The Staff of Motorsport Marketing
The Staff of Motorsport Marketing Writer
10/30/17 7:38 a.m.

Story By Listed Reference • Photo by The Staff of Classic Motorsports

The Triumph TR6 has been a cornerstone of the sports car world since its 1969 debut: strong lines paired with an equally strong engine. These days, however, the newest example is more than 40 years old– and might have an issue or two. Need help righting a few wrongs? We present four experts eager to share their knowledge

Expert: Paul Dierschow
Sports Car Craftsmen
(303) 422-9272

When considering a TR6 for purchase, scrutinizing the items on the following checklist will quickly sort a good candidate from a bad one. This 10-minute examination is not intended to spotlight the relatively minor faults that might be expected of any 40-year-old used car. Instead, it should reveal most of the basic structural issues that can turn an ill-advised purchase into a looming disaster with huge repair costs. Here are the top 10 danger signs to look for:

1. With the engine off, push and release the clutch pedal. Then, with a pry bar placed between the crankshaft damper and the nearby crossmember, push the crankshaft backward into the block. The amount of backward movement ideally should be 0.004 to 0.008 inch–barely noticeable. Upward of 0.030 inch is common and salvageable with immediate attention. A movement of 0.125 inch indicates that the engine is a goner, as it’s most likely fatally damaging to both crank and block.

2. Look under the car, checking sideways from the front edge of the driver’s door, and notice the angle of the clutch release arm–it sticks downward from the left side of the bell housing. If the arm points straight down, all is well. If it points back from vertical, the bolt that holds the clutch release bearing fork to the cross-shaft has sheared, requiring a transmission removal for repair.

3. With the engine running and your foot very firmly on the brake, slowly release the clutch while using the brake to hold the car in place. Then shift into reverse and repeat. You are listening for a sharp clunk from the differential. If you hear one, then the right- front differential mount stud has broken loose from its woefully underdesigned frame attachment. All cars will need this repair at one time or another, and properly making the repair requires removal of the differential.

4. Open the hood and look down at the front corners of the engine. You’re looking for two steel boxes that are welded to the frame, right where the lower control arms mount. The boxes should be perfectly square and solid to the frame. Frequently they are injured, particularly at the right-rear mounting point. Also, look at the number of shims found behind each control arm bracket: more than five or less than one on any of the four bears further examination.

5. Check the chassis member where each rear control arm mounts. These points are very frequently rusted out and may be indicators of more serious chassis rust.

6. Look carefully at the seams between the body panels. The four fenders should join their related scuttle, tonneau, and front and rear panels with a clean, seam-sealed groove. The fenders should join the rocker panels below the chrome strip in a perfectly flush fashion, with the rear fender attached to the rocker with a small dot of brazing to enforce that flushness. The joint lines frequently disappear with shoddy rust repair methods.

7. From the front of the car, sight down the gap between the hood and fender–and continue sighting that line down the top of the door and along the rear fender joint. This line should reveal a gentle, consistent bulge in the middle, with each side being a perfect mirror image of the other. A lack of uniformity reveals some sort of serious incident in the car’s past, which demands further investigation.

8. Inspect the upper fender swage line. The width should be uniform down the entire length of the car, tapering to zero at the end of each fender. Lack of uniformity not only indicates bad bodywork, but it may also be an hint at what lies underneath.

9. Inspect the corners of the fenders. TR6s have numerous built-in rust traps that, if revealed on the outer panels, most likely indicate similar damage to the related inner panels. Look in the pockets above and around the headlamps as well as below the chrome line at the rear of the front fenders. The rear fenders are particularly vulnerable above the tail lamps and along the edges at the top and front of those panels.

10. With the car on the ground, note the gaps at the front and back of the doors relative to the adjacent fenders. The front gap should have a consistent width; the rear almost never does with an original frame. If that rear gap is twice as wide at the top as at the bottom, that’s normal and only a visual annoyance. If the top gap is triple the lower width, however, the car’s mileage is most likely well into six digits, regardless of what the odometer says.

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LanEvo HalfDork
10/30/17 11:40 p.m.

Very useful to me, as I recently got started on a TR6 project. I didn't have much of this information at the time I bought the car, but it looks like a got lucky!

JoeTR6 HalfDork
11/2/17 6:45 a.m.

One thing I'll add.  The rear hubs are prone to fatigue and catastrophic failure.  The stub axle breaks at the threaded end resulting in loss of the wheel.  Given that these parts are now over 40 years old, I would replace them with a newer, stronger alternative as a matter of course.  New hubs aren't much more expensive than rebuilt originals anyway.

wspohn Dork
11/3/17 12:25 p.m.

They also have trouble with the sliding splines in the rear axle shafts - they can bind right in the middle of hard cornering.  Guys racing TR-6s almost always swapped them out for different axles.

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