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

[Harv]

My inlet manifolds are now on with the engine in the car, I could probably get an external dia measurement of the m96 runners if this would help.

Agreed that the simplest way would be an adaptor plate but we are limited by height if raising the whole intake, plenum and throttle body (5mm max might work).

 

[Dammit]

What would that do to injector angle/aim do you think?

 

[Fast Bug]

Is there much scope for porting the standard manifold? I had manifolds for my Beetle tig welded on the outside to add extra material, then ported to death for more flow

 

[paul987]

Might be worth trying to contact this chap he seems to know his stuff on 3.4 interchangeability :dont know:

https://newsite.hamheads.com/2016/11/22/a-tale-of-three-headsthe-3-4lineage-m96m979a1/

 

[Dammit]

Here's a first pass at the plate idea:

A flat plate with pins that locate into the bolt holes on the manifold and holes (with guiding barrels down to the head preferably) that allow bolts through the plate to meet with the mounting holes in the head, clamping the manifold between the plate and the head when the bolts are tightened down.

Insanity?

 

[Martin996RSR]

The plate idea is definitely the way I would go. Don't get hung up on the thickness of the plate/needing long threaded holes to bolt the manifold to. Use a hard steel, such as T45 plate and you can make it quite thin. I have an 8mm adapter plate that joins my Rover v8 to my MGB gearbox. In that location it's under a tremendous amount of stress but it handles it just fine. I've never had a bolt pull through.

I would go for 5mm plate and not bother with captive nuts or anything on the back as these are bound to necessitate removing some material from the head to accomodate them.

For the bolts that hold the plate to the head, use bolts with a very wide countersink and an allen socket head. This will spread the load on the plate and allow the fixings to be flush with the surface of the head, removing the need to make room for them by removing material from the manifold flange.

Design the thing in a package that can produce Autocad .dwg files such as NanoCAD (it's free) and then get the plates laser cut. It's a lot cheaper than you would think for this. Get the company cutting it to do the countersinking for you, but tap the threaded holes yourself.

Don't worry about the injectors being an extra 5mm away from the ports, I really doubt it will make a difference, and if it does then you can still get a remap. Many engines are converted from carbs to injection and the injector location is not that critical. Some have them in the intake runner, and some put them right at the throttle body, so hopefully 5mm further up won't hurt.

 

[andylaurence]

Laser cutting is really cheap. You could probably get a dozen laser cut for £100. I've had 20 similar size 3mm stainless parts cut for about £60.

If you want to print parts, then there are high temperature materials that have been used for this sort of thing before. Graphite SLS and Carbon SLS are good for 170 degrees, which is more than enough for an intake manifold. Team Bath Racing used it for exactly that in Formula Student.

https://3dprintdirect.co.uk/sls-functional-prototypes-and-end-products/

 

[Dammit]

I think for the first pass at this all that needs to happen is that the intake is held to the head sufficiently well that DynoMike can flowtest it to find out if it's actually any better than the stock M96 intake.

If the 3.8l M97 part is less restrictive than the 3.4/3.6l M96 then a more thorough part can be made.

I appreciate the comments on the adapter plate route, and it's the most straightforward, but I'm concerned about clearance in the engine bay and injector position - so for a first pass I think I'll go with the sandwich plate option.

Having that laser/water cut out of 3mm sheet appears to be the easiest route, so I'll get sketching.