected to cylinders 3 & 4

Cyl	1	3	4	2	1	3	4	2
Carb	A	B	B	A	A	B	B	A

You get “two successive sucks followed by an interval” (or a Swedish pop band) as stated in 4.17. So it’s bollocks, strangely Ettore went to some trouble fitting two inlet valves a cylinder then siamesed them, making it just about impossible to predict the outcome. They just run better with one carburettor, so I have ordered a new manifold for hopefully the right reason..

Colin Chapman had the answer for siamesed ports on the Austin 7 engine see here for the story.

I must have far too much time on my hands, I have included a few pics from this week of the Bebe, note the echos of Bugatti in the tappet cover and the unbent banana tappets. Also checked the valve timing which was spot on and read this great article on Model T valve timing which makes a lot of sense in slow revving low compression engines. Lastly people talk about ABS, ESC and even ESP making their car safe, the Bebe on the other hand has automatic ignition cutout if the oil drippers are turned off, now that’s a safety feature.

Cheers

Mark

CarCrank

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Category Archives: Bebe Peugeot

On Bentley tuning, Sizaire axles and Lambda Head Gaskets

One track mind

Bug Bollocks