The GTM Supercar Build Log

Archive for May, 2009

The GTM has shipped!

Sunday, May 17th, 2009

Finally! The shipping day for the GTM arrived, and everything went according to plan. Loading up the car did not take long at all. As always, Stewart Transport was great to work with. It is going to feel weird for a while not having the car to work on, considering it has been such a major time consumer over the last 6 months.

Preparation for Shipping…Body and Underbody, Wiring Secured

Saturday, May 16th, 2009

Finally…preparing the GTM for its voyage out to Ken ( has begun. Mounted the body back on, tightened up the hatch and hood hardware, secured loose wires in the front and rear, set the hatch and hood in place. Wiring under the engine fuse panel was secured so it will not move around much when the car is driven. The rear two underbody panels were put in place, and the final two skid bars were installed.

Only things remaining are to tape everything up so it doesn’t shift during shipping, and pack up the parts Ken’s shop needs (door hardware, etc).

Took lots of pics tonight.

Fuel Leak Drama and Alignment

Saturday, May 16th, 2009

Wednesday afternoon the GTM left me a present in the form of a puddle of fuel under the passenger tank. I traced the leak to the fuel sender unit mount and when I tried tightening down the fuel sender bolts more the leak got worse. I had to pull the fuel tank (after draining all the fuel) and remove the fuel sender unit. A quick inspection showed tears around several of the bolt holes in the tank gasket. I made a quick call to the GM dealer and they had a new pair for me Thursday morning (decided to change the other tank’s gasket as well since I had the passenger tank out already). Unfortunately the gaskets they received were not the correct ones. I promptly ordered another set of gaskets for 97-99 tanks in hopes that they would work. Luckily, I was able to get them overnighted again and got them Friday morning. They were the correct ones and I was able to swap the gaskets as Gorilla Gasket notes and get the tanks reinstalled in a half hour or so. Quick cycle of the fuel pump shows everything to be OK.

With the fuel situation under control we trailored up the GTM and hauled it to the alignment shop. No surprises (good), and the wheels are aligned properly now.

The GTM ships Sunday morning.

Footbox Cover Installed, Alignment and Shipping Dates Scheduled

Wednesday, May 13th, 2009

Tonight I cleaned up some misc. wiring in the footbox (like moving the wiper harness so it will be more easily accessible after the footbox cover is installed) and installed the footbox cover. This is one of the last things I need to do on the car before I have it shipped out for body work.

Friday the car gets aligned, Saturday or Sunday it ships out for a 2-3month visit with Ken (StreetRodPainter). He has done hundreds of cobra replicas and a handful of other GTMs so I know the car is in good hands and will return in great shape.

The to-do list before shipping the car out is pretty small:
– Make sure all wiring under the fuse box is secured
– Install the last two underbody panels and skid bars
– Alignment
– Put the body back on, tape the doors on, tape the hatch and hood on
– Pack up all the goodies (door hardware, windows, headlight buckets, etc) that Ken needs

Rollbar Padding

Monday, May 11th, 2009

Over the last couple nights I worked on the rollbar padding. Since this is part of the ‘interior’ finish it has to be done nicely like the suede, etc.  The side rollbars are first covered with an adhesive-backed foam pad, then covered with the fabric. The rollbar padding/fabric consists of 3 precut foam backed fabric sheets that are wrapped around the rollbars, and then adhered together. The 3M Trim Adhesive 8090 I am using is very easy to work with, dries fast, and holds very well. Applying the fabric is straight-forward: wrap the piece around the bars, ensuring there are no twists on the visible portions of the bar, and tape in place as you go. Make sure the seams are pointed outwards/upwards so the body covers them when it is mounted.  Once the fabric is pre-fit in place simply pull off pieces of tape in sections, glue the fabric, and re-tape.

Body is on!

Wednesday, May 6th, 2009

Exciting night!  Josh and I removed the body from its 6 month home on the body buck and placed it on the go-kart. I am very pleased with the centering and alignment of the body. There is only one area that needs some modification for fitment and that is the passenger door striker. It will need a 1/2″ spacer, or maybe I will just cut off the striker mount and weld it 1/2″ further ahead. Either way, it looks great.  This is a temporary fitment needed to line up the interior firewall/window behind the seats and get some other interior things in order. The body will be removed again so I can do the rollbar padding, then it will be set back on before being shipped out for body work and final fitment.

Getting in and out of the car is not as hard as I thought it would be. Many GTM builders state it is very hard to get in/out, but I guess being flexible helps. I can just do a one legged squat and sit right in and swing my legs up over the door sill. Getting out is just as easy – no barrel roll needed. 🙂

Passenger Suede and AC Blower Motor Installed

Tuesday, May 5th, 2009

Tonight I tackled the passenger suede. This side went on alot easier than the driver’s side suede. Only two obstacles to work around (the footbox frame tube and the ebrake), and simple angles allowed the work to go fast. Once the suede was on I cut out the vent opening.

After the suede was on I finally mounted the AC blower motor into the passenger footbox and tested it out – works good!

Fuel Line/Loom Secured, Underbody and Skid bars, Passenger Tunnel Aluminum, Sound Dampening

Monday, May 4th, 2009

Productive weekend on the GTM. The fuel line was secured to the chassis with some padded clamps, and then then wire loom containing the fuel system wiring was secured to the main braided fuel line.  When I went to secure the braided fuel line to the frame I realized I had ran the line along the wrong side of the frame, so I had to drain some fuel and pull the braided line off of the bulkheads and re-route it. Kind of a pain in the butt, and resulted in a nice gas-fume headache. The hardlines were also secured to the frame.

The engine underbody panel was secured to the frame with the skid bars and the remaining exposed holes were screwed in for easy removal in the future. The previously ‘screwed on’ removable engine panel cover was riveted on instead since I made the entire panel removable. The engine panel piece was also covered with Dynamat. 

The last remaining passenger tunnel aluminum piece was riveted to the frame, then covered with Dynamat and Dynaliner – just needs suede!

My old college roomate came down to visit today and check out the build so I gave him a quick spirited ride in the go-kart. Definitely got on it a little more than last time. This thing is a blast to drive.

Coolant Fill How-to

Friday, May 1st, 2009

Since getting the cooling system filled was pretty annoying, and the FFR manual doesn’t help AT ALL, I thought I would post a step-by-step as to how I did it. Thanks to Henry over at the forums for helping! 

Before I get started it helps to know that you will be using 4.5-5 gallons of coolant.

1. Fill surge tank – should be able to add almost a gallon of coolant to it. Leave the cap off the tank.

2. Disconnect the upper radiator hose on the water pump.

3. Disconnect the bigger of the two ‘smaller’ hoses on the passenger side of the radiator. The hose you want to disconnect runs to the surge tank.

4. Disconnect the two steam vents at the top of the heads on the engine. You only need to open the vents on the belt side of the engine.

5. Start pouring coolant into the water pump hose that was disconnected previously in step 2. When coolant starts overflowing out of the radiator connect the small hose back to it.

6. Keep pouring coolant in until coolant either comes out of the steam vents, or it comes out of the water pump port that is open (from the hose disconnected in step 2).

If you cannot get fluid to come out of either location without the surge tank overflowing, or just cannot get any more fluid in at all, you have an air lock.  Jack up the front of the car, reconnect the water pump/radiator hose and run the engine at idle (still with the cap off the surge tank and vents open) for a minute, then put the cap on and get the temperature up to 210 by revving the engine in intervals. Shut the engine off, carefully remove the cap, and disconnect the water pump hose from step 2.  You should be able to get more fluid in – if not just let the car sit over night with the front end raised, surge tank cap off, vents open, water pump hose off and elevated. Air will work its way out. 

Repeat step 6 until you get fluid to come out of the water pump outlet or the steam vents. The first time I went through this step I had 4 gallons of coolant in the system. It took a few repeats of this step to get the last gallon in.

7. If coolant comes out of the steam vents connect the water pump hose again, and reconnect the steam vent covers/surge hose. 

If coolant comes out of the water pump outlet then top off the coolant that is in the water pump/radiator hose, and carefully connect it back to the water pump without spilling too much. Coolant should now shoot out of the steam vents. 

Run the engine like you did in step 6 and let it sit with the vents, water pump hose, and surge cap off for a few hours (or overnight like I did). If the coolant drops in the surge tank this means more air was released. Top it off again via the water pump hose. 

Repeat this step until the coolant no longer drops in the vents or surge tank while sitting. To ensure I had the coolant topped off each time I injected coolant with a baster into the steam vents until it overflowed. When it finally stayed at the top, and the surge tank didn’t drop, I knew I had the air out.

8. Top off the surge tank as needed and run the car for a while and observe the coolant circulating once your thermostat opens (you can see it circulating at the bottom of the surge tank). Both hardlines should be warm to the touch. If one is hot and the other is cold then you still have an air lock – go back to step 6 or 7.