So I have a pretty significant clearance issue with my next induction setup. (Datsun 1000 with A12)

What can be done to increase the space between the rocker cover and bonnet underside? I am after every millimeter I can get. I'll try list my thoughts in order of complexity (or what I think is more complex).

1) Modify engine mounts and lower engine (done that).

2) Cut, chop and shut rocker cover to a shorter height (I think I can only achieve about 15mm) put PCV to rear of cover and remove filler cap. Fill it up with oil the time-consuming way.

3) Modify sump to clear crank but sit closer to block - then modify engine mounts again to drop engine further.

4) Modify the bonnet to have a small rise going down the middle.

5) Cut, Chop & shut + modify rocker pedestals + custom push-rods (all a bit of a wank really - costs blowout, too much extra work with little annoying things like different rocker arms , push rod angle etc etc).

6) Resort back to A10 (shorter block) which means I'd need to hot that up to suit induction (no thanks $$$).

Any help and bright ideas muchly appreciated! Or a vote on which options people would opt for in order of preference, i.e: #4 , #3 , #1 , #2 etc etc

Chris

Can you cut out the bracing under the bonnet for a few mm (15mm maybe??)?
How about putting spacers between the hinge and bonnet, meaning the bonnet will be on a forward slope, higher at the back.

G'day Deano.

Yeah but I'd need to cut most of the strut intersection out (where they cross over each other).

Bumping the bonnet a bit at the back doesn't sound too bad actually.

I guess dry sump would be the way to go but I'm looking for a fairly cost effective procedure.. will try to get some pictures up soonish.

new bonnet with a bump- heaps of clearance then

Are there fibre bonnets available for a thou? Generally they don't have the X-braces?

Or with a fibre one you could quite happily chop it up to fit a power bulge

Depends if you want to keep the stock look or not I guess?
Popping the bonnet at the back is a pretty old school trick used to help with cooling generally.

Why do you have a rocker cover clearance issue with an A12 ?

A15 is taller and I have them in mine with no clearance issues

I suspect that the plan is to use long runners that swing up & over the top of the engine & use carbs of injection that face the right side instead of the available inductions that all face to the left.

These induction runners need some space above the engine, as will any carbs that are used.

I have seen this setup before & it works OK, sort of, but I have not seen anybody use such a system for very long.

Am I anywhere near the money Chris?

P.S. Setting the tappets with such a system is a bitch.

Hey Gents!

Quote:

Yes indeed. But no it isn't as exciting as super long runners, quite the opposite actually, super short.

I got a matching air housing for my new keihin carbs (Like, brand new carbs!) and it all goes together so well (+ cheap replacement filters) that I'm pretty damn keen to use it as a complete induction unit. It also has a perfect PCV provision right where the A-Series need it.

Yes I know the approach angles are hard to achieve but I don't mind an extra bend in the flow into the head if it has to come to that. I could even put up with a big port round-port head (without the gradient of the oval-port approach angle) if it is easier to fabricate.

I have approximately 75mm clearance maybe a little more and I need about 150mm. I have a design for a shorter rocker cover but I just thought I'd ask before I did anything.

What would happen if I reduced the size of the sump/oil capacity? Perhaps I could make a flying (winged ) sump to compensate for the dimension reduction but maintain capacity?

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bonnet + hole = scoop with cold air induction

I personally think thats just stupid
All that engineerring to fit that ugly thing which will eventually cause the early termination of your motor cause you have no oil supply or other issues

Sure you can make a winged sump ... but you'd be better off dry sumping it if your going that far
Having a scoop like my old racecar but bigger might give you the room.... but you'd have to fab up a new bonnet allowing room for engine movement as well as static clearance
The reduced height rocker cover won't give you enough clearance
Changing the rocker posts and shortening valves,making custom pushrods is alot of work to get the geometry right for what I see as 0 reward using that black monstrosity
Throw it in the bin and make an airbox