TR2/3/3A floundering At High RPM

[sp53]

At High RPM, say between 4K and 5K my car struggles to keep climbing in RPM. The stars good and idles well at 8 hundred RPM. I guess the best way to put the problem is when I try and drive like I am 16 again the car seems to flounder and not keep gathering RPM quickly after 4K or 5K. I am not sure if I could push the engine to 6K. The couple times I have accelerated slower from 4K to try and reach a wide open throttle say at 5K or 6K the car makes it to 5K, but things do not feel correct.



Then again, the after the couple of times I tried to race the car afterward the engine feels stronger. The engine has 500 miles on it and seems to be a nice rebuild and a strong engine. Standing still I could easily rev the engine to 6K, but under load at high RPM the engine feels wrong and does not gathering RPM the way I think it should. There is no hard missing or banging or knocking, just not as fast as it should perform.

steve

 

[Sarastro]

Lots of ignition problems will let the engine run fine at low speeds but not high. Check the dwell, especially, and be sure the resistance of the low-voltage side of the coil is 3-4 ohms. Finally, get a good ignition capacitor, if you are using an original-type one.

Carburetion can be another cause, but I'd check the ignition first, as it's easier.

 

[bobhustead]

I question running a new engine at high RPM. I break in for 1000 miles. The points spring is another arcane point of failure. They can weaken from heat (like leaving the ignition on when not running), or age or poor manufacture, which results in the points floating (not closing properly) at high RPM. As Steve says, it may be a carburetion problem, but there is a not-quite-always-true maxim that says 'when you are sure you have a carburetion problem, replace the ignition components'.
Bob

 

[malbaby]

Electronic ignition is a worthwhile expense.

 

[sp53]

I called Apple Hydraulics and talked with them about a tr2 master cylinder. They basically said we can fix it if the case is not cracked and if it is we have cores for 130.00. The master cylinder on the 1955 is a key component for originality along with the drum brakes in the front, so I want to keep a stock master cylinder in the car plus the brake lines are routed different than a tr3a. The restoration will take years, so I do what I can, when and where I can, as I move forward.

Some of the stuff for the older master cylinder is expensive for what you get. The rods and forks for the cylinders are 109.00 each which is unreasonable in my view, but at least they are available. If anyone is using one for a door stop, please give a call.

steve

 

[CJD]

I would suspect ignition too. One thing to check, though, is whether your mechanical tach is showing correctly. You may be winding it a lot higher than you think you are.

 

[sp53]

Thanks guys I will start with the ignition. Bob I like that possibility with the point floating. I had not heard that one before. Steve I have a cheap HF meter and was wondering do I put one lead on the distributor side of the coil and the other lead into the center hole of the coil? And, what would be the best place to set the meter for OHMs? Thanks Malbaby, it would be nice to have an electronic ignition to see just what is going on with a manual type distributor. John I will watch for that, I do have several tachometers and some very nice SUN analytical equipment, but I guess under load I would need to swap tachs to check proper calibration.

I remember back in the day, I knew a guy who would say, before you do anything make sure the fuel is high quality. Even go to a different gas station, he like Chevron and get their best.

steve

 

[Sarastro]

Set the meter to the lowest resistance scale. Connect the probes together and note the indication--probably something like 0.4-0.7 ohms. Then disconnect the coil and connect the probes to the low-voltage terminals--usually screw or spade connections. You will have to hold the probes fairly firmly to the terminals to get a steady indication. Finally, subtract the first measurement from the second.

Probably, this won't be the problem, but it still should be checked.

Also, I didn't mention this, but it would be a good idea to check the spark advance. Just connect a timing light and rev the engine, making sure the spark advances. You probably don't want to rev the engine too high, but if you are getting 20 degrees of advance (~25 total) at 2500 RPM, it's working well enough.

 

[sp53]

What I have done now is replace the points with some Oriel’s and I did not replace the condenser. The points where very pitted for only 500 miles. It is not really a pit but a bump of metal on one side and dent in the other side of the points. I remember my high school auto shop teacher telling us the condenser absorbs static electrons and is more to do with the coil than the points. Plus depending on which side of the points the dent and bump are on that would tell us something like weak condenser or bad coil. Just cannot remember.

I replaced the plugs and check the dwell, timing, and timing advance with a timing light. The timing mark drilled hole in the pulley at 8 hundred rpm is about a ¼ to 3/16 of an inch before the mark on the chain cover and when I rev the engine to probably 4K the timing marks moves about 3/8+ past the mark on the cover. Maybe that is 20 degrees, I just do not know, perhaps I should get a calibrated wheel for the pulley.

The distributor itself looks good in that the advancement springs spring right back and it is physically clean. I do not know about the vacuum advance; it is hook up.

One thing I did not like was when I pulled the rotor up and off the shaft came up maybe a ¼ inch. I can move the destructor shaft ¼ inch by pulling up and down on the rotor. Not sure about that, but I would not be surprised if the fix was not in shimming the distributor pedestal. I am having trouble visualizing if I need to shim the pedestal up or tighten the pedestal down.

The dwell was 53 degrees--- forgot to check the coil for ohms. The coil is one of those old red top ones with the date on the bottom like 1959 or something.

I will take the car out soon and see if anything changed. Steve, have you ever heard about the pitting of the points story.



Thanks Steve

 

[Hamish Racing]

Is it anything like in this video of mine ? Missing at high revs?

I’d had it on a rolling road but it didn’t show up before event.

Thought it was that left hand bend.
it would Rev easily to the red line whilst not driving.
took it on a road test drive during lunch break and it happened high revs top gear on the straight

blew down fuel line engine bay to tank with elec tyre pump and it built pressure then blew through and it then ran fine.
Traced it to a 3” rubber fuel pipe near rear of car where metal pipe from tank joins metal pipe along chassis to engine bay.
Cheap fix but frustrating.

it was a fuel flow restriction with old pipe breaking down. Only properly manifested itself going fast in 4th where fuel deliver was max.
Rev’d well just sat there.

 

[sp53]

Yes Hamish I had a similar problem once. I had an electric fuel pump with a pressure regulator on a tr3. When I tried going up a steep hill, the car would starve for gas and power would fade away. At the time, I was chasing what I thought was a rich fuel mixture and wanted to see something to help me figure it out, so I was turning the regulator down to like 1lb of pressure. It turned out to be oil rings letting oil up into the chamber.

This car is a 1958 with all metal plumbed in lines. I made a new line for the back section, but the front section is original and I do remember a dent in the fuel line from a rock or something. The dent could be restricting the fuel flow at max fuel consumption, so it is something to consider.

Thanks steve

 

[KVH]

I’m wondering what your spark plugs look like? Also, even though it runs great at lower RPMs, has anyone watched from behind when you shift from 2nd to 3rd at around 3500 RPMs to verify if there’s a small puff from the exhaust? It can be an important question following a rebuild.

 

[karls59tr]

Yes Hamish I had a similar problem once. I had an electric fuel pump with a pressure regulator on a tr3. When I tried going up a steep hill, the car would starve for gas and power would fade away. At the time, I was chasing what I thought was a rich fuel mixture and wanted to see something to help me figure it out, so I was turning the regulator down to like 1lb of pressure. It turned out to be oil rings letting oil up into the chamber.

This car is a 1958 with all metal plumbed in lines. I made a new line for the back section, but the front section is original and I do remember a dent in the fuel line from a rock or something. The dent could be restricting the fuel flow at max fuel consumption, so it is something to consider.

Thanks steve

You may be on to something to what you are experiencing now. Are you running an electric fuel pump on this 3? When I first switched to an electric pump I added a fuel pressure regulator and was getting hesitation at high rpm. I removed the regulator and everything was fine after that. I think my fuel pump puts out 2.5 psi but not sure. Depending on what kind of pressure your pump puts out you may be further ahead to just try removing the regulator entirely?

 

[sp53]

You know KVH my son said the other day there was exhaust smoke coming out, but I cannot see it when I drive. I figured I would drive it more and see what happens because the engine is rebuilt and perhaps seating something. I have been changing the plugs a lot. I made a little holder, so I can keep track of which plug is which. Basically board with 2 rows of holes it and numbered 1 thru 4. This last time when I changed the plugs number 4 looked new and 3 looked carboned up pretty good which does not make sense unless the distributor cap or wire has a problem. Next time someone comes over that can drive a stick, I will have them drive the car, and I will follow them to see the exhaust.

Karl this car has an AC pump that I rebuilt which does not mean much because there could be a problem with that. I actually would trust an electric pump with a regulator better for this application. I might try putting on an electric pump and just leave the mechanical in place. This old time sports car I knew had an electric pump in line with the mechanical pump in case of pump failure. I tried it many years ago, but the electric diaphragm failed. Perhaps the electric one should go in after the mechanical. I do not know. Although the mechanical pumps I have used in the past on many tr3s has always worked like it was bullet proof and never let me down.

If the points where not the problem, I am going to change the coil and see the effect. The tr3 I have had since high school runs great right know and has much more power at high rpm. I am tempted to pull the dizzy and wires off of it and put them on the 1958 I just rebuilt to see what happens.

But, again that front section of metal fuel line has that dent from a rock or something so perhaps there is a restriction of fuel there. It is such a mess to pull those lines out that I am saving that theory for later.

steve


steve

 

[KVH]

Steve, what pistons and rings did you install? What rings? Were they Grant?

 

[sp53]

KVH I am not sure because I bought this car as an abandoned project. The car had a set of new 86mm with 4 rings on each piston; the 3rd ring set below the wrist pin I think. The car was probably from the eighties because the last plate tag was 1982.

Last night I put on a new coil and new cap with wires, and I plan on testing it today. If this has no effect I plan on using a different distributor because I do not like the play in the shaft of this one.

steve

 

[KVH]

Hopefully, it’s something simple and easy. Actually, a lot of this stuff is easy if we take our time and just be careful.

I was concerned reading your post about symptoms and plug appearance because they matched mine when my rings were improperly installed. My oil scraper rings “hopped” during installation. I tried everything, convinced it must have been spark or fuel. New fuel pump, distributor, condenser, endless carb adjustments. New jets and needles. Still, I had no power at high RPMs. No missing; just total weakness at 3500 RPMs.

My mechanic buddy suspected the oil scraper rings and loaned me a camera with a long “wand eye” that fitted right into the spark plug holes. I took four pictures and the problem was clear. Clear beyond a doubt when my neighbor told me I had puffs of smoke with each shift.

Anyway, your issue could and hopefully is something a bit less time consuming to address, though I had those rings removed and replaced in a week. Hardest part was pulling the head and pan, and working under the car to torque the connecting rods.

Let us know how it goes and if you’re sure it’s not fuel or spark.

 

[CJD]

Interesting conversation about oil ring problems. I had no idea that bad installations were so common. My pistons came with 2 oil rings, 4 total rings. I didn't like the idea, thinking they were a low performance design. But after weighing all my options, I chose the 4 ring pistons because they were actually lighter weight than the 3 ring pistons I could get at 85mm.

Back to your car, Steve. I could be wrong, but I would think if it were oil issues, the engine would run great with fresh plugs, and then gradually run worse as the plugs and chamber loaded up with oil residue. If it runs flat with fresh plugs, then I still think ignition would be the most probable fault. The pitted points have me wondering if it isn't a bad condenser. That's what the condenser does, is to prevent a spark from gapping the points as they open...which transfers metal from the negative point to the positive side, and also reduces amperage to the coil.

 

[KVH]

And if you haven’t tried a new condenser maybe pop one in before that test drive—if you have a new one.

Looking at your posts above, so your loss of power only happens above 4000 RPMs? And you left in the existing pistons and rings? You are running what the car had—pistons, rings, and liners were all new, 86mm?

 

[donbmw]

I have had 2 Petronix ignition unit cause similar issues under high load conditions with ignition leads and a distributor cap do thi# also with the Petronix. Swapped back to points with no issues now for years.