On bank holiday Monday I went to Baccaman's place to collect all my engine parts that he had machined for me. He had a problem with the block I supplied him(bad scour marks in the lifter bores) so another one had to be source and I found two(thanks to Latil) but they too had problem so in the end Baccaman had one and he used that and bored it to 40 thou and fitted main cap studs and zero decked it as well. He also polished as set of fully floating rods(which he sold me) and balanced the whole rotating assembly for me(with such light pistons and lots of weight taken off the rods Jon had to heavily drill the crank to balance it). With all that done I could now start my build. On Friday evening I stripped all hardware off the block and checked the ring end gaps and found them to be tight(16 thou), so I filed the rings till the top ring had 26 thou clearance and the second ring had 20 thou, with that done I could clean the block and start assembly. On Saturday I took the block to my work to clean it and when I got home I started assemble but hit a problem with the first thing I tried to installed. The cam bearings supplied by Mancini were for a big block so I spoke to Baccaman and he said I could swap the ones I had for a small block set he had and I will do that next week. There were a couple of other things I could do in the mean time so I installed all the block hardware and then checked the main bearing oil clearance. I installed the main cap studs and lay the crank in and using green installed I bolted the crank in and found the oil clearance to be perfect. I them moved on to the piston and rod assembly. I cleaned the pistons and rods and put them together made all the easier as the rods were fully floating but the gudgeon pin clips were still a bit fiddly. With that done I fitted the rings and called it a day. once I get the correct cam bearings I can install them and get on with the assembly.
Nice new shiney parts Anton , bet you're lookin forward t building this.
Are these thye hypo pistons? . just wondering why the large ring gaps? , while you're at it cut the 2nd ring .002" smaller than top ring , the engine will thank you for it.
The pistons Are Kieth Black KB167 and the instructions say bore(3.950) x 0.0065, which give me 0.026 to gap and after speaking to Baccaman he suggested 0.020 as my second ring gap as KB doesn't say what its meant to be.
I use the KB pistons with the raised "D" shape on the top that fills the quench area of the open chamber head.
One modification I always do with new pistons is to round off and smooth all the sharp edges on the piston tops. I never leave them looking sharp like those.
Maybe cut the top ring around .030" , better being larger than borderline , these hypers are timing sensitive so ere on the conservative side , second groove is pretty much down from top groove so heat should'nt be an issue , so 2nd ring can be formulated for .0045 x bore , larger 2nd ring gaps help towards cooling the underside of piston/gudgeon pin , maybe not an issue with the hypers but a larger 2nd gap can't hurt , what's the reason for using the hypers over forged? , the forged are a lot more forgiving & will give you some scope if you decide on other avenues in the future.
cheers for the info Brutus.
I am following a engine build in popular hot rodding and they used these pistons and am hoping to get close to 400hp out of a 318.
ANTON wrote:cheers for the info Brutus.
I am following a engine build in popular hot rodding and they used these pistons and am hoping to get close to 400hp out of a 318.
Lets hope you can get better than the hot rod article
Dave wrote:I use the KB pistons with the raised "D" shape on the top that fills the quench area of the open chamber head.
One modification I always do with new pistons is to round off and smooth all the sharp edges on the piston tops. I never leave them looking sharp like those.