I was looking through an old GSXtra, and saw that some one was making carbon fiber push rods for the 455. I don't know when the article was written. Is any one running these, or have any information about them? Who is making them? Price? And if anyone is currently running them? Mike Gilbert
Don't know, but I would not use them if they gave them to me. Carbon fiber is great stuff in certain applications but this would not be one of them. Now titanium pushrods could be very cool.
Titanium has a very inflated reputation. I worked with carbon fiber and titianium on a daily basis from '97 to January of this year. I can't really see the advantage in a c/f pushrod, and I see many difficulties in manufacture, such as bond with the ball ends, resin bleed in the hollow part, and voids in the rod itself. C/f is pretty expensive stuff, and it's all hand layup in this application. I'm wondering how repeatability is approached with the c/f rod, and how accurate duplication is in terms of weight for each one. I would be interested in talking to whomever made those rods about the process he/she uses. Carbon fiber is fantastic in carbon/carbon structures such as aircraft, but inside an IC engine I really can't see the point...I'd be interested to learn what the resin matrix is. The Buick 455 isn't a high revving engine, and the question that immediately comes to my mind is: what's the advantage of losing that slight amount of weight from the pushrods really doing for you? Then I'm thinking of the rates of expansion of the steel pushrod and the lifter/rocker vs. the rates of expansion of the c/f rod with the ball ends made of steel (presumably). the expansion factor of the stock rod was considered but what about the c/f rod? The only things that will exapnd are the ball ends, and that makes the bond line on the rod come into scrutiny (part of my job was QA, lol). This idea is making a simple hollw pushrod a complex part...I'd need a lot of info before I used one of these rods, and I'd like a little destructive testing analysis. these things could be the best things ever, but I'd like to see the tests and process. Titanium is cool stuff, bit unfortunately, it enjoys a rep that says it's lighter than steel and just as strong, or stronger. The truth is that it is not as strong as the same part made of steel, it's just lighter. The common form of titanium that I used, Ti-6al-4v, could easily be cut by the machines I used at my last job, whereas the same carbide faced cutters would break cutting the same diameter stainless steel piece.
Not too many years ago, I used to race two different two stroke roadracing 250's. Onwe was a Yamaha TZ250, the other an Aprilia RS250F2. One of my rivals was the Yamaha race team main development person for Team Kenny Roberts, Bud Aksland, good guy. There was also another 250 racer, engineer, resident carbon fibre development person, whom worked at a plastics firm in Texas, Brad Sawyer. We had heard that Sawyer was attemting to build both connectin rods and pistons out of carbon fibre. My shop then, was about 20 miles form Bud's, begind a Yamaha/Honda dealer in Manteca. On one visit to Bud, he showed me one of Brad's carbon fibre pistons. Nice piece. I asked if Bud had treid either/or, and yes he had. Both the rod and the first piston grenaded very quickly. The second piston was the one I saw, it didn't fare well either. When I spoke with Brad, he indicated there were at that time (1990), over 45 different "mixes" of resins for carbon fibre, and were suited for different uses. There's probably many more mixes now. Case in point, carbon fibre is not a bad thing, where it can be used, pistons and rods aren't the place, though. Pusrods aren't, either. INtake manifold, timing cover, oil pan, sure, but not internal parts stressed past the ability of the fibre.
