Engine and Transmission Tech

Hi there

i run a Landrover 110 , V8 3,5 Desert Racer , with Holly inlet manifold , and carb , plus flowed heads , and balanced bottom end . I am now wanting a bit more , so have bought a 3.9 motor , and am asking for advice on getting the best out of this motor , but with good reliability . I am wanting to put in High comp pistons ( suggestions please ) new cam , doubble timing chain , h/v oil pump ,ARP studs and bolts , etc . And also what sort of HP figures i would be looking at

any suggestions on where to get these spares would be great . I am based in Botswana , Africa . I do not want to re invent the wheel , so am asking for advice

look forward to hearing from you

regards

clyde

Is it a 4 bolt main 3.9 technically a 4.0?

Clyde, TRS of "OZ", is claming 600hp. Sounds like a good sales pitch, to me .I suspect you can benefit, from the additional torque, from a 4.6L crank ? What are your engine rules ? Cheers, roverman.

Art no way, that could not possibly be naturally aspirated or not have extensive cylinder head modifications and even then?!?!?! Someone help me out here.......

I know nothing about LandRover desert racers... But I'm thinking a relatively heavy vehicle operating on relatively varied terrain means you'll need an engine with a flatter torque curve than someone who races lightweight sports cars on smooth racetracks. Right? Obviously, that will have a lot of bearing on your camshaft decision. Will time and mileage between engine rebuilds also be greater?

The first thing to do is study the rule book. What are you allowed to do? If you can upgrade from 3.5L to 3.9L, what stops you from upgrading all the way to 4.6L or beyond?

Most of the vintage racecars I know about aren't allowed to run crank fired ignition systems... but I'm certain all the most competitive guys WOULD run them if they could.

Ok Jacques,Suppose a theoretical 300 cfm.,(their claim, not mine) on the intake side, what does YOUR math say ? Perhaps you should contact them, to explain, how that is not possible ? Onward, roverman.

Art, you brought the claim onboard, not me! I'm not the Rover engine expert, but no matter what brand engines you're running they are all air pumps. Can someone recall a posting by Dan Jones stating that this kind of horse-power wasn't possible from a Rover engine displacement? It would also require huge valves and ports with a very radical camshaft profile, and no I'm not familiar with these people; obviously, it's not your claim and neither mine. Although, I would be interested in a link to their website; do you have it?

Cheers!

"Triumph Rover Spares", in Oz. 300 cfm claim, is from "Mike"/owner of TA Products. Reportedly with 1.94" int. I'll be testing a 2.02". Cheers, roverman.

> Can someone recall a posting by Dan Jones stating that this kind of horse-power wasn't
> possible from a Rover engine displacement?

I don't recall saying that. You can make that sort of HP if (and it is a really big if)
you have sufficient air flow. You run into a hard limit of what a port will flow as the
flow in the port approaches the speed of sound (Mach 1). That sets the required minimum
port cross-sectional area. Usually this is no more that 90% of the area provided by the
valve diameter (area is less due to seat width). Well before the port chokes, the port
flow becomes less efficient (harder to make the power, even if the flow bench shows
sufficient air flow).

I can't imagine a Rover V8 would stay together very long making 600+ HP (naturally
aspirated).

> It would also require huge valves and ports with a very radical camshaft profile

Yes. Would also require a maximum effort intake manifold (e.g sheet metal tunnel
ram), custom headers, large CFM carb, high compression, etc. I ran a quick optimization
in Dynomation assuming AFR 185 (2.02"/1.6") SBF head flow with 90% port area assuming
a 1.94" intake and 1.6" exhaust. Those heads flow 270 CFM through a 2.02" intake valve
but that flow is likely optimistic for a 1.94" valve diameter Rover head. The
simulation suggests a 4.9L Rover stroker with 11.5:1 compression, 830 CFM carb flow,
big solid roller race cam, large diameter stepped headers and a max effort intake
manifold could make 600 HP at 7500 RPM with the above head flow.

> 300 cfm claim, is from "Mike"/owner of TA Products. Reportedly with 1.94" int.
> I'll be testing a 2.02".

Keep us informed. According to the TA catalog, the Rover heads flow 225 CFM intake
and 140 CFM exhaust out-of-the-box. It'll take a bunch of porting to get to 300
CFM. We've made over 600 HP in a (larger displacement) street engine with heads
flowing in the 320 CFM range but those heads had much larger valves (2.15" to 2.19"
diameter). Some flow benches are more optimistic than others and the heads we've
tested generally come in lower than the advertised numbers. As far as I know, no
one has posted independent flow bench numbers for the TA Rover heads. Looking
around, I did find this for the TA Buick V6 heads upon which the Rover heads are
supposedly based:

[www.hotrod.com]
Kenny Duttweiler ported TA Performance Buick V6 heads
Valve size: 1.940/1.600
Intake-port volume: 156 cc before porting
Max flow as ported: 250/190 cfm @ 28 in H20

According to the article, the flow numbers above were achieved with fairly
straightforward porting. Elsewhere it says those heads are 211/166 CFM
out-of-the-box.

I've noticed the Aussies are fond of advertising heads by HP. There's a rule of
thumb that says you can make approximately 2.2 HP (normally aspirated) for each
CFM of flow (for a V8, a 4 or 6 cylinder engine has fewer ports so needs higher
head flow to make the same power). So a head that flows approximately 273 CFM
(at a 28" pressure drop) could theoretically support a 600 HP engine. It will,
of course, be much easier to make that 600 HP with a higher flowing head, say
320 CFM.

Everything (intake, carb, headers, mufflers, cam timing, compression, etc.) else
in the engine build needs to be capable of supporting that head flow and that's
often not the case. We've tested heads that flowed 322 CFM @ 0.600" of valve lift
for a bare port but when an intake manifold was bolted up, that dropped to 254 CFM.

Dan Jones

Also the engine has to hold together. At 600 hp this might be right much of a challenge.

Jim

Dan, thanks for the clarification. You'll never find me arguing your knowledge. I'm the kind of novice hot rodder that learns from proven facts based on well established and reliable formulas, however, it's a hobby to me and I'm not making a living at it but I do make many miscalculations trying to improve things. I wasn't sure when I was following a forum exchange if it was you that described the potential of the Rover engine; my apologies, I was wrong.

Besides all of that Aussie non-sense horse-power exaggeration, here's what I believe; the LS series shines as a much superiorly developed engine with healthy valve diameter and better heads has to have some extensive work to put out that kind of horse-power in a naturally aspirated form which makes the 600 H.P. claim questionable.

In today's modern performance engine, IMHO, anytime thermal efficiency is raised then everything else follows including MPG. I personally like the new approach of pushing the air through, direct injection, and good exhaust scavenging; are we approaching maximum thermal efficiency for internal combustion engines yet? IMHO, we're getting close to achieving standard pump fuel BTU efficiency :)

It also helps to quote head flow, through what size bore, as this dictates the amount of shrouding. I suspect nearly all exhaust flows are enhanced with a port tube. As I stated in my original post,"sounds like a good sales pitch". I feel about airflow #'s as David Vizard does about opinions, when asked for one, he stated: "I don't have an opinion, I have a dyno". The flowbench is just one of many tools, to find the best combination build, for a given application. Quoting air flow at maximum lift, is good as a sales tool,(they all seem to do it), but low and mid lifts, are equally important, especially on street duty engines. Cheers, roverman.

> I wasn't sure when I was following a forum exchange if it was you that described the
> potential of the Rover engine; my apologies, I was wrong.

Just because I don't recall saying, doesn't mean I didn't :-) It's quite possible
there was a different context, maybe relative to heads or some other part that wouldn't
support the HP level.

> You'll never find me arguing your knowledge.

Don't worry about that. If I'm wrong, I'd much rather it be pointed out than
continue in my ignorance. I'm very much of the mind that what you don't know
can hurt you and paranoia is an engine builder's best friend.

> the LS series shines as a much superiorly developed engine with healthy valve diameter
> and better heads has to have some extensive work to put out that kind of horse-power
> in a naturally aspirated form which makes the 600 H.P. claim questionable.

Agreed. Few off-the-shelf Rover parts would support that kind of power level.
Yo're looking at fully porting the TA Performance heads, making a custom sheetmetal
intake, solid roller cam, custom headers, etc. If you do some how make that kind
of power normally aspirated, then you have to face Jim's concern on how long it would
hold together.

> are we approaching maximum thermal efficiency for internal combustion engines yet?

I don't think so. Even current variable valve timing is quite limited when compared
against theoretical limits which may be achieved with direct valve control. Also
much potential energy is currently wasted into the water jackets.

> It also helps to quote head flow, through what size bore, as this dictates the
> amount of shrouding.

Yes. You'll find most shops (in the Untied States) don't bore tubes less than
4" diameter.

> I suspect nearly all exhaust flows are enhanced with a port tube.

Agreed.

> I feel about airflow #'s as David Vizard does about opinions, when asked for one,
> he stated: "I don't have an opinion, I have a dyno". The flowbench is just one of
> many tools, to find the best combination build, for a given application.

Roger that.

Dan Jones

Let's not kid ourselves that a near 600 hp rover, is going to last long with an oem crank. If it's externally balanced, even less. GB has several stroker cranks, with higher strength material "SG" iron alloy. Good stuff to peep, over at J E Developements. I wish the sbb guys would, look around more. Cheers, roverman.

I'm a bit late into this conversation,
Curtis, your comment on vintage racing rules restricting crank fired ignitions is true. But they don't say anything about using the cam gear. My old Europa gordini ran under sovereign rules and I built a COP setup that triggered off the cam gear. It worked well and was dead accurate even at eye watering RPMs. The car was returned to street use probably 10 years ago and it still uses the same system today.
Cheers
Fred

Fred, "Smokey" would be proud. "If the rules don't say you can't"..... Onward, roverman.

Fred, What about using the steel cam sprocket, as a triggering wheel ? Is this possible with something like a programable controller, like Megasquirt/or ? Cheers, roverman.

So guys,

What year and model is the 4.0 Rover engine - particularly the ones with the 4 bolt mains ?

And how do you spot the engine at the wrecking yard when you find a Rover (Discovery model ?) that might
hold the 3.9 or 4.0 engine ?

help

phillip g

Try this, Phillip.

[www.motorcarsltd.com]

I believe all the 4.0s were four bolt mains blocks.

From Wiki:

3.9/4.0
The 3.9 L Rover V8, a bored-out version of the original 3.5 L engine, was used in several Land Rover vehicles, TVRs, and the MG RV8.

Land Rover used a 3,946 cc (240.8 cu in) version of the Rover V8 through the 1990s. Bore was increased to 94.0 mm (3.70 in) and stroke remained the same at 71.0 mm (2.80 in). The engine was revised in 1995 (and thereafter referred to as a 4.0 to differentiate it from the earlier version, although displacement remained the same at 3,946 cc) with a new intake and exhaust system, extra block ribbing, revised pistons, and larger cross-bolted main-bearings. The 1995 4.0 produced 190 hp (142 kW) and 236 lb·ft (320 N·m) .

Production of the 4.0 ended in 2003. The final version of the engine, used in the 2003 Land Rover Discovery, produced 188 hp (140 kW) at 4,750 rpm and 250 lb·ft (340 N·m) at 2,600 rpm.