Standard Rover camshafts SD1 v's Rangie ?

[Rage Rover]

Been thinking about detuning my old Rangie based 4x4 . It's a 3.5 on 9.75 pistons , 4 branch manifolds and stage 1 heads on carbs. At the moment i believe I have an RP4 cam in it , i've not a lot of mid range power but when it gets to 3000 rpm it comes on song with a bang . Not a lot of use on a mud plugger with huge tyres and an old 4 speed manual box .

Anyway , I was thinking of going back to a std cam ( stop the madness )and was thinking of a std 3.5 or even the 3.9 cam to get my low rpm torque back . I see from the rimmer bros website they are listing cams for high compression and low compression V8's with different part numbers ?. Is it an SD1 cam I should be looking at with the high comp pistons or is it one for a low comp engine - is there any differance in the high and low compression cams at all ?. Any help appreciated

[ChrisJC]

I thought that the RP4 was supposed to be a torquey cam?

More cubes is definitely better for torque. Go the whole hog and fit a 4.6 block. My landie pulls like a train from idle.

Chris.

[katanaman]

You might have a bit of a miss match of components there. I though the RP4 cam was for torque as well but headers and stage one might not be so they are at odds with each other.

[katanaman]

Ok I looked up the RP4 and it isn't what I thought. The blurb states its best suited to 3.9 with hotwire injection so it might be the cam that is making the hole in the torque. Their torque max cam might be more what your after.

[kiwicar]

Hi
when you say stage 1 heads, what was done to to them, if they have been opened out to the gasket on the inlet side side, this could be some of the problem here. If this has been done then the fuel could be dropping out of suspension from the incomming charge as the gas speed will drop very low at low revs before the charge accelerates again as it enters the port. Stage 1 heads should be good for torque and pick-up if done correctly, but some tuners open the ports at the gasket face because that is what customers expect.
with regard the cam I agree with those above.
Best regards
Mike

[Rage Rover]

Thanks very much gents , aye , I wish i'd just bought a 4.6 and saved myself all the bother .

My heads are RPI stage 1 and I don't think there is anything massively mentol about them , just mildly ported clean heads . I do have a doubt about the cam , it came invoiced as an RP4 but the box was Piper when I saw it later , bit confused but I assumed it was made by piper .

I'm on the Edelbrock / weber 500 carb . I'm getting not bad power off idle , dull around 2000 rpm , but as I say when you get to 3000 it's like flicking a switch . When I try to dial in more advance it pinks at 2000 I was thinking of going back to my SU's at the same time as the Weber isn't that good at angles even with the offroad needles .

I'd be keen to try the Torquemax if anyone can recomend it as definetely giving me decent low to mid range torque , if not I'd rather go back to a std cam - the engine ran bloomin great before I tried to re invent the wheel

Happy New Year guys

[ChrisJC]

I did use a Torquemax in my 4.6, and it definitely did what it said on the tin. How well it would work on a 3.5 though I don't know. I switched to a Piper 270 as well as porting and raising compression, and it's not quite as torquey as it was.

Chris.

[kiwicar]

It could be that carb, 4 barrel carbs are a bit rough and ready until the engine revs get up above 2.5k, how was it set up? on rollers, or just jetted to engine spec?
Best regards
Mike

[Rage Rover]

Thanks very much Chris and Mike , cheers .

Aye , I was thinking about that carb after I posted . The carb wasn't set up on a rolling road at all . I tried the next size up needles / or jets and it was definetely too rich . I also tried the softer springs on the current needles and it was too rich and fouling up . I'm assuming that at 2000 rpm on a 3.5 i'm miles away from the secondaries opening up . The kick and power at 3000 is also a bit confusing as I don't think they'd be really req'd at that rpm either .

I've had a lot of bother with the Weber carb at any sideways angle offroad with the engine flooding etc so I'm pretty much convinced to slap the SU's back on .I've been looking at that Torquemax cam and it sounds good - is it just RPI that do it ?

[katanaman]

RP4 cam is a Piper cam as are all the RPI cams including the tourque max. You can get a kit for the webber to make it more off roadable. No idea what it is but some of the guys on here use it to good effect. One thing I would suggest is only change one thing at a time. If you go changing too much at once you might get to where you want but cost you too much money or you could easy end up somewhere you definitely don't want to be. Another option could also be choose whatever can you think is best and also use a set of Rhoads lifters. They leak down at low revs increasing the torque. Generally used on lumpy cams to tame them a bit but no reason you cant use them to good effect on a smaller cam to give that extra torque monster effect. They do clatter a little on idle mind you but its a small price to pay.

[Darkspeed]

I was told by a well respected tuner that the stock 3.9 cam is hard to beat for providing a smooth torquey engine and that it works very well with a stage 1 or 2 head tune. SU's are also hard to better for smooth power delivery from a heavy car. And it also all matches with the existing dizzy which is the biggest issue I have found with fitting cams and heads and carbs, the dizzy is completely overlooked and if the sparks are not where they should be the effort and expense is just wasted.


Andrew

[CastleMGBV8]

I would agree with Andrew. keep the heads and exhaust as is and change the cam to a 3.9 one with new standard lifters as you are not looking for high RPM.

V8 Tuner has the 3.9 cam and standard lifters for very good prices, Rimmers and RPI can be very pricey.

http://www.v8tuner.co.uk/product.php?id=62

See how it runs after the cam change but it's certainly worth having the timing checked and you will probably get quite a bit of improvement by increasing the initial advance to 10-12 degrees, should be set with the vacuum advance disconnected also woth checking the advance curve to see if it's actually working properly, igeally you would want it all in at 36 degrees total advance by 3500 but don't be surprised if you don't max advance until 4500 RPM or more.

For the 3.5 with the Edelbrock I found that the 1441 Rods and 1421 jets worked well and gave good economy and that was with standard springs.

The SU's can perform very well for off road use and with some free flowing filters you will probably need to go one needle richer.

Kevin.

Kevin.

[Rage Rover]

Cheers Marki , Andrew and Kevin , really apreciate the replies , thanks .

I've got the offroad needle kit in the Webber and it works great going up and down hills . After advice from Webber i've also lowered the float level a wee bit which definetely helped . On sideslopes it's not that good mind ....The kit is basically spring loaded float needles. Still think the carbs a bit big for a 3.5 , but i've done a few thousand miles and it's always got me home no problem .
Advance is up around 12 at the moment to stop that 2ooo rpm pink , I'm running a Mallory Unilit electronic dizzy . I've had it apart dozens of times changing springs and limiting advance etc . I've got it set up for a straight line curve with all in around 3,500 rpm . None of the dizzy mods have really had much effect on the mid range flat spot though .
The advice about using a std 3.9 cam is what I have heard from a lot of other people and I think i'll maybe go that way . I'll speak to V8 Tuner as I've got a lot of stuff from him and he's a sound bloke .

Thanks very much indeed , gordon .

[badger]

Mate, seriously, take that mallory off and skip it! (And if you ever end up on the phone to RiPoffInternational, don't be suckered in by the total drivel that man spouts about mallory's - he is a salesman, nothing more!) I've had no end of issues with customers cars with mallory's and all have been cured over the years by fitting a good or new lucas dizzy - the type with the amp module on the side.
I had a rangie in with a 3.9, webber 500 and mallory - I fitted a std dizzy to cure all sorts of weird issues (after trying all sorts of "fixes" with springs etc) then played with the carb breather pipes to eliminate some pinking exactly as you describe..... caused by the carbs gulping oil vapour as the secondaries opened. I prefer the webber to the old holley, but I'd still take SU's for general use.
As for cams, well, a lot has been written about 3.9 cams over the years, but i will say this - it is a low-comp 3.5 cam advanced 2 degrees, that is all, no more. (The high-comp 3.5 cam is a softer profile, designed to give a slightly less peaky torque delivery) Most people are comparing a new 3.9 cam (and raving about how good it is for torque etc) after replacing an old worn 3.5 cam which no doubt had half its lobes missing....! If you really want one, then go for the low-comp (SD1) cam (ETC6850 / ERC2003) and invest some money in a good vernier pulley setup to time it to the 3.9 figures. You will end up with a very accurately timed 3.9, better than an original. I have found the standard cams (especially aftermarket versions) to be anything up to 3 degrees out from where they ought to be!
I build a lot of engines to the following spec, which works very well for low-mid torque, and has a good kick at higher rpms as well :-
3.9 block and pistons.
Mildly gas flowed heads (back of valve seat area mainly).
Real Steel Viper Hurricane cam and std followers.
Steel timing gears with vernier pulley.
SU carbs, std filters and BAC needles.

Hope this helps to dispel some myths....?

[Rage Rover]

Cheers for that badger , yeah you've put a few myths to bed there
The mallory comes with a ridiculous advance curve - I'm fed up taking it apart and f'ing with springs , only thing going for it over the lucas is it's not 30 years old . Yeah , sold by a salesman right enough
Ta much for the advice on cams . This was my first ever performance cam and I've been pretty disapointed . Granted , a lot of it is probably down to other factors. Think i'll just go with the 3.5 one while i'm getting the Weber off - my bottle's gone ( mind, i'll try it without the engine breathers first - ta )
Think my mate Ian from Glasgow had his red 90 up to you last month for a new cam/followers .Was out landying with him last week - it sounds nice and sweet
Thanks very very much , gordon .