The V8 Owners Forum -

Hi

Ive been having lots of trouble with cold starts, somtimes firing up on 6 or 7, im using a Mallory unilite, promaster coil, HyFire ignition, Plugs are BP7ES whilst it was on the dyno the operator suggested maybe trying a 6 and/or a resistor plug
Any thoughts

Thanks, steve

Engine spec;
5.0 litre with off set ground 86.36 crank, forged 96mm pistons, steel h section rods, stg4 big valve heads, h404 cam kit, 10.5-1 compression ratio,
cloyes chain and gears
adj pushrods
steel rockers
crane hi rev lifters
Quad Weber 48 DCO/SP’s
John Eales manifolds
helix motorsport clutch
lightened flywheel
Powerlite Starter motor (RAC 318)
oil cooler (Stainless Braided oil lines)
Mallory unilite, promaster coil, HyFire ignition

For the cost why not just get some B6ES's or ECS's, not sure what the licting is now, they will only cost about £10 and you will not do any harm with them. Just keep an eye on temp guage. with the compression your running you should get away with 6's but I'm surprised the 7's are giving you problems. If you put 6's in and have the same problem I'd have a good look at the cap and see if there is any movement, we had to go to a screw down cap on one of the cars because it moved around. If it's only doing it at start up also look for a bit of overfueling with the 48's on choke. Do you know if it's the same cylinders that are fouling, (you could check with a pyrometer on the headers), if it's the same ones then maybe run through the carbs on those cylinders. [/i]

Just out of interest theres a Inovate wideband AFR gauge in the car, on idle its in the hight 10's and low 11's.
One thought was that the fuel was pooling on the carb/manifold seals? so they got changed to some better seals (The old ones were compressing in and causing a ledge), still no luck, thats when the opperator mentioned changing to a 6 plug, also the resistor type plug? not sure if the Mallory stuff should run with R plugs?

way too rich

on idle should be 0.92 on lambda =AFR 13.5 = 2.6 %CO
full throttle from the point of maximum torque to maximum power 0.88 on lambda =AFR 13.0 = 3.8 %CO
accelaration phase from standstill on maximum throttle 0.85 on lambda = AFR 12.5 =5.0 %CO
peak power all ways 0.87-0.88 on lambda
cruise on a road engine 1.05 on a lambda AFR 15.4 = % 0.15 CO for economy

Gil