Sam what shape were his calipers? If doing a depth differential and 5-6 mm error could easily creep in. If he could pinch both surfaces with one tool his thickness judgment may be right on. That said Great Plains heads are not thickened for 3/4" reach and they fit a 10mm plug all the time... I personally like how Mofoco puts secondary plugs in but not how they conduct business.
Matt On Wed, Jun 28, 2023 at 9:28 PM Samuel Spanovich via KRnet < [email protected]> wrote: > Question for all the VW guru’s out there regarding dual spark plug setup, > specifically with AA Volkswagen cylinder heads. > > After one year of use with single ignition (the same ones that made it > across the country with me for the gathering last year), I recently took my > AA heads in to get them machined for a second spark plug, in hopes of > converting back to dual ignition. I told the machinist originally to keep > the same size plug as the original spark plug (12mm x 3/4” reach). > > However just before the machinist was supposed to perform the work, he > informed me that these particular heads (the AA ones) do not have enough > metal up near the combustion chamber and they are not thick enough to > support a 3/4” reach spark plug (he said he measured the width with > calipers, and compared it to an older MOFOCO cylinder head of mine, and the > AA head was supposedly not as thick. > > I asked if it would be possible to machine the second spark plug port for > something smaller, such as a 10mm x 1/2” reach plug. He sounded like it > would physically fit, however he sounded a little hesitant about running > that small of a plug into a fairly powerful engine (~80 HP). > > My question is whether or not it would be safe to have this type of setup > (1x spark plug 12mm x 3/4”, and a secondary plug 10mm x 1/2”). I was > fairly certain older VW heads accepted 14mm x 1/2”, so I was a little > surprised when the machinist said he wouldn’t think a 1/2” plug would > suffice. > > Any input would be greatly appreciated; just trying to make sure I’m not > missing something completely obvious here. > > V/R > > Sam Spanovich > > Sent from my iPhone > -- > KRnet mailing list > [email protected] > https://list.krnet.org/mailman/listinfo/krnet > -- 'Any sufficiently advanced technology is indistinguishable from magic’. Arthur C Clarke
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