'65 Mustang - Pull Away Problems

[geordie]

Car:

Modified ’65 Mustang coupe. Engine is 302 cubic inch, .030-inch oversize, heads are high flow 351 Windsor 11:1 compression ratio and cam is Shelby hydraulic. Transmission is Tremec TR-3550 manual 5 speed and rear end is 9 inch Ford.
Car is used as a daily driver, traveling approx. 15 miles a day to and from work and some mileage at weekends. Car is not raced or driven hard, most mileage done at less than 50 mph, under 3000 rpm.

Problem:

1. Pulling away from a standing start in first gear is difficult without causing engine to vibrate or judder severely. It is only possible to pull away in first gear slowly and carefully, concentrating hard on clutch pedal release. Pulling away on an incline is very difficult. Moving slowly and smoothly a line of traffic, when coming up to a junction, for instance is difficult. It is currently believed that this vibration is clutch chatter however, I not sure.

2. Clutch chatter seems generally worse when engine is at temperature. Similarly, the car is easier to drive when the choke is out after cold start up.

3. When pulling away at a junction, particularly when turning right, there is often a ‘clunking’ sound from underneath the center of the car and sometimes it appears to come from the rear end. In addition there is a regular thumping sound from the front passenger wheel on pull away especially on a right hand bend. Sounds are always heard when engine is at temperature.

4. All other gears including reverse operate normally with no chatter, apparent clutch slippage or noise.

For the reasons described above there is little pleasure to be had driving the car at present and the inability to pull away smoothly at junctions makes the car potentially dangerous, increasing the likelihood of a rear end shunt.

Bottom line is that with the horsepower available from the engine, I should be being careful not to spin the rear tires at pull away, however, with the current problem there is no way that this is possible.

History of Problem:

Car was purchased from colleague at work with Ford Motorsport clutch fitted. Previous owner had the car for about 22 years and had restored it himself over the last 7 years or so. It was explained to me that the car did have some minor clutch chatter but that given time I would get used to the clutch and be able to minimize this. The previous owner gave me a new more ‘streetable’ clutch disc and pressure plate in the event that I wanted to replace the Motorsport clutch. I drove the car for about four months before deciding to have the Motorsport clutch replaced.

I took the car to a garage to have the clutch changed. The owner of the garage seemed very knowledgeable about Mustangs, indeed he owned a ’65 Coupe himself, however, I subsequently believe that most of the clutch work carried out on the car was done by someone else, one of his mechanics. The garage told me that the alternative clutch, which the previous owner had given me, did not fit. The garage bought another clutch to complete the work. When the Motorsport clutch was taken out the disc was shown to me. An area covering 180 degrees of the disc was blued (from heat build up) and abraded. The remaining area of the disc looked unmarked. This looked like an indication of misalignment to me. The garage informed me that the Motorsport clutch had been incorrectly fitted. In addition the pilot-bushing bore was lobed. The garage replaced the bushing with a rolling element bearing. In addition the garage removed the dowels, which located the Motorsport clutch to the flywheel. When the job was complete and I went to pick the car up it drove no better and had developed an exhaust rattle. The car was returned. I found out that the flywheel had not been skimmed, because it looked OK to the garage. The clutch was refitted with a skimmed flywheel. I don’t know what method the garage used to machine the flywheel. In addition the garage told me that they had lifted the transmission and shimmed it to re-align the drive shaft to the rear end, as this was part of the problem. The car appeared to drive better initially, however it developed a problem whereby the clutch pedal would go over a cam, or over center, and stick to the floor of the car. The car was returned to the shop, they spent time adjusting the linkage and welded a makeshift stop to the clutch pedal to prevent the possibility of it sticking to the floor pan. I argued that the work was unsatisfactory and to cut a long story short got most of my money back from the garage.

Has anyone encountered this type of probelm before? Any suggestions on how to cure the shuddering? Thanks.