| Author | Message | ||
     Teddagreek |
My Neighbor is a old Harley guy he's got slew of bikes, He's in some club thats pre 50 bikes only.. He's always been very cool to me and let me use his lathe if I needed it.. Couldn't ask for nicer neighbor.. We where talking about my bike and fan and what not and asked me why they didn't do a Finned Rocker Cover if heat was an issue. He went on describing some old bike that had them. Would a finned Rocker Cover help? An Actual Decent fin, not these 1/4" cosmetic things you see once in while.. | ||
| Rubberdown |
I think it's a great idea. Any clearance issues? | ||
| Ustorque |
i think your problem would always be that the airflow to the rear is so limited due to its positioning that it would not make a difference. i could be wrong! | ||
| Bombardier |
If you have changed a head temp sensor you will see how far the cylinder actually is from the top of the rocker cover. It couldn't hurt but I don't think it will make much difference at all. Better to get the sensors and tuning right first. | ||
| Teddagreek |
I don't think anyone makes finned cover that would fit or at least a decent one... It would have to made.. You figure guys are paying 2 Bills Plus on Right side scoops I really love the look of these Original Indians..  | ||
| Corporatemonkey |
Would it cause uneven cylinder temps? Wouldn't that effect emissions? Power? | ||
| Teddagreek |
You gotta figure the temps are already uneven without help from fan or from the scoop... I really don't know how much it would help if any but I'm curious if my Old School Neighbor was right.. As far as old bikes the guy is Aces,He machines tools to work on his and friends bikes, They also make parts.. | ||
| Jayvee |
It would have to help, that's just physics, but how much? Not worth it, an oil cooler would be more effective. But even so, I bought some of those 'cosmetic' billet finned covers from Cycle engineering, just because to me they should be finned, that's all there is to it. Not doing so is an economy move on the part of the manufacturer. If money were no object they would be finned. If you can do it, do both, not just the rear. The back one needs it more, but the front one gets enough air that it would be more effective. But still both would benefit. If I were able to cast and then machine them, I would do it. (Message edited by jayvee on May 19, 2008) | ||
| Rich |
You only have so much clearance for the rocker arms, then add to that the height of the fins, and you might have a problem with clearance to the head. Heat travels to a point, if I remember rght, so maybe machined groves in the covers might help some. Good topic. | ||
| Djkaplan |
"It would have to help, that's just physics, but how much?" This is a very interesting subject. I concur with Jay here... it will help, but not nearly enough to justify the cost or effort. Rocker covers are one of the very few places on an engine that fins would actually be somewhat effective (as opposed to a sump) because of the very thin layer of oil that constanly splashes and coats the insides of the covers. However... it wouldn't be a very efficient way to try to cool the entire volume of oil because of the very small surface area inside a rocker cover and the fact that these covers are usually buried inside the confines of a fairing or compartment (in automotive uses especially). Oil coolers essentially push oil through very thin, flat passages that fold back over on theselves to increase this internal area as much as possible and then locates the whole thing in an area that's much cooler to begin with. It's the thin layer of oil that's the key to oil cooling, but there just isn't enough area inside of rocker cover compared to the volume of oil that needs to be cooled. So the answer is; it's not going to hurt, but the results will be negligible. This was outlined really well in a classic book by P.E. Irving; "Motorcycle Engineering". Kevin Cameron used it as resource for a TDC column on this very subject in Cycle Magazine years ago. For some reason, I never forgot it. | ||
| Jayvee |
Not a very good picture, but one I had. No access to machines, nor knowledge, skill, nor time, so I bought these sort-of-crappy cosmetic billet covers. They are way the f%&^ over-priced but whattaya gonna do? They even shaved down the one for the rear, for clearance on a Sportster, and they wouldn't trade me for a non-shaved one. There's room for MUCH higher fins than this, maybe 1.75 inches? These are like quarter inch fins. I did have to file down the left-front corner to clear the hanging mount. Don't forget to leave clearance for the wrench to get them on and off! Real pain!  | ||
| Blake |
To remove heat from the cylinder head, the hot thing that needs cooling, it must be able to be conducted to ambient air or an external radiating surface. Gaskets are poor conductors of heat. The rocker cover is separated from the hot cylinder head by a relatively poor conducting gasket interface. The upper parts of the rocker cover are even more isolated from the high heat. I don't see a lot of added cooling coming from fins on the rockerbox cover. | ||
| Djkaplan |
"I bought these sort-of-crappy cosmetic billet covers." Hey... those look great! Never seen those on a Buell before. That's damn good bling! | ||
| Djkaplan |
"Gaskets are poor conductors of heat. The rocker cover is separated from the hot cylinder head by a relatively poor conducting gasket interface. The upper parts of the rocker cover are even more isolated from the high heat." Those 3 observations also make the inside surface of the rocker covers a better path for heat transfer when hot oil is splashed on them. Fins on rocker covers will shed heat... just a neglible amount though. | ||
| Teddagreek |
When I first I got my bike, I was getting cooked prior to knowing about and getting Odie's heat shields... I shot the motor and exhaust all over the place with my buddies Thermo Gun trying to figure out where the heat was coming from.... I don't recall any seeing a drop in temp on the Rocker Covers.. I'll shoot it again and write the temps down once I get the bike back together.. | ||
| Mr_grumpy |
I'm an old git so I remember Suzuki's answer to the heat imbalance on aircooled triples "Ram-Air" That'll do it!  | ||
| Jayvee |
Another useless item I'm looking for is a horizontally FINNED primary inspection cover. Cycle engineering sells Sportster ones, but not Buell, the bums. If I had a machine shop and casting equipment, I would be dangerous. | ||
| Djkaplan |
What about finned exhaust flanges? That would be cool too. I got nothing against a little foo-foo. | ||
| Jayvee |
Yeah we had a long thread on finned exhaust flanges a while back. I tried to pencil-cad some up on a sketch pad, but that was as far as I got on that. Anybody know if ACME sells a 'home-casting kit' ? | ||
| Thumper74 |
Make you desired shape out of wax. Once you've done that, coat it in plaster (anything that will take the heat), then take the molten metal of choice and pour it through a hole in the top of the wax casting, then let it run through. The metal will melt and displace the wax. It's worked for a couple thousand years... | ||
| Djkaplan |
I know a guy who casts with molten lead to make cannonballs. He buries styrofoam balls in sand and pours the lead through a little little hole in the sand. The molten lead displaces the foam but not the sand. Works good, but you gotta stay away from the fumes. | ||
| Arcticktm |
If you want to know where the best places to reject heat are, look where they cooling (water) passaged are on liquid cooled bikes. You will not find liquid cooled rocker covers. Just not an efficient way to get rid of heat that started in the combustion chamber, several inches lower in the motor. Old motorcycles, especially dirt bikes, had big visible fins on the top because they were 2 strokes and the top was the cylinder head. I would bet you would not be able to repeatedly measure any difference in temps that matter (oil temps or cyl head temps). There is also very little clearance from the rocker cover to the frame on modern Buells (my XB, anyway). I would be better off going to a finned seat, to get rid of the butt-roasting effect in the summer! | ||
| Djkaplan |
I think everyone has agreed the cooling would be negligible and it's come down to a bling-thing. "Old motorcycles, especially dirt bikes, had big visible fins on the top because they were 2 strokes and the top was the cylinder head." Old motorcycles have finned heads because they are aircooled, not because they were 2-strokes. The Indian pictured above has a finned cylinderhead and it's a 4-stroke (albeit a flathead). | ||
| Jayvee |
Flathead same as a two-stroke, right? There's no valve cover per se there, underhead valves... But I know guys with V8 car motors with finned valve covers. Similar situation to modern harley. The just should be finned. |
