Greetings Everyone, I am getting my Model T ready for a tour to Okochobee FL this weekend. I installed a high compression aluminum head (Z Type) with 14mm plugs (Autolite 66). The car ran great before changing the head. I now have a high speed miss that is only slightly helped by retarding the timing. I initially had the new plugs gapped at .035 then changed the gap to .025 (miss was slightly helped by this) I have a 26 roadster with a freshly rebuilt engine. I am running a Texas T Parts distributor with electronic ignition, and a Mitsubishi alternator all on 6 volts. I have checked the fuel filter in the sediment bulb and it was clean. Does anyone have any ideas as to it's origins?
THANKS IN ADVANCE!
It is time to change your plugs!Honestly,pickup a spare and try it in each cylinder and see if anything changes.
I put 4 new Autolights in my T pickup projects engine,2 have croaked and it aint been drove probably 30-40 miles,just short trips around the hood since it was running Christmas.
I had a problem with my t doing the same thing & it drove me nuts till i figured it out ,i ran a ground wire from the dist to a good ground & the miss was gone .but on my other t the dist isnt grounded & ive never had a miss,i think its just like a t model 2 are not alike.....
I think you may have the wrong choice of plugs. Try to get a plug with a fairly high heat range. That seems to work for me. Not sure what range the Autolite 66's are, but the fact that you could somewhat alter your problem by altering the plug gap tells me that plugs are the issue.
I had a problem in that my car wouldn't wind out at high RPM's. Even the "X" plugs would fail. I changed to Bosch 4302 plugs and have had the same set in for 3 or 4 years. You need adapters but the price and common availability beats the X plugs. They are now in all my T's. Autolite 66's are too cold in heat range. My $.02.
High Speed Miss; Didn't I know her ?
Are the Autolite 66 plugs the one's recommended for your Z head?
I'm thinking they may have too much reach?