TR6 First drive in the TR6 went well...until it didn't

[sammyb]

I got all my TR6 project all buttoned up, the clutch hydraulics bled and decided to actually take it on its first shakedown on the road. First thing I noticed was that it was running very well despite having the head off, carbs off, etc... and it was shifting well -- and even the Overdrive was working like a champ. Speedo wasn't working, but given it came with a new cable, I figured it wouldn't work.

I decided to turn around about six blocks down the road and start heading back to my garage. About a block later...

...no engine power. It was firing a little, but just coughing.

When I went to neutral and revved it, it seemed to rev up. In gear under load it just crapped out. I was able to cough and sputter the rest of the way at about 10mph back to the garage. It would idle fine and rev in neutral. Managed to get it back into the garage under its own power after it stalled in the driveway.


My gut tells me something like a bad coil or condenser. (I replaced the condenser, but not the coil.) Seems to me that if it was fuel, it wouldn't make a difference if it was in gear or out of gear, right?

I did the typical ADD thing -- once in the garage, instead of troubleshooting, I decided to attack fixing the speedo cable and redoing the seats and carpet.

But if anyone has had this symptom happed to them in the past, I'm all ears about the source of the problem.

Thanks,
Sam

 

[Darrell_Walker]

Any chance the timing slipped for some reason?

 

[sammyb]

Here's another thought -- there oil pressure looked really good -- but maybe even too high. Could I have stuck the valves because oil wasn't flowing well through the rockers? Maybe I goofed putting the rocker shaft back in? I had to replace one broken rocker, so maybe I did something stupid?

I'm trying to figure out what might cause a problem once the car heats up -- that's why I was thinking electrical. My dad's 1929 Franklin had a problem that if the felt pads weren't oiled manually from time to time, the valves would stick, but usually worse under engine load.

Thoughts?

 

[sammyb]

Darrell,
Would the timing slip enable it to rev under no load, but not under load?

As I mentioned, when I got it back, it was revving fine in neutral.

 

[TR3driver]

Seems to me that if it was fuel, it wouldn't make a difference if it was in gear or out of gear, right?

On the contrary, pulling under load (in gear) takes a lot more fuel than just revving the engine without a load on it. Sounds exactly like a fuel delivery problem to me. First thing I would do is either replace the fuel filter, or try bypassing it.

Ignition can also be load (and temperature) related. One way to distinguish them is to note what happens when you let off the throttle. If it immediately smooths out, it might be an ignition problem. But if it takes a beat or two and then starts running good, it's very likely fuel. The float bowls get drained when there isn't enough fuel delivered, and it takes a few strokes of the pump to fill them back up.

 

[NutmegCT]

What Randall said! Sure sounds like a fuel flow problem.

Tom

 

[sammyb]

My first thought was fuel, but then I went with the wrong assumption about load vs. no load and fuel consumption. I kept thinking "most fuel problems are ignition." I suppose fuel would be the easiest to deal with. I actually drained the tank and the lines about a month ago. If memory serves, there is no inline filter on it right now, which was a stupid oversight on my part not to put one in.

Thanks boys! I'll root through the fuel system again and see what I can find. I tell you, this car has made me feel dumber than a box of rusty tools. All my common sense mechanics and skill seem to fly out the window when I'm working on this thing!!!

 

[bobh]

Did you use a new gasket when you installed the valve cover?
In one of my TVRs I had a similar problem. The car ran great until the engine came up to temperature. Then it would barely run.
After a bunch of troubleshooting. I found the valve cover gasket was old, hard and saturated with oil. The oil was sticky when the engine was cold but became thinner as the temperature increased. The cork gasket was no longer flexible enough to seal the cover. Once the oil thinned the seal was broken.
I found the problem when I swapped out some SUs for the Strombergs. I connected the vacuum line where ever they would fit. After the engine warmed there was a loud sucking sound coming from the joint between the head and the valve cover. Basically a gigantic vacuum leak. Not exactly an application of The Scientific Method, but it did allow me to isolate the cause.

I run a Pertronics unit instead of points on my TR6. You may want to consider doing the same. Some people say they have had bad luck with these. Others say do not leave the ignition key on the run position of the engine is not running. They say this was the cause of theor Pertronix failure.
I've been using the sane unit for 8 years without problems. I do carry a spare pertronox and my points setup just in case.

Let us know when you find the problem.

BOBH

 

[Marvin Gruber]

Fuel delivery would be my first place to look. Hopefully you have an original type fuel pump with the hand primer. If so, disconnect gas line at the carbs ( use a small can to catch gas) and operate the lever on the pump. You should be able to tell if you are getting plenty of gas. The last 3 or 4 TR6s I've bought that have been sitting for a while, the gas lines are clogged up with varnished gas. The lines will have to be replaced or cleaned out.

Marv

 

[poolboy]

I think I'd try flipping open the gas cap if it happened again.