Rover V8 Upgrade Advice

[jabooth]

In mid '05 I bought my first Cobra, a Pilgrim with what now seems a bog standard ex-1978 SD1 3.5V8. With K&Ns on the SUs, and 4" sidepipes, it wouldn't run cleanly above 3,000rpm under power, and previous owners over the 10 years of its life have obviously accepted this! Thanks to all you knowledgable Cobra nuts on this site, I confirmed my diagnosis of "wrong needles" (they were the standard SD1 BAF needles), and shelled out the massive sum of £20 to almost solve the problem with BCAs. It's still a bit lean above 5,000 on full throttle, and it smells a bit rich at lower speeds, but at least it goes!
I'm considering ditching the SUs in favour of a 500cfm 4 barrel (Weber/Edelbrock) on Edelbrock manifold plus a fast road cam to give it a bit more "zip". You see these advertised for £500+ and £250+, but how much power uplift can I expect for these changes (155bhp was the quoted output for the SD1, which should be a little more without the strangled intakes and exhausts)? Can these prices be significantly beaten, and where's the best place to look? Also, the ignition seems to be working OK, so is it worth the expense of dual point, or even electronic distributor replacement? I'm not looking for a racing engine, I'd be happy with up to 250bhp and no more than 6,000rpm. How near can I get to this without spending a fortune? If I wanted more, I'd go for a Yank small block transplant, but I really don't want the hassle, I'd rather drive it than build it!
Any advice will be much appreciated!

Tony

[v8robert]

Speak to John Eales the guru of rover v8's. JED.

[bluetoon]

Tony,
These are figures i have been quoted regarding the rebuild of my rover V8

The Edelbrock 500 will give you + 20 bhp
Fast road camshaft + 20 bhp
That will take you to just under the 200bhp mark from a standard SD1.

Change piston ratio from 9.35:1 to 9.75:1 +25 bhp

To get 250 bhp from a standard SD1 is expensive. ie performance heads, change piston stroke etc.

Hope that helps
Jim

[maxGD059]

How about a quick butchers at David Hardcastle's book -it maybe a bit dated now but still has some excellent advice for starters. I think you'll find it on the CRC amazon link

[bluetoon]

Oh and as for suppliers there are loads to choose from; here is some

V8 tuner
jrv8
RPI
v8 developments
DJE
rimmer brothers

Some of the above sell on ebay where you can shave off a few pounds
eg partsrange, modifiedv8engines, p5-p6-sd1, rockercover, pointeng

also good used parts are much in demand and dont go cheap

The edelbrock bits are quite a bit cheaper in the usa, but when you factor in the delivery,customs, VAT etc there is not much in it. Unless you are visiting the states at some point

cheers
jim

[robinj66]

Tony
I agree that you should take a look at David Hardcastle's book. You should also check out www.v-8.org.uk where you will find lots of advice about performance enhancing bits & bobs.

I got my carb, manifold and air filter from e-bay but it may take a while for the right bits to come along at the right price. Remember all the "hidden" extras like new thermostat housing, throttle linkage etc. If you put in a drastic cam then you may have to think about modified springs, cam followers and possibly roller rockers. All are reasonable prices but they will affect your final bill!

Best advice is check the prices from the sellers already listed - you will be surprised by the differences. Also try www.pegasusparts.co.uk .

[jabooth]

Thanks a million for all your useful advice; I knew I'd get more that my money's worth out of my subscription to the Cobra Club!

I didn't want to spend a lot on this Cobra, I'd originally got my eyes on a Dax with small block Ford or Chevvy (probably another 6 grand!), but budget constraints took over; although my wife's almost as keen as I am, she still wants summer holidays, and to be honest, so do I! I felt I could squeeze another grand or so out of this year, which would probably do the 4 barrel and cam (the pistons suggested by Bluetoon look like a lot of work and expense!), and be satisfied by 200bhp (thanks robinj66, I won't go wild on the cam). Is there anyone who's done this conversion, and did you really notice a big difference? I've also got a Fiesta ST with 150 bhp, and it flies when it's wound up, so that's my benchmark.

I've also read that a dual point or electronic distributor is "essential", but does a dizzy change make all that much difference? And finally, I suppose I should get it all set up properly, and I guess a rolling road is the best way. Anyone know a good (inexpensive) one not a million miles from Knutsford, Cheshire?

Thanks again,
Tony

[tony]

Tony.

The 3.5 sd1 produced around 150bhp , but remember this is a figure quoted from a new engine unfortunately age has a detrimental effect on all engines and wear over the years will see bhp figures fall dramatically on those qouted by manufacturers .

There are plenty of people claiming huge bhp figures for RV8 but they come at a substantial cost.Unfortunately bhp is irrelevant unless you have the torque to back it up, it`s all about power delivery and in this case a Yank V8 will almost always be ahead, from my experience the RV8 doesn`t produce sufficient torque to give you that power delivery the 3.5 simply doesn`t have the cubic capacity.

Having said all that my old AK ran with a 3.5 Vitesse block, fast road cam and big valve stage 2 ported heads, Webber 4 barrel,it never felt more than about 190- 200 bhp and you had to work it to get the performance.

The 4 barrel webber is a good carb along with a new inlet manifold and with a fast road cam kit, timing chain etc. you should see about 190 bhp with acceptable (20 -25 mpg) fuel ecconomy.If your current Dizzy works ok. then stick with it.You`ll end up with a Cobra that will beat most tin tops off the lights but don`t expect too much.

Tony.

[osgood]

Tony have to agree with Tony above there are some very big BHP claims made by some RV8 owners but much of a myth I am afraid, best I could manage from my new 4:6 after re-jeting was 265 @ the flywheel having spent 5K and building it myself. The car was not pleasant to drive on the road either.

I think if you want comfortable tractable power change to a mildly tuned RV8 4:6 which are around for about £600 to £1,000 Osgood :angel:

[neil still building it]

and ALWAYS budget a hundred quid or so on an MSD ignition unit -it makes SOOOOOO much difference (i suspect this is where so much hp / torque ,and bad economy come to that,dissappears on an 'old' engine)- a 6 A is plenty good enough,just wire it in where the coil feed would be after the electronic std version so you get a clean 'trigger'
i had to add a lumenition to help as mine was still points!!

Also simply adding a new cam 'std' makes for good economy-i think these engines, like chevvies, 'eat cams' i e they wear out quite quickly so a gentle fall off in performance happens so gradually you dont realize its a problem.........)i changed a cam and head gaskets on my '68 p6 v8 just before a long 400 mile round trip and economy jumped to 34mpg from its usual best 25 mpg -ish it didn't really seem to drive any better but i think opening the valves to their 'normal' level after so long at a lower lift is what helped......
so don't whatever you do go too wild with the cam -you'll always regret it!! and these days EMISSIONS problems come MOT time........
good luck
NEIL