quietest straight cut cam gears?

[CaptSammy]

Is there a set that would be least annoying for a daily driver? Anyone running straights that can testify as to how noticable they are?

Cpt

[vdubin71]

I am running a set of Magnum gears in my 2110cc and I can't hear them at all. I used a brand new case for this engine and a lot of people tell me thats why they don't make any noise. I guess if the machining in the case is near to perfect the gears will mesh properly and not make any noise. Thats just what I have been told.

[Marc]

http://www.shoptalkforums.com/viewtopic.php?t=50550
http://www.shoptalkforums.com/viewtopic.php?t=49221

I would expect that steel-on-steel would be louder than steel-on-aluminum, but the manufacturing process and dimensions seem to have at least as much to do with the final noise level. I ran one set of steel/aluminums for a few race seasons, probably less than 2000 miles, that weren't super-loud but I had to sideline them for excess backlash (the aluminum gear wore much more rapidly than a stocker does...can't remember the brand (maybe from Claude's Buggies) but it was so long ago they probably aren't around anymore anyway. Hoping that the cheapo EMPI steel set I got for a grenade drag motor will hold up better.

[britegreenVWSB]

I'm having the same experience as vdubin71. I have a set of straight cuts (steel on steel) that I bought from Aircooled.net, and they do have a whine, but not annoying at all. This motor has just over 100 miles on it, and the case is new. Another thing to consider, even with new cases, is the distance between the crank bore and the cam bore. This distance varies slightly (we're talkin' thousanths or ten thousanths of inches here) from case to case and that is why VW made so many different gear sizes on stock motors. If the distance between the crank bore and the cam bore is tight - or loose, for that matter - the gears are going to make more noise. I definitely hear my cam gears, and my case is on the "tight" side, but as I said, it is not bad. While driving, the road noise from the tires going over the pavement is louder than the gears. I only really hear them when the car's not moving.

TG

[Marc]

So, that's one vote for John's steel/steel gears, Next?

[Bruce2]

The quietest gears are stock helical gears. If you don't like the noise, don't get straight cut gears. What makes you think you need straight cut gears?

[petevw]

i have a set of straight cuts from ac.net. i like the whine, but the 911 fan also adds to the noise.

Bruce2: running straight cuts in a 2332, 86c cam, cromo pushrods, roller rockers, titanium ret, k-800's, on 48x38 valves.

[milo]

The magnums always seem to be quiet and do not have problems collapsing.. There are two differnt type of cheapo straight cuts I have seen.. There is a DG (DynaGear) that has oval style holes in it.. and a style with round holes in it.. From my understanding the oval style collapse under high spring pressure.. While the round style don't have this problem.. The other difference is the round style tend to sell for around 60 while the other goes for $40-50.. Oh, both of these are louder than the magnums (I am not sure if they are annoyingly loud.. But, they are noticable louder).. The gear mesh and backlash are apparently what determine how loud they are.. The less backlash the quieter they will be...


Nathan

[CaptSammy]

Thanks for all the input guys. Where do you find the Magnum gears?

[milo]

Kustom1 Warehouse has them... I believe Erco does as well.. There may be some others.. But, those are the places I know of..

Nathan

[Kobiashi'63]

My magnums are also pretty quiet....can't even really hear them.

[CaptSammy]

I found what I beleive to be a picture of the Magnums, shows oval holes. Some say round is better for strength, has there been reports of Magnum failures?

[Mark H]

Bigger cams and heavier valve springs create more noise from a set of straight cut gears. If you use a small cam and single springs you won`t hear much whine at all.

[builtbychevy]

Steel on aluminum/ magnesium is a bad idea. To reduce the whine you can have your gears Chromed is #1, Send to REM #2, or Microfinished is #3. We do this to our transmissions and quick change ring and pinions. on a 600hp race car the ring and pinion chroming or rem is worth 11hp

[builtbychevy]

I have interest in using billet cam/ crank journals and or using girdles/ straps. That woud cut down on the block flex and you could use a roots blower with excellent results... anyone have any experience with this subject?