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Saturday Night Racer >> RACE TECH >> Vibrations
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Message started by Dietzsch_Racing25 on 02/02/16 at 7:24pm

Title: Vibrations
Post by Dietzsch_Racing25 on 02/02/16 at 7:24pm

Hi Guys,

I need some help. I am having some vibration issues. I will give you a bit of history... hopefully some of you will have suggestions.

Since 2005 I have run a powerglide in first gear. I have always been told that running in high gear is better because you're not going through a gear reduction in the trans.

In 2013 I bit the bullet and bought a 6.33 gear for Perris. I had a mild vibration at about 5500-6000 rpm. I figured it was my driveshaft and took it to have it balanced. I found out at the next race that it didn't fix my vibration so I went back to my 3.50 rear gear and first gear. The vibration went away.

Later that year, I went to orange show and installed a 7.33 so I could run in high gear. I had the same vibration. Since then I have been running in first gear.

Until two races ago. I put in a new powerglide and a new drive shaft and my 6.33. I had the same vibration. I put a new trans mount in for the second race and vibration got worse.

Does anyone have any idea what the cause could be. It only happens in high gear when the drive shaft is spinning at same rpm as the engine.

I have tried two different transmissions, two different rear gears, two different drive shafts and two different engines. I don't know what it could be that would cause the vibration in high gear but not in low.

People have suggested axles and tires but those are both turning at the same speed regardless of what gear I am in.

Any suggestions would be greatly appreciated.

CD

Title: Re: Vibrations
Post by DaveBauerSC6 on 02/02/16 at 10:48pm

Who built each tranny?

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/03/16 at 7:26am

Hi Dave,

Lukes Transmission in Riverside (red 98 car). He builds the transmissions for a bunch of guys down here.

CD

Title: Re: Vibrations
Post by dirtmopar44 on 02/03/16 at 7:47pm

Sounds like the exact same problem I had. In my case I had to much pinion angle (pinion down at static ride height) but it sure looked OK and I thought there was no way it had to much angle. As I moved it up the vibration went away. You can get wedges to try before you cut the purches loose.

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/04/16 at 8:05am

Thanks Mike, Were you going through u-joints(I am not)? Do you know what angle you started with and what ended up getting rid of the vibration?

CD

Title: Re: Vibrations
Post by dirtmopar44 on 02/04/16 at 10:35am

I don't remember what angle I ended up with. I had the clamp on purches so I just moved a little at a time until it went away. Don't get caught up in the more pinion angle = more forward bite.

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/04/16 at 11:55am

I haven't played with pinion angle at all. It has been what it has been since '05. I haven't had problems with u-joints and I was under the impression that I would be running through them on a regular basis if my angle was excessive.

Title: Re: Vibrations
Post by Chris Swank on 02/05/16 at 10:33pm

this might help
http://www.ringpinion.com/technicalhelp/contentframe.aspx?FilePath=%7e%2fContent%2fHowTo%2fGeneralInfo%2f%2fDriveline_Angles_%26_Vibration.inc

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/09/16 at 9:56am

Once I get everything back together I will take a look at my angles. Thanks Chris.

CD

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/29/16 at 9:30am

Well.... Unfortunately, I still have a vibration.

I started with 3 degrees down at the trans and 11 up at the 3rd member. I put wedges in to get it down to 7 degrees up at the 3rd member. The vibration was still there and I don't think it was any better.

Did I not go far enough? Any thoughts.

I ran decent lap times but I need to get rid of this vibration.

Title: Re: Vibrations
Post by Dietzsch_Racing25 on 02/29/16 at 9:31am

Also a friend of mine sent me this link.

https://www.youtube.com/watch?v=gmV4qwLfOMY

Title: Re: Vibrations
Post by doggie1956 on 03/06/16 at 8:19pm

might want to change the front yoke on the rearend, unless your using the same yoke for both gear sets. We traced one down after three weeks of vibrating and found it was the front yoke.