Engine Progress Report

The reground and balanced crank is in. Two of the old connecting rods were a little blued from the spun bearings, but I got lucky and found a never-used set for sale on Craig's list for $100. I got them balanced by House of Balance in Elkridge, MD - the same people who had previously balanced the rest of the engine. Here's a picture of the balance card. The pistons are attached to the new rods and I'm in the process of installing them into the block.

Fuel Rail Mods

The car has braided stainless steel fuel lines with -6AN fittings all the way from the fuel cell to the fuel rail. However the one weak link was the attachment of the ss hoses to the stock fuel rail barbed steel tubes - the hoses were just pushed onto the barbs and secured with hose clamps. I decided to modify the fuel rail to accept a proper -6AN fitting to attach to the ss hoses with a swivel hose end.
I measured the fuel rail tubing and determined it was made from 8mm o.d. tubing. After some searching the Internet, I found http://www.discounthydraulichose.com who sell a line of metric compression fittings and adapters to convert them to JIC 37 degree flare fittings, which will connect up to a -6AN hose end.

The first job was to cut the barbs off the fuel rail tubing - I used an air powered cutoff tool - and filed the ends smooth. Then I removed the paint. The photo shows one of the two barbs removed and I'm holding the 8mm tube nut and sleeve.


Next, slide the tube nut and sleeve over the fuel rail tube, and screw it onto the JIC adapter.


The finished article. I jst need to add some -6AN swivel hose ends to my fuel lines and they will connect right up to the fuel rail - no more hose clamps.


Here are the part numbers from DiscountHydraulicHose:
9605S-06-L08-14 | 3/8" Male JIC x 8mm Tube / M14x1.5 Port (Steel)
9201LL-08 | DIN 2353 LL Metric Tube Nut, 8mm Tube (Steel)
9202LL-08 | DIN 2353 LL Metric Tube Sleeve/Cutting Ring, 8mm Tube (Steel)

Brake Balance Problems

One of the few things we did learn on the MARRS 7 test day before the engine expired was that the car wanted to swap ends any time I got hard on the brakes. Clearly we had grossly too much brake pressure on the rear brakes compared to the front. Moving the brake balance adjuster around seemed to make no difference. Once we got the car home I put pressure gauges on the front and rear calipers and took some measurements while depressing the brake pedal by varying amounts. Plotting the results showed that the Tilton lever-style balance adjuster was not working - the output pressure was basically the same as the input pressure (minus a small constant offset due to the stock VW pressure limiter mounted at the master cylinder). See the upper graph in the embedded Google spreadsheet below. We switched out the Tilton regulator for a (much cheaper) Summit Racing knob-style regulator and as the lower graph shows, we now are able to actually reduce the rear brake pressure by an appropriate amount. Hopefully next time at the track we'll be able to use the brakes properly.



The new (working) balance adjuster. It accepts 1/8" NPT fittings so an adapter to -3AN was required on each side.

2009 Summary

Well the 2009 racing season was basically a bust for the Corrado. After spending the winter converting to a megasquirt fuel injection system, and getting the broken gearbox rebuilt, we were ready for MARRS 7 at Summit Point, WV in July. Unfortunately at the test day before the race, an incorrectly plumbed oil cooler resulted in two spun connecting rod bearings. With limited time to work on the car we switched to racing our ITC scirroco for the remainder of the season. Happily I can report the engine rebuild is well underway with a crank reground by CGM Motorsports of Millersville, MD, and we have high hopes for the 2010 season.