Ok guys.....the polishing's done on the PM7, timing cover, Mallory dizzy and Offy 400 heads for my 8BA. Heres some pix... My question is about my Offy 400 heads.... Which plugs should I run with these new Offy heads ? I trial fitted a set of Champion H10's (yeah I know, there crap quality) and also a set of equivalent NGK's....the problem is , they are 4 to 5 threads shy of the chamber. The ground strap is almost UNDER the level of the chamber !! Whilst I know these Offys are all over the place in chamber volumes/machining quality, could it be possible the machined plug seating surface on the topside of the head could be varying in depth ?? I dont think unshrouding the chamber around the plug will compensate for a plug that sits 4-5 threads under. Then I sampled another plug with a 3/4" reach. On all chambers except two in the middle of one head, the plug's threads ended FLUSH with the chamber surface, allowing the ground strap/electrode to sit above the surface of the chamber, but not massively. On the two that were'nt, the plug's threaded end sat 2 to 3 threads ABOVE the chambers surface?? I dont get it? What gives? Question time.... i. What is the correct plug reach required for these heads? ii. How far out of the chamber should the plugs tip protrude? iii. Could the Offy heads machining be that fat all over the place ? Any info would be great !! Thanx.... Rat
Hey Frank, Best thing to do would probably be to get out of flatheads all together. I'll come over and pick that shit up and take it to my place... you get onto the Chev guys for a small block Danny
RB, you can't set anything up if all the depths are not the same. Find a depth gauge and check them all. If only off a small amount you can shimm them, if not you should have them remachined. You can set them up inside or level but they must all be the same and you shouldn't have theds exposed.--TV
you can get copper shim washers for plugs, and set the heights that way,but i guess its a band aid fix. basically im no help at all. i bought my plugs at supa-cheap and screwed em in.(actually psycho boi screwed em in!!. fuck i hope they are tight!! ) great looking shiny bits there.. makes me want to polish my valve covers, but would look a bit too nice on my pile. seeya sunday!
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