General Tech Initial Start Up After Rebuild

[KVH]

I have some questions regarding my efforts to "start-up" my TR4A engine following rebuild. The pistons, rings, and bearings are new and "tight" and the extra stress and effort to crank the engine appears to have killed my battery--but the engine sure sounded great for the very few seconds it lasted. Here are my questions:

1) On start-up, albeit for fleeting seconds, the engine was racing and then just cut out. It did this five or six times--just cut out. Like it was cold or out of gas. I looked at my carbs and see that even though I had adjusted the jets at 12 flats open, the top of the jet was almost level with the carb bridge. Would I be correct that an engine racing on first start then cutting out might be indicative of plenty of gas initially (due to the cold choke I'd pulled), but insufficient gas after that? In other words, might I have the carbs way too lean? I'll be trying again after addressing my dead battery.

2) I think I've got the timing right on, and I don't think the starting trouble I'm having is symptomatic of poor timing. Does that assessment seem right? And finally,

3) I can put a different distributor in the car, but I like the one I'm using. It's a "race" distributor (Moss 143-165) with no vacuum advance. So I've plugged the vacuum line on my lead carb. Is either my distributor or the lack of a vacuum advance likely part of the problem?

Thanks for any thoughts.

 

[charlie74]

It still cranks over on the starter?

If so and it started then your timing is in the ballpark. If it stopped after you pushed the choke in then it will be fuel related.
years ago after i had been futzing with my distributor I had a roadside breakdown and found that I hadn’t seated the distributor completely and so it had crept up in the pedestal and was no longer being driven by the gear. Maybe just take the cap off and make sure that the rotor still turns when you crank the engine over…

congratulations on hearing it run! Try to get the rpms up for a period of time (20-25 minutes) without any idling if possible.

there will be other suggestions along shortly I’m sure,

good luck and post a video of you can!

 

[Mickey Richaud]

RE: item #1 - if you adjusted the jet bearings 12 flats down and they're nearly level with the bridge, something's wonky there. Might want to be sure all the parts are in their proper places. Also, are the needles' shoulders flush with the bottom of the piston?

Sounds like you just need to do a bit more fiddling with it - surely on your way to getting it sorted!


Mickey

 

[DrEntropy]

12 flats with choke fully home. Don't futz with the ignition until the thing runs on its own, warmed up to temp and checked for oil pressure, leaks, etc. Some "smoke" will likely be inevitable, usually just stuff burning off the exterior of header & exhaust. Vary the RPM as it warms up, but not over about 3500.

Have a fire extinguisher at-the-ready, just in case.

And Congratulations!

 

[auprichard]

I don't want to be the worry wart, but I would be concerned that you describe the engine as cutting out suddenly. How suddenly is it? Is there a clunk as it stops?

I'm also a little concerned by your statement "The pistons, rings, and bearings are new and "tight" and the extra stress and effort to crank the engine appears to have killed my battery"

Again, not wanting to cause undue alarm, a couple of years ago I had a fresh rebuild on a TR3 which did exactly as you described: run for a few seconds and suddenly stop. In an attempt to get it running, I screwed in the idle screw to get it to run. Bad idea. After about 30 seconds it seized. I called my cousin, Darryl Uprichard, who owns Racetorations in the UK and he said "I'll bet it's the rear main bearing - I have seen this several times." And he was right. No idea how it happened and after a rebuild it was - and remains - fine.

So my suggestion - for what it's worth - it to coax it along gently and not push things until you have it running (idling) on its own.

 

[sp53]

I guess I would pull the plugs and spin it with no compression until I got good oil pressure and a feel for how thing sound.

stteve

 

[CJD]

What rpm was it running before it died? If it was rather high (north of 2000rpm), then I would look for a vacuum leak in the intake somewhere. You can forget about ignition for now. Ignition would be accompanied with popping or rough running.

 

[KVH]

"Vacuum leak in the intake"? That's a thought. What do I do with the unused vacuum port on the lead carburetor? Just plug it off?

 

[auprichard]

Why would a vacuum leak cause the symptoms of suddenly stopping?

 

[KVH]

The “suddenly stopping” was only when I released the choke and gas pedal due to the engine racing at 3000 rpms. IOW, the issue was the engine racing, and the stopping was most likely fuel related the instant I let up. It was me. I think I have two issues—fuel/carb adjustments and hard start for battery on rebuild. I probably should’ve installed a high torque starter.

 

[KVH]

RE: item #1 - if you adjusted the jet bearings 12 flats down and they're nearly level with the bridge, something's wonky there. Might want to be sure all the parts are in their proper places. Also, are the needles' shoulders flush with the bottom of the piston?

Sounds like you just need to do a bit more fiddling with it - surely on your way to getting it sorted!


Mickey

Thx--The needle shoulders are level with the piston, but there is something odd about the jet height and the "flat" count. I'm going to examine that issue further and compare to my other car that also has HS6 SUs. I'm thinking this is a fuel issue.

 

[charleyf]

Thx--The needle shoulders are level with the piston, but there is something odd about the jet height and the "flat" count. I'm going to examine that issue further and compare to my other car that also has HS6 SUs. I'm thinking this is a fuel issue.

These cars are very "cold blooded ".
Once you get it started you will continue to need the choke for several minutes. If it is racing at 3000 rpm then use less choke or adjust the choke idle screw to reduce that idle.
The choke should work at less than full on but you may need to hold it in an intermediate position. Note that if you pull the choke and then turn the knob to the right it should hold the choke in that position.
Charley

 

[CJD]

I take it you are not running a vacuum advance? If that is the case, then "yes" just cap the fitting at the front carb.

Just for reference, if my choke is fully out my engine will start and rev to close to 3000rpm. That is not abnormal. I then have to reduce the choke to bring the idle down to about 1500 rpm until it warms enough to idle. There is no use trying to adjust the mixture until you get the engine to warm up. 15 flats should be fine until then. I have never paid attention to the level of the jet, and cannot believe it would be important so long as you rebuilt the carb properly by the manual.

For cam and lifter break in...which are the most important in initial starting of a new engine...you should allow it to rev to 2-3000rpm for the first 20 minutes. This splashes ample lubricant on the lifters to prevent lobe scuffing until they wear in together.

 

[KVH]

I've got it. It was fuel and carbs. I had it way too lean, and I plugged that vacuum stub since I've got no vacuum advance on the distributor. It starts every time, though the starter is struggling. Runs great, and I had it at 2500 rpms for 7 mins but had to shut down for a coolant leak.

I'll fix it and finish the 25 minute 2500 rpm break-in drill. I had no choice, but to shut it down.

Thanks a bunch for all the advice here. I should be in good shape by tomorrow. The good news (for a worrier like me) is that I've got 70psi, no knocks and no funny noises. I may be a bit rich on the mixture, though, because I noticed it running a bit rough at the end of it's run this evening.

I don't know how I screwed up with a coolant leak. It's the thermostat housing. That's never happened before. I have a new ceramic thermostat housing from Moss and I can't figure how or why it started leaking so fast. I may use silicone this time, instead of hylomar.

Thank again.

 

[CJD]

excellent!

 

[RJS]

Thumbs up

 

[KVH]

Thanks guys. Now, about that coolant leak at the thermostat housing, was I supposed to fill the coolant directly at the head before installing the thermostat to avoid an air pocket, or will it fill from the radiator even though the thermostat is closed? I think I poured the “capacity” into the radiator, so I’d think I’m OK.

 

[charleyf]

Thanks guys. Now, about that coolant leak at the thermostat housing, was I supposed to fill the coolant directly at the head before installing the thermostat to avoid an air pocket, or will it fill from the radiator even though the thermostat is closed? I think I poured the “capacity” into the radiator, so I’d think I’m OK.

Considering the heater and thermostat area, I always figure that I will need to add more fluid after it has run a bit.
No need to prefill the head IMHO.
Charley

 

[CJD]

+1. Just check the level after a good run that brings the engine to temperature.

 

[KVH]

In trying to fine tune, I’m noticing something weird is going on. On one of my carbs, while the engine is off but still hot, if I lift the piston I see fuel literally shooting up out of the jet. Lasted a good fifteen seconds. Why would there be pressure and fuel delivered like that? I checked the float bowl and didn’t notice anything. The level was about 2/3rds and the float seemed textbook. The other carb showed no such behavior. Thx all.