2 replies to this topic

[JimmyB]

Does anyone have any ideas on which needle I will require for first start and running in of an engine I am about to build.

 

Specs are as follows:

1293cc

SW10 camshaft

1.3 roller rockers

New 35/29 race spec valves.

Head ported and chambers reshaped to optimal for the cam.

Valve guide bosses reduced bronze valve guides etc

Medium bore lcb and RC40 twin box system

Minispares inlet manifold with HIFF 44 attached.

MED stub stack with ITG foam filter

 

S/C CR gearset

3.44:1 final drive ratio.

 

I cant think of any other parameters that would effect needle choice.

 

Thanks

 

James

[jaydee]

I would get a BBW needle and start the engine with a CO meter in the exhaust, see if you get about 2.5 CO at idle (1200 rpm) and 1.5 at 3500 rpm.

If readings get too high try BDL or even BHD.

You need the engine to run a bit on the lean side during the running in, best bet would be booking two RR session (before and after running in)  with a VERY reputable tuner (Baldwin, Dodd, Slark..)

[JimmyB]

Hi Jaydee, thanks

 

I'm in New Zealand so I will have to look around for somebody suitable. I'll get a hold of those needles and find a good tuner here in NZ.

 

Thanks for your help