The helical cut gears are designed to take the whine out as opposed to straight cut gears, although they still have that distinct quickie sound just not as loud. The rear cover is the same.
I run helical gears in my Speedway champ rear end. The gears don't need a different cover. They take 90% of the whine out of a QC. They take a little more power to pull, but not noticable on the street.
One reason racers don't use them much is the higher side loads helical gears place on the cover. In a cruiser, it shouldn't be an issue. But yeah, what fun is it if they're not whining?
Yes, that is the issue..the helical gears push themselves into the bearings of the cover all the time when turning. Weather that is an issue for a street car, I don't know. If I had to guess.....I would say it is not a big deal. I have ZERO scientific information to back that up, I just don't think the load would be enough to hurt anything on your basic 400 horse street car. One way to find out is buy a set and see what happens. Worse case you would wear out your cover bearings and maybe your cover bearing bores, but it is not likely something that will cause instant catastrophic failure. For the record, I like my loud quick change... Good luck, -Abone.
I installed a set in this roadster with a "Red Ram" Dodge engine when it was just built, it has 19,000 mi on it without any problems. Since new, you hear a click at times when letting the clutch out at the start, I thought about shimming the change gears a little tighter, but left it alone. Since the car is light (2,000 lbs) and the skinny rear tires spin easily, we haven't worried about "blowing the rear cover" off.
I have been running them for 15 years with no problems. They cut the noise about 50%. Still noisey though.
The bearings in my Winters rear cover got real loose after about 20,000 miles, I contacted Winters and they have an improved bearing that should last longer. If the bearings desintegrated I think they could do al lot of damage if they got to the gears.
Actually, the top and bottom gear thrusts are in opposite directions, the old equal & opposite reaction thing from Physics Class. So one shaft is always thrusting toward the cover & the other towards the case. When you back uo the thrust directions are also reversed. If someone really wanted quiet QC gears there is a lot that can be done with the design of the teeth. Most modern car transmissions [post 1995] have extra deep tooth forms so they get more teeth in contact. The same "improvements" could be applied to cam and pump drives on engines. That gear whine is traditional though so why fix what isn't broken. Chuck Schultz, PE 42 years in the gear business and still enjoying it.
I have always thought double herringbone gears could be made, but they would be expensive. lapping the gearset might also quiet them down.
I got mine from Speedway Engineering with the rear end. All champ size maunfacturers gears interchange. Halibrand, Speedway, Winters and Frankland gears fit any champ rear end, and from what I've seen, all have the same ratios available.
Some gear sets are louder than others, strangely enough.. I have two sets that are close to the same ratio and one set is way louder than the other. There does not seem to be any correlation in ratio to loudness that I can find, but some sets are definately louder. Also, I noticed synthetic oil seems to make a diffrence. My advise it still to buy a set and try them out. I don't think they would ever cause any catastrophic failure, just might wear your bearings a bit quicker. Or, maybe they won't... Good luck, -Abone.
A lot of gearsets that are close in ratio have vastly different tooth counts. I'd think that the higher the tooth count the quieter the gearset would be, regardless of ratio.
Treb11: The problem with double helical or herringbone QC gears would be insuring that they can still self center under load. One member has to float and the other has to be prevented from floating. Plus herringbone gears tend to be significantly lower in quality [accuracy of form, spacing, and alignment]. The reports of one set being noisier than another are probably quality related too. Lower price QC gears may be finish milled or hobbed while the better ones are ground. Despite being in the gear trade and having friends who could make custom sets I buy mine through the usual channels. Custom ground tooth sets would have to sell for more than $1000 for a qualified shop to be interested in the market.
Yep, one way they'll push against the case, the other way they'll push against the cover. Even helicals will have a slight whine at a certain RPM. Mine talk a little on deceleration between 25 and 35mph. If I turn 'em around, they whine at the same speed, but on acceleration. Pick your poison.
After thousands of miles it seems to me that they have gotten quieter. Or its my imagination and I'm just used to it? It's really not even noticable to me anymore.
Can someone tell me if when using the helical gears you need to use two spacer shims ,one on each pinion shaft or just one on the gear that pushes against the rear cover . Thanks
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