Pinto Car Club of America

I have a 1970 2.0 Pinto motor in my sand rail and the guy that had it before me had one or two of the spark plugs pop out once he got it under load going down a sand wash.  During initial warm up everything appeared okay but twice under load a plug popped out after seperate trips to the shop.

I now bought it, tore it down and the pistons have no dings or scratches.  The outer two pistons have carbon build up and the inner two have no build up but I assume this is due to the 4 into 1 Mikuini carb setup.  That will be first to go as it must be a nightmare to tune.  The plugs seem to fit good but they had like 1" long spacers on them to hold the away from the pistons... but obviously (I think) that if they fit right, there would be no way that they could pop out.

So... I am thinking that the spacers just did not fit right and once under real load they pop out, but that would mean the head was decked too many times and then compression being too high?  How can I tell if the head has been decked too many times?  How can I tell if the block has been decked too many times?

What you have is adapters used to allow the use of small thread'd Chev spark plugs because these plugs come in so many heat ranges. Throw them away and use the pluga made for a 2.0L.

How can I tell if the head has been decked too many times?

How can I tell if the block has been decked too many times?

I read the rocker rail to head face is 3.8 in, if you have less...they have been cut.