Has anyone ever seen this kind of safety blow off valve
on a supercharger. Simon mentioned using a plate and 4
motorbike valves with bolts with nylon nuts.
Im interested in this single spring version, maybe I can
use a single L series double valve spring?

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I think a valve spring from an L-series would be too strong. Something of a much smaller cc engine would do well. Perhaps looking for something that carries a lighter valve would be more suited.

It also comes down to how big the valve/surface is and how much it has to travel to purge the excess pressure.

You can get blow off valves for cheap, but the whoosh factor is a bit undesirable. Pretty sure you could mod one as a straight purge valve though?

Yes the double valve spring would be too much and although modern BOVs are avail
I just love the look of this setup along with the rest of it period finishings.
Im thinking of a similar setup using a long diesel truck inlet valve positioned
so the spring and retainer are on one side of the plenum in the open and a seat
like finish for the valve on the other side of the plenum. That way if theres a
backfire the valve will just pop open. As long as the spring can keep pressures
under 20psi as Ill be running 10psi it should be fine?

Sounds good,just need to machine some decent platforms up to make sure the valve doesn't walk and leave it's seat. I'm sure any machine shop could machine the opposite face of the valve, but whether you need a synthetic seal or not I'm not sure. I liked the idea of the rubber platform with the springs, would me easier to do I think.

Are you still supercharging your A10? I have a new Eaton M45 and factory EFI A14 coming together, bit of a plumbing nightmare at the moment. Just need to sell my old engine to free up some dosh (very hard to part with ).

Yes I will still SC the A10. I have most parts coming together.

Chris can you post a pic of your eaton m45? is it like a mini one?
I found that model also hard lay out properly without to many plumbing
but it all depends on which model you have.

This is my decision
http://datsun1200.com/modules/newbb/v ... id=361379#forumpost361379

As it will allow the su to face the left hand guard and still allow a filter
without touching it but no longer will i run the kangaroo water bag.
Crank and Alternator will run twin pulleys and rear of alternator the same or
4 row ribbed belt to the supercharger pulley. So no piping at all.

This is the layout viewed from the front (radiator cap height)
It will make a clean setup with support from the engine mount
and further support from the back of the head with another bracket
not pictured but double side engine mount supports might be enough.

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That setup looks tight!
Is that diagram a blow through or draw through? Looks like a draw through. Are you still considering using a blowoff on a draw through? A draw through blowoff valve will blow fuel all over your engine compartment.

I was thinking of having no blow off valve just the spring thingy setup
in case of backfires which are rare by detrimental to the SC.
If go for a BOV I would plumb them out somehow if possible using some
tubing to either the wheel wells, below the road, gearbox tunnel non
exhaust side or windscreen to clean the bugs off :)

Good! You don't need an Afterburner? Speaking of burning, I've gone through 10 gallons of fuel today. This car sucks the tank dry, but it pulls hard!
Left GG early. Drove through and the place was packed. Didn't park the car but it took me over a half an hour to drive through it and see all the cars. Not one 1200 on the lot. DD was suppose to be there but I didn't see him. Just spent the rest of the day racing around the country side.

10 gallons is like 37 litres so not too bad for a day of aggression.
Can you get LPG your way?