Which Cam For Twin 40's

[tay]

Alright lads.

My GTE on twin 40's is still running poorly after about a year of throwing money at it and getting nowhere :cry:

I'm looking at the cam that i had fitted which was 'supposed' to be the specific cam for twin 40's, but i'm starting to have my doubts that it is the right one......

The one I've got is a piper KBV13285H FAST ROAD/RALLY for a ASTRA/NOVA 1.2/1.3/1.4/1.6 GTE BP285 (well thats what is says on the box) - is this the right one ? I was under the impression that i needed a specific one for the twin 40's as there needs to be more overlap with the carbs than on an injection engine.

If this isn't the right one can anyone tell me for definite which cam i should be using, cos at the moment i'm thinking of going back to injection :(

Cheers for any help

Tay

[Jim]

I've got the Piper Road-Rally Cam with my twin 40's. I think its a 285degree cam. Theres peeps on here with the AST2 cam which is either 290 or 295 degrees.

From the sounds of it, it might not be your cam thats causing the problem. Where are you getting the carbs set up? Are you doing it yourself? If so, then it might be worth taking it to somewhere recommended for setting up twin 40's. Velos (http://www.vmotorsport.fsnet.co.uk) in the Staffordshire area is well recommended by many people on this site. If you can, take a trip over there and see what they say.

Hope this helps

Jim

P.S. Don't go back to injection, you'll regret it soooooooo much ;)

[dathers]

I used to run a gte with twin 40's on and i used a nova 1.4SR 14NV cam and it ran spot on!
Take it somewhere good like velos for balancing and rejetting, i thought mine was running great,i took it to a local rolling road place and got an extra 24bhp,MUCH smoother tickover,dead easy cold starting and used much less petrol aswell.
When you say it is poorly what is it doing?
What is tickover like?
Does it cold start easy?
Maybe the cam you have is just a bit to wild for your tastes.
I have a low milage 14NV cam if you wanna buy that,it has more lift than a gte cam but is a carb cam rather than injection.
Dave

[mikeoxford]

i run an ast2

never had any experiuence with another cam kit so cant comment but i think its great

and comes recommended by velos

[Dan]

Can u please define not running right, abit more info would help us help you alot easier.

[mikeoxford]

if its not running right between idle and foot to the floor - try the emulsion tubes in your 40s

[tay]

Well let me start by listing what has been done to the engine

1.6GTE engine transplanted into 1.4SR shell
Weber Twin 40's (apparently jetted correctly)
Piper fast road/rally cam
Weber Alpha 3D ignition management (replacing distributor)
PMC 4-2-1 Manifold
Powerflow full stainless exhaust



Basically the car has a bad flat spot between 1000 - 2500rpm and just bogs down even if you floor it, then it picks up again - but still doesn't seem to really shift like I would expect it to !

Cold starting is fine (well after a couple of pumps before you start it), Tickover is a bit lumpy (thats what i would expect from the cam though)
The carbs were setup by Southern Carburettors in Wimbledon, who also installed the Weber Alpha ignition management. When they rolling roaded it afterwards it only produced 98bhp at the flywheel - which they said was 'pretty good' ! Thats not even what a standard GTE puts out though ?!?
They seemed to know what they were talking about, as they do engines for Lotus so i would have expected them to take care of me little ol nova !
I will post up the jet sizes etc if that will be of any use ?

To be honest I dont really know much about engines so any possible info / help would be appreciated !!

cheers

[mikeoxford]

for those mods 98 is not good

i got 93 on a standard 1.6 engine running a weber 32 34 and nothing else at velos.

with a shit suqare port head also.

[mikeoxford]

try taking that ignition management system off and whacking the good ol 1.4sr dizzy system on........

[dathers]

My old gte with 40'sand 14NV cam ran 14NV(1.4SR) ignition and put out a tad over 120bhp and gave LOADS more mid range torque,cant remember the figure though,and the sound was sex to your ears!!
It still sounds like a setup prob to me.
Also using different length trumpets on you 40's can make a big difference.
When mine was setup on a rolling road he tried several different sizes of jets to get the best from it,and he recommended to go back every six months or so to check the carbs were still balanced and performing properly.
when i first built it,it gobbled through petrol like it was going out of fashion,it WOULD NOT start when cold on the key,it had to be bump started and it was slower that a standard gte,i couldnt stop smiling on the way home from the rolling road after initial setup,and you could still get 30mpg out of it if you didnt boot it all the time.
Dave

[mikeoxford]

what engine were you running dathers?

[tay]

Hmmm I think ill definetley get it booked in - velos is a bit far from mr though, but SBD is round the corner are they any good ?

[tay]

I think I may have sussed this one out ????

I'm running a facet red top fuel pump which i believe is a high pressure injection type one ? When the engine was originally fitted i only used the one fuel line running to the carbs and blocked off the return one. What i reckon is that the pump is overfuelling the carbs cos theres nowhere for the fuel to return to ?

What im thinking of doing is linking the return back up but shall i do it before or after the fuel pressure regulator ?

Anyone think this could be what the problem is and if so before or after the regulator ?

Cheers