Mud-club

Vehicle & Technical => Discovery => Topic started by: oilburningcossack on November 05, 2005, 13:00:54

Title: V8 re-build
Post by: oilburningcossack on November 05, 2005, 13:00:54: On re-building a V8 3.5 what is the advantages of fitting a 3.9 cam if any
Title: V8 re-build
Post by: Range Rover Blues on November 05, 2005, 14:18:41: Almost all the power gains between a 3.5 and 3.9 are down to the cam.
Title: V8 re-build
Post by: Bulli on November 05, 2005, 15:02:08: yup, rrb is right, the 3.9 cam has more lift and a longer duration which means more go...
Title: V8 re-build
Post by: gords on November 05, 2005, 15:05:05: Would that mean that the ECU needs reprogramming to suit? :?
Title: V8 re-build
Post by: oilburningcossack on November 05, 2005, 17:17:09: Whats an ECU I'm still on carbs :? less to go wrong [-o< well can but hope. On that point I've got a choice of either CD175s or SU's both sets cleaned and rebuilt with new insides which would suite the 3.9 cam the best
Title: V8 re-build
Post by: Range Rover Blues on November 06, 2005, 13:03:30: I'd go SU if I had to, personally i prefer EFi (when it's working) and ours has been ok.
Title: V8 re-build
Post by: Bulli on November 06, 2005, 14:00:26: you get heaps more engine braking through efi...which comes in useful+ no problem with stalling on inclines.
Title: V8 re-buield
Post by: oilburningcossack on November 06, 2005, 16:49:56: So if I go for the efi what dose this mean that i'll need a new fly-wheel for the pick-up point, lambda sensors,pelnum chamber, ecu,injection inlet manifold, injectors,and what else
Title: V8 re-build
Post by: muddysteve on November 06, 2005, 16:53:01: i've got the whole lot inc loom, ecu afm etc etc all except the fuel pump and fuel tank

its attached to a dead 3.5 at the moment. you can take the lot for Ã‚Â£100

Steve
Title: V8 re-build
Post by: Xtremeteam on November 06, 2005, 18:05:31: sod that,fit a pair of su's & get them properly set up
Title: V8 re-build
Post by: hingmy on November 06, 2005, 20:54:17: I agree - for simplicity a pair of SU carbs set up properley take a lot of beating (except for economy).
BTW a 3.9 cam adjusts the timing of the valve opening so tweaking the timing is called for. It will lower where peak torque comes in quite drastically
Title: V8 re-build
Post by: Xtremeteam on November 06, 2005, 20:57:35: Quote from: "hingmy"
I agree - for simplicity a pair of SU carbs set up properley take a lot of beating (except for economy).
BTW a 3.9 cam adjusts the timing of the valve opening so tweaking the timing is called for. It will lower where peak torque comes in quite drastically

steve:please stop backing me up as im feeling thretened :lol: :lol:
Title: V8 re-build
Post by: oilburningcossack on November 06, 2005, 23:40:35: Lets start from the beginning again I have two disco's.One the wife's shopping trolly (a G-WAC) both V8s. Shopping trolly does not need to be a racing machine but will need power/torque as its used for towing.Second disco is for play which will get wet . So I thought that play would have 3.5 with 3.9 cam su carbs (well set up) and every thing that could be water proofed, proofed with all the off road bits. And the G-WAC fitted with injection, gas (twin under sill tanks) and up-rated rear springs, and the gear boxes on both striped and fitted with new shaft and cross drilled cog to get rid of the clonk on take up,I have for the play disco a new distributor with a steel cover and screw in HT leads (if I can get the leads) twentyfive pounds off of e-bay :D
Title: WATER PROOFING
Post by: DISCO-CHRIS on November 06, 2005, 23:56:25: I,VE GOT A WATER PROOF KIT TO DO THE DIZZY+COIL STILL BRAND NEW IN THE PACKET FROM TUFF TOYS IF YOU,D BE INTERESTED Ã‚Â£20? :?
Title: V8 re-build
Post by: oilburningcossack on November 07, 2005, 00:07:03: will it fit this
Title: V8 re-build
Post by: DISCO-CHRIS on November 07, 2005, 00:14:22: GOOD QUESTION?
NOT TOO SURE.
IT,S DESIGNED TO FIT OVER THE STANDARD DIZZY CAP AND THEN YOU NICK LITTLE HOLES FOR EACH HT LEAD TO COME THROUGH AND SECURE AROND THEM WITH A SMALL CABLE TIE.
IT,S MADE FROM SILICONE SO IS QUITE PLYABLE.
:?
Title: V8 re-build
Post by: Range Rover Blues on November 07, 2005, 01:27:13: They're made from dog poo, mine lasted 6 months and then melted into a sticky mass I couldn't shift. I won't be buying another.
Title: V8 re-build
Post by: Range Rover Blues on November 07, 2005, 01:28:16: Quote from: "Bulli"
you get heaps more engine braking through efi..

I didn't know that :D
Title: V8 re-build
Post by: hingmy on November 07, 2005, 13:31:33: Quote from: "Range Rover Blues"
Quote from: "Bulli"
you get heaps more engine braking through efi..

I didn't know that :D

Err Bulli care to elaborate?
I'm pretty sure that engine braking is a result of engine compression and is modified by your choice of gear.
Title: V8 re-build
Post by: Bulli on November 07, 2005, 15:00:07: well im not sure if its a design feature or if mine is weird but i have had a v8 Lr before on carbs and the engine had the tendancy to run away when on steep decents. I had to use cadence braking a few times. The disco is superb and as slow as most of the diesels i go out playing with - simply stick it in first and let the engine braking do the rest- couldnt do that most of the time with my old one.
Me and rolla have noticed it and both well impressed with the performance over my previous " well set up carbs"
Title: V8 re-build
Post by: Range Rover Blues on November 08, 2005, 00:57:53: Actually I'm not too surprised, the idle sytem on an EFi is controlled by a stepper motor, the throttle plate shuts completely, unlike a carb, so you get much higher "pump losses" with an EFi as the idle circuit will shut when the engine is over-run ie engine braking. The throttle plate does make it harder to control on LPG though unless you have a sequential system, so I off-road on petrol.
Title: V8 re-build
Post by: Bulli on November 08, 2005, 01:03:03: Thanks , i knew there had to be a technical explaination. :D