Category: Racing

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20R – no oil pressure

Chumpy

We have been rebuilding our first ChumpCar. It is a 1975 Toyota Celica. The car belongs to our team mechanic. He has found he has cancer so we have all pitched in to build it for him to race at Daytona.

When we got the freshly rebuilt engine in the car, we found it would not make any oil pressure. We tried priming the oil pump and every other thing we could think of. It simply would not build oil pressure.

After studying the oil flow diagrams, I noticed there was a galley plug in the bottom of the engine. I had noticed that the front and rear plugs were pulled by the machine shop. Of course the builder had replaced those. I called him and asked about the lower one. No one could remember putting that one back.

celica-oil

I really did not want to pull the engine back out just to check to see if the plug was missing.

My first check was to run a wire down the passage from the oil filter to the bottom of the engine on a spare block. I then did the same on the engine in the car. The one in the car would go an extra inch or so.

My next step was to see if I could get the oil pan off with the engine still in the car. There is very little clearance between the oil pan and the cross member.

I began by seeing if I could access all the bolts. I got most by using a short 12mm socket on a wobble extension.
The two right above the cross member I got using a wobble socket.

I had to remove the two engine to transmission braces to get to the back four bolts.

Next, I disconnected the steering rod from the pitman arm and the idler allowing it to drop. I then removed the four bolts holding the motor mounts in place.

I set a jack under the front pulley and began to slowly lift the engine. I had to raise it a couple of inches to get the pan to clear the oil pick up.

With the pan off I could easily see that the lower galley plug was missing.

oil-galley-plug

I pulled the one from the spare block and transferred it to the engine in the car. Then I had to figure out how to get the pan and gasket back on.

It would have been easier to just glue the gasket to the pan but I used a trick I have learned on the Jeeps. I threaded long wire ties through the pan holes into the gasket. I put one on each of the four sides. I then lifted the pan into place and put on the two nuts for the two studs. I then carefully slid the wire ties out while inserting bolts into the holes that were opened up.

Once the pan bolts were snug, I set the engine back in place and reattached the motor mounts. I then reinstalled the engine to transmission braces and the steering rod.

After refilling with oil, I tentatively turned the engine over. I was very happy to see the oil pressure gauge start to move. We were back on schedule with our Daytona Build.

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Racing at Road Atlanta

2016 ChumpCar race at Road Atlanta

We ran our 1986 Porsche 944 at Road Atlanta.

The car ran flawlessly all day. We got a couple of new battle scars but still drove it on the trailer after the checker flag.

Our pits stops went well and even though our laps times were not as fast as we would have liked, we finished 32nd out of 110 cars. We found that there car can go over three hours on fuel so we skipped fuel on two of our driver swap pit stops. That gained us a lap or two. We completed 338 laps this year in the 14 hour race.

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Lexan Rear Hatch for Porsche 944

Lexan Rear Hatch for Porsche 944

944lexan

In order to improve the aerodynamics of our Porsche 944 ChumpCar racer, we decided to add a Lexan hatch. The ChumpCar rules require all glass other than the windshield to be removed. For our first race, we removed the glass and ran just the hatch frame. After looking at the other 944s racing against us we decided to add a Lexan hatch like they had.

We ordered the material from Five Star Race Car bodies on the advice of one of the other teams. This is the same material sold by Porsche specialty shops for about $100 less. The material surprisingly comes rolled up in a small box so shipping costs were reasonable.

Since we already had the glass out of the hatch we were able to start right away. Removing the glass from the hatch frame is challenging and requires a lot of patience. I have seen youtube videos of people breaking theirs out but they still had to deal with all the little pieces in the channels. I used an oscillating tool to cut the bonding material and carefully removed the glass. I had a heat gun for some places but mostly where the bonding material was cut, the glass lifted out.

We began by laying out the screw holes making sure there was no more than ten inches between holes. We paid extra to have the material cut to the size of the original rear glass. We may have been better off buying the oversized version as ours was just a little smaller than we would have liked.

We marked and drilled all the holes in the perimeter of the frame. Then we set the Leaxan in the upper groove and pressed it into place. We then carefully drilled through each hole into the Lexan. I found that if the bit ran too fast, the material would melt rather than drill and would refill the holes when the drill bit was removed. After a few holes I had the technique down. The biggest trouble we had was finding the right place to drill the holes. The best spacing away fort eh edge of the window put us in a ridge on the inside of the frame. This caused some of the holes to be angled which gave us trouble later.

We used a hand brace and a large drill bit to cut the counter sinks. We used the screws provided in the mounting kit from Five Star. The kit seemed a good value as it came with the right screws, locking nuts and a drill bit.

Due to the way the nuts hit the back of the frame, the ridge caused the nuts to not seat right. We ended up using a cutting tool to notch the frame at each of the screw holes so the nuts could sit flat. This also allowed us to use the shorter screws in the kit allowing the hatch to fit better when back on the car. Notching the frame took away some strength but once careful handling allowed us to get the Lexan mounted without it bending. Once the Lexan was in place the rigidity returned.

We added the two required one inch wide aluminum strips over the hatch and bolted them top and bottom. We then put all the rubber trim pieces back on the hatch to cover the holes and retain the look and function of the original spoiler.

The new hatch is very light weight and looks nice. We hope the performance improvement will be worth the cost and two weekends of work required to make the swap.