Noz Posted May 4, 2012 Share Posted May 4, 2012 Just read something back along about this. Has anyone ever done it? Quote Link to comment Share on other sites More sharing options...
Ricky49 Posted May 4, 2012 Share Posted May 4, 2012 Proberbly Rob Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 4, 2012 Share Posted May 4, 2012 Proberbly Rob Nah, he's gold plate them! Quote Link to comment Share on other sites More sharing options...
antno Posted May 5, 2012 Share Posted May 5, 2012 Porsche factory used to do it back in the day on there race car rods. Just from half way down the main body of the rod to the little end. Think it was to do with surface blemishes causing cracks. I suppose today's forging methods are better than the 60s 70s and it's not required. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 5, 2012 Share Posted May 5, 2012 Polishing things like con rods etc was mainly done to help strengthen, and remove any stress risers, IE casting marks etc, with con rods it was usually done on the front and rear faces, and not the sides, the trouble with polishing is that it also needs to be stress relived afterwords, as the actual polishing imparts stress of its own, so the usual format was to then shot or bead blast the surface afterwords. Quote Link to comment Share on other sites More sharing options...
Noz Posted May 5, 2012 Author Share Posted May 5, 2012 Yea a radius would definitely reduce chances of cracking spreading the stress I'll have to see what they are like when I take them out. Can't wait to get on with this summer I'll probably just leave them if they seem ok without any obviously issues. No point in mucking about with the surface too much if I can help it, thought I'd ask though. Quote Link to comment Share on other sites More sharing options...
Digsy Posted May 5, 2012 Share Posted May 5, 2012 Polishing things like con rods etc was mainly done to help strengthen, and remove any stress risers, IE casting marks etc, with con rods it was usually done on the front and rear faces, and not the sides, the trouble with polishing is that it also needs to be stress relived afterwords, as the actual polishing imparts stress of its own, so the usual format was to then shot or bead blast the surface afterwords. Shot blasting can improve the fatige life of a stressed part like a rod. It pits a small amount of compressive stress into the surface, which must first be overcome by any tensile stress before the suafeca material can be "stretched". Its like a chaep alternative to fillet rolling on a crankshaft. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 6, 2012 Share Posted May 6, 2012 You mean like this? : http://www.chriswilson.tv/mugen_parts/mugen_parts.html These are some photos of the titanium rods in my Mugen V8. There are some photos of the liners, too. Quote Link to comment Share on other sites More sharing options...
Noz Posted May 6, 2012 Author Share Posted May 6, 2012 Any reason you polished them chris, also where they are sides you didnt polish for any particular reason. Did you blast them afterwards? Sorry for lots of questions. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 6, 2012 Share Posted May 6, 2012 I didn't do anything to them, that's how they come new. The polished bits are the bits where the tension and compression stresses are the greatest. The black coating is some sort of special graphited impregnation, as Ti galls against normal steel, so the coating stops material transfer. Unless your engine is going to turn a lot of revs there's probably no point, and if it IS going to run high revs you need some decent aftermarket steel rods, IMO. Quote Link to comment Share on other sites More sharing options...
Noz Posted May 6, 2012 Author Share Posted May 6, 2012 I work with all sorts of different metals, and didn't know Ti galls on normal steel. Good piece of information there for future product design considerations! What do you class as alot of rev's? I was hoping for 272 duration cams so not going to need anything silly with the power band. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 6, 2012 Share Posted May 6, 2012 Over 7000 you should definitely be using better rods. There'll be no need to go over that on a 3 litre turbo with those cams, they are pretty mild. Of course, if the budget allows I would always recommend forged or billet rods. Quote Link to comment Share on other sites More sharing options...
Noz Posted May 6, 2012 Author Share Posted May 6, 2012 My aim was to just use TT pistons with just the other NA internals with uprated bearings. I've seen alot of 600hp builds with stock internals, so I was hoping I wouldn't need uprated rods. Jamesy had 800 on his at high boost, though 500 on low boost, what would you recommend for a 700hp build high boost? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 6, 2012 Share Posted May 6, 2012 It's no good using TT pistons without adding oil squirters. the crown design is such it needs the gallery oil cooling. I would want to use a steel carank and rods at that sort of BHP. I have all steel internals in my RB26 and still keep below 650 BHP. A 700 BHP 3 litre will be a high maintenance beast, it's a huge amount of power from a road car based engine of that capacity. Others will disagree, but if you intend to use that sort of power on track it may prove unreliable without proper intrnals. 700 BHP on the road will make for a dreaful car with a lousy torque curve. A reliable 500 BHP with a decent torque curve will be much nicer, IMHO. Quote Link to comment Share on other sites More sharing options...
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