Hey all, I'm back again. I've got a buddy with a D2 who's planning to refresh his engine in the next few months. It's an '04 model 4.6. I told him while is was apart, let's hop it up and really see what we can get out of it. I told him I had some valves out of a Dodge 318 he could have, and I'd port the heads and intake out for him. He's got the old headers out of my D2 to go on it as well.

I'll post the picture of the details below, but essentially what I'm thinking is this:

1.75" intake/1.50" exhaust valves
Big time port job on both heads and intake
Custom ground cam with roughly the following specs:
.475/.480 lift
265*/270* duration
109* LSA
9.5:1 or 10:1 compression

That's a decent valve size increase, very healthy increase in cam lift. I shortened up the duration, made it a split pattern, and tightened up the LSA for more bottom end and mid range power, especially since the factory rev limiter is so low. 4500 rpm if I recall.

The specs I don't have and would like to are the following:

Factory compression ratio. 9:1? 9.1:1? I don't recall off hand.
Combustion chamber volume?
Head gasket crushed thickness?
Piston height below deck?
Valve spring diameter, ID and OD?

Throw your thoughts at me. I've been wanting to.build a hot Rover V8 for a while now, glad to get the opportunity.

And don't worry, the cooling system will be modified tremendously to take care of the extra heat.

 

The ratio is marked on the drivers side of the block my 04 is 9:37:1. Try some of the UK Rover V8 pages versions of this engine were used in a ton of stuff including morgan sports cars

 

You're going to need to modify the Engine management computer if you take it too far out of spec. You may want to contact this company for some ideas on what it will take:
Tornado Systems | Product categories Thor

Good luck and keep us posted.

 

Also check out these guys: https://www.lloydspecialistdevelopme...engine-tuning/

They even turbocharge these old V8's!

 

Check out the Rover V8 Appreciation Group on Facebook. There's tons of folks in the UK building Rover V8's.

Seems to me like the formula is Top Hat liners, a Cam, optimized cylinder heads with bigger valves, and engine management to match. Could do all that and get pretty major horsepower gains over factory without changing compression. RPI engineering is known to twin turbo charge the 4.6.

 

Programming is the issue on this side of the pond. I’ve built a 4.6 up with head porting, crower cam, long tube headers, full rebuild, and although it runs good I can tell it’s not 100%. As soon as I get my axles sorted and small stuff set I’ll be ordering a chip from tornado in the UK. Hopefully that will bring it all together.

 

The programming is my concern. I feel like with the build I've got planned it should run decent even with the factory tune. If the AFR is wonky throughout the curve, that could be helped with some injectors and a BMW maf housing (larger, so less air is registered and less fuel demanded, making up for larger injectors) and we could restrict the MAF as needed to enrichen.

Definitely a bit of a jack job fix, but would work fine as long as AFRs are fairly consistent throughout the curve and throttle positions.

If there's too much timing, Ive read you can wire the CPS up backwards and it'll retard timing 3*. Probably would the injector pulses as well, but I don't think that would be an issue.

Just food for thought. I've gotten a lot more used to carbs and distributors in the past couple years, so I'm hoping some of that translates into ways to fool the ECU as needed.

Worse comes to worse, we can always get a D1 timing cover and a Buick 215 4bbl intake and swap it over to carb/distributor.

 

So you want to take a barely in tolerance block and an engine prone to overheating and make it run hotter?

Ok.

 

Not hotter temperature wise, bit hotter performance.

 

These are bit pricey, but would give you full control over the entire engine tune:
https://www.lloydspecialistdevelopme...nagement-kits/