I think Daras's 350 is "just" a late AK B - so totally normal M28/late gearbox brakes setup. IIRC, the only other M4 350 in the UK is Pete & Bev's "Stimpy" AKL Weekend.

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The biggest achilles heel (in my opinion) is that those car's haven't any oilpressure indicator, so there is no indication when oilpressure drops/is gone (less of oil), so you have to check oil level almost for any ride (daily bases)..........

Maintenance cost as much time as a new 602 only make more oilchanges (3000/5000 km).

But these are very fine engines, especially torque at low rpm, especially engines with the big single valve carburator (1966/67) they have more torque at low rpm 1500/3500 then a 2cv6 engine.........

Which Hetty has - it's a late Ami 6 M4 engine - big valves, high compression, big carb. Nominally 28bhp, IIRC.

Adrian,
wonder if that should be 'higher' compression, as 7.75:1 doesn't really count as being 'high compression' except in relation to 7.5:1...
Those jampot carburettor don't seem to have been a huge success, judging by the short period during which they were fitted.
Still, there's one amongst the boxes of bits here, so I'll do my best to get that up and running again.

@ Ipgo,
I suspect that the 'higher torque at lower rpm' characteristic may be closely linked with the camshaft profile and timing, so yet another reason to hope that the bottom end of an M4 engine can be retained?

ken

All things are relative! It's not so much as a compression stroke as a gentle hug of the mixture.



Probably more because the M4 was superceded by the M28 than anything else - although it should be noted that it's bigger than the carb that Citroen were fitting to lower-spec DSs at the time!

talking about M4 manifolds, do anybody know if the manifold is the same on M4 425ccm and 602ccm?
Reason why asking is, that the preheating camber on the manifold on my M4 602ccm/ Dyane D6, has seen better days. The other manifold I have is in worse condition that the one fitted, but I know were to find some from 425ccm engines.

425 and 602 do not share same mainfold, just look at the carby, two completely designs

True, but...



There's at least three different manifolds for M4 602s.

- Dynamo & small carb
- Alternator & small carb
- Alternator & big carb

But they're detail differences - generator mounting & carb flange. Rather more fundamental is the shorter stroke on the 425...

Shans - the hotboxes all rot out. They're easy enough to weld, though. They're just sheet steel, and the head mounting faces are flat, so just bolt it to something very solid to prevent distortion (Louis Barbour's big workbench has the bolt pattern drilled into it!), and patch away.

If you're really stuffed, I think I've got a spare big carb/alternator manifold or two somewhere. I just bought 'em any time I saw 'em.

sounds good

Mine is the alternator and big carb ones, due to centrifugal clutch and 12volt alternator.
The shitty one, we have tried to weld, but from factory they have used brass or something to seal the welds with.
Therefor you just can't weld in it.