Serious Tech!!

[hglenn55]

I'm on the inside of my FZR 600 engine and I have just completed port matching and polishing the head (If you want to do it yourself go www.samotorsports.com/diyports.shtm). Now I want to gather information on lightening and balancing connecting rods. I don't really want to lighten them but I want them polished and the rough edges taken off. The I want to weight match them and make sure they are balanced. Yes I could take them to a shop, but this is a garage project that I want to do myself. If I screw up and blow it up I'll build another one, but I want to do it. Trolling the internet can be frustrating if you don't key in the right words in google. Any help would be appreciated and I will continue to post tech sites as I find them.

[dragracer1951]

remove material from rods without re shot peening will make the motor go bang


polishing rods without re shotpeening will make the motor go bang


But you're gonna do what you're gonna do....

[DAVE]

polishing rods without re shotpeening will make the motor go bang

Why is it so

[dragracer1951]

because shotpeening is a process by which the material is strengthened by almost cold forging...the outer layer of material is harder because it's been bombarded by thousands ot strikes from steel balls. When you polish after shotpeen, you remove that stronger layer of material, weakening the rod. It WILL fail

[hglenn55]

But can you give a more detailed explaination? I understand what you are saying and why, but there seems to be contradictory info (see www.sa-motorsports.com/blockdiy/blkdiy.shtm). In this article it explains deburring and lightening the I-beam and the small end of the rod but it says nothing about shoy-peening afterwards? I know shot-peening works I've used it but the explaination that is given also seems to make sense. Give me more info someone!

[hglenn55]

Drag I just visited your website and I must say I am impressed! I have zapped a email to the website I have been using to gather my microscopic knowledge and asked about any other processes that may need to be done. I am a social engineer not a mechanical one so I conceed(?) the field of honor to you. Lead the way and I will follow OK that was a bit corny but hey how else do you tell someone that you know they are politely calling you an idiot I stand corrected!

[dragracer1951]

I just read the site you posted and was a little surprised that they would post such stuff.
They are however in the business of selling flap wheels...
Removing parting line markes and flash is a good thing...However adding a rad in excess of about .02 is not the hot ticket as the shotpeen process is going to increase that rad to .04 to .06 depending on shot size and intensity and coverage...

[hglenn55]

The depth of the shot-peening is probably not deep enough for the flap wheel. I've taken a rod that was burnt and practiced on it. Even a light hand produces dramatic results when you are trying to remove manufacturing imperfections. I have also looked into sites which cater to 4-stroke outboards and they have write-ups on lightening rods and they preach the same gospel as sa-motorsports. The rod is show after a flap-wheel and as it does not appear to have been peened. Maybe the difference in the process is the fact that sa-motorsports is utilizing torque monster car engines and not rev monster bike engines? I don't see how this would make a difference but I trying to figure this one out.

[F5]

In production especially in the old days Rods have Stress Raisers, sharp edges that will promote crack from those points. Removing these areas is clearly a good idea.

However with the way rods are made they end up with a toughened skin which is a integral part of the strength of the rod if under decent load. So removing this is bad news. Further designers have gone to some lengths to remove these points in production. As Jim Sez, get it shot-peened by a crowd that know what they are doing after.

Or don’t bother polishing. That said the FZR600 did have a tendency to aerate their crankcases when raced or given severe hard time. Some of this was down to the small ends ovalising or something [strains, memory goes -buuuur- file not found].


I'd say they are trying to sell their wares & any excuse to sell them the better. To be honest polishing the ports is often debunked & Yams of that vintage are generally better off with their ports smaller as well. A friend did this to a 600 he was tuning but I never found out what the outcome was, but he usually knows what he is doing.

[Hooligan]

listen to jim and f5, they know their stuff. no job is out of the hands of a good do-it-yourselfer, but these guys will give you good advice!

trust me, i have bugged them both plenty of times.

[DAVE]

Thanks Jim for the insight. That seems to make a bit of sense at least, I wonder if the shot peening does also evenly stress relieve the surface of metal in the rods, preventing cracking..

I see in one of the Aus. motor magazines (Street Machine) where a lot of high performance parts are being cryotemp processed in liquid nitrogen to -198c, making them stronger and relieving stress. They were doing engine blocks, cranks, pistons, gears and even brake rotors.

[dragracer1951]

Yes ...shot peening is used as a stress relief process .
Cryo peocessing is also a stress relief process. I shoot big handguns (XP100 remington and Contenders) and have had a couple barrels cryoed. The accuracy is quite improved due to stress relieving. The advantage of shotpeening is the added strength it imparts to the part...

[hglenn55]

The light just went off! I think I'll leave the rods alone and move to something else. I have enough rods that I'm weighing them and finding four (4) rods that arae close to the same wieht and yes I have a very very good electronic scale. My next tech question is this. The pistons on the FZR 600 look like a moonscape on the top. has this area also been peened or is this just poor manufacturing? sa-motorsports also has the section on piston polishing, but I don't like the area were they want the skirts hard edges smoothed. this just seems like you're asking for trouble? Polishing the roof and walls I can understand because it's a pretty even process, but smoothing the skirts seems like it would/could lead to a unbalanced piston? Teach me?





F5 If the first thing out of my mouth is "You have the right to remain silent...you have a problem

[dragracer1951]

there are a couple schools of thought on the polishing of pistons
The rough surface is the as cast finish of the stock piston. The thing is that that surface will lightly carbon and promote turmulance in the cyl and promote cyl filling
Sometimes you don't want mirror finishes in the ports either for just that reason...

[hglenn55]

I was thinking along the lines of a polished exhaust port. I have been told and read that a mirror finnish port on the exhaust is what you want to decrease deposit build-up. It's harder for carbon to cling to a very smooth surface. Would it be better to have fewer deposit's junking up your charge (when they break lose) or a clean chamber that allows even turbulence? I'm thinking along the lines of aero-dynamics related to the skin of a bike or car. Objects flapping in the wind are not a good thing. Drag is there a form of laminar(? spelling) flow inside the chamber? I know there is in the intake port. The intake port of my head was smoothed almost to a mirror finish then I made lateral scratched using a rough sanding drum. As the air charge flows over the troughs they should tumble and produce so-what even turbulence (I hope).

[dragracer1951]

How smooth the intakes are is dependent upon the combustion chamber shape, port shape, compression ratio, number of valves, rpm range...lots of things. I've never heard of putting lateral grooves in the ports though

[hglenn55]

I'm not saying the grooves work I just listen and try to take the most logical (in my mind anyway) step. I was working at a site were they where in the process of building a large concrete canal. At over-passes and feeder intersections the engineers were placing what looked like speedbumps at the bottom. I asked what they were for. One engineer stated that it was something that he wanted to try. At the points I just mentioned he stated that debris has a tendency to accumulate. The speedbumps were to cause a rolling turbulence in the water. When the current was strong and fast enough it should break up the jams. After it was build I when down during a storm and saw that there was alot of large particles floating or being kicked up. I then went downstream and could see that the larger particles were dragging the bottom and the little/light stuff was floating. When I was polishing the head I thought why wouldn't this work with the intake ports. I know water an air flow differently, but I think they are enough alike to at least try. I doubt it will in anyway strangle the intake charge, it may have no effect what-so-ever, or I might see a quarter of a horsepower

[dragracer1951]

I always take a casting of the ports and pour a plaster head...install the valves and set the valve opening and piston height and take flow tests there. It's very easy to build a home made flow bench that will gain you noticable results. I can then see readily what will and what will not make an improvement. At that point ...it's pretty easy to put into a cad file and program from there. Put the head on the machine and push the button. Then go get a coke...
Or Dr Pepper. Your choice

[FZRDude]

Iced Tea (sweet)... hes from the South

[dragracer1951]

Well then....Wouldn't that be Sweet tea????
Not Iced tea...

Snerk