Triumph GT6 Engine Bay Respray, Interior Refresh and Overdrive Installation

I've had my 1971 GT6 MKIII for six years and have already rebuilt the engine and rear suspension ( among other smaller projects).  I always wanted to have an overdrive unit.  Cruising on US freeways is a strain on the engine and 4-speed gearbox with speeds usually around 70 MPH.  The paint job was pretty good on most of the car, but the engine bay was not so good.  Normal wear and tear along with a series of brake fluid leaks had really taken its toll.



I found a very nice rebuilt overdrive unit on eBay that had been updated to higher specs on gear bushings and synchros.



 As most GT6 owners know it is really difficult to get the gearbox out.   The frame design means it can not be dropped out below like a "normal" car.  It is possible to remove thru the interior but that is very difficult.   I have found it much easier to remove the entire engine and gearbox at once.  I have it down to three hours more or less.

In addition to brake fluid leaks my car had the usual battery box rust issues.  I installed an AGM battery so hopefully, this will not be a problem in the future.



As you can see here I have attempted several repairs and resprays after the fluid leaks.  I converted to DOT 5 for the brakes and clutch so this should not happen again.

The interior needed a refresh as well.  I replaced the dash a few years ago but I wasn't a big fan of the satin finish so I replaced with a new gloss dash.   The carpets were pretty bad, low-cost tufted nylon with poor insulation and no heat shielding.

This is a California car so I am fortunate that it only has surface rust here and there.  The only repair was the driver floor which had some holes.   I replaced with a new panel using industrial adhesive vs welding.  Much easier and a good seal.

It is always interesting to find out what takes a lot longer than it should.  Removing the foam glued to the floor under the carpets was awful.  Eventually, I just soaked it all in Goof-Off and let it sit for a day.



Speaking of tasks that take much longer than expected, cleaning and prepping the engine bay and frame took for-ever.  I used paint stripper and wire brush but this did not work very well on the small areas and frame parts.  Initially, I was trying to leave the suspension, gas line, steering, and exhaust in place.  If I had to do it again I would just remove it all, more work to reassemble but much easier on the prep and paint.



Progress but still a long way to go.  I would consider soda blasting next time.  Again, messy but probably much fast than all the handwork to get this far.




Almost ready for painting.  High fill primer on most of the flat surfaces.  I covered the suspension with plastic bags for the primer.  I needed the wheels in place to get the car to the paint shop.



The front valances needed help, always take a lot of photographs of the fitting locations for good panel gaps later.



The front wheel wells were pretty bad, chips and worn paint.  I didn't want to do a full hood (bonnet) respray so just did the wheel wells outer frame parts.  I was able to do this with color matched spray cans.

Back from the paint shop, looking much better.  Unfortunately, the suspension and steering rack paint took a beating in the prep process so I eventually removed it all and repainted with Trim Black.



Interior painted and ready for reassembly.   The lighting is different so the paint color looks like it doesn't match but it does.



The undercarriage needed a lot of help too.  I did what I could without taking the body off.  As I previously mentioned, very little rust damage other than on the surface.   I sealed with undercarriage spray and a coat of paint.



This shot is after the rust, dirt, and grime were removed.



Same shot after several coats of undercoating.  Much improved.




Front view.



A major step, engine back in the car!





On the list of things that took longer than it should have, installing the wiring harness.  The car had the original 1971 harness and had the usual problems with grounds, dim bulbs, and looked terrible.  The new harness, made for my year, was surprisingly difficult to fit.  I should have taken many more photos of the exact routing of every harness wire.  The new harness is made to the exact dimensions of the original but since it is new it is pretty stiff.  Fitting and routing was really a pain.




Interior complete (or almost, a few electrical connections still not working).  New molded carpets from Newton Commercial.

Ready for the Triumphest 2018 in Sacramento.

Its been a year, here are a few interesting maintenance items...

The car has been running great, I have over 1500 miles on the rebuild and no problems, barely any oil leaks.  

About 6 months ago things got a little scary when the car started shaking badly whenever I made a right turn, even the slightest of turns.  I managed to get it to the shop before anything serious happened but just barely.  As you may know the GT6 has the rotoflex configuration which was somewhat state of the art at the time, this was certainly better than straight axle for handling.  The rotoflex is essentially a very large heavy duty rubber donut that transfers the power while allowing flex in the suspension.   It seems the source of the vibration and shaking was my right rotoflex, it had failed and now had a break in the rubber. 

This job was too much for me to handle but fortunately Dave at British Motorsports in Campbell CA was able to get the axle off (no easy task given the age of the bolts).  Once on the bench it was pretty obvious where the break happened.  Fortunately rotoflex replacements are easy to find.

 Here is the completed right axle unit, freshly painted and ready to be re-installed.  I had new brakes put on as well, there was a minor leak and the shoe's were a little wet.

 Back on the car now.  I should not that I had the leaf spring replaced as well which greatly increased the stiffness and added an inch or two to the right height in the back.

A side note, it turns out that my bushings had essentially disintegrated and I was riding on metal to metal in the back.  Quality bushings are very hard to come by as many aftermarket parts are not of NOS quality.

And of course I did the other side too just in case.

The second major problem happened about 2 months ago when I was backing my car out of the garage down a ramp and went to put on the brakes, nothing...nada.  Complete brake failure.   I knew i had a slow leak from the master cylinder but once the level got too low the system filled with air and that was it.  I planned to get a rebuild kit but decided it much easier to just get a new master.  The change was pretty simple, it was the preparation that was most of the work.  Brake fluid eats through paint so the main task was to strip, sand, primer and paint under the master where the paint had been ruined

Here is what it looked like when I took out the old master.  Some of you may be wondering why the brake safety valve wasn't working,  Brake systems of this era had a dual reservoir system so that if the front went the back would still work.  There is also a switching mechanism in the silver brake line splitter (see at the top of this photo).  A prior owner had the switch removed and just a bleed valve installed.  That explains why it all failed at once.

I used some paint stripper to get most of this out.  There was some surface rust but nothing serious.  I was not going for a concours quality repair, this is a nice driver but someday I'll have to reshoot the whole engine compartment.

Primed and masked off, ready for paint.

And after two coats it was looking pretty good.  I was fortunate to find my exact paint color in a spray can from TouchupDirect.com, this is color code 54, Saffron yellow. 

Back on the road again...

After nearly 4 months the car is back on the road and doing well.  

The engine starts quickly and runs fine, still in the break in period so not pushing it too hard.  Managed to find a proper two cable choke so that problem is solved.  Steering is a bit sloppy so will have to do some tightening up of that at some point.  Had a chance to put this up on a lift and found out that the muffler has a few holes.   Sounds ok but will also have to be replaced at some point.  

Here is a few photos of the first test drive after engine assembly.  Ran a bit rough which is understandable.  No hood as you can see.  The engine ran much better after Dave (from British Motor Sports in Campbell) pointed out that the vacuum advance hose was incorrectly attached to the vacuum retard.  He also pointed out that the vacuum advance module was not working at all.   Runs much better with the new module and proper attachment. 

The link below is a short video of the first drive, notice that the transmission cover is not installed as well. This made it easier to check the drive shaft bolts and top off the gear box oil.

Video of the first test drive

Interior is basically done as well, just have to install the radio and speaker and put in the final piece of carpet over the transmission tunnel.  The temp gauge is now working fine, the ground wire was not connected so that is why it read high all the time.  Like many GT6's the heater unit is installed by the water hoses are not connected.  Behind the dash is pretty messy, at some point I will have to pull everything out and re-install the heater, wiring etc,  but not any time soon.

 Out for a drive on Christmas eve, perfect kind of road for this car!

The car even made its way into the family Christmas card this year!  

Part 3 - re-installation and problem solving

After several long weeks all the parts are ready for assembly and re-installing in the Triumph  GT6.

First step was to rent another engine hoist, cheap but very heavy, around $40/day.  Fortunately the $20 engine stand held up, I really thought it would collapse under the weight of this cast iron beast, my guess is it weighed 500lbs.   I am sure it would have if we put on the head and manifolds first, it would have collapsed,   but we decided to wait until the engine was in the car.

Once the engine was hoisted we could install the clutch and pressure plate.  Didn't have the $5 clutch alignment tool but did have the old main shaft from the gearbox that had to be replaced.  The old clutch looked fine but as they say with consumables "if you are looking at it - you should replace it" so we did.  

The gear box had to be rebuilt due to rust and other bearing issues.  The car sat for more than 10 years and the moisture in the gearbox caused severe rust.  Fortunately Dave at British Motorsports  in Campbell CA (shameless plug) had enough donor gear boxes to create a new one for me, many thanks Dave!

The shifter unit was also pretty rusty but fortunately there is a Triumph rebuild kit for it, and even more fortunately Dave had a donor shifter unit that was in much better shape. Thanks again Dave! (shameless plug)

The rebuilt gear box mounted easily and here is Scott test fitting to make sure the shifter fits.  We left this off for now, will install once it is in the car.

Here is the engine and gear box about to be installed, was a tight fit but with some tipping and shoving it worked out.

Time to assemble the cylinder head.  The new valves, springs and valve guides were already installed at the machine shop so just had to attach the intake manifold (silver) and exhaust manifold (black) then ready to go.   As I mentioned, we converted this to unleaded so no more lead additive for each tank of gas.

Head gasket installed with some head gasket copper spray to make sure it is a tight fit.  Then time to put it all together.   Cast iron head unit with manifolds is pretty heavy but worked out fine.

Torquing the head bolts is critical, have to have the right sequence and the right torque amount.  After this we installed the rocker arm assembly and reset the gaps, .010 in, pretty tight but has to be right or else.  You may note the rubber hammer, that was needed to get the head unit to seat right.

And finally the installed unit all together.

But there was a problem, the first of several.  After installing the engine and gearbox, the drive shaft was about 1/2 inch off from connecting, what was up with that?  After a spot of tea, and some pondering, I figured out that the motor mounts were trapezoidal and on the wrong side.   Note that there is a long side and a short side on the motor mount flange below.

After switching left and right motor mounts the engine was back in the right position for the drive shaft and all was well.   Rather than rent the engine hoist again for a 10 min task I took a chance and used my floor jack with a 4x4 to lift the engine a bit and quickly switch the mounts.  Worked out fine.   Whew...

Some final installations like the radiator and hoses, emission controls, etc.

So time to try to start this puppy...but wait...what's this?  The starter is bad!!  Arghhhh....  Amazingly I was able to find an original Lucas unit at O'Reiley's in San Jose on a Sunday no less, and for $45.  Yes it was covered in dust and had been there for 20 years. The store manager had never seen a starter like this and didn't know he even had one until his computer said he did.  I kept the original 40 year old Lucas starter for posterity.

But there was another problem, the choke cables.  This car has two carb's so two chokes.   That requires a single pull - headed two cable choke.  The one on the car was already broken, only one cable, so I ordered another from a site in England which arrived in a week or so.  But there was an issue, each of the choke cables was short by about 8 inches.

After some deliberation and a spot of tea I figured out that these cables were meant for a UK version of this car with the steering on the right....hence the choke handle was on the right....further hence the cables were shorter to the carbs then on a left hand drive car.

So now what to do.  I called around to various parts houses, no luck, too rare.  There were plenty of TR6 dual choke cables but they were also too short.

Some suggested a bike shop for custom cables.   So I went to the best custom bike shop on the peninsula, the have cables but cannot fit this unit with a single pull.  They suggested a motorcycle shop on Fifth in Atherton.  Went there, they said no-can-do, but sent me to a custom cable shop in San Carlos.  But alas they said the same thing...no  can do.  So for now the choke is installed on the right hand side, hanging inelegantly below the glove box until I can find a better long term solution.

The second issue was connecting the dual cables to the carbs.   The new unit was a bit larger than the old so the standard carb clips wouldn't work.  I managed to get it working partially with two vice grips holding the cable housing to the carb mount, not ideal.  Eventually I found some Dorman clamps for 25c at Napa Auto (thanks!) that did the trick.  There wasn't a mounting screw so a pair of zip lock ties to hold the clamps in place and we are in business.

And now the moment of truth, would it start?  The engine fired up! Wasn't pretty at first I must say but did settle in after 30 seconds of smoke and billowing.

 A major victory though it did take two batteries to eventually get it going.   Turns out we had the distributor 180 off which was quickly rectified. And there is a small gas leak in the hose just below the fuel filter.   And we seemed to have lost the radiator drain plug.   All easily sourced so all is good.

And finally all reassembled, well - almost all.  New dash, new seats, all the instruments and lights work.  Car starts, even managed to drive it 100 ft. back in to the garage for tuning.  Still have to do the final timing, pressure check the cooling system, re install the transmission housing and carpets and a few minor interior items like the radio.

Next blog will be the final test drive....stay tuned....pcow