casper88

Have a word mate would be intressting to know

orion turbo

if the rs2k head apparently flows less and the same cams. where does the xtra 12 or so bhp come from over the scorpio 2.0 16v

casper88

Well after my research and speaking to a few people. I have wrote a list of parts that will aquired. Boa engine, full freshen up new shells and gaskets, bob cams, custom loom to emearld ecu, 2wd cosworth clutch, 2.8 flywheel, 2wd mt75 box and 4x4 v6 box to make box up. Caprisport adaptor for flywheel, shortshift kit, uprated front springs.polybushed front bushses and front mounts

dojj

iTrader: (3)

buy a 2.9 xr4x4 and you will have the majority of your parts there

and use the 2.9 flywheel and starter, much easier and cheaper than the 2.8 converstion kit, plus a lot easier to get hold of

on't forget the spigot bearing int he end of the crank either

casper88

I got a quote of 75quid for the conversion kit. Then run 2wd cossie clutch, ahhhh spigot bearing do I use 2.8? Or cossie one? And what starter do I use 2.8 one? To match 2.8 flywheel?

Marcyg

The Scorpio has low comp pistons. Hence using the Sierra bottom end rather than just throwing a whole Scorp engine in it. The heads do bolt straight on, the mechanics are easy, it's the wiring that's an arse if you aon't no good at it I'm using the Scorpio VIS inlet, which when the air is free flowing through both throttle openings draws in more air than the standard 8V twinky AND the RS2K. That's where yer extra ponies comes from

As for fitting the 24V heads the the 4.0 block, I think they'll physically fit, but the timing gear will be an issue. Only 1 bank is driven from the front. The drivers side (I think) is driven from the back via a jack shaft, which is where the cam shaft used to be on the old 12V. If you hear rattly timing chains on a 4.0, it's usually the back set as it's an engine out job to do and most people don't bother

mk22door

Where in the rev range would you back off, to be safe??

Marc sierra

iTrader: (1)

Around 6500 rpm is what is safe on a standard engine. But the BOB is a bit stronger around the main caps than the BOA. With a girdle they can rev a bit further, I think past 7k.

I have both, a BOA and a YB, and to be honest I find the BOA a much nicer drive for daily use. Of course that doesn't mean the YB is not fun, but the BOA is much more relaxed to drive, no lag, enough torque at low rpm (below 2k) and sounds better too IMO.

mk22door

I might have had it around that area.

I can't comment on the YB, but the BOA is my daily drive in an XR4x4.

It's good, I like it.

dojj

iTrader: (3)

if you buy a 2.9 xr4x4 sierra you already have all the parts to fit everything
the spigot bearing is the same as the 2.9 12V as fitted to the xr version of the engine, you simply need to use the 12v flywheel and flywheel bolts and the cossie clutch is a direct fitment in any case as it's the same size, the only difference being the clamping is harder on the cossie and it should come with 6 springs in the plate rather than the xr's 4

i may have just binned the clutch i had that was scrapped

as for the starter, use the same one from the 12v as yuo will need to use the 12v front of the mt75 box as well as the input shaft so that everything matches up correctly

some starts have 2 bolts and osme have 3 and osme have 8 teeth and some have 9 so make sure you don't get stuff mixed up

6500 is plenty as the engine will make the torque low down put the power starts to taper off at around this point, plus they can hold a lot of oil in the heads and if you are continuously keeping the revs up it can lead to starvation or too much frothing of the oil as it returns to the sump through the extra drainage tubes in the sides
a gated big wing sump would be a good investment if you aren't running 4wd to prevent this sort of thing, expecially if you are considering tracking it

dojj

iTrader: (3)

from memory there were 4 different versions of casting for the boa and another 3 for the bob, so 7 in total, the last of the line ones had much thicker webbing in the bottom end so would be the ones to look for, but the boa and bob blocks are swappable so you can swap last off the line to first out of the blocks if you know what i mean

tieing the caps via a girdle is only worth it if you are looking for BIG power, but there are other things to worry about first

robrs2

There are some bolt holes for the timing cover that are missing on the bob to that on the boa

casper88

Some very usefull info coming up thanks a lot guys very much appricated

dojj

iTrader: (3)

Could be, I know mine was a bob block with bob heads and stuff fitted to it, but is it a case like the I4 engines where the castings are there but depending on the engine being fwd or rwd the holes aren't tapped ?

Cossiemainful

iTrader: (1)

But naturally aspirated engines have no "turbo kick" (I'd like to think the BOA is standard), the power band is too linear and there's no extra boost on high revs and this is boring sooner or later. And with automatic the BOA is "slow". If a daily driven BOA than with manual gearbox and a turbo. Couldn't decide, both are great fun.

I prefer a bit lag instead of linear power without maximisation.

ShiftyOldScoob

iTrader: (3)

NEITHER!....

The V6 is the better daily engine IMO, nice noise, nice torque curve, good reliability.

However, if you get bored, it's not the most tunable lump out there.

My choice would be a 302 or a 351 V8

Mark V8

iTrader: (2)

My choice too

opposite lock

iTrader: (3)

I like a V8 but would always choose the 6 over one. They sound far nicer imo and for a daily they're much more practical . A clean BOA under the bonnet looks the tits and being a cosworth engine is hand n glove for a Sierra.
All this chat i wish my friend would get his one done so i can drive it

Mark V8

iTrader: (2)

V6 is by far the best daily driver option.

But it will always have two cylinders missing

V6 will never sound like this...

opposite lock

iTrader: (3)

mm that sounds the bollox.

PileOfRust

Of course they're tuneable, just not compared to the yb's as they haven't had as much money and research put into them.
With abit of money and research I reckon you could get fucking huge Hp figures out of them, skogenracing on YouTube had a 450hp 2.9 12v turbo in a Capri, granted the 12v has slightly lower compression but it was basically a bolt on turbo, a cam and some pissing about with the inlet


http://www.youtube.com/watch?v=p059xTOyP4w oh that noise is pure porn

PileOfRust

There's also a Tt 24v Capri and triumph stag on the tube

Ade500

iTrader: (1)

If your getting a aftermarket ecu it would be rude not to boost it and the T5 fits with a Rickwood kit.