RA/SB engine option

[jerrybus]

Hi, does anyone know if an RA cylinder head and other bits are interchangeable with SB engine parts. I've tried to find a new SB head from AMC or someone similar, but they only seem to list RA heads. Also, 'prechambers'...What the hell are they? Cheers

[clift_d]

My understanding is that SB and RA are basically the same engine so the cylinder head should be interchangeable.

The SB/RA and the JX are InDirect Injection (IDI) engines, meaning the injectors don't squirt directly into the cylinder, but into a prechamber in the head. Supposedly it gives advantages in respect of smooth running, engine simplicity and engine life, at the expense of fuel efficiency and power.

[jerrybus]

Cheers Clift. I'm just removing the old JX and gearbox...I can't upload a photo unfortunately, but the exhaust downpipe is a non=standard thingy that looks like a cat and there is a certificate for it in the docs I got from Germany. Keep it or revert to standard? Has anyone seen one of these, I don't want to bin it if it actually cleans up the emissions?

[busbuddy]

ive seen quite a few cats on the karmanns coming in from germany, they drop the emissions so the vans were allowed into some german cities but they also seem to drop the power as well

usually this shape


think it makes the engine euro2 compliant, still antique but better than euro1

[jerrybus]

Thanks busbuddy, the 'cat' on my exhaust looks pretty ancient compared to the one your photo and seems to be integral with the downpipe as far as I can tell, although it's so rusted I'm not sure if there is a joint somewhere. I got my LHD van from Germany and when I registered with DVLA they took most of the original German paperwork, but I recall seeing something about the emissions rating. Has anyone had something similar on their bus (or car).or know how they clean up the emissions and whether you can test them to see if they still actually work? Thanks again.

[busbuddy]

im guessing yours is either straight off the turbo flange or on the pipe running front to back before the silencer

if you google euro2 it will show values emissions should be, a garage will be able to print out emission results

[jerrybus]

Thanks busbuddy. You're right, it bolts to the turbocharger flange and there isn't a lower flange to the pipe which connects to the transverse silencer box-it all appears to be a single component. I suppose I could get a conventional pipe and get the emissions compared...? I assume these things are just a 'dumb' device, but I read something about the EGR being connected to it's function, although I can't see any connecting pipes, additional electrics etc, although I've found a funny little white box which is wired into the main loom and attached to inside of the nearside rear wheel arch and seems to be a non standard thing, but what it's for is a mystery to me. Cheers for all the advice, much appreciated.