Looking for a gear drive for a New Century block

In need of a gear drive for a New Century block, RCD no longer offers one, I'm going to call New Century Monday morning hopefully they will have one. Just putting this out there in case they don't, I need it SOON. The Fowler I have now has excessive (to put it mildly) backlash, I've run out of ideas to fix it.

 

Dang you just can't catch a break ...

 

Not a new build. I broke a 4340 crank at the front rod journal after 50 passes. Switched to a Bryant crank last year went 45 passes and found repairable cracks at the same place. I attributed the broken crank to not running a crank support. I did add a crank support for last year but apparently it didn't help. I haven't actually measured the backlash on the gear drive, but I would estimate it is .050-.060 or so. Now I'm thinking that that backlash is causing the gear to hammer/chatter on the nose of the crank causing those cracks. At this point I am very short on time to get ready for my first race. I will call Lowell at New Century Monday and hopefully he can shed some light on this.....

 

I forgot to say I just got the crank back from being repaired and figured I could offset the cover with offset bushings enough to take the excessive backlash out. I tried to do that but I have to move it .065 and that will cause the front seal to leak in the fuel pump drive won't line up. Didn't think I have to move it that much.....

 

Both, equally that's why I think it's the cover. I used offset bushings that are made to go on the cam dowel pin to move the cover. Using the bushings that are offset .065 I get the backlash where it needs to be. I can rotate the position of the bushings to move the cover up, down or towards the cam/crank. When I move it towards the crank the backlash is gone from both cam and crank gears, that's why I think it's the cover. Does all that make sense to you?

 

https://www.rbssuperchargers.com/Pr...ive_Assm._Billet_.250__Raised_Cam--2400-0004F

 

Wizbang, that is the same Fowler drive I have now. I really want something different.....

 

I did not buy the block new, and yes it has always been this way

 

I would think if the cam to crank distance is too much it would be one or the other, not both making the backlash too much on the one the is out. But yes I agree I need to check the distance between the two. I'm going to get ahold of Lowell at New Century first thing Monday to see what he has to say. Maybe he's seen this before.....

 

Thank you! I'll look him up.

 

I searched the ITA forum classifieds and couldn't find it. Are there ITA classifieds on Facebook too? I can only see ITA Tech questions on Facebook

 

Huh I'll look on Facebook again all I could come up with wasn't the text questions group

 

I got a hold of him on Facebook messenger, thanks again!

 

Well turns out the gear drive he has is for a .400 raised cam. I need a +.250. The search continues.....

 

Barry at RCD said they would make the drives if they can get five orders to justify a run. All they need is to make the covers as the BBC parts all swap over and they are still making them. Is it possible that the pin for the idler is off some? Mistakes happen. One time I got a RCD crank support hub that was two thou undersized. I beat the hell out of it before I figured out it was the problem. Never thought it would be off coming from the manufacturer. Maybe Jeff can give you some measuring points and see if it's off?

 

All good thoughts there. I contacted Fowler today and they told me that there was a problem with some of the cam gears being hobbed wrong. There is a new run of them in process, but not done yet. I talked to JR at RBS and we determined that the Donovan gears are the same, so I have those on the way. Time will tell if this is the issue.

 

You are 100% correct, I got the Donovan cam and idler gears from RBS today, the back lash is gone from the idler to cam and reduced, but not gone from the crank to idler. I didn't replace the crank gear because it is brand new from Fowler, figured after talking to them that it would be OK. Now I have the Donovan crank gear coming from RBS overnight...………..

 

Looks good! I was wondering about that ball bearing on the idler...……….FWIW the Fowler gears are black like yours, the Donovan's are a greyish color.

 

Would that crank trigger piece interfere with an external crank support?

 

Good to know