Thanks chuffer, the 45 ts are the hotter one’s ?
To be precise they are R45TS to give them the proper code and the 5 is the heat rating on a rising scale and a hotter plug . Hot rated plugs can cause pre ignition on high compression engines but I have not had issues with the 9 : 1 comp ratio . If you go with NGK be aware their heat ratings are in reverse order to AC Delco , ie lower the number the higher the temp rating .
Hmm that’s interesting, very occasionally I have had like half a rotation run on , I am running ngk ( or were they champion)
but correct for my motor. Think I will try the ac delco ‘s
I have had that with NGK plugs when the engine was brand new - I would run-on for a few revs. Bearing in mind the engine has a 'cam' it seemed to needed a fairly rich idle mixture due to the reduced vacuum created by the cam. I put if down to carbon deposits from the rich mixture settling on what would have been freshly machined sharp edges to piston valve reliefs. And it did go away after a few hundred miles. However due to a lot of use in urban traffic and that idle jetting actually works up to 1000/1100 rpm (and only then transitions on to main jets) it would usually foul-up and eventually short-out one or two plugs every year or 18 months.....even using a MSD ignition.Hmm that’s interesting, very occasionally I have had like half a rotation run on , I am running ngk ( or were they champion)
Useful info ross,
when I fit the new plugs it will be interesting to see how clean or dirty the old plugs are. They have been in there since I got the 72 4 years ago but probably only have1500 miles on them. The motor has done 5500 since the rebuild. I have never had a very smooth transition from idle to main jets, (especially if driving gently) is that just a feature of a 50 year old carbureted motor or something a good Holley guy can “tune “ out ?
Have to say that it took me quite a while over a period of several months to 'optimise' the transition 'issue' going from idle to main using the 'Old school' method. Other things seemingly unassociated come in play - ignition timing and the advance curve and engine temperature.Useful info ross,
I notice mine is worse for longer if left unused and much better if car driven 2/3 times in one week. Also much better when properly up to temp, saying that, it still runs very cool and will sit in traffic for as long as needed. The PO in buffalo ny did re curve the ignition timing , I will dig out the notes he sent over with the car
autolite plugs arrived from john wolfe racing , a blast from the past 44years plus, since I went to their shop at staples corner. We went up from cornwall a few times to the Battersea cruise nights.
I remember going up to JWR for bits up at Staples Corner just under the flyover. Didn't last long there unfortunately.I notice mine is worse for longer if left unused and much better if car driven 2/3 times in one week. Also much better when properly up to temp, saying that, it still runs very cool and will sit in traffic for as long as needed. The PO in buffalo ny did re curve the ignition timing , I will dig out the notes he sent over with the car