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That's the wrong part, what are you doing?

Dammit

Paul Ricard
Joined
23 Sep 2016
Messages
3,135
Context: I'd like, over the next couple of years, to re-build my engine to either 3.7 or 3.9 litres, because I have no sense of proportion and little in the way of self control.

This brings a whole host of challenges - one of which is that the M96 manifold is restrictive as stock - and as more is better, it would be nice to use an intake that allowed the new capacity to breath more easily.

I wanted to purchase an X51 manifold - but they're NLA, and have roughly the same available as Unicorns on the second hand market.

Enter the 3.8 litre M97 manifold - pictured alongside the lower, aluminium section of the M96:

38695497312_0a06664000_b.jpg


The injector ports line up precisely, as do the ports.

But, and it's a big but - the retaining bolt ports do not.

The M97 manifold is wholly plastic.

Would anyone have a clever suggestion for bringing the M96 bolt pattern to the M97 manifold?

Currently I am at "mill out the current mounting sections, bond in new 3D printed sections", but I would be the first to admit that I'm beyond the frontier of my own ignorance here.
 
Or:

Cut away only those parts of the manifold flange that foul the position which the bolts need to be*, put a plate over the top of the flange that can take bolts down into the head, compressing the M97 manifold between the plate and the head, holding it in place.

*A tiny amount of material, it must be said
 
Drill & tap new holes in your cylinder head to suit the different manifold.
 
Could you make a small adapter plate like folks do to fit different gearboxes :dont know:
 
The injector makes that problematic.

Following up on Alex's suggestion, here's a shot of an M96 - note that there are bosses, undrilled, in what look to be the positions that the M97 manifold needs;

80-img_8822_ae4d43972fd0f6f947f17382e226a39d4c07b399.jpg


Now the question is, do all M96 heads have these?
 
paul987 said:
Could you make a small adapter plate like folks do to fit different gearboxes :dont know:

I would've thought the injectors would then be too far away :dont know:
 
3.4 head:

rebuilthead.jpg
 
Actually looking back at the picture of the intake side of the head that I posted I was wrong - the bosses are not in the correct place to mate to the M97 manifold - the mounting points between the ports on the M97 are central, but offset from the centre line (if that makes sense).
 
Damn more work!!

I would be inclinded to develop an adaptor runner to replace the exiting m96 one. This would bolt to the m96 head but then have spacing to suit the m97 runner and could be 3D modelled and produced in printed form but may need to be cast ultimately due to the temps involved here at the head.

Are the 3.8 runners readily/intake readily available?

Harv
 
They do come up - I paid £80 for this one, with £20 postage, at which price I thought it came within the realm of worthwhile experiment.

If we could resolve the injector position issue then an adapter plate would be the most painless solution, allowing us to modify neither head nor manifold.

That would also mean we could use the M97 X51 manifold if the standard one doesn't turn out to have a flow advantage over the M96.
 
Harv - if you could measure you existing manifold I can take the same measurements from this one, it would give us an agricultural comparison between the two.
 

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