Monday, June 22, 2015

Getting a Boost, part 1

Long time no blog.  I've been busy with my fledgeling consulting business, my family, and my church.  While I have been enjoying 'Nell', I haven't really made any improvements.

Earlier this year, I finally corrected a grievous oversight and had Uncle Packard drive the car.

Uncle Packard seems to be enjoying himself!
This is the man who gave me so much advice, encouragement, and resources to do the restoration two years ago, and he never even drove the car!  Well, he greatly enjoyed the experience of driving his Mother's last car.  He had two interesting and wise comments:

  • "The car seems to want to go much faster than is reasonable."  I guess that means that my engine modifications were highly successful!
  • "The car could use more assist on the power brakes." I agree... the brakes, even with power assist on the aftermarket front disks, require much more pedal pressure than a typical modern car.  If I didn't know better, I'd even say they were manual brakes.
I've been thinking of improving the power assist on the car for several years.  At the CTCI western regionals in 2013 I remember seeing Gill Bumgarner's '57 with a larger brake booster for his aftermarket front disk brakes.  He explained to the eager crowed gathered around his engine compartment that the stock Midland C3400 booster can only develop about 500psi brake pressure, but that most disk brake conversions need closer to 1000psi.  He had installed a slightly larger booster, only on the front disks, and claimed that the better pedal pressure was much lighter and more typical of modern cars.  

Since I want this car to be easy and non-threatening for anyone to drive, I have been on the lookout for one of these larger boosters for some time.  After doing some research, I am convinced that Gil was using a Midland C490 hydro-vac booster, which is available rebuilt from Cardone (stock #51-9241).  These occasionally turn up on eBay for under $250, and I finally picked one up


The C490B is slightly larger than the stock C3400, but the connections are nearly identical.  
 Since Gil had one under the hood of his '57, I know it will fit.  The next question is if I need to fabricate a new bracket.  Time to check some clearances.

The string is a reference for the hood clearance. The string is straight, but the hood is slightly arched.

5" from the bracket to the string.  

There is an additional 1 3\8" clearance over the brake booster location, for a total of 6 3/8" above the bracket.

The new C490 booster will require just over 5" clearance, once I rotate the clamp out of the way.
This gives me some confidence that I will not need a new bracket.   After I pull the stock C3400, I can dry-fit the C490 and very carefully check clearances.

Before I do, I plan on painting the C490 with gloss black enamel.  I think it will look much better than the 'rust-through remanufactured grey', and maybe even dress up the engine compartment a little.

I need to be careful about this, though, or I may end up buying stainless steel fuel and vacuum lines and chroming the throttle linkage!

No comments:

Post a Comment

I value your comments, and will read each one before it appears on my blog. Thank you for your wisdom and encouragement!