As a lot of you know I'm farting about with all sorts of things with my two zeds. Addiction does that to you if you haven't noticed. I've been searching a lot of late on porting and polishing heads. Now I know knowledge is a dangerous thing in the hands of an idiot but I'm prepared to take the chance on this one. Before I "attack" my heads I thought I'd get a bit of practice in on a lower plenum I got from Ross on the tech day. The patient before surgery. By gargoyle123 at 2011-08-03 Now I deal with casting marks on a daily basis so I'm thinking I'll just apply my work skills on this job and get cracking. This mold join is a ridge that sticks up. Now I don't want to remove too much material so I go in a circular motion to knock the ridge off. If I was to go back and forth it would run alongside this ridge and make matters worse. I also don't want to distrupt the flow either so the least I remove, the better. By gargoyle123 at 2011-08-03 A few minutes later I'm at this stage. By gargoyle123 at 2011-08-03 See those little pin holes? I feel it's best to leave them as the turblance they create is like that of a golf ball and will create a lot less turblance than if I chopped them out and increased to volume of the port. And of course you have to go all the way through. By gargoyle123 at 2011-08-03 This is as far as I'm going with this one, looks worse that it is though. By gargoyle123 at 2011-08-03 This as far as I'm going this arvo, tomorrow it's polish time. By gargoyle123 at 2011-08-03
Polish time??? Youve already done it. Leave it m8. There is no evidence to support the theory that highly polished surfaces support better flow than rough ground. Its the shape and angle of the ports and the size of the valves where the real secrets lay! Unless you have a whole yard full of spare heads to fark up and a flowbench to test your changes as you go, like the vast majority of head porters, ur just pissing in the wind by thinking/getting all funky! Ive said this many times in the past, IF the ports look and "feel" good, then your most likely running along with the majority of "commercial" head porters. Some get good results, some get spectacular results but the bottom line is very few of them have actually resorted to destroying some sets of heads in order to find actual improvements and have those improvements actually demonstrable and repeateable. Youve done a nice job there M8! Keep at it! L8r E
Probably the only exception to the no polish rule would be exhaust ports in 2 stroke engines purely to reduce/eliminate the deposit of carbon and ash in the exhaust ports. I used to (as a very young bloke) hand polish the exhaust ports in my race bikes with ever decreasing grit paper down to Crocus cloth and then after that to a mirror finish with Brasso!!!!!! it took frikken hours and hours just to do one pissy port.........gawwwd! l8r E
This is what I did at this end, thinking was to let the air flow at the fuel asap to maximise dispersion ... also important to "match" the ports particularly the intake manifold > head join.
looks like a brumby flap wheel to me http://www.josco.com.au/newsite/jia/products/abrasives/abrasives_jbfw.htm
I have very aggressive tools for my work but for safety I use the sanding wheels on this job. Takes longer but harder to make a blue. I did say an idiot with knowledge is dangerous. I have a plan! Port matching sounds like the go to me so I'm off tomorrow to get some mechanics dye and spray it down the ports to see what's overhanging and shave that off. By gargoyle123 at 2011-08-04 By gargoyle123 at 2011-08-04 Even the locals are interested in what I'm up to. By gargoyle123 at 2011-08-04 So the plan is to get more supplies tomorrow and "it's on". I'll attack the inside of the plenum tomorrow too. God help me.
Hmmm... Just reading that u can use a gasket and machinists dye also John! Whack the gasket on, spray the dye, machine off the edges
Only thing to watch with port matching is gasket thickness, it can throw off your ports by quite a lot. This includes both the head gasket and the lower intake manifold-head gaskets.
Gasket, you getting technical on me? I don't seem to have one of those on me. I don't suppose you have one in your back pocket Jamie? I'll go through the pile of bits stretch sent me and see if ones there.
Hmmmmm... might do! I think I saw a plenum gasket in the plastic box of goodies from Stretch but I'll have a look as well
