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Engine noise - towed home - what could it be?

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RedTR3

RedTR3

Jedi Trainee
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Drove the TR3 to Safeway this morning and when I started up to come home, there was a loud rat-tat-tat noise coming from engine. I decided not to drive home but called AAA and got a tow. The noise sounds like it is from the upper end, perhaps from valve cover area. Any suggestions on what this could be and where to start?
 
I'd start by removing the valve cover and making sure that you've still got all your valve-springs, rocker arms and whatnot under the cover and that nothing's come loose, and that there's been sufficient lubrication at the top end so that nothing looks worn. Then based on what I saw, I'd think about changing the oil and looking for any metal flecks in the oil.

Cant help you more than that, but that's at least where I would start looking.
 
RedTR4, have a look at the distributor, if you were driving a bit speedily, they have been known to pop up a bit and it does make a racket.

Wayne
 
Also check the plugs. A loose one can cause a really amazing amount of noise.
 
thanks for all the good hints, I just finished checking all of the above, so I am afraid this is not looking or sounding good!
 
Take a look at valve clearances, of course.
 
Next pull the plugs to see if any are damaged. If a valve broke, or you swallowed something down the carb the plug will show it.
 
Bent pushrod maybe? Those earlier, thinner diameter rods have been known to fail occasionally.
 
I wonder if you run it for a couple seconds and can diagnose with a stethascope which cylinder is causing you grief....
 
mrv8q said:
I wonder if you run it for a couple seconds and can diagnose with a stethascope which cylinder is causing you grief....
Click to expand...
I thought about suggesting that, but it could be "iffy"! Can you detect the noise while turning the engine by hand, either with the fan belt or with the crank (starting handle)?
 
I was baffled by a rat-tat-tat on my TR3 once and it turned out to be from the fan pulley hub nut not being tight enough which caused the water pump shaft"key" to wear the pulley hub slot groove out to 1&1/2".It would bang back and forth sounding all the world like a bad valve.
 
OK, I pulled the plugs and noticed that #4 looked like it had some scratches on it....So I put a magnetic probe down the hole and pulled out the steel shards shown in the photo.

I assume that these are pieces of valve? Thanks
 

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Hard to say what those are, but valve wouldn't be my first guess. Doesn't really matter, though, it's time to pull the head and get the rest of the bad news.
 
Looks like you might have sucked something down the intake. Can't tell the size of what you've got. Was the spark plug intact?
 
well from the looks of that you did the right thing by not running it.
 
Yes the spark plug is intact and actually just looked barely scratched - I almost missed it.

But I only drove for a couple of blocks. For once I had the wisdom to not try to drive the 5 miles home.

So if it is a piston, how much more difficult is that to repair than just the valve? I will probably have the car towed to my shop but I want to be prepared before I get the sticker shock.
 
IMO, these are the easiest motors in the world to work on. I've got a good set of 83mm pistons and liners if you should elect to replace one or all.
 
I had a rat-a-tat sound from my 1958 TR3A and even with a stethoscope, I couldn't figure out what was wrong. I was at TRA in Auburn in 2002, about 1000 miles from home. It would always be there when I started but the noise later sometimes disappeared. At Mosport, still 400 miles from home, I pulled Carb #2 - then the starter and found that it was the teeth on the pinion gear for the starter which was rattling on the teeth of the flywheel. A new rubber coupling was needed. But in the meantime I installed my old spare that I always carry with me where I had MIG welded the two parts together without the rubber "cushion" in between. It ran just fine for months that way till I got a new spare.
 
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