Manco Interceptor Refurb.

[dustin.s]

She done! Had to weld on a new bolt on the right spindle because the previous owner had cut through half the bolt. Did notice it until I started putting her back together. Got her up to 31MPH before I got scared and let out. The front end at those speeds is loose. No doubt it would go faster, but I’m limiting the throttle to 10MPH until I can figure out a better steering setup. The 2” springs don’t have a lot left in them. Thoughts!

 

[BaconBitRacing]

I like the kingpin suspension, but I can see it being suspicious when worn and at high speed. Other than that it's setup like any old Manco.

 

[Denny]

Looks great? Not much you can do to tighten them up but new bronze bushings, rod ends and a good alignment.

 

[dustin.s]

Looks great? Not much you can do to tighten them up but new bronze bushings, rod ends and a good alignment.

I ended up adding, by accident, a little positive camber to the right spindle when I welded a new bolt on. I have a feeling when I made the first tack weld it bent the bolt down a bit. I bought new 2” springs from McMaster Carr with a spring rate of 107.83 lb/in. I couldn’t find any information on the OEM spring rate, so these may be over kill. Time will tell.

 

[BaconBitRacing]

A digital bathroom or kitchen scale (don't tell your wife) and a large C-clamp or just you pushing down could get you somewhere in measuring old spring pressure, if you care.

https://www.acxesspring.com/how-to-measure-spring-tension.html This is for calculating the original springs brand-new force. However age can definitely effect stiffness.

 

[G.W]

A digital bathroom or kitchen scale (don't tell your wife) and a large C-clamp or just you pushing down could get you somewhere in measuring old spring pressure, if you care.

https://www.acxesspring.com/how-to-measure-spring-tension.html This is for calculating the original springs brand-new force. However age can definitely effect stiffness.

I just borrow my neighbor's crack scale.

 

[dustin.s]

A digital bathroom or kitchen scale (don't tell your wife) and a large C-clamp or just you pushing down could get you somewhere in measuring old spring pressure, if you care.

https://www.acxesspring.com/how-to-measure-spring-tension.html This is for calculating the original springs brand-new force. However age can definitely effect stiffness.

I appreciate the advice. I’ll see how they work out, if they are to stiff I may end up cutting it down to one inch with a spacer or ordering a lower spring rate and making it a progressive suspension.

 

[BaconBitRacing]

I appreciate the advice. I’ll see how they work out, if they are to stiff I may end up cutting it down to one inch with a spacer or ordering a lower spring rate and making it a progressive suspension.

Even if your suspension is a lil stiff it's better than our rigid karts. I wouldn't cut the springs, mostly just lowering the suspension travel. Dual-stage springs are very cool, be careful with having spring-rates too far apart. Great job with this kart.

 

[dustin.s]

Even if your suspension is a lil stiff it's better than our rigid karts. I wouldn't cut the springs, mostly just lowering the suspension travel. Dual-stage springs are very cool, be careful with having spring-rates too far apart. Great job with this kart.

Cutting the springs and adding spacers will only change the spring rate and total travel. It’s a linear equation. Spring rate with the new springs will be about 216lbs for the 2”. I bought 6 springs for the price of 2 off any go kart site, so no reason not to play around.

 

[BaconBitRacing]

Cutting the springs and adding spacers will only change the spring rate and total travel. It’s a linear equation. Spring rate with the new springs will be about 216lbs for the 2”. I bought 6 springs for the price of 2 off any go kart site, so no reason not to play around.

Oh, then by all means experiment around.

 

[dustin.s]

Got the new springs installed. I didn’t realize when I put it together how much the original springs had sagged. Close to a 1/4” shorter over the new 2” springs. The springs took a lot of extra noise away when driving, increased the feed back in steering and took away 90% of the slop. Not sure that the spring rate is much different although there is a difference in diameter.

original spring: ID 0.745”, OD 0.995, wire dia. 0.1235, spring rate unknown
new spring: ID 0.635”, OD 0.875”, wire dia. 0.12,spring rate 107.83 lbs./in.