Wanted machined Rover V8 Plenum lowered to fit under bonnet.

[Harry Ragg]

Hi everyone first time on the forum, been a member for years and always found it interesting and informative.

I'm looking for a machined / lowered plenum chamber for my RV8 EFi conversion. I've had a Holley set up for years and I've decided to convert to EFi and I'm nearly there apart from clearance.
Monarch who are usually able to supply these are unable to help for some months and I was hoping someone out there may be able to help. Hey if you don't ask.....
There was a set up advertised in the club mag last April but tele no did not know about the advert and no reply from the email address.
So other than slamming the bonnet hard and cutting out around the raised bumps....
Cheers

[EFI Stag]

Hi Harry i have a machined/ lowered plenum sitting in my garage you can have it for £25 plus postage
cheers Martin

[Harry Ragg]

Thanks Martin I'll pm you my details.

[Seaking]

just seen this on e bay Item: 190919307248

Cheers Glenn

[ABZ]

Anyone else got a modified plenum ?
Looking for one before I decide to get my own one done.

[73stagman]

What needs to be done to lower the plenum? Can i help with machining one?

[bullstarz]

All you have to do is get the base milled. Getting the pipes on the injectors can be hard if you take loads off. There's loads of metal on the base.

[73stagman]

If the bolts run through from the very top and not on some flange affair that could get milled off I cant see why I cant put a standard one upside down on our mill and run a cutter around the face.

[atc40]

Neil;
The work that I did to my plenum chamber sandwich plate was to mill off 0.250" from it`s lower face, that takes the thickness down from 2.135" to 1.885". Then fitted 0.500" aluminium spacer blocks between the chassis legs and engine cross member. Bonnet now closes with no fouling.
Hope this is of help.
Andy.

[73stagman]

Hi Andy
I dont need to do the job I was just offering a helping hand to the OP!

I dont understand why putting a spacer between the cross member and the body helps with under bonnet clearance. The engine is bolted to the body not the cross member so when the body goes up so does the engine so the bonnet and engine relation stays the same. I do realise that some more clearance between the sump pan and the steering rack would be good and the spacers definitely help with that. I have left them out on my Rover V8 engine conversion and the rack only just fits but the carb still needs the bonnet hump due to the adapter plate i had to fit between the carb and the inlet manifold.

[bullstarz]

A 25 mm cross member spacer will give you 25 mm an extra sump cross member space. So that allows you to lower the engine by 25 mm giving you 25 mm more clearance on the top/bonnet.

Should have mentioned that you have to alter the engine mount to.

[73stagman]

A 25 mm cross member spacer will give you 25 mm an extra sump cross member space. So that allows you to lower the engine by 25 mm giving you 25 mm more clearance on the top/bonnet.

Should have mentioned that you have to alter the engine mount to.

And so 1" lower than usual RV8 lowered springs would also be needed to bring the body and road height back to normal. Maybe a future alteration if I get sick of the lump in the bonnet. (Which was already there on my car)

[djw113uk]

Does anyone have one of these going spare now?

How much should be machined from the plenum? Is it machined flat, or more to the front or back?

Also how does lowering the crossmember help if you have the engine mounted on the chassis. How do you modify the mounts to drop the engine?

Thanks

[bullstarz]

As far as i can recall there is a limit to how much you can machine off as the trumpet will not have any base to sit in. Take as much off as still leaves metal for the trumpets to rest on. Has to be machined flat it will not line up correctly. Any decent machine shop will do it if you explain what you need.

I did have a spare but it might have got ebayed.

You can get modified mount that lower the engine if the cross member is lowered. I did have some mounts but can't recall if they were for the original stag or rover stag.

[V Mad]

Also how does lowering the crossmember help if you have the engine mounted on the chassis. How do you modify the mounts to drop the engine?

Thanks

Try not to think of it as a standard conversion. Many of these Rover conversions were done by small garages or private owners making up their own brackets etc. If you dont have adjustable brackets then to lower the engine you would have to change your brackets for something else. If you cant DIY it, you could try on of the companies that specialises in stag RV8 conversions.