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Putting off piston ring repair, for how long?


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Edited because this is WRONG.  Sorry.  I hope I did not mess up anyone. I still thank Rob.  It is all my fault that I over analyzed the issue.

Rob H,

I owe you a pint of Guinness!!!!

I have posted two videos to prove how smart you are!!!

I adjusted the choke linkage to get the jet down as you suggested, but the over-riding issue was my fuel level was way way down the jet tube as viewed from above with carb piston removed.  I never would have checked it without your suggestion.  I bent the lever in the carb bowl so that the fuel level was per SU specs.  And the rest is history!   Almost started from cold on first try, and started on second try.  My TR3A has never cold started so well, ever!  The old procedure of setting the float level by a 7/16" drill bit did not work for me over all these years.  It was good enough most of the time, but certainly the fuel was not high enough to aspirate into the throttle on full choke.  Thanks Rob.   I now have to rethink my whole driver-ship issue about whether I care about low compression anymore.   ha... That is ok with me.  I'll think about it as I drive. 

And Mickey, I still plan to do the re-bedding.  Maybe soon.

Thanks again, Rob H.!!!!!

Opie (Isaac) 

videos (not edited but the wrong conclusion was reached)

https://www.youtube.com/watch?v=BvI8kl15ctE

https://www.youtube.com/watch?v=JJKwT5Sqd58

 

Edited by Opie
Ima dummy (see post on Feb 3.)
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Good result.

You will learn the ‘milk the choke’ trick on cold starting.   ie. Push and pull to get the right tick over and pick up when cold once the engine is started.

 

While you are waiting for the warmer weather just get on and dose the upper cylinders with Marvel Mystery or Seafoam VS lube and leave to soak for a while.    Do the restart as they advise, something like crank with the plugs out and a cloth over the holes to catch excess lube that may be pumped out.   

Peter W

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Opie,

Bypass all the c r a p (ha ha beat the My little pony censure programme). Spray some petrol direct into the inlet manifold with a spray can or a pipe underneath the carb pistons. Then try a start, if you get any combustion, even if it just fires a couple of times and then stops then it’s a carb problem.

Mick Richards

 

Edited by Motorsport Mickey
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Mick,
I knew I was not getting enough fuel, but I thought that the "other side" of low compression meant "low suction" on intake stroke and, because I had "low suction," the manifold was not negative enough because of the bad rings and that in turn caused insufficient pull on the fuel aspiration.  So, yes, spraying would have started my car but that is no way to live.   However, I now have reason to believe that I now can both, start car and have low compression.  

Edited by Opie
wrong conclusion - see Feb 3 post)
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One more observation: Over the years, I set my carb mixture setting very carefully.  Before I began the float level adjustment, the mixture setting was exactly per the book, then lifting the pin on the carb piston, etc, etc.

In my recent text above, entered this morning, I adjusted the float to cause the fuel level to move up between 3/16" and 5/16".  That increased height of fuel helped my inadequate air flow to aspirate more fuel into engine and my car cold started on second try whereas it had not done so for years (about 40 deg F).

The observation I want to make now is that I assumed that I would have to redo my carburetor mixture adjustment.  After all, wasn't more fuel available to the jet now?  But, to my surprise, the SU carburetor mixture setting needed no change after changing the fuel level !  Not even one flat adjustment of the mixture screw was needed even though my fuel level was increased.

I did some reading and SU basically says the same thing. In their literature they advise against altering the float level unless there is fuel starvation or fuel flooding.  So, it seems that fuel level in the jet has nothing to do with tuning the operation.

SU says: "Since the carburetter is of the constant vacuum type the depression at the jet never falls below its normal operating value, and it is for this reason that variations of fuel level in the float chamber are unimportant."

Link to above SU quote here.

What the SU manual fails to mention, for good reason of course, is that old, leaking-ring pistons will cause less Bernoulli aspiration.  SU, therefore, needs to add this to the above,  " ....are unimportant, except if your engine is worn out and can no longer create the air flow over the jet needed for starting, and in this case any variations of fuel level are critical and so, in the worn-engine situation, make very sure the fuel level is exactly just at the top of the jet when it is fully choked."  (  ha.... the green words are mine, of course.

Opie

Edited by Opie
See Feb 3 post. Do not stray from good SU practice.
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Thing is and this has been discussed elsewhere is that with the modern fuels available these days all the original SU setting  instructions are now pretty much meaningless and you have to go with whatever makes your engine run correctly and forget book settings.

Stuart.

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47 minutes ago, stuart said:

Thing is and this has been discussed elsewhere is that with the modern fuels available these days all the original SU setting  instructions are now pretty much meaningless and you have to go with whatever makes your engine run correctly and forget book settings.

Stuart.

+1

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Sorry.  I am afflicted with I-like-to-talk-a-lot syndrome.  My wife reminds me often.

I'll hold off posting anything more until I fulfill Mick's hit-it-hard on the highway request.

Opie

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Question to Mick,

Tomorrow is warm here.  Would it make any difference if I hit-it-hard on a 45 mph road in third gear or will it take going on a 70 mph road in 4th gear?

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3 hours ago, Opie said:

Question to Mick,

Tomorrow is warm here.  Would it make any difference if I hit-it-hard on a 45 mph road in third gear or will it take going on a 70 mph road in 4th gear?

Depends upon your rear axle ratio, max torque on a standard camshaft is 3500 revs. If you can get it  below there in 4 th gear ( to maximise the engine loading) and keep your foot buried for minimum 7 or 8 secs on an uphill stretch then you’ll get some affect on it. Failing that try your local rolling road and tell them what you are doing, they can load the engine on the rollers and complete some “ bedding” runs for you, probably only take 30 mins and maybe $50.

Mick Richards

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Feb 3.

The trouble with open forums is that a shade tree mechanic like me can get something wrong and then think he is right and boast on-line that he "discovered" something.  Well, when I threw away the good SU practice of setting the float level at 7/16", I thought I did something wonderful.  The TR started easily and idled great during a 10 minute tick-over.  But, today, on the way to the petrol station to fill up prior to a hard run, the TR could barely run on the open road.  I did get it home and I won't go into the details but I was seriously flooding the engine.  So, I will go back and re-set the float level to SU specs.  I edited out my previous posts on how smart I though I was.  Sure, pouring gasoline into the cylinders works every time.   ha

Opie

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The carbs should be quite happy with the fuel level visible at about 1/4 inch below the bridge. With that setting flooding really shouldn't happen.  

If the setting is good and the carbs are OK at idle without flooding, that shouldn't change when you are driving unless something is wrong - maybe with the floats or valves in the float chambers? 

 

 

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  • 2 weeks later...

Mick and Rob, et al,

I am still planning to do the hard run.  But I fiddled with the carbs for bad reasons and got bad results and finally messed up the cork gland washers inside the jet.  So, that has delayed me.  Yesterday, after putting the new carb bits back together I tried to start and my starter froze up with a loud clank.  Smoke started billowing out.  I have three fire extinguishers but in my frantic frame of mind, I couldn't find them.  My wife had a half-full 3 gallon garden bucket on the driveway, so I grabbed it and poured it into the engine over the smoking starter because I could envision  possible flames and my garage going up in a blaze.  As my aim was wobbly at least a pint of water also hit the open rear carb intake.  My engineering mind kicked in and I realized that the starter was shorted out and the battery 12v had to be removed quickly or the starter would continue to cook and smoke.  All will be well, I am sure.  Eventually................................................

 

Edited by Opie
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  • 1 month later...

I ordered a high torque starter, LMS006, by WOSP.  I finished my carb repairs. The TR3 starts like a showroom modern auto. High speed starter revolutions make my starting woes a thing of the past.  

I did the Italian tuneup and no better results.  My engine is just plain worn. But, this is the conclusion of this thread for me.  I won't use all caps to say it, but imagine me doing so.

"My low compression TR3A engine, with a new high torque starter, solves 100% of my problems. I still have plenty of power for the road and a quick starter button push,  cold weather tested, gets me going quickly. Very, very, pleased.  I -- can live with low compression after all --and I will not be rebuilding the engine."

signed,

Opie (thanks for putting up with me on this long topic.)

Case closed....

(but, comments welcome.... :-)

 

 

 

 

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6 hours ago, Opie said:

I ordered a high torque starter, LMS006, by WOSP.  I finished my carb repairs. The TR3 starts like a showroom modern auto. High speed starter revolutions make my starting woes a thing of the past.  

I did the Italian tuneup and no better results.  My engine is just plain worn. But, this is the conclusion of this thread for me.  I won't use all caps to say it, but imagine me doing so.

"My low compression TR3A engine, with a new high torque starter, solves 100% of my problems. I still have plenty of power for the road and a quick starter button push,  cold weather tested, gets me going quickly. Very, very, pleased.  I -- can live with low compression after all --and I will not be rebuilding the engine."

signed,

Opie (thanks for putting up with me on this long topic.)

Case closed....

(but, comments welcome.... :-)

 

 

 

 

Good outcome.

Now get out there and enjoy your car.

Peter W

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